rfc9692v2.txt   rfc9692.txt 
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Internet Engineering Task Force (IETF) T. Przygienda, Ed. Internet Engineering Task Force (IETF) T. Przygienda, Ed.
Request for Comments: 9692 J. Head, Ed. Request for Comments: 9692 J. Head, Ed.
Category: Standards Track Juniper Networks Category: Standards Track Juniper Networks
ISSN: 2070-1721 A. Sharma ISSN: 2070-1721 A. Sharma
Hudson River Trading Hudson River Trading
P. Thubert P. Thubert
B. Rijsman B. Rijsman
Individual Individual
D. Afanasiev D. Afanasiev
Yandex Yandex
December 2024 January 2025
RIFT: Routing in Fat Trees RIFT: Routing in Fat Trees
Abstract Abstract
This document defines a specialized, dynamic routing protocol for This document defines a specialized, dynamic routing protocol for
Clos, Fat Tree, and variants thereof. These topologies were Clos, fat tree, and variants thereof. These topologies were
initially used within crossbar interconnects and consequently router initially used within crossbar interconnects and consequently router
and switch backplanes, but their characteristics make them ideal for and switch backplanes, but their characteristics make them ideal for
constructing IP fabrics as well. The protocol specified by this constructing IP fabrics as well. The protocol specified by this
document is optimized towards the minimization of control plane state document is optimized towards the minimization of control plane state
to support very large substrates as well as the minimization of to support very large substrates as well as the minimization of
configuration and operational complexity to allow for a simplified configuration and operational complexity to allow for a simplified
deployment of said topologies. deployment of said topologies.
Status of This Memo Status of This Memo
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received public review and has been approved for publication by the received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 7841. Internet Standards is available in Section 2 of RFC 7841.
Information about the current status of this document, any errata, Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc9692. https://www.rfc-editor.org/info/rfc9692.
Copyright Notice Copyright Notice
Copyright (c) 2024 IETF Trust and the persons identified as the Copyright (c) 2025 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of (https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
include Revised BSD License text as described in Section 4.e of the include Revised BSD License text as described in Section 4.e of the
Trust Legal Provisions and are provided without warranty as described Trust Legal Provisions and are provided without warranty as described
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6.7.6. Resulting Topologies 6.7.6. Resulting Topologies
6.8. Further Mechanisms 6.8. Further Mechanisms
6.8.1. Route Preferences 6.8.1. Route Preferences
6.8.2. Overload Bit 6.8.2. Overload Bit
6.8.3. Optimized Route Computation on Leaves 6.8.3. Optimized Route Computation on Leaves
6.8.4. Mobility 6.8.4. Mobility
6.8.5. Key/Value (KV) Store 6.8.5. Key/Value (KV) Store
6.8.6. Interactions with BFD 6.8.6. Interactions with BFD
6.8.7. Fabric Bandwidth Balancing 6.8.7. Fabric Bandwidth Balancing
6.8.8. Label Binding 6.8.8. Label Binding
6.8.9. Leaf-to-Leaf Procedures 6.8.9. L2L Procedures
6.8.10. Address Family and Multi-Topology Considerations 6.8.10. Address Family and Multi-Topology Considerations
6.8.11. One-Hop Healing of Levels with East-West Links 6.8.11. One-Hop Healing of Levels with East-West Links
6.9. Security 6.9. Security
6.9.1. Security Model 6.9.1. Security Model
6.9.2. Security Mechanisms 6.9.2. Security Mechanisms
6.9.3. Security Envelope 6.9.3. Security Envelope
6.9.4. Weak Nonces 6.9.4. Weak Nonces
6.9.5. Lifetime 6.9.5. Lifetime
6.9.6. Security Association Changes 6.9.6. Security Association Changes
7. Information Elements Schema 7. Information Elements Schema
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Acknowledgments Acknowledgments
Contributors Contributors
Authors' Addresses Authors' Addresses
1. Introduction 1. Introduction
Clos [CLOS] topologies have gained prominence in today's networking, Clos [CLOS] topologies have gained prominence in today's networking,
primarily as a result of the paradigm shift towards a centralized primarily as a result of the paradigm shift towards a centralized
data center architecture that is poised to deliver a majority of data center architecture that is poised to deliver a majority of
computation and storage services in the future. Such networks are computation and storage services in the future. Such networks are
commonly called a Fat Tree / network in modern IP fabric commonly called a fat tree / network in modern IP fabric
considerations [VAHDAT08] as a homonym to the original definition of considerations [VAHDAT08] as a similar term for the original
the term [FATTREE]. In most generic terms, and disregarding definition of the term Fat Tree [FATTREE]. In most generic terms,
exceptions like horizontal shortcuts, those networks are all and disregarding exceptions like horizontal shortcuts, those networks
variations of a structured design isomorphic to a ranked lattice are all variations of a structured design isomorphic to a ranked
where the least upper bound is the "top of the fabric" and links lattice where the least upper bound is the "top of the fabric" and
closer to the top may be "fatter" to guarantee non-blocking links closer to the top may be "fatter" to guarantee non-blocking
bisectional capacity. bisectional capacity.
Many builders of such IP fabrics desire a protocol that Many builders of such IP fabrics desire a protocol that
autoconfigures itself and deals with failures and misconfigurations autoconfigures itself and deals with failures and misconfigurations
with a minimum amount of human intervention. Such a solution would with a minimum amount of human intervention. Such a solution would
allow local IP fabric bandwidth to be consumed in a "standard allow local IP fabric bandwidth to be consumed in a "standard
component" fashion, i.e., provision it much faster and operate it at component" fashion, i.e., provision it much faster and operate it at
much lower costs than today, much like compute or storage is consumed much lower costs than today, similar to how compute or storage is
already. consumed already.
In looking at the problem through the lens of such IP fabric In looking at the problem through the lens of such IP fabric
requirements, Routing in Fat Trees (RIFT) addresses those challenges requirements, Routing in Fat Trees (RIFT) addresses those challenges
not through an incremental modification of either a link-state not through an incremental modification of either a link-state
(distributed computation) or distance-vector (diffused computation) (distributed computation) or distance-vector (diffused computation)
technique but rather a mixture of both, briefly described as "link- technique but rather a mixture of both, briefly described as "link-
state towards the spines" and "distance vector towards the leaves". state towards the spines" and "distance vector towards the leaves".
In other words, "bottom" levels are flooding their link-state In other words, "bottom" levels are flooding their link-state
information in the "northern" direction while each node generates information in the "northern" direction while each node generates
under normal conditions a "default route" and floods it in the under normal conditions a "default route" and floods it in the
"southern" direction. This type of protocol naturally supports "southern" direction. This type of protocol naturally supports
highly desirable address aggregation. Alas, such aggregation could highly desirable address aggregation. Alas, such aggregation could
drop traffic in cases of misconfiguration or while failures are being drop traffic in cases of misconfiguration or while failures are being
resolved or even cause persistent network partitioning and this has resolved. It could also cause persistent network partitioning, which
to be addressed by some adequate mechanism. The approach RIFT takes has to be addressed by some adequate mechanism. The approach RIFT
is described in Section 6.5 and is based on automatic, sufficient takes is described in Section 6.5 and is based on automatic,
disaggregation of prefixes in case of link and node failures. sufficient disaggregation of prefixes in case of link and node
failures.
The protocol further provides: The protocol further provides:
* optional fully automated construction of Fat Tree topologies based * optional fully automated construction of fat tree topologies based
on detection of links without any configuration (Section 6.7) on detection of links without any configuration (Section 6.7)
while allowing for conventional configuration methods or an while allowing for conventional configuration methods or an
arbitrary mix of both, arbitrary mix of both,
* the minimum amount of routing state held by nodes, * the minimum amount of routing state held by nodes,
* automatic pruning and load balancing of topology flooding * automatic pruning and load balancing of topology flooding
exchanges over a sufficient subset of links (Section 6.3.9), exchanges over a sufficient subset of links (Section 6.3.9),
* automatic address aggregation (Section 6.3.8) and consequently * automatic address aggregation (Section 6.3.8) and consequently
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on their level of interest. The authors recommend reading the HTML on their level of interest. The authors recommend reading the HTML
or PDF versions of this document due to the inherent limitation of or PDF versions of this document due to the inherent limitation of
text version to represent complex figures. text version to represent complex figures.
The "Terminology" (Section 3.1) section should be used as a The "Terminology" (Section 3.1) section should be used as a
supporting reference as the document is read. supporting reference as the document is read.
The indications of direction (i.e., "top", "bottom", etc.) referenced The indications of direction (i.e., "top", "bottom", etc.) referenced
in Section 1 are of paramount importance. RIFT requires a topology in Section 1 are of paramount importance. RIFT requires a topology
with a sense of top and bottom in order to properly achieve a sorted with a sense of top and bottom in order to properly achieve a sorted
topology. Clos, Fat Tree, and other similarly structured networks topology. Clos, fat tree, and other similarly structured networks
are conducive to such requirements. Where RIFT allows for further are conducive to such requirements. Where RIFT allows for further
relaxation of these constraints will be mentioned later in this relaxation of these constraints will be mentioned later in this
section. section.
Several of the images in this document are annotated with "northern Several of the images in this document are annotated with "northern
view" or "southern view" to indicate perspective to the reader. A view" or "southern view" to indicate perspective to the reader. A
"northern view" should be interpreted as "from the top of the fabric "northern view" should be interpreted as "from the top of the fabric
looking down", whereas "southern view" should be interpreted as "from looking down", whereas "southern view" should be interpreted as "from
the bottom looking up". the bottom looking up".
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different algorithms whether the link should be included. different algorithms whether the link should be included.
Bow-tying: Bow-tying:
Traffic patterns in fully converged IP fabrics normally traverse Traffic patterns in fully converged IP fabrics normally traverse
the shortest route based on hop count towards their destination the shortest route based on hop count towards their destination
(e.g., leaf, spine, leaf). Some failure scenarios with partial (e.g., leaf, spine, leaf). Some failure scenarios with partial
routing information cause nodes to lose the required downstream routing information cause nodes to lose the required downstream
reachability to a destination and force traffic to utilize routes reachability to a destination and force traffic to utilize routes
that traverse higher levels in the fabric in order to turn south that traverse higher levels in the fabric in order to turn south
again using a different route to resolve reachability (e.g., leaf, again using a different route to resolve reachability (e.g., leaf,
spine-1, super-spine, spine-2, leaf). spine-1, superspine, spine-2, leaf).
Clos / Fat Tree: Clos / fat tree:
This document uses the terms "Clos" and "Fat Tree" interchangeably This document uses the terms "Clos" and "fat tree" interchangeably
where it always refers to a folded spine-and-leaf topology with where it always refers to a folded spine-and-leaf topology with
possibly multiple Points of Delivery (PoDs) and one or multiple possibly multiple Points of Delivery (PoDs) and one or multiple
Top of Fabric (ToF) planes. Several modifications such as leaf- Top of Fabric (ToF) planes. Several modifications such as L2L
to-leaf shortcuts and shortcuts that span multiple levels are shortcuts and multi-level shortcuts are possible and described
possible and described further in the document. further in the document.
Cost: Cost:
A natural number without a unit associated with two entities. The A natural number without the unit associated with two entities.
usual natural numbers algebra can be applied to costs. A cost may The cost is a monoid under addition. A cost may be associated
be associated with either a single link or prefix, or it may with either a single link or prefix, or it may represent the sum
represent the sum of costs (distance) of links in the path between of costs (distance) of links in the path between two nodes.
two nodes.
Crossbar: Crossbar:
Physical arrangement of ports in a switching matrix without Physical arrangement of ports in a switching matrix without
implying any further scheduling or buffering disciplines. implying any further scheduling or buffering disciplines.
Directed Acyclic Graph (DAG): Directed Acyclic Graph (DAG):
A finite directed graph with no directed cycles (loops). If links A finite directed graph with no directed cycles (loops). If links
in a Clos are considered as either being all directed towards the in a Clos are considered as either being all directed towards the
top or vice versa, each of two such graphs is a DAG. top or vice versa, each of two such graphs is a DAG.
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is performed to prevent traffic loss and suboptimal routing to the is performed to prevent traffic loss and suboptimal routing to the
more specific prefixes. more specific prefixes.
Distance: Distance:
The sum of costs (bound by the infinite cost constant) between two The sum of costs (bound by the infinite cost constant) between two
nodes. A distance is primarily used to express separation between nodes. A distance is primarily used to express separation between
two entities and can be used again as cost in another context. two entities and can be used again as cost in another context.
East-West (E-W) Link: East-West (E-W) Link:
A link between two nodes at the same level. East-West links are A link between two nodes at the same level. East-West links are
normally not part of Clos or Fat Tree topologies. normally not part of Clos or fat tree topologies.
Flood Repeater (FR): Flood Repeater (FR):
A node can designate one or more northbound neighbor nodes to be A node can designate one or more northbound neighbor nodes to be
flood repeaters. The flood repeaters are responsible for flooding flood repeaters. The flood repeaters are responsible for flooding
northbound TIEs further north. The document sometimes calls them northbound TIEs further north. The document sometimes calls them
flood leaders as well. flood leaders as well.
Folded Spine-and-Leaf: Folded Spine-and-Leaf:
In case the Clos fabric input and output stages are equivalent, In case the Clos fabric input and output stages are equivalent,
the fabric can be "folded" to build a "superspine" or top, which the fabric can be "folded" to build a "superspine" or top, which
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Leaf-to-Leaf (L2L) Shortcuts: Leaf-to-Leaf (L2L) Shortcuts:
East-West links at leaf level will need to be differentiated from East-West links at leaf level will need to be differentiated from
East-West links at other levels. East-West links at other levels.
Leaf: Leaf:
A node without southbound adjacencies. Level 0 implies a leaf in A node without southbound adjacencies. Level 0 implies a leaf in
RIFT, but a leaf does not have to be level 0. RIFT, but a leaf does not have to be level 0.
Level: Level:
Clos and Fat Tree networks are topologically partially ordered Clos and fat tree networks are topologically partially ordered
graphs, and "level" denotes the set of nodes at the same height in graphs, and "level" denotes the set of nodes at the same height in
such a network. Nodes at the top level (i.e., ToF) are at the such a network. Nodes at the top level (i.e., ToF) are at the
level with the highest value and count down to the nodes at the level with the highest value and count down to the nodes at the
bottom level (i.e., leaf) with the lowest value. A node will have bottom level (i.e., leaf) with the lowest value. A node will have
links to nodes one level down and/or one level up. In some links to nodes one level down and/or one level up. In some
circumstances, a node may have links to other nodes at the same circumstances, a node may have links to other nodes at the same
level. A leaf node may also have links to nodes multiple levels level. A leaf node may also have links to nodes multiple levels
higher. In RIFT, level 0 always indicates that a node is a leaf higher. In RIFT, level 0 always indicates that a node is a leaf
but does not have to be level 0. Level values can be configured but does not have to be level 0. Level values can be configured
manually or automatically as described in Section 6.7. As a final manually or automatically as described in Section 6.7.
footnote: Clos terminology often uses the concept of "stage", but
due to the folded nature of the Fat Tree, it is not used from this | As a final footnote: Clos terminology often uses the concept
point on to prevent misunderstandings. | of "stage", but due to the folded nature of the fat tree, it
| is not used from this point on to prevent misunderstandings.
LIE: LIE:
This is an acronym for a "Link Information Element" exchanged on This is an acronym for a "Link Information Element" exchanged on
all the system's links running RIFT to form _ThreeWay_ adjacencies all the system's links running RIFT to form _ThreeWay_ adjacencies
and carry information used to perform RIFT Zero Touch Provisioning and carry information used to perform RIFT Zero Touch Provisioning
(ZTP) of levels. (ZTP) of levels.
Metric: Metric:
Used interchangeably with "cost". Used interchangeably with "cost".
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Northbound Representation: Northbound Representation:
The subset of topology information flooded towards higher levels The subset of topology information flooded towards higher levels
of the fabric. of the fabric.
Overloaded: Overloaded:
Applies to a node advertising the _overload_ attribute as set. Applies to a node advertising the _overload_ attribute as set.
The overload attribute is carried in the _NodeFlags_ object of the The overload attribute is carried in the _NodeFlags_ object of the
encoding schema. encoding schema.
Point of Delivery (PoD): Point of Delivery (PoD):
A self-contained vertical slice or subset of a Clos or Fat Tree A self-contained vertical slice or subset of a Clos or fat tree
network normally containing only level 0 and level 1 nodes. A network normally containing only level 0 and level 1 nodes. A
node in a PoD communicates with nodes in other PoDs via the ToF node in a PoD communicates with nodes in other PoDs via the ToF
nodes. PoDs are numbered to distinguish them, and PoD value 0 nodes. PoDs are numbered to distinguish them, and PoD value 0
(defined later in the encoding schema as _common.default_pod_) is (defined later in the encoding schema as _common.default_pod_) is
used to denote "undefined" or "any" PoD. used to denote "undefined" or "any" PoD.
Prefix TIE: Prefix TIE:
This is an acronym for a "Prefix Topology Information Element", This is an acronym for a "Prefix Topology Information Element",
and it contains all prefixes directly attached to this node in and it contains all prefixes directly attached to this node in
case of a North TIE and the necessary default routes the node case of a North TIE and the necessary default routes the node
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Radix: Radix:
A radix of a switch is the number of switching ports it provides. A radix of a switch is the number of switching ports it provides.
It's sometimes called "fanout" as well. It's sometimes called "fanout" as well.
Routing on the Host (RotH): Routing on the Host (RotH):
A modern data center architecture variant where servers/leaves are A modern data center architecture variant where servers/leaves are
multihomed and consequently participate in routing. multihomed and consequently participate in routing.
Security Envelope: Security Envelope:
RIFT packets are flooded within an authenticated security envelope RIFT packets are flooded within an authenticated security envelope
that allows to protect the integrity of information a node accepts that optionally enables protection of the integrity of information
if any of the mechanisms in Section 10.2 are used. This is a node accepts if any of the mechanisms in Section 10.2 are used.
further described in Section 6.9.3. This is further described in Section 6.9.3.
Shortest Path First (SPF): Shortest Path First (SPF):
A well-known graph algorithm attributed to Dijkstra [DIJKSTRA] A well-known graph algorithm attributed to Dijkstra [DIJKSTRA]
that establishes a tree of shortest paths from a source to that establishes a tree of shortest paths from a source to
destinations on the graph. The SPF acronym is used due to its destinations on the graph. The SPF acronym is used due to its
familiarity as a general term for the node reachability familiarity as a general term for the node reachability
calculations RIFT can employ to ultimately calculate routes, of calculations RIFT can employ to ultimately calculate routes, of
which Dijkstra's algorithm is a possible one. which Dijkstra's algorithm is a possible one.
South Reflection: South Reflection:
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aware of each other's node Topology Information Elements (TIEs). aware of each other's node Topology Information Elements (TIEs).
South SPF (S-SPF): South SPF (S-SPF):
A reachability calculation that is progressing southbound, for A reachability calculation that is progressing southbound, for
example, SPF that is using North Node TIEs only. example, SPF that is using North Node TIEs only.
South/Southbound and North/Northbound (Direction): South/Southbound and North/Northbound (Direction):
When describing protocol elements and procedures, in different When describing protocol elements and procedures, in different
situations, the directionality of the compass is used, i.e., situations, the directionality of the compass is used, i.e.,
"lower", "south", and "southbound" mean moving towards the bottom "lower", "south", and "southbound" mean moving towards the bottom
of the Clos or Fat Tree network and "higher", "north", and of the Clos or fat tree network and "higher", "north", and
"northbound" mean moving towards the top of the Clos or Fat Tree "northbound" mean moving towards the top of the Clos or fat tree
network. network.
Southbound Link: Southbound Link:
A link to a node one level down or, in other words, one level A link to a node one level down or, in other words, one level
further south. further south.
Southbound Representation: Southbound Representation:
The subset of topology information sent towards a lower level. The subset of topology information sent towards a lower level.
Spine: Spine:
Any nodes north of leaves and south of ToF nodes. Multiple layers Any nodes north of leaves and south of ToF nodes. Multiple layers
of spines in a PoD are possible. of spines in a PoD are possible.
Superspine, Aggregation/Spine, and Edge/Leaf Switches: Superspine, Aggregation/Spine, and Edge/Leaf Switches:
Traditional level names in 5 stages folded Clos for levels 2, 1, Typical level names in 5 stages folded Clos for levels 2, 1, and
and 0, respectively (counting up from the bottom). We normalize 0, respectively (counting up from the bottom). We normalize this
this language to talk about ToF, Top-of-Pod (ToP), and leaves. language to talk about ToF, Top-of-Pod (ToP), and leaves.
System ID: System ID:
RIFT nodes identify themselves with a unique network-wide number RIFT nodes identify themselves with a unique network-wide number
when trying to build adjacencies or describe their topology. RIFT when trying to build adjacencies or describe their topology. RIFT
System IDs can be auto-derived or configured. System IDs can be auto-derived or configured.
ThreeWay Adjacency: ThreeWay Adjacency:
RIFT tries to form a unique adjacency between two nodes over a RIFT tries to form a unique adjacency between two nodes over a
point-to-point interface and exchange local configuration and point-to-point interface and exchange local configuration and
necessary RIFT ZTP information. An adjacency is only advertised necessary RIFT ZTP information. An adjacency is only advertised
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|Leaf111+~~~~~~~~~~+Leaf112| |Leaf121| |Leaf122| |Leaf111+~~~~~~~~~~+Leaf112| |Leaf121| |Leaf122|
+-+-----+ +-+---+-+ +--+--+-+ +-+-----+ +-+-----+ +-+---+-+ +--+--+-+ +-+-----+
+ + \ / + + + + \ / + +
Prefix111 Prefix112 \ / Prefix121 Prefix122 Prefix111 Prefix112 \ / Prefix121 Prefix122
multihomed multihomed
Prefix Prefix
+---------- PoD 1 ---------+ +---------- PoD 2 ---------+ +---------- PoD 1 ---------+ +---------- PoD 2 ---------+
Figure 2: A Three-Level Spine-and-Leaf Topology Figure 2: A Three-Level Spine-and-Leaf Topology
____________________________________________________________________________
| [Plane A] . [Plane B] . [Plane C] . [Plane D] |
|..........................................................................|
| +-+ . +-+ . +-+ . +-+ |
| |n| . |n| . |n| . |n| |
| +++ . +++ . +++ . +++ |
| . | | . . | | . . | | . . | | |
| . | | . . | | . . | | . . | | |
| +-+ | | . +-+ | | . +-+ | | . +-+ | | |
| |1| +-+ | . |1| +-+ | . |1| +-+ | . |1| +-+ | |
| +++ | | . +++ | | . +++ | | . +++ | | |
| || | | . || | | . || | | . || | | |
| || | | . || | | . || | | . || | | |
| |+--|--+| . |+--|--+| . |+--|--+| . |+--|----+ |
| | | || . | | || . | | || . | | || |
| | | || . | | || . | | || . | | +|---+ |
=====|===|==||=========|===|==||=========|===|==||=========|===|====|===|=== |
/ | | | || . | | || . | | || . | | / | | / |
/ | | | || . | | || . | | || . | | / ++---++ / |
/ | | | || . | | || . | | || . | | / | n | / |
/ | | | || . | | || . | | || . | | / +++-+++ / |
/ | ++---++ || . ++---++ || . ++---++ || . ++---++/ / |
/ | | 1 | || . | 2 | || . | 3 | || . | 4 |/ / |
/ | +++-+++ || . +++-+++ || . +++-+++ || . +++-+++/ / |
/ | || || || . || || || . || || || . || || / / |
/ \__||_||_____________||_||_____________||_||_____________||_||_/_________/_/
/ || || || || || || || || / || || /
/ || || +-----------+| || || || || || / || || /
/ || || |+-----------|-||-------------+| || || || / || || /
/ || || ||+----------|-||--------------|-||-------------+| || / || || /
/ || || ||| | || | || +-------+ || / || || /
/ || || ||| | |+--------------|-||------|---+ || / || || /
/ || || ||| | | | || | | +-+| / || || /
/ || || ||| | +-----------+ | || | | | | / || || /
/ || +|-|||----------|------------+| | |+------|---|---|-+| / || || /
/ || +-|||----------|------------||---|-|-------|-+ | | || / || || /
/ || ||| | +------||---+ | | | | | || / || || /
/ |+----|||-----+ | |+-----||-----|-------+ | | | || / || || /
/ | ||| | | || || | | | | || / || || /
/ | ||| | | || || | +----|-|---+ || / || || /
/ | ||| | | || || | | | | || / || || /
/ |+----+|| | | || || | | | | || / || || /
/ || +---+| | | +---+| |+---+ | | | +---+ || / +++-+++ /
/ || |+---+ +---+| |+---+ +---+| |+---+ +----+| || / | n | /
/ || || || || || || || || / +++-+++ /
/ +++-+++ +++-+++ +++-+++ +++-+++/=========/
/ | 1 | | 2 + | 3 | . . . | n |/ ^^
/ +++-+++ +-----+ +-----+ +-----+/ //
/ / PoDs
================================================================== //
Figure 3: Topology with Multiple Planes
The topology in Figure 2 is referred to in all further The topology in Figure 2 is referred to in all further
considerations. This figure depicts a generic "single plane Fat considerations. This figure depicts a generic "single-plane fat
Tree" and the concepts explained using three levels apply by tree" and the concepts explained using three levels apply by
induction to further levels and higher degrees of connectivity. induction to further levels and higher degrees of connectivity.
(Artwork only available as SVG: see
https://www.rfc-editor.org/rfc/rfc9692.html)
Figure 3: Topology with Multiple Planes
Further, this document will also deal with designs that provide only Further, this document will also deal with designs that provide only
sparser connectivity and "partitioned spines", as shown in Figure 3 sparser connectivity and "partitioned spines", as shown in Figure 3
and explained further in Section 5.2. and explained further in Section 5.2.
4. RIFT: Routing in Fat Trees 4. RIFT: Routing in Fat Trees
The remainder of this document presents the detailed specification of The remainder of this document presents the detailed specification of
the RIFT protocol, which in the most abstract terms has many the RIFT protocol, which in the most abstract terms has many
properties of a modified link-state protocol when distributing properties of a modified link-state protocol when distributing
information northbound and a distance-vector protocol when information northbound and a distance-vector protocol when
skipping to change at line 857 skipping to change at line 811
The most singular property of RIFT is that it only floods link-state The most singular property of RIFT is that it only floods link-state
information northbound so that each level obtains the full topology information northbound so that each level obtains the full topology
of levels south of it. Link-State information is, with some of levels south of it. Link-State information is, with some
exceptions, not flooded East-West nor back south again. Exceptions exceptions, not flooded East-West nor back south again. Exceptions
like south reflection is explained in detail in Section 6.5.1, and like south reflection is explained in detail in Section 6.5.1, and
east-west flooding at the ToF level in multi-plane fabrics is east-west flooding at the ToF level in multi-plane fabrics is
outlined in Section 5.2. In the southbound direction, the necessary outlined in Section 5.2. In the southbound direction, the necessary
routing information required (normally just a default route as per routing information required (normally just a default route as per
Section 6.3.8) only propagates one hop south. Those nodes then Section 6.3.8) only propagates one hop south. Those nodes then
generate their own routing information and flood it south to avoid generate their own routing information and flood it south to avoid
the overhead of building an update per adjacency. For the moment, the overhead of building an update per adjacency. The East-West
describing the East-West direction is left out until later in the direction is described later in the document.
document.
Those information flow constraints create not only an anisotropic Those information flow constraints create not only an anisotropic
protocol (i.e., the information is not distributed "evenly" or protocol (i.e., the information is not distributed "evenly" or
"clumped" but summarized along the north-south gradient) but also a "clumped" but summarized along the north-south gradient) but also a
"smooth" information propagation where nodes do not receive the same "smooth" information propagation where nodes do not receive the same
information from multiple directions at the same time. Normally, information from multiple directions at the same time. Normally,
accepting the same reachability on any link, without understanding accepting the same reachability on any link, without understanding
its topological significance, forces tie-breaking on some kind of its topological significance, forces tie-breaking on some kind of
distance function. And such tie-breaking ultimately leads to hop-by- distance function. And such tie-breaking ultimately leads to hop-by-
hop forwarding by shortest paths only. In contrast to that, RIFT, hop forwarding by shortest paths only. In contrast to that, RIFT,
skipping to change at line 883 skipping to change at line 836
valley-free [VFR] forwarding behavior. In the shortest terms, valley-free [VFR] forwarding behavior. In the shortest terms,
valley-free paths allow reversal of direction from a packet heading valley-free paths allow reversal of direction from a packet heading
northbound to southbound while permitting traversal of horizontal northbound to southbound while permitting traversal of horizontal
links in the northbound phase at most once. Those principles links in the northbound phase at most once. Those principles
guarantee loop-free forwarding and with that can take advantage of guarantee loop-free forwarding and with that can take advantage of
all such feasible paths on a fabric. This is another highly all such feasible paths on a fabric. This is another highly
desirable property if available bandwidth should be utilized to the desirable property if available bandwidth should be utilized to the
maximum extent possible. maximum extent possible.
To account for the "northern" and the "southern" information split, To account for the "northern" and the "southern" information split,
the link state database is partitioned accordingly into "north the link state database (LSDB) is partitioned accordingly into "north
representation" and "south representation" Topology Information representation" and "south representation" Topology Information
Elements (TIEs). In the simplest terms, the North TIEs contain a Elements (TIEs). In the simplest terms, the North TIEs contain a
link-state topology description of lower levels and South TIEs simply link-state topology description of lower levels and South TIEs simply
carry a node description of the level above and default routes carry a node description of the level above and default routes
pointing north. This oversimplified view will be refined gradually pointing north. This oversimplified view will be refined gradually
in the following sections while introducing protocol procedures and in the following sections while introducing protocol procedures and
state machines at the same time. state machines at the same time.
5.2. Generalized Topology View 5.2. Generalized Topology View
This section and Section 6.5.2 are dedicated to multi-plane fabrics, This section and Section 6.5.2 are dedicated to multi-plane fabrics,
in contrast with the single plane designs where all ToF nodes are in contrast with the single-plane designs where all ToF nodes are
topologically equal and initially connected to all the switches at topologically equal and initially connected to all the switches at
the level below them. the level below them.
The multi-plane design is effectively a multidimensional switching The multi-plane design is effectively a multidimensional switching
matrix. To make that easier to visualize, this document introduces a matrix. To make that easier to visualize, this document introduces a
methodology depicting the connectivity in two-dimensional pictures. methodology depicting the connectivity in two-dimensional pictures.
Further, it can be leveraged that what is under consideration here is Further, it can be leveraged that what is under consideration here is
basically stacked crossbar fabrics where ports align "on top of each basically stacked crossbar fabrics where ports align "on top of each
other" in a regular fashion. other" in a regular fashion.
skipping to change at line 947 skipping to change at line 900
ToF Plane: ToF Plane:
Set of ToFs that are aware of each other by means of south Set of ToFs that are aware of each other by means of south
reflection. Planes are designated by capital letters, e.g., plane reflection. Planes are designated by capital letters, e.g., plane
A. A.
N: N:
Denotes the number of independent ToF planes in a topology. Denotes the number of independent ToF planes in a topology.
R: R:
Denotes a redundancy factor, i.e., the number of connections a Denotes a redundancy factor, i.e., the number of ToP nodes in a
spine has towards a ToF plane. In a single plane design, K_TOP is PoD that are connected to a ToF plane. In a single-plane design,
equal to R. R is equal to K_LEAF
Fallen Leaf: Fallen Leaf:
A fallen leaf in a plane Z is a switch that lost all connectivity A fallen leaf in a plane Z is a switch that lost all connectivity
northbound to Z. northbound to Z.
5.2.2. Clos as Crossed, Stacked Crossbars 5.2.2. Clos as Crossed, Stacked Crossbars
The typical topology for which RIFT is defined is built of P number The typical topology for which RIFT is defined is built of P number
of PoDs and connected together by S number of ToF nodes. A PoD node of PoDs and connected together by S number of ToF nodes. A PoD node
has K number of ports. From here on, half of them (K=Radix/2) are has 2K number of ports. From here on, half of them (K=Radix/2) are
assumed to connect host devices from the south, and the other half is assumed to connect host devices from the south, and the other half is
assumed to connect to interleaved PoD top-level switches to the assumed to connect to interleaved PoD top-level switches to the
north. The K ratio can be chosen differently without loss of north. The K ratio can be chosen differently without loss of
generality when port speeds differ or the fabric is oversubscribed, generality when port speeds differ or the fabric is oversubscribed,
but K=Radix/2 allows for more readable representation whereby there but K=Radix/2 allows for more readable representation whereby there
are as many ports facing north as south on any intermediate node. A are as many ports facing north as south on any intermediate node. A
node is hence represented in a schematic fashion with ports "sticking node is hence represented in a schematic fashion with ports "sticking
out" to its north and south, rather than by the usual real-world out" to its north and south, rather than by the usual real-world
front faceplate designs of the day. front faceplate designs of the day.
skipping to change at line 1008 skipping to change at line 961
+----+ +------------------------------------------------+ +----+ +------------------------------------------------+
|| || || || || || || || || || || || || ||
Side Views Side Views
Figure 4: A Leaf Node, K_LEAF=6 Figure 4: A Leaf Node, K_LEAF=6
The Radix of a PoD's top node may be different than that of the leaf The Radix of a PoD's top node may be different than that of the leaf
node. Though, more often than not, a same type of node is used for node. Though, more often than not, a same type of node is used for
both, effectively forming a square (K*K). In the general case, both, effectively forming a square (K*K). In the general case,
switches at the top of the PoD with K_TOP southern ports not switches at the top of the PoD with K_TOP southern ports not
necessarily equal to K_LEAF could be considered . For instance, in necessarily equal to K_LEAF could be considered. For instance, in
the representations below, we pick a 6-port K_LEAF and an 8-port the representations below, we pick a 6-port K_LEAF and an 8-port
K_TOP. In order to form a crossbar, K_TOP leaf nodes are necessary K_TOP. In order to form a crossbar, K_TOP leaf nodes are necessary
as illustrated in Figure 5. as illustrated in Figure 5.
+---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
| O | | O | | O | | O | | O | | O | | O | | O | | O | | O | | O | | O | | O | | O | | O | | O |
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
| O | | O | | O | | O | | O | | O | | O | | O | | O | | O | | O | | O | | O | | O | | O | | O |
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
skipping to change at line 1073 skipping to change at line 1026
^ | ^ |
| | | |
| ---------- ----------------------- | | ---------- ----------------------- |
+----- Leaf Node Top-of-PoD Node (Spine) --+ +----- Leaf Node Top-of-PoD Node (Spine) --+
---------- ----------------------- ---------- -----------------------
Figure 6: Northern View of a PoD's Spines, K_TOP=8 Figure 6: Northern View of a PoD's Spines, K_TOP=8
Side views of this PoD is illustrated in Figures 7 and 8. Side views of this PoD is illustrated in Figures 7 and 8.
Connecting to Spine Nodes Connecting to ToP Nodes
|| || || || || || || || || || || || || || || ||
+----------------------------------------------------------------+ N +----------------------------------------------------------------+ N
| Top-of-PoD Node (Sideways) | ^ | Top-of-PoD Node (Sideways) | ^
+----------------------------------------------------------------+ | +----------------------------------------------------------------+ |
|| || || || || || || || * || || || || || || || || *
+----+ +----+ +----+ +----+ +----+ +----+ +----+ +----+ | +----+ +----+ +----+ +----+ +----+ +----+ +----+ +----+ |
|Leaf| |Leaf| |Leaf| |Leaf| |Leaf| |Leaf| |Leaf| |Leaf| v |Leaf| |Leaf| |Leaf| |Leaf| |Leaf| |Leaf| |Leaf| |Leaf| v
|Node| |Node| |Node| |Node| |Node| |Node| |Node| |Node| S |Node| |Node| |Node| |Node| |Node| |Node| |Node| |Node| S
+----+ +----+ +----+ +----+ +----+ +----+ +----+ +----+ +----+ +----+ +----+ +----+ +----+ +----+ +----+ +----+
|| || || || || || || || || || || || || || || ||
Connecting to Client Nodes Connecting to Client Nodes
Figure 7: Side View of a PoD, K_TOP=8, K_LEAF=6 Figure 7: Side View of a PoD, K_TOP=8, K_LEAF=6
Connecting to Spine Nodes Connecting to ToP Nodes
|| || || || || || || || || || || ||
+----+ +----+ +----+ +----+ +----+ +----+ N +----+ +----+ +----+ +----+ +----+ +----+ N
|ToP | |ToP | |ToP | |ToP | |ToP | |ToP | ^ |ToP | |ToP | |ToP | |ToP | |ToP | |ToP | ^
|Node| |Node| |Node| |Node| |Node| |Node| | |Node| |Node| |Node| |Node| |Node| |Node| |
+----+ +----+ +----+ +----+ +----+ +----+ * +----+ +----+ +----+ +----+ +----+ +----+ *
|| || || || || || | || || || || || || |
+------------------------------------------------+ v +------------------------------------------------+ v
| Leaf Node (Sideways) | S | Leaf Node (Sideways) | S
+------------------------------------------------+ +------------------------------------------------+
skipping to change at line 1117 skipping to change at line 1070
As a next step, observe that a resulting PoD can be abstracted as a As a next step, observe that a resulting PoD can be abstracted as a
bigger node with a number K of K_POD = K_TOP * K_LEAF, and the design bigger node with a number K of K_POD = K_TOP * K_LEAF, and the design
can recurse. can recurse.
It will be critical at this point that, before progressing further, It will be critical at this point that, before progressing further,
the concept and the picture of "crossed crossbars" is understood. the concept and the picture of "crossed crossbars" is understood.
Else, the following considerations might be difficult to comprehend. Else, the following considerations might be difficult to comprehend.
To continue, the PoDs are interconnected with each other through a To continue, the PoDs are interconnected with each other through a
ToF node at the very top or the north edge of the fabric. The ToF node at the very top or the north edge of the fabric. The
resulting ToF is *not* partitioned if and only if (IIF) every PoD resulting ToF is *not* partitioned if and only if (IIF) every ToP
top-level node (spine) is connected to every ToF node. This topology node is connected to every ToF node. This topology is also referred
is also referred to as a single plane configuration and is quite to as a single-plane configuration and is quite popular due to its
popular due to its simplicity. There are K_TOP ToF nodes and K_LEAF simplicity. There are K_TOP ToF nodes and K_LEAF ToP nodes because
ToP nodes because each port of a ToP node connects to a different ToF each port of a ToP node connects to a different ToF node.
node. Consequently, it will take at least P * K_LEAF ports on a ToF Consequently, it will take at least P * K_LEAF ports on a ToF node to
node to connect to each of the K_LEAF ToP nodes of the P PoDs. connect to each of the K_LEAF ToP nodes of the P PoDs. Figure 9
Figure 9 illustrates this, looking at P=3 PoDs from above and 2 illustrates this, looking at P=3 PoDs from above and 2 sides. The
sides. The large view is the one from above, with the 8 ToF of 3 * 6 large view is the one from above, with the 8 ToF of 3 * 6 ports each
ports each interconnecting the PoDs and every ToP Node being interconnecting the PoDs and every ToP Node being connected to every
connected to every ToF node. ToF node.
[ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] <-----+ [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] <-----+
| | | | | | | | | | | | | | | | | |
[=================================] | -------------- [=================================] | --------------
| | | | | | | | +----- ToF | | | | | | | | +----- ToF
[ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] +----- Node ---+ [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] +----- Node ---+
| -------------- | | -------------- |
| v | v
+-+ +-+ +-+ +-+ +-+ +-+ +-+ +-+ <-----+ +-+ +-+ +-+ +-+ +-+ +-+ +-+ +-+ +-+ <-----+ +-+
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
skipping to change at line 1161 skipping to change at line 1114
| | | | | | | | | | | | | | | | -+ +- +-+ v | | | | | | | | | | | | | | | | | | -+ +- +-+ v | |
[ |o| |o| |o| |o| |o| |o| |o| |o| ] | | --| |--[ ]--| | [ |o| |o| |o| |o| |o| |o| |o| |o| ] | | --| |--[ ]--| |
[ |o| |o| |o| |o| |o| |o| |o| |o| ] | ----- | --| |--[ ]--| | [ |o| |o| |o| |o| |o| |o| |o| |o| ] | ----- | --| |--[ ]--| |
[ |o| |o| |o| |o| |o| |o| |o| |o| ] +--- PoD ---+ --| |--[ ]--| | [ |o| |o| |o| |o| |o| |o| |o| |o| ] +--- PoD ---+ --| |--[ ]--| |
[ |o| |o| |o| |o| |o| |o| |o| |o| ] | ----- | --| |--[ ]--| | [ |o| |o| |o| |o| |o| |o| |o| |o| ] | ----- | --| |--[ ]--| |
[ |o| |o| |o| |o| |o| |o| |o| |o| ] | | --| |--[ ]--| | [ |o| |o| |o| |o| |o| |o| |o| |o| ] | | --| |--[ ]--| |
[ |o| |o| |o| |o| |o| |o| |o| |o| ] | | --| |--[ ]--| | [ |o| |o| |o| |o| |o| |o| |o| |o| ] | | --| |--[ ]--| |
| | | | | | | | | | | | | | | | -+ +- +-+ | | | | | | | | | | | | | | | | | | -+ +- +-+ | |
+-+ +-+ +-+ +-+ +-+ +-+ +-+ +-+ +-+ +-+ +-+ +-+ +-+ +-+ +-+ +-+ +-+ +-+
Figure 9: Fabric Spines and ToFs in Single Plane Design, 3 PoDs Figure 9: Fabric Spines and ToFs in Single-Plane Design, 3 PoDs
The top view can be collapsed into a third dimension where the hidden The top view can be collapsed into a third dimension where the hidden
depth index is representing the PoD number. One PoD can be shown depth index is representing the PoD number. One PoD can be shown
then as a class of PoDs and hence save one dimension in the then as a class of PoDs and hence save one dimension in the
representation. The spine node expands in the depth and the vertical representation. The ToF node expands in the depth and the vertical
dimensions, whereas the PoD top-level nodes are constrained in the dimensions, whereas the ToP nodes are constrained in the horizontal
horizontal dimension. A port in the 2-D representation effectively dimension. A port in the 2-D representation effectively represents
represents the class of all the ports at the same position in all the the class of all the ports at the same position in all the PoDs that
PoDs that are projected in its position along the depth axis. This are projected in its position along the depth axis. This is shown in
is shown in Figure 10. Figure 10.
/ / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / /
/ / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / /
/ / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / /
/ / / / / / / / / / / / / / / / ] / / / / / / / / / / / / / / / / ]
+-+ +-+ +-+ +-+ +-+ +-+ +-+ +-+ ]] +-+ +-+ +-+ +-+ +-+ +-+ +-+ +-+ ]]
| | | | | | | | | | | | | | | | ] ----------------------- | | | | | | | | | | | | | | | | ] -----------------------
[ |o| |o| |o| |o| |o| |o| |o| |o| ] <-- Top of PoD Node (Spine) [ |o| |o| |o| |o| |o| |o| |o| |o| ] <-- Top of PoD Node (Spine)
[ |o| |o| |o| |o| |o| |o| |o| |o| ] ----------------------- [ |o| |o| |o| |o| |o| |o| |o| |o| ] -----------------------
[ |o| |o| |o| |o| |o| |o| |o| |o| ]]]] [ |o| |o| |o| |o| |o| |o| |o| |o| ]]]]
skipping to change at line 1194 skipping to change at line 1147
[ |o| |o| |o| |o| |o| |o| |o| |o| ] // (depth) [ |o| |o| |o| |o| |o| |o| |o| |o| ] // (depth)
| |/| |/| |/| |/| |/| |/| |/| |/ // | |/| |/| |/| |/| |/| |/| |/| |/ //
+-+ +-+ +-+/+-+/+-+ +-+ +-+ +-+ // +-+ +-+ +-+/+-+/+-+ +-+ +-+ +-+ //
^ ^
| -------- | --------
+----- ToF Node +----- ToF Node
-------- --------
Figure 10: Collapsed Northern View of a Fabric for Any Number of PoDs Figure 10: Collapsed Northern View of a Fabric for Any Number of PoDs
As simple as a single plane deployment is, it introduces a limit due As simple as a single-plane deployment is, it introduces a limit due
to the bound on the available radix of the ToF nodes that has to be to the bound on the available radix of the ToF nodes that has to be
at least P * K_LEAF. Nevertheless, it will become clear that a at least P * K_LEAF. Nevertheless, it will become clear that a
distinct advantage of a connected or non-partitioned ToF is that all distinct advantage of a connected or non-partitioned ToF is that all
failures can be resolved by simple, non-transitive, positive failures can be resolved by simple, non-transitive, positive
disaggregation (i.e., nodes advertising more specific prefixes with disaggregation (i.e., nodes advertising more specific prefixes with
the default to the level below them that is not propagated further the default to the level below them that is not propagated further
down the fabric) as described in Section 6.5.1. In other words, non- down the fabric) as described in Section 6.5.1. In other words, non-
partitioned ToF nodes can always reach nodes below or withdraw the partitioned ToF nodes can always reach nodes below or withdraw the
routes from PoDs they cannot reach unambiguously. And with this, routes from PoDs they cannot reach unambiguously. And with this,
positive disaggregation can heal all failures and still allow all the positive disaggregation can heal all failures and still allow all the
ToF nodes to be aware of each other via south reflection. ToF nodes to be aware of each other via south reflection.
Disaggregation will be explained in further detail in Section 6.5. Disaggregation will be explained in further detail in Section 6.5.
In order to scale beyond the "single plane limit", the ToF can be In order to scale beyond the "single-plane limit", the ToF can be
partitioned into N number of identically wired planes where N is an partitioned into N number of identically wired planes where N is an
integer divider of K_LEAF. The 1:1 ratio and the desired symmetry integer divider of K_LEAF. The 1:1 ratio and the desired symmetry
are still served, this time with (K_TOP*N) ToF nodes, each of are still served, this time with (K_TOP*N) ToF nodes, each of
(P*K_LEAF/N) ports. N=1 represents a non-partitioned Spine, and (P*K_LEAF/N) ports. N=1 represents a non-partitioned ToF
N=K_LEAF is a maximally partitioned Spine. Further, if R is any (superspine), and N=K_LEAF is a maximally partitioned ToF. Further,
integer divisor of K_LEAF, then N=K_LEAF/R is a feasible number of if R is any integer divisor of K_LEAF, then N=K_LEAF/R is a feasible
planes and R is a redundancy factor that denotes the number of number of planes and R is a redundancy factor that denotes the number
independent paths between 2 leaves within a plane. It proves of independent paths between 2 leaves within a plane. It proves
convenient for deployments to use a radix for the leaf nodes that is convenient for deployments to use a radix for the leaf nodes that is
a power of 2 so they can pick a number of planes that is a lower a power of 2 so they can pick a number of planes that is a lower
power of 2. The example in Figure 11 splits the Spine in 2 planes power of 2. The example in Figure 11 splits the ToF in 2 planes with
with a redundancy factor of R=3, meaning that there are 3 non- a redundancy factor of R=3, meaning that there are 3 non-intersecting
intersecting paths between any leaf node and any ToF node. A ToF paths between any leaf node and any ToF node. A ToF node must have,
node must have, in this case, at least 3*P ports and be directly in this case, at least 3*P ports and be directly connected to 3 of
connected to 3 of the 6 ToP nodes (spines) in each PoD. The ToP the 6 ToP nodes (spines) in each PoD. The ToP nodes are represented
nodes are represented horizontally with K_TOP=8 ports northwards horizontally with K_TOP=8 ports northwards each.
each.
+---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+
+-| |--| |--| |--| |--| |--| |--| |--| |-+ +-| |--| |--| |--| |--| |--| |--| |--| |-+
| | O | | O | | O | | O | | O | | O | | O | | O | | | | O | | O | | O | | O | | O | | O | | O | | O | |
+-| |--| |--| |--| |--| |--| |--| |--| |-+ +-| |--| |--| |--| |--| |--| |--| |--| |-+
+-| |--| |--| |--| |--| |--| |--| |--| |-+ +-| |--| |--| |--| |--| |--| |--| |--| |-+
| | O | | O | | O | | O | | O | | O | | O | | O | | | | O | | O | | O | | O | | O | | O | | O | | O | |
+-| |--| |--| |--| |--| |--| |--| |--| |-+ +-| |--| |--| |--| |--| |--| |--| |--| |-+
+-| |--| |--| |--| |--| |--| |--| |--| |-+ +-| |--| |--| |--| |--| |--| |--| |--| |-+
| | O | | O | | O | | O | | O | | O | | O | | O | | | | O | | O | | O | | O | | O | | O | | O | | O | |
skipping to change at line 1263 skipping to change at line 1215
+---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+
^ ^
| |
| --------------------- | ---------------------
+----- ToF Node Across Depth +----- ToF Node Across Depth
--------------------- ---------------------
Figure 11: Northern View of a Multi-Plane ToF Level, K_LEAF=6, N=2 Figure 11: Northern View of a Multi-Plane ToF Level, K_LEAF=6, N=2
At the extreme end of the spectrum, it is even possible to fully At the extreme end of the spectrum, it is even possible to fully
partition the spine with N=K_LEAF and R=1 while maintaining partition the ToF with N=K_LEAF and R=1 while maintaining
connectivity between each leaf node and each ToF node. In that case, connectivity between each leaf node and each ToF node. In that case,
the ToF node connects to a single port per PoD, so it appears as a the ToF node connects to a single port per PoD, so it appears as a
single port in the projected view represented in Figure 12. The single port in the projected view represented in Figure 12. The
number of ports required on the spine node is more than or equal to number of ports required on the ToF node is more than or equal to P,
P, i.e., the number of PoDs. i.e., the number of PoDs.
Plane 1 Plane 1
+---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ -+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ -+
+-| |--| |--| |--| |--| |--| |--| |--| |-+ | +-| |--| |--| |--| |--| |--| |--| |--| |-+ |
| | O | | O | | O | | O | | O | | O | | O | | O | | | | | O | | O | | O | | O | | O | | O | | O | | O | | |
+-| |--| |--| |--| |--| |--| |--| |--| |-+ | +-| |--| |--| |--| |--| |--| |--| |--| |-+ |
+---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ | +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ |
----------- . ------------------- . ------------ . ------- | ----------- . ------------------- . ------------ . ------- |
Plane 2 | Plane 2 |
+---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ | +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ |
skipping to change at line 1332 skipping to change at line 1284
for fabrics with a north-south orientation and a high level of for fabrics with a north-south orientation and a high level of
interleaving paths. A non-partitioned fabric makes a total loss of interleaving paths. A non-partitioned fabric makes a total loss of
connectivity between a ToF node at the north and a leaf node at the connectivity between a ToF node at the north and a leaf node at the
south a very rare but possible occasion that is fully healed by south a very rare but possible occasion that is fully healed by
positive disaggregation as described in Section 6.5.1. In large positive disaggregation as described in Section 6.5.1. In large
fabrics or fabrics built from switches with a low radix, the ToF may fabrics or fabrics built from switches with a low radix, the ToF may
often become partitioned in planes, which makes it more likely that a often become partitioned in planes, which makes it more likely that a
given leaf is only reachable from a subset of the ToF nodes. This given leaf is only reachable from a subset of the ToF nodes. This
makes some further considerations necessary. makes some further considerations necessary.
A "Fallen Leaf" is a leaf that can be reached by only a subset of ToF A "fallen leaf" is a leaf that can be reached by only a subset of ToF
nodes due to missing connectivity. If R is the redundancy factor, nodes due to missing connectivity. If R is the redundancy factor,
then it takes at least R breakages to reach a "Fallen Leaf" then it takes at least R breakages to reach a "fallen leaf"
situation. situation.
In a maximally partitioned fabric, the redundancy factor is R=1, so In a maximally partitioned fabric, the redundancy factor is R=1, so
any breakage in the fabric will cause one or more fallen leaves in any breakage in the fabric will cause one or more fallen leaves in
the affected plane. R=2 guarantees that a single breakage will not the affected plane. R=2 guarantees that a single breakage will not
cause a fallen leaf. However, not all cases require disaggregation. cause a fallen leaf. However, not all cases require disaggregation.
The following cases do not require particular action: The following cases do not require particular action:
* If a southern link on a node goes down, then connectivity through * If a southern link on a node goes down, then connectivity through
that node is lost for all nodes south of it. There is no need to that node is lost for all nodes south of that link. There is no
disaggregate since the connectivity to this node is lost for all need to disaggregate since the connectivity to this node is lost
spine nodes in the same fashion. for all spine nodes in the same fashion.
* If a ToF node goes down, then northern traffic towards it is * If a ToF node goes down, then northern traffic towards it is
routed via alternate ToF nodes in the same plane and there is no routed via alternate ToF nodes in the same plane and there is no
need to disaggregate routes. need to disaggregate routes.
In a general manner, the mechanism of non-transitive, positive In a general manner, the mechanism of non-transitive, positive
disaggregation is sufficient when the disaggregating ToF nodes disaggregation is sufficient when the disaggregating ToF nodes
collectively connect to all the ToP nodes in the broken plane. This collectively connect to all the ToP nodes in the broken plane. This
happens in the following case: happens in the following case:
skipping to change at line 1377 skipping to change at line 1329
* If the breakage is the last northern link from a leaf node within * If the breakage is the last northern link from a leaf node within
a plane (there is only one such link in a maximally partitioned a plane (there is only one such link in a maximally partitioned
fabric) that goes down, then connectivity to all unicast prefixes fabric) that goes down, then connectivity to all unicast prefixes
attached to the leaf node is lost within the plane where the link attached to the leaf node is lost within the plane where the link
is located. Southern Reflection by a leaf node, e.g., between ToP is located. Southern Reflection by a leaf node, e.g., between ToP
nodes, if the PoD has only 2 levels, happens in between planes, nodes, if the PoD has only 2 levels, happens in between planes,
allowing the ToP nodes to detect the problem within the PoD where allowing the ToP nodes to detect the problem within the PoD where
it occurs and positively disaggregate. The breakage can be it occurs and positively disaggregate. The breakage can be
observed by the ToF nodes in the same plane through the north observed by the ToF nodes in the same plane through the north
flooding of TIEs from the ToP nodes However, the ToF nodes need to flooding of TIEs from the ToP nodes. However, the ToF nodes need
be aware of all the affected prefixes for the negative, possibly to be aware of all the affected prefixes for the negative,
transitive, disaggregation to be fully effective (i.e., a node possibly transitive, disaggregation to be fully effective (i.e., a
advertising in the control plane that it cannot reach a certain node advertising in the control plane that it cannot reach a
more specific prefix than default, whereas such disaggregation in certain more specific prefix than the default prefix, whereas such
the extreme condition must be propagated further down southbound). disaggregation in the extreme condition must be propagated further
The problem can also be observed by the ToF nodes in the other down southbound). The problem can also be observed by the ToF
planes through the flooding of North TIEs from the affected leaf nodes in the other planes through the flooding of North TIEs from
nodes, together with non-node North TIEs, which indicate the the affected leaf nodes, together with non-node North TIEs, which
affected prefixes. To be effective in that case, the positive indicate the affected prefixes. To be effective in that case, the
disaggregation must reach down to the nodes that make the plane positive disaggregation must reach down to the nodes that make the
selection, which are typically the ingress leaf nodes. The plane selection, which are typically the ingress leaf nodes. The
information is not useful for routing in the intermediate levels. information is not useful for routing in the intermediate levels.
* If the breakage is a ToP node in a maximally partitioned fabric * If the breakage is a ToP node in a maximally partitioned fabric
(in which case it is the only ToP node serving the plane in that (in which case it is the only ToP node serving the plane in that
PoD that goes down), then the connectivity to all the nodes in the PoD that goes down), then the connectivity to all the nodes in the
PoD is lost within the plane where the ToP node is located. PoD is lost within the plane where the ToP node is located.
Consequently, all leaves of the PoD fall in this plane. Since the Consequently, all leaves of the PoD fall in this plane. Since the
Southern Reflection between the ToF nodes happens only within a Southern Reflection between the ToF nodes happens only within a
plane, ToF nodes in other planes cannot discover fallen leaves in plane, ToF nodes in other planes cannot discover fallen leaves in
a different plane. They also cannot determine beyond their local a different plane. They also cannot determine beyond their local
skipping to change at line 1459 skipping to change at line 1411
possible to connect them together by interplane bidirectional rings possible to connect them together by interplane bidirectional rings
as illustrated in Figure 13. The rings will be used to exchange full as illustrated in Figure 13. The rings will be used to exchange full
north topology information between planes. All ToFs having the same north topology information between planes. All ToFs having the same
north topology allows, by the means of transitive, negative north topology allows, by the means of transitive, negative
disaggregation described in Section 6.5.2, to efficiently fix any disaggregation described in Section 6.5.2, to efficiently fix any
possible fallen leaf scenario. Somewhat as a side effect, the possible fallen leaf scenario. Somewhat as a side effect, the
exchange of information fulfills the requirement for a full view of exchange of information fulfills the requirement for a full view of
the fabric topology at the ToF level without the need to collate it the fabric topology at the ToF level without the need to collate it
from multiple points. from multiple points.
____________________________________________________________________________ _______________________________________________________________________
| [Plane A] . [Plane B] . [Plane C] . [Plane D] | | [Plane A] . [Plane B] . [Plane C] . [Plane D] |
|..........................................................................| |.....................................................................|
| +-------------------------------------------------------------+ | | +------------------------------------------------------------+ |
| | +---+ . +---+ . +---+ . +---+ | | | | +---+ . +---+ . +---+ . +---+ | |
| +-+ n +-------------+ n +-------------+ n +-------------+ n +-+ | | +-+ n +-------------+ n +-------------+ n +------------+ n +-+ |
| +--++ . +-+++ . +-+++ . +--++ | | +--++ . +-+++ . +-+++ . +--++ |
| || . || . || . || | | || . || . || . || |
| +---------||---------------||----------------||---------------+ || | | +---------||---------------||----------------||--------------+ || |
| | +---+ || . +---+ || . +---+ || . +---+ | || | | | +---+ || . +---+ || . +---+ || . +---+ | || |
| +-+ 1 +---||--------+ 1 +--||---------+ 1 +--||---------+ 1 +-+ || | | +-+ 1 +---||--------+ 1 +--||---------+ 1 +--||--------+ 1 +-+ || |
| +--++ || . +-+++ || . +-+++ || . +-+++ || | | +--++ || . +-+++ || . +-+++ || . +-+++ || |
| || || . || || . || || . || || | | || || . || || . || || . || || |
| || || . || || . || || . || || | | || || . || || . || || . || || |
Figure 13: Using Rings to Bring All Planes and Bind Them at the ToF Figure 13: Using Rings to Bring All Planes and Bind Them at the ToF
5.5. Addressing the Fallen Leaves Problem 5.5. Addressing the Fallen Leaves Problem
One consequence of the "Fallen Leaf" problem is that some prefixes One consequence of the "fallen leaf" problem is that some prefixes
attached to the fallen leaf become unreachable from some of the ToF attached to the fallen leaf become unreachable from some of the ToF
nodes. RIFT defines two methods to address this issue, denoted as nodes. RIFT defines two methods to address this issue, denoted as
positive disaggregation and negative disaggregation. Both methods positive disaggregation and negative disaggregation. Both methods
flood corresponding types of South TIEs to advertise the impacted flood corresponding types of South TIEs to advertise the impacted
prefix(es). prefix(es).
When used for the operation of disaggregation, a positive South TIE, When used for the operation of disaggregation, a positive South TIE,
as usual, indicates reachability to a prefix of given length and all as usual, indicates reachability to a prefix of given length and all
addresses subsumed by it. In contrast, a negative route addresses subsumed by it. In contrast, a negative route
advertisement indicates that the origin cannot route to the advertisement indicates that the origin cannot route to the
skipping to change at line 1576 skipping to change at line 1528
observable behavior equivalent to the behavior of the standardized observable behavior equivalent to the behavior of the standardized
FSMs. FSMs.
The FSMs can use "timers" for different situations. Those timers are The FSMs can use "timers" for different situations. Those timers are
started through actions, and their expiration leads to queuing of started through actions, and their expiration leads to queuing of
corresponding events to be processed. corresponding events to be processed.
The term "holdtime" is used often as shorthand for "holddown timer" The term "holdtime" is used often as shorthand for "holddown timer"
and signifies either the length of the holding down period or the and signifies either the length of the holding down period or the
timer used to expire after such period. Such timers are used to timer used to expire after such period. Such timers are used to
"hold down" the state within an FSM that is cleaned if the machine "holddown" the state within an FSM that is cleaned if the machine
triggers a _HoldtimeExpired_ event. triggers a _HoldtimeExpired_ event.
6.1. Transport 6.1. Transport
All normative RIFT packet structures and their contents are defined All normative RIFT packet structures and their contents are defined
in the Thrift [thrift] models in Section 7. The packet structure in the Thrift [thrift] models in Section 7. The packet structure
itself is defined in _ProtocolPacket_, which contains the packet itself is defined in _ProtocolPacket_, which contains the packet
header in _PacketHeader_ and the packet contents in _PacketContent_. header in _PacketHeader_ and the packet contents in _PacketContent_.
_PacketContent_ is a union of the LIE, TIE, TIDE, and TIRE packets, _PacketContent_ is a union of the LIE, TIE, TIDE, and TIRE packets,
which are subsequently defined in _LIEPacket_, _TIEPacket_, which are subsequently defined in _LIEPacket_, _TIEPacket_,
skipping to change at line 1611 skipping to change at line 1563
state, at which point it is ready to exchange TIEs as described in state, at which point it is ready to exchange TIEs as described in
Section 6.3. The adjacency exchanges RIFT ZTP information Section 6.3. The adjacency exchanges RIFT ZTP information
(Section 6.7) in any of the states, i.e., it is not necessary to (Section 6.7) in any of the states, i.e., it is not necessary to
reach _ThreeWay_ for ZTP to operate. reach _ThreeWay_ for ZTP to operate.
RIFT supports any combination of IPv4 and IPv6 addressing, including RIFT supports any combination of IPv4 and IPv6 addressing, including
link-local scope, on the fabric to form adjacencies with the link-local scope, on the fabric to form adjacencies with the
additional capability for forwarding paths that are capable of additional capability for forwarding paths that are capable of
forwarding IPv4 packets in the presence of IPv6 addressing only. forwarding IPv4 packets in the presence of IPv6 addressing only.
IPv4 LIE exchange happens by default over well-known administratively IPv4 LIE exchange happens by default over a well-known IPv4 multicast
locally scoped and configured or otherwise well-known IPv4 multicast address [RFC2365] that may also be administratively configured (e.g.,
address [RFC2365]. For IPv6 [RFC8200], exchange is performed over with a local scope). For IPv6 [RFC8200], exchange is performed over
the link-local multicast scope [RFC4291] address, which is configured the link-local multicast scope [RFC4291] address, which is configured
or otherwise well-known. In both cases, a destination UDP port or otherwise well-known. In both cases, a destination UDP port
defined in the schema (Section 7.2) is used unless configured defined in the schema (Section 7.2) is used unless configured
otherwise. LIEs MUST be sent with an IPv4 Time to Live (TTL) or an otherwise. LIEs MUST be sent with an IPv4 Time to Live (TTL) or an
IPv6 Hop Limit (HL) of either 1 or 255 to prevent RIFT information IPv6 Hop Limit (HL) of either 1 or 255 to prevent RIFT information
reaching beyond a single Layer 3 (L3) next hop in the topology. reaching beyond a single Layer 3 (L3) next hop in the topology.
Observe that, for the allocated link-local scope IP multicast Observe that, for the allocated link-local scope IP multicast
address, the TTL value of 1 is a more logical choice since the TTL address, the TTL value of 1 is a more logical choice since the TTL
value of 255 may, in some environments, lead to an early drop due to value of 255 may, in some environments, lead to an early drop due to
the suspicious TTL value for a packet addressed to such a the suspicious TTL value for a packet addressed to such a
skipping to change at line 1691 skipping to change at line 1643
_ipv4_forwarding_capable_ flag setting across the same address family _ipv4_forwarding_capable_ flag setting across the same address family
combinations. The table is symmetric, i.e., the local and remote combinations. The table is symmetric, i.e., the local and remote
columns can be exchanged to construct the remaining combinations. columns can be exchanged to construct the remaining combinations.
The specific forwarding implementation to support the described The specific forwarding implementation to support the described
behavior is out of scope for this document. behavior is out of scope for this document.
+==========+==========+==========================================+ +==========+==========+==========================================+
| Local | Remote | LIE Exchange Behavior | | Local | Remote | LIE Exchange Behavior |
| Neighbor | Neighbor | | | Neighbor | Neighbor | |
| AF | AF | | | Address | Address | |
| Family | Family | |
+==========+==========+==========================================+ +==========+==========+==========================================+
| IPv4 | IPv4 | LIEs and TIEs are exchanged over IPv4 | | IPv4 | IPv4 | LIEs and TIEs are exchanged over IPv4 |
| | | only. The local neighbor receives TIEs | | | | only. The local neighbor receives TIEs |
| | | from remote neighbors on any of the LIE | | | | from remote neighbors on any of the LIE |
| | | source addresses. | | | | source addresses. |
+----------+----------+------------------------------------------+ +----------+----------+------------------------------------------+
| IPv6 | IPv6 | LIEs and TIEs are exchanged over IPv6 | | IPv6 | IPv6 | LIEs and TIEs are exchanged over IPv6 |
| | | only. The local neighbor receives TIEs | | | | only. The local neighbor receives TIEs |
| | | from remote neighbors on any of the LIE | | | | from remote neighbors on any of the LIE |
| | | source addresses. | | | | source addresses. |
skipping to change at line 1723 skipping to change at line 1676
| | | the remote neighbors on any of the IPv4 | | | | the remote neighbors on any of the IPv4 |
| | | or IPv6 LIE source addresses. | | | | or IPv6 LIE source addresses. |
+----------+----------+------------------------------------------+ +----------+----------+------------------------------------------+
| IPv4, | IPv4 | The local neighbor sends LIEs for both | | IPv4, | IPv4 | The local neighbor sends LIEs for both |
| IPv6 | | IPv4 and IPv6, while the remote neighbor | | IPv6 | | IPv4 and IPv6, while the remote neighbor |
| | | only sends LIEs for IPv4. The resulting | | | | only sends LIEs for IPv4. The resulting |
| | | adjacency will exchange TIEs over IPv4 | | | | adjacency will exchange TIEs over IPv4 |
| | | on any of the IPv4 LIE source addresses. | | | | on any of the IPv4 LIE source addresses. |
+----------+----------+------------------------------------------+ +----------+----------+------------------------------------------+
Table 1: Control Plane Behavior for Neighbor AF Combinations Table 1: Control Plane Behavior for Neighbor Address Family
Combinations
+==========+==========+==========================================+ +==========+==========+==========================================+
| Local | Remote | Forwarding Behavior | | Local | Remote | Forwarding Behavior |
| Neighbor | Neighbor | | | Neighbor | Neighbor | |
| AF | AF | | | Address | Address | |
| Family | Family | |
+==========+==========+==========================================+ +==========+==========+==========================================+
| IPv4 | IPv4 | Only IPv4 traffic can be forwarded. | | IPv4 | IPv4 | Only IPv4 traffic can be forwarded. |
+----------+----------+------------------------------------------+ +----------+----------+------------------------------------------+
| IPv6 | IPv6 | If either neighbor sets | | IPv6 | IPv6 | If either neighbor sets |
| | | _ipv4_forwarding_capable_ to false, only | | | | _ipv4_forwarding_capable_ to false, only |
| | | IPv6 traffic can be forwarded. If both | | | | IPv6 traffic can be forwarded. If both |
| | | neighbors set _ipv4_forwarding_capable_ | | | | neighbors set _ipv4_forwarding_capable_ |
| | | to true, IPv4 traffic is also forwarded | | | | to true, IPv4 traffic is also forwarded |
| | | via IPv6 gateways. | | | | via IPv6 gateways. |
+----------+----------+------------------------------------------+ +----------+----------+------------------------------------------+
skipping to change at line 1755 skipping to change at line 1710
+----------+----------+------------------------------------------+ +----------+----------+------------------------------------------+
| IPv4, | IPv4, | IPv4 and IPv6 traffic can be forwarded. | | IPv4, | IPv4, | IPv4 and IPv6 traffic can be forwarded. |
| IPv6 | IPv6 | If IPv4 and IPv6 LIEs advertise | | IPv6 | IPv6 | If IPv4 and IPv6 LIEs advertise |
| | | conflicting _ipv4_forwarding_capable_ | | | | conflicting _ipv4_forwarding_capable_ |
| | | flags, the behavior is unspecified. | | | | flags, the behavior is unspecified. |
+----------+----------+------------------------------------------+ +----------+----------+------------------------------------------+
| IPv4, | IPv4 | IPv4 traffic can be forwarded. | | IPv4, | IPv4 | IPv4 traffic can be forwarded. |
| IPv6 | | | | IPv6 | | |
+----------+----------+------------------------------------------+ +----------+----------+------------------------------------------+
Table 2: Forwarding Behavior for Neighbor AF Combinations Table 2: Forwarding Behavior for Neighbor Address Family
Combinations
The protocol does *not* support selective disabling of address The protocol does *not* support selective disabling of address
families after adjacency formation, disabling IPv4 forwarding families after adjacency formation, disabling IPv4 forwarding
capability, or any local address changes in _ThreeWay_ state, i.e., capability, or any local address changes in _ThreeWay_ state, i.e.,
if a link has entered ThreeWay IPv4 and/or IPv6 with a neighbor on an if a link has entered ThreeWay IPv4 and/or IPv6 with a neighbor on an
adjacency and it wants to stop supporting one of the families, change adjacency and it wants to stop supporting one of the families, change
any of its local addresses, or stop IPv4 forwarding, it MUST tear any of its local addresses, or stop IPv4 forwarding, it MUST tear
down and rebuild the adjacency. It MUST also remove any state it down and rebuild the adjacency. It MUST also remove any state it
stored about the remote side of the adjacency such as associated LIE stored about the remote side of the adjacency such as associated LIE
source addresses. source addresses.
skipping to change at line 1779 skipping to change at line 1735
in the _level_ of the _PacketHeader_ schema element. It MAY also be in the _level_ of the _PacketHeader_ schema element. It MAY also be
provisioned with its PoD. If the level is not provisioned, it is not provisioned with its PoD. If the level is not provisioned, it is not
present in the optional _PacketHeader_ schema element and established present in the optional _PacketHeader_ schema element and established
by ZTP procedures, if feasible. If PoD is not provisioned, it is by ZTP procedures, if feasible. If PoD is not provisioned, it is
governed by the _LIEPacket_ schema element assuming the governed by the _LIEPacket_ schema element assuming the
_common.default_pod_ value. This means that switches except ToF do _common.default_pod_ value. This means that switches except ToF do
not need to be configured at all. Necessary information to configure not need to be configured at all. Necessary information to configure
all values is exchanged in the _LIEPacket_ and _PacketHeader_ or all values is exchanged in the _LIEPacket_ and _PacketHeader_ or
derived by the node automatically. derived by the node automatically.
Further definitions of leaf flags are found in Section 6.7 given they Further leaf flag definitions are found in Section 6.7 as they have
have implications in terms of level and adjacency forming here. Leaf implications in terms of level and adjacency formation. Leaf flags
flags are carried in _HierarchyIndications_. are carried in _HierarchyIndications_.
A node MUST form a _ThreeWay_ adjacency if, at a minimum, the A node MUST form a _ThreeWay_ adjacency if, at a minimum, the
following first order logic conditions are satisfied on a LIE packet, following first order logic conditions are satisfied on a LIE packet,
as specified by the _LIEPacket_ schema element and received on a link as specified by the _LIEPacket_ schema element and received on a link
(such a LIE is considered a "minimally valid" LIE). Observe that, (such a LIE is considered a "minimally valid" LIE). Observe that,
depending on the FSM involved and its state further, conditions may depending on the FSM involved and its state further, conditions may
be checked, and even a minimally valid LIE can be considered be checked, and even a minimally valid LIE can be considered
ultimately invalid if any of the additional conditions fail: ultimately invalid if any of the additional conditions fail:
1. the neighboring node is running the same major schema version as 1. the neighboring node is running the same major schema version as
indicated in the _major_version_ element in _PacketHeader_; indicated in the _major_version_ element in _PacketHeader_ *and*
2. the neighboring node uses a valid System ID (i.e., a value 2. the neighboring node uses a valid System ID (i.e., a value
different from _IllegalSystemID_) in the _sender_ element in different from _IllegalSystemID_) in the _sender_ element in
_PacketHeader_; _PacketHeader_ *and*
3. the neighboring node uses a different System ID than the node 3. the neighboring node uses a different System ID than the node
itself; itself *and*
4. the advertised MTU values in the _LiePacket_ element match on 4. (the advertised MTU values in the _LiePacket_ element match on
both sides, while a missing MTU in the _LiePacket_ element is both sides, while a missing MTU in the _LiePacket_ element is
interpreted as _default_mtu_size_; interpreted as _default_mtu_size_) *and*
5. both nodes advertise defined level values in the _level_ element 5. both nodes advertise defined level values in the _level_ element
in _PacketHeader_, *and* in _PacketHeader_ *and*
6. either: 6. [
a. the node is at the _leaf_level_ value and has no _ThreeWay_ a. the node is at the _leaf_level_ value and does not already
adjacencies already to nodes at Highest Adjacency _ThreeWay_ have any _ThreeWay_ adjacencies to nodes that are at the
(HAT), as defined later in Section 6.7.1, with the level Highest Adjacency _ThreeWay_ (HAT), as defined in
different than the adjacent node; Section 6.7.1, with a level that is different than the
adjacent node *or*
b. the node is not at the _leaf_level_ value and the neighboring b. the node is not at the _leaf_level_ value and the neighboring
node is at the _leaf_level_ value; node is at the _leaf_level_ value *or*
c. both nodes are at the _leaf_level_ values *and* both indicate c. both nodes are at the _leaf_level_ value *and* both indicate
support for that described in Section 6.8.9; *or* support for that described in Section 6.8.9 *or*
d. neither node is at the _leaf_level_ value and the neighboring d. neither node is at the _leaf_level_ value and the neighboring
node is, at most, one level away. node is, at most, one level away.
]
LIEs arriving with IPv4 Time to Live (TTL) or an IPv6 Hop Limit (HL) LIEs arriving with IPv4 Time to Live (TTL) or an IPv6 Hop Limit (HL)
different than 1 or 255 MUST be ignored. different than 1 or 255 MUST be ignored.
6.2.1. LIE Finite State Machine 6.2.1. LIE Finite State Machine
This section specifies the precise, normative LIE FSM, which is also This section specifies the precise, normative LIE FSM, which is also
shown in Figure 14. Additionally, some sets of actions often repeat shown in Figure 14. Additionally, some sets of actions often repeat
and are hence summarized into well-known procedures. and are hence summarized into well-known procedures.
Events generated are fairly fine grained, especially when indicating Events generated are fairly fine grained, especially when indicating
skipping to change at line 2036 skipping to change at line 1995
from LIE's address, then PUSH NeighborChangedAddress, else from LIE's address, then PUSH NeighborChangedAddress, else
d. if any of the neighbor's flood address port, name, or d. if any of the neighbor's flood address port, name, or
local LinkID changed, then PUSH NeighborChangedMinorFields local LinkID changed, then PUSH NeighborChangedMinorFields
e. CHECK_THREE_WAY e. CHECK_THREE_WAY
* CHECK_THREE_WAY: if the current state is _OneWay_, do nothing, * CHECK_THREE_WAY: if the current state is _OneWay_, do nothing,
else else
1. if LIE packet does not contain a neighbor and if the current 1. if LIE packet does not contain a neighbor then if the current
state is _ThreeWay_, then PUSH NeighborDroppedReflection, else state is _ThreeWay_, then PUSH NeighborDroppedReflection, else
2. if the packet reflects this System ID and local port and the 2. if the packet reflects this System ID and local port and the
state is _ThreeWay_, then PUSH the ValidReflection event, else state is _ThreeWay_, then PUSH the ValidReflection event, else
PUSH the MultipleNeighbors event. PUSH the MultipleNeighbors event.
States: States:
* OneWay: The initial state the FSM is starting from. In this * OneWay: The initial state the FSM is starting from. In this
state, the router did not receive any valid LIEs from a neighbor. state, the router did not receive any valid LIEs from a neighbor.
skipping to change at line 2112 skipping to change at line 2071
* MTUMismatch: MTU mismatched. * MTUMismatch: MTU mismatched.
* NeighborChangedMinorFields: Minor fields changed in the neighbor's * NeighborChangedMinorFields: Minor fields changed in the neighbor's
LIE. LIE.
* HoldtimeExpired: Adjacency holddown timer expired. * HoldtimeExpired: Adjacency holddown timer expired.
* MultipleNeighbors: More than one neighbor is present on the * MultipleNeighbors: More than one neighbor is present on the
interface. interface.
* MultipleNeighborsDone: Multiple neighbors' timers expired. * MultipleNeighborsDone: Multiple neighbors timer expired.
* FloodLeadersChanged: Node's election algorithm determined new set * FloodLeadersChanged: Node's election algorithm determined new set
of flood leaders. of flood leaders.
* SendLie: Send a LIE out. * SendLie: Send a LIE out.
* UpdateZTPOffer: Update this node's ZTP offer. This is sent to the * UpdateZTPOffer: Update this node's ZTP offer. This is sent to the
ZTP FSM. ZTP FSM.
Actions: Actions:
skipping to change at line 2140 skipping to change at line 2099
* on UnacceptableHeader in _OneWay_ finishes in OneWay: no action * on UnacceptableHeader in _OneWay_ finishes in OneWay: no action
* on NeighborChangedMinorFields in _OneWay_ finishes in OneWay: no * on NeighborChangedMinorFields in _OneWay_ finishes in OneWay: no
action action
* on SendLie in _OneWay_ finishes in OneWay: SEND_LIE * on SendLie in _OneWay_ finishes in OneWay: SEND_LIE
* on HALSChanged in _OneWay_ finishes in OneWay: store the HALS * on HALSChanged in _OneWay_ finishes in OneWay: store the HALS
* on MultipleNeighbors in _OneWay_ finishes in * on MultipleNeighbors in _OneWay_ finishes in
MultipleNeighborsWait: start multiple neighbors' timers with the MultipleNeighborsWait: start multiple neighbors timer with the
interval _multiple_neighbors_lie_holdtime_multipler_ * interval _multiple_neighbors_lie_holdtime_multiplier_ *
_default_lie_holdtime_ _default_lie_holdtime_
* on NeighborChangedLevel in _OneWay_ finishes in OneWay: no action * on NeighborChangedLevel in _OneWay_ finishes in OneWay: no action
* on LieRcvd in _OneWay_ finishes in OneWay: PROCESS_LIE * on LieRcvd in _OneWay_ finishes in OneWay: PROCESS_LIE
* on MTUMismatch in _OneWay_ finishes in OneWay: no action * on MTUMismatch in _OneWay_ finishes in OneWay: no action
* on ValidReflection in _OneWay_ finishes in ThreeWay: no action * on ValidReflection in _OneWay_ finishes in ThreeWay: no action
skipping to change at line 2214 skipping to change at line 2173
* on HALSChanged in _TwoWay_ finishes in TwoWay: store the HALS * on HALSChanged in _TwoWay_ finishes in TwoWay: store the HALS
* on MTUMismatch in _TwoWay_ finishes in OneWay: no action * on MTUMismatch in _TwoWay_ finishes in OneWay: no action
* on NeighborChangedAddress in _TwoWay_ finishes in OneWay: no * on NeighborChangedAddress in _TwoWay_ finishes in OneWay: no
action action
* on SendLie in _TwoWay_ finishes in TwoWay: SEND_LIE * on SendLie in _TwoWay_ finishes in TwoWay: SEND_LIE
* on MultipleNeighbors in _TwoWay_ finishes in * on MultipleNeighbors in _TwoWay_ finishes in
MultipleNeighborsWait: start multiple neighbors' timers with the MultipleNeighborsWait: start multiple neighbors timer with the
interval _multiple_neighbors_lie_holdtime_multipler_ * interval _multiple_neighbors_lie_holdtime_multiplier_ *
_default_lie_holdtime_ _default_lie_holdtime_
* on TimerTick in _ThreeWay_ finishes in ThreeWay: PUSH the SendLie * on TimerTick in _ThreeWay_ finishes in ThreeWay: PUSH the SendLie
event, if the last valid LIE was received more than _holdtime_ ago event, if the last valid LIE was received more than _holdtime_ ago
as advertised by the neighbor, then PUSH the HoldtimeExpired event as advertised by the neighbor, then PUSH the HoldtimeExpired event
* on LevelChanged in _ThreeWay_ finishes in OneWay: update the level * on LevelChanged in _ThreeWay_ finishes in OneWay: update the level
with the event value with the event value
* on HATChanged in _ThreeWay_ finishes in ThreeWay: store HAT * on HATChanged in _ThreeWay_ finishes in ThreeWay: store HAT
* on MTUMismatch in _ThreeWay_ finishes in OneWay: no action * on MTUMismatch in _ThreeWay_ finishes in OneWay: no action
* on UnacceptableHeader in _ThreeWay_ finishes in OneWay: no action * on UnacceptableHeader in _ThreeWay_ finishes in OneWay: no action
* on MultipleNeighbors in _ThreeWay_ finishes in * on MultipleNeighbors in _ThreeWay_ finishes in
MultipleNeighborsWait: start multiple neighbors' timers with the MultipleNeighborsWait: start multiple neighbors timer with the
interval _multiple_neighbors_lie_holdtime_multipler_ * interval _multiple_neighbors_lie_holdtime_multiplier_ *
_default_lie_holdtime_ _default_lie_holdtime_
* on NeighborChangedLevel in _ThreeWay_ finishes in OneWay: no * on NeighborChangedLevel in _ThreeWay_ finishes in OneWay: no
action action
* on HALSChanged in _ThreeWay_ finishes in ThreeWay: store the HALS * on HALSChanged in _ThreeWay_ finishes in ThreeWay: store the HALS
* on LieRcvd in _ThreeWay_ finishes in ThreeWay: PROCESS_LIE * on LieRcvd in _ThreeWay_ finishes in ThreeWay: PROCESS_LIE
* on FloodLeadersChanged in _ThreeWay_ finishes in ThreeWay: update * on FloodLeadersChanged in _ThreeWay_ finishes in ThreeWay: update
skipping to change at line 2266 skipping to change at line 2225
* on NeighborChangedAddress in _ThreeWay_ finishes in OneWay: no * on NeighborChangedAddress in _ThreeWay_ finishes in OneWay: no
action action
* on HALChanged in _ThreeWay_ finishes in ThreeWay: store the new * on HALChanged in _ThreeWay_ finishes in ThreeWay: store the new
HAL HAL
* on SendLie in _ThreeWay_ finishes in ThreeWay: SEND_LIE * on SendLie in _ThreeWay_ finishes in ThreeWay: SEND_LIE
* on MultipleNeighbors in MultipleNeighborsWait finishes in * on MultipleNeighbors in MultipleNeighborsWait finishes in
MultipleNeighborsWait: start multiple neighbors' timers with the MultipleNeighborsWait: start multiple neighbors timer with the
interval _multiple_neighbors_lie_holdtime_multipler_ * interval _multiple_neighbors_lie_holdtime_multiplier_ *
_default_lie_holdtime_ _default_lie_holdtime_
* on FloodLeadersChanged in MultipleNeighborsWait finishes in * on FloodLeadersChanged in MultipleNeighborsWait finishes in
MultipleNeighborsWait: update _you_are_flood_repeater_ LIE MultipleNeighborsWait: update _you_are_flood_repeater_ LIE
elements based on the flood leader election results elements based on the flood leader election results
* on TimerTick in MultipleNeighborsWait finishes in * on TimerTick in MultipleNeighborsWait finishes in
MultipleNeighborsWait: check MultipleNeighbors timer, if the timer MultipleNeighborsWait: check MultipleNeighbors timer, if the timer
expired, PUSH MultipleNeighborsDone expired, PUSH MultipleNeighborsDone
skipping to change at line 2374 skipping to change at line 2333
As an example illustrating a database holding both representations, As an example illustrating a database holding both representations,
the topology in Figure 2 with the optional link between spine 111 and the topology in Figure 2 with the optional link between spine 111 and
spine 112 (so that the flooding on an East-West link can be shown) is spine 112 (so that the flooding on an East-West link can be shown) is
shown below. Unnumbered interfaces are implicitly assumed and, for shown below. Unnumbered interfaces are implicitly assumed and, for
simplicity, the key value elements, which may be included in their simplicity, the key value elements, which may be included in their
South TIEs or North TIEs, are not shown. First, Figure 15 shows the South TIEs or North TIEs, are not shown. First, Figure 15 shows the
TIEs generated by some nodes. TIEs generated by some nodes.
ToF 21 South TIEs: ToF 21 South TIEs:
Node South TIE: South Node TIE:
NodeTIEElement(level=2, NodeTIEElement(level=2,
neighbors( neighbors(
(Spine 111, level 1, cost 1, links(...)), (Spine 111, level 1, cost 1, links(...)),
(Spine 112, level 1, cost 1, links(...)), (Spine 112, level 1, cost 1, links(...)),
(Spine 121, level 1, cost 1, links(...)), (Spine 121, level 1, cost 1, links(...)),
(Spine 122, level 1, cost 1, links(...)) (Spine 122, level 1, cost 1, links(...))
) )
) )
Prefix South TIE: South Prefix TIE:
PrefixTIEElement(prefixes(0/0, metric 1), (::/0, metric 1)) PrefixTIEElement(prefixes(0/0, metric 1), (::/0, metric 1))
Spine 111 South TIEs: Spine 111 South TIEs:
Node South TIE: South Node TIE:
NodeTIEElement(level=1, NodeTIEElement(level=1,
neighbors( neighbors(
(ToF 21, level 2, cost 1, links(...)), (ToF 21, level 2, cost 1, links(...)),
(ToF 22, level 2, cost 1, links(...)), (ToF 22, level 2, cost 1, links(...)),
(Spine 112, level 1, cost 1, links(...)), (Spine 112, level 1, cost 1, links(...)),
(Leaf111, level 0, cost 1, links(...)), (Leaf111, level 0, cost 1, links(...)),
(Leaf112, level 0, cost 1, links(...)) (Leaf112, level 0, cost 1, links(...))
) )
) )
Prefix South TIE: South Prefix TIE:
PrefixTIEElement(prefixes(0/0, metric 1), (::/0, metric 1)) PrefixTIEElement(prefixes(0/0, metric 1), (::/0, metric 1))
Spine 111 North TIEs: Spine 111 North TIEs:
Node North TIE: North Node TIE:
NodeTIEElement(level=1, NodeTIEElement(level=1,
neighbors( neighbors(
(ToF 21, level 2, cost 1, links(...)), (ToF 21, level 2, cost 1, links(...)),
(ToF 22, level 2, cost 1, links(...)), (ToF 22, level 2, cost 1, links(...)),
(Spine 112, level 1, cost 1, links(...)), (Spine 112, level 1, cost 1, links(...)),
(Leaf111, level 0, cost 1, links(...)), (Leaf111, level 0, cost 1, links(...)),
(Leaf112, level 0, cost 1, links(...)) (Leaf112, level 0, cost 1, links(...))
) )
) )
Prefix North TIE: North Prefix TIE:
PrefixTIEElement(prefixes(Spine 111.loopback) PrefixTIEElement(prefixes(Spine 111.loopback)
Spine 121 South TIEs: Spine 121 South TIEs:
Node South TIE: South Node TIE:
NodeTIEElement(level=1, NodeTIEElement(level=1,
neighbors( neighbors(
(ToF 21, level 2, cost 1, links(...)), (ToF 21, level 2, cost 1, links(...)),
(ToF 22, level 2, cost 1, links(...)), (ToF 22, level 2, cost 1, links(...)),
(Leaf121, level 0, cost 1, links(...)), (Leaf121, level 0, cost 1, links(...)),
(Leaf122, level 0, cost 1, links(...)) (Leaf122, level 0, cost 1, links(...))
) )
) )
Prefix South TIE: South Prefix TIE:
PrefixTIEElement(prefixes(0/0, metric 1), (::/0, metric 1)) PrefixTIEElement(prefixes(0/0, metric 1), (::/0, metric 1))
Spine 121 North TIEs: Spine 121 North TIEs:
Node North TIE: North Node TIE:
NodeTIEElement(level=1, NodeTIEElement(level=1,
neighbors( neighbors(
(ToF 21, level 2, cost 1, links(...)), (ToF 21, level 2, cost 1, links(...)),
(ToF 22, level 2, cost 1, links(...)), (ToF 22, level 2, cost 1, links(...)),
(Leaf121, level 0, cost 1, links(...)), (Leaf121, level 0, cost 1, links(...)),
(Leaf122, level 0, cost 1, links(...)) (Leaf122, level 0, cost 1, links(...))
) )
) )
Prefix North TIE: North Prefix TIE:
PrefixTIEElement(prefixes(Spine 121.loopback) PrefixTIEElement(prefixes(Spine 121.loopback)
Leaf112 North TIEs: Leaf112 North TIEs:
Node North TIE: North Node TIE:
NodeTIEElement(level=0, NodeTIEElement(level=0,
neighbors( neighbors(
(Spine 111, level 1, cost 1, links(...)), (Spine 111, level 1, cost 1, links(...)),
(Spine 112, level 1, cost 1, links(...)) (Spine 112, level 1, cost 1, links(...))
) )
) )
Prefix North TIE: North Prefix TIE:
PrefixTIEElement(prefixes(Leaf112.loopback, Prefix112, Prefix_MH)) PrefixTIEElement(prefixes(Leaf112.loopback, Prefix112, Prefix_MH))
Figure 15: Example TIEs Generated in a 2-Level Spine-and-Leaf Figure 15: Example TIEs Generated in a 2-Level Spine-and-Leaf
Topology Topology
It may not be obvious here as to why the Node South TIEs contain all It may not be obvious here as to why the South Node TIEs contain all
the adjacencies of the corresponding node. This will be necessary the adjacencies of the corresponding node. This will be necessary
for algorithms further elaborated on in Sections 6.3.9 and 6.8.7. for algorithms further elaborated on in Sections 6.3.9 and 6.8.7.
For Node TIEs to carry more adjacencies than fit into an MTU-sized For Node TIEs to carry more adjacencies than fit into an MTU-sized
packet, the _neighbors_ element may contain a different set of packet, the _neighbors_ element may contain a different set of
neighbors in each TIE. Those disjointed sets of neighbors MUST be neighbors in each TIE. Those disjointed sets of neighbors MUST be
joined during corresponding computation. However, if the following joined during corresponding computation. However, if the following
occurs across multiple Node TIEs: occurs across multiple Node TIEs:
1. _capabilities_ do not match, 1. _capabilities_ do not match *or*
2. _flags_ values do not match, *or* 2. _flags_ values do not match *or*
3. the same neighbor repeats in multiple TIEs with different values. 3. the same neighbor repeats in multiple TIEs with different values.
The implementation is expected to use the value of any of the valid The implementation is expected to use the value of any of the valid
TIEs it received, as it cannot control the arrival order of those TIEs it received, as it cannot control the arrival order of those
TIEs. TIEs.
The _miscabled_links_ element SHOULD be included in every Node TIE; The _miscabled_links_ element SHOULD be included in every Node TIE;
otherwise, the behavior is undefined. otherwise, the behavior is undefined.
skipping to change at line 2578 skipping to change at line 2537
return TIEHeader with larger tie_nr is larger return TIEHeader with larger tie_nr is larger
else: else:
return TIEHeader with larger TIEType is larger return TIEHeader with larger TIEType is larger
Figure 16: TIEHeader Comparison Function Figure 16: TIEHeader Comparison Function
All valid TIE types are defined in _TIETypeType_. This enum All valid TIE types are defined in _TIETypeType_. This enum
indicates what TIE type the TIE is carrying. In case the value is indicates what TIE type the TIE is carrying. In case the value is
not known to the receiver, the TIE MUST be reflooded with the scope not known to the receiver, the TIE MUST be reflooded with the scope
identical to the scope of a prefix TIE. This allows for future identical to the scope of a prefix TIE. This allows for future
extensions of the protocol within the same major schema with types extensions of the protocol that are within the same major schema and
opaque to some nodes with some restrictions defined in Section 7. that have types that are opaque to some nodes; some restrictions are
defined in Section 7.
6.3.3.1. Normative Flooding Procedures 6.3.3.1. Normative Flooding Procedures
On reception of a TIE with an undefined level value in the packet On reception of a TIE with an undefined level value in the packet
header, the node MUST issue a warning and discard the packet. header, the node MUST issue a warning and discard the packet.
This section specifies the precise, normative flooding mechanism and This section specifies the precise, normative flooding mechanism and
can be omitted unless the reader is pursuing an implementation of the can be omitted unless the reader is pursuing an implementation of the
protocol or looks for a deep understanding of underlying information protocol or looks for a deep understanding of underlying information
distribution mechanism. distribution mechanism.
skipping to change at line 2731 skipping to change at line 2691
"stuck" in a part of a network while the originator reboots and "stuck" in a part of a network while the originator reboots and
reissues TIEs many times to the point its sequence number rolls over reissues TIEs many times to the point its sequence number rolls over
and forms an incomparable distance to the "stuck" copy), which and forms an incomparable distance to the "stuck" copy), which
implies that a comparison relation is possible between two elements. implies that a comparison relation is possible between two elements.
With that, it is implicitly possible to compare TIEs, TIEHeaders, and With that, it is implicitly possible to compare TIEs, TIEHeaders, and
TIEIDs to each other, whereas the shortest viable key is always TIEIDs to each other, whereas the shortest viable key is always
implied. implied.
6.3.3.1.2.1. TIDE Generation 6.3.3.1.2.1. TIDE Generation
As given by the timer constant, periodically generate TIDEs by:
NEXT_TIDE_ID: ID of the next TIE to be sent in the TIDE. NEXT_TIDE_ID: ID of the next TIE to be sent in the TIDE.
As given by the timer constant, periodically generate TIDEs by:
1. NEXT_TIDE_ID = MIN_TIEID 1. NEXT_TIDE_ID = MIN_TIEID
2. while NEXT_TIDE_ID is not equal to MAX_TIEID, do the following: 2. while NEXT_TIDE_ID is not equal to MAX_TIEID do:
a. HEADERS = Exactly TIRDEs_PER_PKT headers from FILTERED_TIEDB a. HEADERS = Exactly TIRES_PER_TIDE_PKT headers from
starting at NEXT_TIDE_ID, unless fewer than TIRDEs_PER_PKT FILTERED_TIEDB starting at NEXT_TIDE_ID, unless fewer than
remain, in which case all remaining headers. TIRES_PER_TIDE_PKT remain, in which case all remaining
headers.
b. if HEADERS is empty, then START = MIN_TIEID, else START = b. if HEADERS is empty, then START = MIN_TIEID, else START =
first element in HEADERS first element in HEADERS
c. if HEADERS' size is less than TIRDEs_PER_PKT, then END = c. if HEADERS size is less than TIRES_PER_TIDE_PKT, then END =
MAX_TIEID, else END = last element in HEADERS MAX_TIEID, else END = last element in HEADERS
d. send *sorted* HEADERS the as TIDE, setting START and END as d. send *sorted* HEADERS as TIDE, setting START and END as its
its range range
e. NEXT_TIDE_ID = END e. NEXT_TIDE_ID = END
The constant _TIRDEs_PER_PKT_ SHOULD be computed per interface and The constant _TIRES_PER_TIDE_PKT_ SHOULD be computed per interface
used by the implementation to limit the amount of TIE headers per and used by the implementation to limit the amount of TIE headers per
TIDE so the sent TIDE PDU does not exceed the interface of MTU. TIDE so the sent TIDE PDU does not exceed the MTU of the interface.
TIDE PDUs SHOULD be spaced on sending to prevent packet drops. TIDE PDUs SHOULD be transmitted at a rate that does not lead to
packet drops.
The algorithm will intentionally enter the loop once and send a The algorithm will intentionally enter the loop once and send a
single TIDE, even when the database is empty; otherwise, no TIDEs single TIDE, even when the database is empty; otherwise, no TIDEs
would be sent for in case of an empty database and break the intended would be sent for in case of an empty database and break the intended
synchronization. synchronization.
6.3.3.1.2.2. TIDE Processing 6.3.3.1.2.2. TIDE Processing
On reception of TIDEs, the following processing is performed:
TXKEYS: Collection of TIE headers to be sent after processing of the TXKEYS: Collection of TIE headers to be sent after processing of the
packet packet
REQKEYS: Collection of TIEIDs to be requested after processing of REQKEYS: Collection of TIEIDs to be requested after processing of
the packet the packet
CLEARKEYS: Collection of TIEIDs to be removed from flood state CLEARKEYS: Collection of TIEIDs to be removed from flood state
queues queues
LASTPROCESSED: Last processed TIEID in the TIDE LASTPROCESSED: Last processed TIEID in the TIDE
DBTIE: TIE in the Link State Database (LSDB), if found DBTIE: TIE in the LSDB, if found
On reception of TIDEs, the following processing is performed:
1. LASTPROCESSED = TIDE.start_range 1. LASTPROCESSED = TIDE.start_range
2. For every HEADER in the TIDE, do the following: 2. For every HEADER in the TIDE do:
a. DBTIE = find HEADER in the current LSDB a. DBTIE = find HEADER in the current LSDB
b. if HEADER < LASTPROCESSED, then report the error and reset b. if HEADER < LASTPROCESSED, then report an error and reset the
the adjacency and return adjacency and return
c. put all TIEs in LSDB, where TIE.HEADER > LASTPROCESSED and c. put all TIEs in LSDB, where (TIE.HEADER > LASTPROCESSED and
TIE.HEADER < HEADER, into TXKEYS TIE.HEADER < HEADER) into TXKEYS
d. LASTPROCESSED = HEADER d. LASTPROCESSED = HEADER
e. if DBTIE is not found, then e. if DBTIE is not found, then
i. if originator is this node, then bump_own_tie i. if originator is this node, then bump_own_tie
ii. else put HEADER into REQKEYS ii. else put HEADER into REQKEYS
f. if DBTIE.HEADER < HEADER, then f. if DBTIE.HEADER < HEADER then
i. if the originator is this node, then bump_own_tie, else i. if the originator is this node, then bump_own_tie, else
1. if this is a North TIE header from a northbound 1. if this is a North TIE header from a northbound
neighbor, then override DBTIE in LSDB with HEADER neighbor, then override DBTIE in LSDB with HEADER
2. else put HEADER into REQKEYS 2. else put HEADER into REQKEYS
g. if DBTIE.HEADER > HEADER, then put DBTIE.HEADER into TXKEYS g. if DBTIE.HEADER > HEADER, then put DBTIE.HEADER into TXKEYS
h. if DBTIE.HEADER = HEADER, then h. if DBTIE.HEADER = HEADER, then
i. if DBTIE has content already, then put DBTIE.HEADER into i. if DBTIE has content already, then put DBTIE.HEADER into
CLEARKEYS, else CLEARKEYS, else
ii. put HEADER into REQKEYS ii. put HEADER into REQKEYS
3. put all TIEs in LSDB, where TIE.HEADER > LASTPROCESSED and 3. put all TIEs in LSDB, where (TIE.HEADER > LASTPROCESSED and
TIE.HEADER <= TIDE.end_range, into TXKEYS TIE.HEADER <= TIDE.end_range) into TXKEYS
4. for all TIEs in TXKEYS, try_to_transmit_tie(TIE) 4. for all TIEs in TXKEYS, try_to_transmit_tie(TIE)
5. for all TIEs in REQKEYS, request_tie(TIE) 5. for all TIEs in REQKEYS, request_tie(TIE)
6. for all TIEs in CLEARKEYS, remove_from_all_queues(TIE) 6. for all TIEs in CLEARKEYS, remove_from_all_queues(TIE)
6.3.3.1.3. TIREs 6.3.3.1.3. TIREs
6.3.3.1.3.1. TIRE Generation 6.3.3.1.3.1. TIRE Generation
Elements from both TIES_REQ and TIES_ACK MUST be collected and sent Elements from both TIES_REQ and TIES_ACK MUST be collected and sent
out as fast as feasible as TIREs. When sending TIREs with elements out as fast as feasible as TIREs. When sending TIREs with elements
from TIES_REQ, the _remaining_lifetime_ field in from TIES_REQ, the _remaining_lifetime_ field in
_TIEHeaderWithLifeTime_ MUST be set to 0 to force reflooding from the _TIEHeaderWithLifeTime_ MUST be set to 0 to force reflooding from the
neighbor even if the TIEs seem to be the same. neighbor even if the TIEs seem to be the same.
6.3.3.1.3.2. TIRE Processing 6.3.3.1.3.2. TIRE Processing
On reception of TIREs, the following processing is performed:
TXKEYS: Collection of TIE headers to be sent after processing of the TXKEYS: Collection of TIE headers to be sent after processing of the
packet packet
REQKEYS: Collection of TIEIDs to be requested after processing of REQKEYS: Collection of TIEIDs to be requested after processing of
the packet the packet
ACKKEYS: Collection of TIEIDs that have been acknowledged ACKKEYS: Collection of TIEIDs that have been acknowledged
DBTIE: TIE in the LSDB, if found DBTIE: TIE in the LSDB, if found
1. for every HEADER in TIRE, do the following: On reception of TIREs, the following processing is performed:
1. for every HEADER in TIRE do:
a. DBTIE = find HEADER in the current LSDB a. DBTIE = find HEADER in the current LSDB
b. if DBTIE is not found, then do nothing b. if DBTIE is not found, then do nothing
c. if DBTIE.HEADER < HEADER, then put HEADER into REQKEYS c. if DBTIE.HEADER < HEADER, then put HEADER into REQKEYS
d. if DBTIE.HEADER > HEADER, then put DBTIE.HEADER into TXKEYS d. if DBTIE.HEADER > HEADER, then put DBTIE.HEADER into TXKEYS
e. if DBTIE.HEADER = HEADER, then put DBTIE.HEADER into ACKKEYS e. if DBTIE.HEADER = HEADER, then put DBTIE.HEADER into ACKKEYS
skipping to change at line 2886 skipping to change at line 2848
TXTIE: TIE to transmit TXTIE: TIE to transmit
DBTIE: TIE in the LSDB, if found DBTIE: TIE in the LSDB, if found
1. DBTIE = find TIE in the current LSDB 1. DBTIE = find TIE in the current LSDB
2. if DBTIE is not found, then 2. if DBTIE is not found, then
a. if the originator is this node, then bump_own_tie with a a. if the originator is this node, then bump_own_tie with a
short remaining lifetime, else short remaining lifetime
b. insert TIE into LSDB and ACKTIE = TIE b. else insert TIE into LSDB and ACKTIE = TIE
else else
a. if DBTIE.HEADER = TIE.HEADER, then a. if DBTIE.HEADER = TIE.HEADER, then
i. if DBTIE has content already, then ACKTIE = TIE, else i. if DBTIE has content already, then ACKTIE = TIE
ii. process like the "DBTIE.HEADER < TIE.HEADER" case ii. else process like the "DBTIE.HEADER < TIE.HEADER" case
b. if DBTIE.HEADER < TIE.HEADER, then b. if DBTIE.HEADER < TIE.HEADER, then
i. if the originator is this node, then bump_own_tie, else i. if the originator is this node, then bump_own_tie
ii. insert TIE into LSDB and ACKTIE = TIE ii. else insert TIE into LSDB and ACKTIE = TIE
c. if DBTIE.HEADER > TIE.HEADER, then c. if DBTIE.HEADER > TIE.HEADER, then
i. if DBTIE has content already, then TXTIE = DBTIE, else i. if DBTIE has content already, then TXTIE = DBTIE
ii. ACKTIE = DBTIE ii. else ACKTIE = DBTIE
3. if TXTIE is set, then try_to_transmit_tie(TXTIE) 3. if TXTIE is set, then try_to_transmit_tie(TXTIE)
4. if ACKTIE is set, then ack_tie(TIE) 4. if ACKTIE is set, then ack_tie(TIE)
6.3.3.1.5. Sending TIEs 6.3.3.1.5. Sending TIEs
On a periodic basis, all TIEs with a lifetime of > 0 left MUST be On a periodic basis, all TIEs with a lifetime of > 0 left MUST be
sent out on the adjacency, removed from the TIES_TX list, and sent out on the adjacency, removed from the TIES_TX list, and
requeued onto TIES_RTX list. The specific period is out of scope for requeued onto TIES_RTX list. The specific period is out of scope for
this document. this document.
6.3.3.1.6. TIEs Processing in LSDB 6.3.3.1.6. TIEs Processing in LSDB
The Link State Database (LSDB) holds the most recent copy of TIEs The LSDB holds the most recent copy of TIEs received via flooding
received via flooding from according peers. Consecutively, after from according peers. Consecutively, after version tie-breaking by
version tie-breaking by LSDB, a peer receives from the LSDB the LSDB, a peer receives from the LSDB the newest versions of TIEs
newest versions of TIEs received by other peers and processes them received by other peers and processes them (without any filtering)
(without any filtering) just like receiving TIEs from its remote just like receiving TIEs from its remote peer. Such a publisher
peer. Such a publisher model can be implemented in several ways, model can be implemented in several ways, either in a single thread
either in a single thread of execution or in multiple parallel of execution or in multiple parallel threads.
threads.
LSDB can be logically considered as the entity aging out TIEs, i.e., LSDB can be logically considered as the entity aging out TIEs, i.e.,
being responsible to discard TIEs that are stored longer than being responsible to discard TIEs that are stored longer than
_remaining_lifetime_ on their reception. _remaining_lifetime_ on their reception.
LSDB is also expected to periodically reoriginate the node's own LSDB is also expected to periodically reoriginate the node's own
TIEs. Originating at an interval significantly shorter than TIEs. Originating at an interval significantly shorter than
_default_lifetime_ is RECOMMENDED to prevent TIE expiration by other _default_lifetime_ is RECOMMENDED to prevent TIE expiration by other
nodes in the network, which can lead to instabilities. nodes in the network, which can lead to instabilities.
6.3.4. TIE Flooding Scopes 6.3.4. TIE Flooding Scopes
In a somewhat analogous fashion to link-local, area, and domain In a somewhat analogous fashion to link-local, area, and domain
flooding scopes, RIFT defines several complex "flooding scopes", flooding scopes, RIFT defines several complex "flooding scopes",
depending on the direction and type of TIE propagated. depending on the direction and type of TIE propagated.
Every North TIE is flooded northbound, providing a node at a given Every North TIE is flooded northbound, providing a node at a given
level with the complete topology of the Clos or Fat Tree network that level with the complete topology of the Clos or fat tree network that
is reachable southwards of it, including all specific prefixes. This is reachable southwards of it, including all specific prefixes. This
means that a packet received from a node at the same or lower level means that a packet received from a node at the same or lower level
whose destination is covered by one of those specific prefixes will whose destination is covered by one of those specific prefixes will
be routed directly towards the node advertising that prefix, rather be routed directly towards the node advertising that prefix, rather
than sending the packet to a node at a higher level. than sending the packet to a node at a higher level.
A node's Node South TIEs, consisting of all node's adjacencies and A node's South Node TIEs, consisting of all node's adjacencies and
prefix South TIEs limited to those related to default IP prefix and South Prefix TIEs limited to those related to default IP prefix and
disaggregated prefixes, are flooded southbound in order to inform disaggregated prefixes, are flooded southbound in order to inform
nodes one level down of connectivity of the higher level as well as nodes one level down of connectivity of the higher level as well as
reachability to the rest of the fabric. In order to allow an E-W reachability to the rest of the fabric. In order to allow an E-W
disconnected node in a given level to receive the South TIEs of other disconnected node in a given level to receive the South TIEs of other
nodes at its level, every Node South TIE is "reflected" northbound to nodes at its level, every South Node TIE is "reflected" northbound to
the level from which it was received. It should be noted that East- the level from which it was received. It should be noted that East-
West links are included in South TIE flooding (except at the ToF West links are included in South TIE flooding (except at the ToF
level); those TIEs need to be flooded to satisfy the algorithms level); those TIEs need to be flooded to satisfy the algorithms
described in Section 6.4. In that way, nodes at same level can learn described in Section 6.4. In that way, nodes at same level can learn
about each other without using a lower level except in case of leaf about each other without using a lower level except in case of leaf
level. The precise, normative flooding scopes are given in Table 3. level. The precise, normative flooding scopes are given in Table 3.
Those rules also govern what SHOULD be included in TIDEs on the Those rules also govern what SHOULD be included in TIDEs on the
adjacency. Again, East-West flooding scopes are identical to adjacency. Again, East-West flooding scopes are identical to
southern flooding scopes, except in case of ToF East-West links southern flooding scopes, except in case of ToF East-West links
(rings), which are basically performing northbound flooding. (rings), which are basically performing northbound flooding.
Node South TIE "south reflection" enables support of positive South Node TIE "south reflection" enables support of positive
disaggregation on failures, as described in Section 6.5, and flooding disaggregation on failures, as described in Section 6.5, and flooding
reduction, as described in Section 6.3.9. reduction, as described in Section 6.3.9.
+===========+======================+==============+=================+ +===========+======================+==============+=================+
| Type / | South | North | East-West | | Type / | South | North | East-West |
| Direction | | | | | Direction | | | |
+===========+======================+==============+=================+ +===========+======================+==============+=================+
| Node | flood if the level | flood if the | flood only if | | South | flood if the level | flood if the | flood only if |
| South TIE | of the originator | level of the | this node is | | Node TIE | of the originator | level of the | this node is |
| | is equal to this | originator | not ToF | | | is equal to this | originator | not ToF |
| | node | is higher | | | | node | is higher | |
| | | than this | | | | | than this | |
| | | node | | | | | node | |
+-----------+----------------------+--------------+-----------------+ +-----------+----------------------+--------------+-----------------+
| non-Node | flood self- | flood only | flood only if | | non-Node | flood self- | flood only | flood only if |
| South TIE | originated only | if the | it is self- | | South TIE | originated only | if the | it is self- |
| | | neighbor is | originated and | | | | neighbor is | originated and |
| | | the | this node is | | | | the | this node is |
| | | originator | not ToF | | | | originator | not ToF |
| | | of TIE | | | | | of TIE | |
+-----------+----------------------+--------------+-----------------+ +-----------+----------------------+--------------+-----------------+
| all North | never flood | flood always | flood only if | | all North | never flood | flood always | flood only if |
| TIEs | | | this node is | | TIEs | | | this node is |
| | | | ToF | | | | | ToF |
+-----------+----------------------+--------------+-----------------+ +-----------+----------------------+--------------+-----------------+
| TIDE | include at least | include at | if this node is | | TIDE | include at least | include at | if this node is |
| | all non-self- | least all | ToF, then | | | all non-self- | least all | ToF, then |
| | originated North | Node South | include all | | | originated North | South Node | include all |
| | TIE headers and | TIEs and all | North TIEs; | | | TIE headers and | TIEs and all | North TIEs; |
| | self-originated | South TIEs | otherwise, only | | | self-originated | South TIEs | otherwise, only |
| | South TIE headers | originated | include self- | | | South TIE headers | originated | include self- |
| | and Node South TIEs | by a peer | originated TIEs | | | and South Node TIEs | by a peer | originated TIEs |
| | of nodes at same | and all | | | | of nodes at same | and all | |
| | level | North TIEs | | | | level | North TIEs | |
+-----------+----------------------+--------------+-----------------+ +-----------+----------------------+--------------+-----------------+
| TIRE as | request all North | request all | if this node is | | TIRE as | request all North | request all | if this node is |
| Request | TIEs and all peer's | South TIEs | ToF, then apply | | Request | TIEs and all peer's | South TIEs | ToF, then apply |
| | self-originated | | north scope | | | self-originated | | north scope |
| | TIEs and all Node | | rules; | | | TIEs and all South | | rules; |
| | South TIEs | | otherwise, | | | Node TIEs | | otherwise, |
| | | | apply south | | | | | apply south |
| | | | scope rules | | | | | scope rules |
+-----------+----------------------+--------------+-----------------+ +-----------+----------------------+--------------+-----------------+
| TIRE as | Ack all received | Ack all | Ack all | | TIRE as | Ack all received | Ack all | Ack all |
| Ack | TIEs | received | received TIEs | | Ack | TIEs | received | received TIEs |
| | | TIEs | | | | | TIEs | |
+-----------+----------------------+--------------+-----------------+ +-----------+----------------------+--------------+-----------------+
Table 3: Normative Flooding Scopes Table 3: Normative Flooding Scopes
skipping to change at line 3039 skipping to change at line 3000
To illustrate these rules, consider using the topology in Figure 2, To illustrate these rules, consider using the topology in Figure 2,
with the optional link between spine 111 and spine 112, and the with the optional link between spine 111 and spine 112, and the
associated TIEs given in Figure 15. The flooding from particular associated TIEs given in Figure 15. The flooding from particular
nodes of the TIEs is given in Table 4. nodes of the TIEs is given in Table 4.
+============+==========+===========================================+ +============+==========+===========================================+
| Local | Neighbor | TIEs Flooded from Local to Neighbor Node | | Local | Neighbor | TIEs Flooded from Local to Neighbor Node |
| Node | Node | | | Node | Node | |
+============+==========+===========================================+ +============+==========+===========================================+
| Leaf111 | Spine | Leaf111 North TIEs, Spine 111 Node South | | Leaf111 | Spine | Leaf111 North TIEs, Spine 111 South Node |
| | 112 | TIE | | | 112 | TIE |
+------------+----------+-------------------------------------------+ +------------+----------+-------------------------------------------+
| Leaf111 | Spine | Leaf111 North TIEs, Spine 112 Node South | | Leaf111 | Spine | Leaf111 North TIEs, Spine 112 South Node |
| | 111 | TIE | | | 111 | TIE |
+------------+----------+-------------------------------------------+ +------------+----------+-------------------------------------------+
| ... | ... | ... | | ... | ... | ... |
+------------+----------+-------------------------------------------+ +------------+----------+-------------------------------------------+
| Spine | Leaf111 | Spine 111 South TIEs | | Spine | Leaf111 | Spine 111 South TIEs |
| 111 | | | | 111 | | |
+------------+----------+-------------------------------------------+ +------------+----------+-------------------------------------------+
| Spine | Leaf112 | Spine 111 South TIEs | | Spine | Leaf112 | Spine 111 South TIEs |
| 111 | | | | 111 | | |
+------------+----------+-------------------------------------------+ +------------+----------+-------------------------------------------+
| Spine | Spine | Spine 111 South TIEs | | Spine | Spine | Spine 111 South TIEs |
| 111 | 112 | | | 111 | 112 | |
+------------+----------+-------------------------------------------+ +------------+----------+-------------------------------------------+
| Spine | ToF 21 | Spine 111 North TIEs, Leaf111 North TIEs, | | Spine | ToF 21 | Spine 111 North TIEs, Leaf111 North TIEs, |
| 111 | | Leaf112 North TIEs, ToF 22 Node South TIE | | 111 | | Leaf112 North TIEs, ToF 22 South Node TIE |
+------------+----------+-------------------------------------------+ +------------+----------+-------------------------------------------+
| Spine | ToF 22 | Spine 111 North TIEs, Leaf111 North TIEs, | | Spine | ToF 22 | Spine 111 North TIEs, Leaf111 North TIEs, |
| 111 | | Leaf112 North TIEs, ToF 21 Node South TIE | | 111 | | Leaf112 North TIEs, ToF 21 South Node TIE |
+------------+----------+-------------------------------------------+ +------------+----------+-------------------------------------------+
| ... | ... | ... | | ... | ... | ... |
+------------+----------+-------------------------------------------+ +------------+----------+-------------------------------------------+
| ToF 21 | Spine | ToF 21 South TIEs | | ToF 21 | Spine | ToF 21 South TIEs |
| | 111 | | | | 111 | |
+------------+----------+-------------------------------------------+ +------------+----------+-------------------------------------------+
| ToF 21 | Spine | ToF 21 South TIEs | | ToF 21 | Spine | ToF 21 South TIEs |
| | 112 | | | | 112 | |
+------------+----------+-------------------------------------------+ +------------+----------+-------------------------------------------+
| ToF 21 | Spine | ToF 21 South TIEs | | ToF 21 | Spine | ToF 21 South TIEs |
skipping to change at line 3105 skipping to change at line 3066
guarantees correct behavior of algorithms like disaggregation or guarantees correct behavior of algorithms like disaggregation or
default route origination. Furthermore though, the use of this bit default route origination. Furthermore though, the use of this bit
presents an inherent trade-off between processing load and presents an inherent trade-off between processing load and
convergence speed since significantly slowing down flooding of convergence speed since significantly slowing down flooding of
northbound prefixes from neighbors for an extended time will lead to northbound prefixes from neighbors for an extended time will lead to
traffic losses. traffic losses.
6.3.6. Initial and Periodic Database Synchronization 6.3.6. Initial and Periodic Database Synchronization
The initial exchange of RIFT includes periodic TIDE exchanges that The initial exchange of RIFT includes periodic TIDE exchanges that
contain descriptions of the link state database and TIREs, which contain descriptions of the LSDB and TIREs, which perform the
perform the function of requesting unknown TIEs as well as confirming function of requesting unknown TIEs as well as confirming the
the reception of flooded TIEs. The content of TIDEs and TIREs is reception of flooded TIEs. The content of TIDEs and TIREs is
governed by Table 3. governed by Table 3.
6.3.7. Purging and Rollovers 6.3.7. Purging and Rollovers
When a node exits in the network, if "unpurged", residual stale TIEs When a node exits the network, if "unpurged", residual stale TIEs may
may exist in the network until their lifetimes expire (which in case exist in the network until their lifetimes expire (which in case of
of RIFT is by default a rather long period to prevent ongoing RIFT is by default a rather long period to prevent ongoing
reorigination of TIEs in very large topologies). RIFT does not have reorigination of TIEs in very large topologies). RIFT does not have
a "purging mechanism" based on sending specialized "purge" packets. a "purging mechanism" based on sending specialized "purge" packets.
In other routing protocols, such a mechanism has proven to be complex In other routing protocols, such a mechanism has proven to be complex
and fragile based on many years of experience. RIFT simply issues a and fragile based on many years of experience. RIFT simply issues a
new, i.e., higher sequence number, empty version of the TIE with a new, i.e., higher sequence number, empty version of the TIE with a
short lifetime given by the _purge_lifetime_ constant and relies on short lifetime given by the _purge_lifetime_ constant and relies on
each node to age out and delete each TIE copy independently. each node to age out and delete each TIE copy independently.
Abundant amounts of memory are available today, even on low-end Abundant amounts of memory are available today, even on low-end
platforms, and hence, keeping those relatively short-lived extra platforms, and hence, keeping those relatively short-lived extra
copies for a while is acceptable. The information will age out and, copies for a while is acceptable. The information will age out and,
skipping to change at line 3154 skipping to change at line 3115
propagation and processing delay by all the nodes that are within the propagation and processing delay by all the nodes that are within the
TIE's flooding scope. TIE's flooding scope.
TIE sequence numbers are rolled over using the method described in TIE sequence numbers are rolled over using the method described in
Appendix A . The first sequence number of any spontaneously Appendix A . The first sequence number of any spontaneously
originated TIE (i.e., not originated to override a detected older originated TIE (i.e., not originated to override a detected older
copy in the network) MUST be a reasonably unpredictable random number copy in the network) MUST be a reasonably unpredictable random number
(for example, [RFC4086]) in the interval [0, 2^30-1], which will (for example, [RFC4086]) in the interval [0, 2^30-1], which will
prevent otherwise identical TIE headers to remain "stuck" in the prevent otherwise identical TIE headers to remain "stuck" in the
network with content different from the TIE originated after reboot. network with content different from the TIE originated after reboot.
In traditional link-state protocols, this is delegated to a 16-bit In typical link-state protocols, this is delegated to a 16-bit
checksum on packet content. RIFT avoids this design due to the CPU checksum on packet content. RIFT avoids this design due to the CPU
burden presented by computation of such checksums and additional burden presented by computation of such checksums and additional
complications tied to the fact that the checksum must be "patched" complications tied to the fact that the checksum must be "patched"
into the packet after the generation of the content, which is a into the packet after the generation of the content, which is a
difficult proposition in binary, hand-crafted formats already and difficult proposition in binary, hand-crafted formats already and
highly incompatible with model-based, serialized formats. The highly incompatible with model-based, serialized formats. The
sequence number space is hence consciously chosen to be 64-bits wide sequence number space is hence consciously chosen to be 64-bits wide
to make the occurrence of a TIE with the same sequence number but to make the occurrence of a TIE with the same sequence number but
different content as much or even more unlikely than the checksum different content as much or even more unlikely than the checksum
method. To emulate the "checksum behavior", an implementation could method. To emulate the "checksum behavior", an implementation could
skipping to change at line 3180 skipping to change at line 3141
Under certain conditions, nodes issue a default route in their South Under certain conditions, nodes issue a default route in their South
Prefix TIEs with costs as computed in Section 6.8.7.1. Prefix TIEs with costs as computed in Section 6.8.7.1.
A node X that A node X that
1. is *not* overloaded *and* 1. is *not* overloaded *and*
2. has southbound or East-West adjacencies 2. has southbound or East-West adjacencies
SHOULD originate such a default route in its south prefix TIE if and SHOULD originate such a default route in its South Prefix TIE if and
only if only if
1. all other nodes at X's' level are overloaded, 1. all other nodes at X's level are overloaded *or*
2. all other nodes at X's' level have NO northbound adjacencies, 2. all other nodes at X's level have NO northbound adjacencies, *or*
*or*
3. X has computed reachability to a default route during N-SPF. 3. X has computed reachability to a default route during N-SPF.
The term "all other nodes at X's' level " obviously describes just The term "all other nodes at X's level" obviously describes just the
the nodes at the same level in the PoD with a viable lower level nodes at the same level in the PoD with a viable lower level
(otherwise, the Node South TIEs cannot be reflected; the nodes in PoD (otherwise, the South Node TIEs cannot be reflected; the nodes in PoD
1 and PoD 2 are "invisible" to each other). 1 and PoD 2 are "invisible" to each other).
A node originating a southbound default route SHOULD install a A node originating a southbound default route SHOULD install a
default discard route if it did not compute a default route during default discard route if it did not compute a default route during
N-SPF. This basically means that the top of the fabric will drop N-SPF. This basically means that the top of the fabric will drop
traffic for unreachable addresses. traffic for unreachable addresses.
6.3.9. Northbound TIE Flooding Reduction 6.3.9. Northbound TIE Flooding Reduction
RIFT chooses only a subset of northbound nodes to propagate flooding RIFT chooses only a subset of northbound nodes to propagate flooding
skipping to change at line 3258 skipping to change at line 3218
In a fully connected Clos network, this means that a node selects one In a fully connected Clos network, this means that a node selects one
arbitrary parent as the FR and then a second one for redundancy. The arbitrary parent as the FR and then a second one for redundancy. The
computation can be relatively simple and completely distributed computation can be relatively simple and completely distributed
without any need for synchronization among nodes. In a "PoD" without any need for synchronization among nodes. In a "PoD"
structure, where the level L+2 is partitioned into silos of structure, where the level L+2 is partitioned into silos of
equivalent grandparents that are only reachable from respective equivalent grandparents that are only reachable from respective
parents, this means treating each silo as a fully connected Clos parents, this means treating each silo as a fully connected Clos
network and solving the problem within the silo. network and solving the problem within the silo.
In terms of signaling, a node has enough information to select its In terms of signaling, a node has enough information to select its
set of FRs; this information is derived from the node's parents' Node set of FRs; this information is derived from the node's parents'
South TIEs, which indicate the parent's reachable northbound South Node TIEs, which indicate the parent's reachable northbound
adjacencies to its own parents (the node's grandparents). A node may adjacencies to its own parents (the node's grandparents). A node may
send a LIE to a northbound neighbor with the optional boolean field send a LIE to a northbound neighbor with the optional boolean field
_you_are_flood_repeater_ set to false to indicate that the northbound _you_are_flood_repeater_ set to false to indicate that the northbound
neighbor is not a flood repeater for the node that sent the LIE. In neighbor is not a flood repeater for the node that sent the LIE. In
that case, the northbound neighbor SHOULD NOT reflood northbound TIEs that case, the northbound neighbor SHOULD NOT reflood northbound TIEs
received from the node that sent the LIE. If received from the node that sent the LIE. If
_you_are_flood_repeater_ is absent or _you_are_flood_repeater_ is set _you_are_flood_repeater_ is absent or _you_are_flood_repeater_ is set
to true, then the northbound neighbor is a flood repeater for the to true, then the northbound neighbor is a flood repeater for the
node that sent the LIE and MUST reflood northbound TIEs received from node that sent the LIE and MUST reflood northbound TIEs received from
that node. The element _you_are_flood_repeater_ MUST be ignored if that node. The element _you_are_flood_repeater_ MUST be ignored if
skipping to change at line 3299 skipping to change at line 3259
bidirectionally reachable over adjacency ADJ(N, P); bidirectionally reachable over adjacency ADJ(N, P);
* let G be a grandparent node of N, reachable transitively via a * let G be a grandparent node of N, reachable transitively via a
parent P over adjacencies ADJ(N, P) and ADJ(P, G). Observe that N parent P over adjacencies ADJ(N, P) and ADJ(P, G). Observe that N
does not have enough information to check bidirectional does not have enough information to check bidirectional
reachability of ADJ(P, G); reachability of ADJ(P, G);
* let R be a redundancy constant integer; a value of 2 or higher for * let R be a redundancy constant integer; a value of 2 or higher for
R is RECOMMENDED; R is RECOMMENDED;
* let S be a similarly constant integer; a value in range 0 .. 2 for * let S be a similarity constant integer; a value in range 0 .. 2
S is RECOMMENDED, and the value of 1 SHOULD be used. Two for S is RECOMMENDED, and the value of 1 SHOULD be used. Two
cardinalities are considered as equivalent if their absolute cardinalities are considered as equivalent if their absolute
difference is less than or equal to S, i.e., |a-b|<=S; and difference is less than or equal to S, i.e., |a-b|<=S
* let RND be a 64-bit random number (for example, as described in * let RND be a 64-bit random number (for example, as described in
[RFC4086]) generated by the system once on startup. [RFC4086]) generated by the system once on startup.
The algorithm consists of the following steps: The algorithm consists of the following steps:
1. Derive a 64-bit number by XORing N's System ID with RND. 1. Derive a 64-bit number by XORing N's System ID with RND.
2. Derive a 16-bit pseudo-random unsigned integer PR(N) from the 2. Derive a 16-bit pseudo-random unsigned integer PR(N) from the
resulting 64-bit number by splitting it into 16-bit-long words resulting 64-bit number by splitting it into 16-bit-long words
W1, W2, W3, W4 (where W1 are the least significant 16 bits of the W1, W2, W3, W4 (where W1 are the least significant 16 bits of the
64-bit number, and W4 are the most significant 16 bits) and then 64-bit number, and W4 are the most significant 16 bits) and then
XORing the circularly shifted resulting words together: XORing the circularly shifted resulting words together:
(W1<<1) xor (W2<<2) xor (W3<<3) xor (W4<<4); where << is the A. (W1<<1) xor (W2<<2) xor (W3<<3) xor (W4<<4);
circular shift operator.
where << is the circular shift operator.
3. Sort the parents by decreasing number of northbound adjacencies 3. Sort the parents by decreasing number of northbound adjacencies
(using decreasing System ID of the parent as a tie-breaker): (using decreasing System ID of the parent as a tie-breaker):
sort |P(N) by decreasing CN(P), for all P in |P(N), as the sort |P(N) by decreasing CN(P), for all P in |P(N), as the
ordered array |A(N) ordered array |A(N)
4. Partition |A(N) in subarrays |A_k(N) of parents with equivalent 4. Partition |A(N) in subarrays |A_k(N) of parents with equivalent
cardinality of northbound adjacencies (in other words, with cardinality of northbound adjacencies (in other words, with
equivalent number of grandparents they can reach): equivalent number of grandparents they can reach):
a. set k=0; // k is the ID of the subarray a. set k=0; // k is the ID of the subarray
b. set i=0; b. set i=0;
c. while i < CN(N) do the following: c. while i < CN(N) do
i. set j=i; i. set j=i;
ii. while i < CN(N) and CN(|A(N)[j]) - CN(|A(N)[i]) <= S: ii. while i < CN(N) and CN(|A(N)[j]) - CN(|A(N)[i]) <= S:
1. place |A(N)[i] in |A_k(N) // abstract action, maybe 1. place |A(N)[i] in |A_k(N) // abstract action, maybe
noop noop
2. set i=i+1; 2. set i=i+1;
iii. /* At this point, j is the index in |A(N) of the first iii. /* At this point, j is the index in |A(N) of the first
member of |A_k(N) and (i-j) is C_k(N) defined as the member of |A_k(N) and (i-j) is C_k(N) defined as the
cardinality of |A_k(N). */ cardinality of |A_k(N). */
set k=k+1. set k=k+1;
/* At this point, k is the total number of subarrays, initialized /* At this point, k is the total number of subarrays, initialized
for the shuffling operation below. */ for the shuffling operation below. */
5. Shuffle each subarrays |A_k(N) of cardinality C_k(N) within |A(N) 5. Shuffle each subarrays |A_k(N) of cardinality C_k(N) within |A(N)
individually using the Durstenfeld variation of the Fisher-Yates individually using the Durstenfeld variation of the Fisher-Yates
algorithm that depends on N's System ID: algorithm that depends on N's System ID:
a. while k > 0 do the following: a. while k > 0 do
i. for i from C_k(N)-1 to 1 decrementing by 1, do the i. for i from C_k(N)-1 to 1 decrementing by 1 do
following:
1. set j to PR(N) modulo i; 1. set j to PR(N) modulo i;
2. exchange |A_k[j] and |A_k[i]; 2. exchange |A_k[j] and |A_k[i];
ii. set k=k-1. ii. set k=k-1;
6. For each grandparent G, initialize a counter c(G) with the number 6. For each grandparent G, initialize a counter c(G) with the number
of its southbound adjacencies to elected flood repeaters (which of its southbound adjacencies to elected flood repeaters (which
is initially zero): is initially zero):
a. for each G in |G(N), set c(G) = 0. a. for each G in |G(N), set c(G) = 0;
7. Finally, only keep FRs as parents that are needed to maintain the 7. Finally, only keep FRs as parents that are needed to maintain the
number of adjacencies between the FRs and any grandparent G equal number of adjacencies between the FRs and any grandparent G equal
or above the redundancy constant R: or above the redundancy constant R:
a. for each P in reshuffled |A(N): a. for each P in reshuffled |A(N):
i. if there exists an adjacency ADJ(P, G) in |NA(P) such i. if there exists an adjacency ADJ(P, G) in |NA(P) such
that c(G) < R, then that c(G) < R, then
skipping to change at line 3426 skipping to change at line 3386
Item 6. Item 6.
5. The indication of flood reduction capability MUST be carried in 5. The indication of flood reduction capability MUST be carried in
the Node TIEs in the _flood_reduction_ element and MAY be used to the Node TIEs in the _flood_reduction_ element and MAY be used to
optimize the algorithm to account for nodes that will flood optimize the algorithm to account for nodes that will flood
regardless. regardless.
6. A node generates TIDEs as usual, but when receiving TIREs or 6. A node generates TIDEs as usual, but when receiving TIREs or
TIDEs resulting in requests for a TIE of which the newest TIDEs resulting in requests for a TIE of which the newest
received copy came on an adjacency where the node was not a flood received copy came on an adjacency where the node was not a flood
repeater, it SHOULD ignore such requests on first and only first repeater, it SHOULD ignore such requests on only the first
request. Normally, the nodes that received the TIEs as flooding request. Normally, the nodes that received the TIEs as flooding
repeaters should satisfy the requesting node and, with that, no repeaters should satisfy the requesting node and, with that, no
further TIREs for such TIEs will be generated. Otherwise, the further TIREs for such TIEs will be generated. Otherwise, the
next set of TIDEs and TIREs MUST lead to flooding independent of next set of TIDEs and TIREs MUST lead to flooding independent of
the flood repeater status. This solves a very difficult "incast" the flood repeater status. This solves a very difficult "incast"
problem on nodes restarting with a very wide fanout, especially problem on nodes restarting with a very wide fanout, especially
northbound. To retrieve the full database, they often end up northbound. To retrieve the full database, they often end up
processing many inrushing copies, whereas this approach load processing many inrushing copies, whereas this approach load
balances the incoming database between adjacent nodes and flood balances the incoming database between adjacent nodes and flood
repeaters and should guarantee that two copies are sent by repeaters and should guarantee that two copies are sent by
skipping to change at line 3521 skipping to change at line 3481
Prefixes are carried in different types of TIEs indicating their Prefixes are carried in different types of TIEs indicating their
type. For the same prefix being included in different TIE types, type. For the same prefix being included in different TIE types,
tie-breaking is performed according to Section 6.8.1. If the same tie-breaking is performed according to Section 6.8.1. If the same
prefix is included multiple times in multiple TIEs of the same type prefix is included multiple times in multiple TIEs of the same type
originating at the same node, the resulting behavior is unspecified. originating at the same node, the resulting behavior is unspecified.
6.4.1. Northbound Reachability SPF 6.4.1. Northbound Reachability SPF
N-SPF MUST use exclusively northbound and East-West adjacencies in N-SPF MUST use exclusively northbound and East-West adjacencies in
the computing node's node North TIEs (since if the node is a leaf, it the computing node's North Node TIEs (since if the node is a leaf, it
may not have generated a Node South TIE) when starting SPF. Observe may not have generated a South Node TIE) when starting SPF. Observe
that N-SPF is really just a one-hop variety since Node South TIEs are that N-SPF is really just a one-hop variety since South Node TIEs are
not reflooded southbound beyond a single level (or East-West), and not reflooded southbound beyond a single level (or East-West), and
with that, the computation cannot progress beyond adjacent nodes. with that, the computation cannot progress beyond adjacent nodes.
Once progressing, the computation uses the next higher level's Node Once progressing, the computation uses the next higher level's South
South TIEs to find corresponding adjacencies to verify backlink Node TIEs to find corresponding adjacencies to verify backlink
connectivity. Two unidirectional links MUST be associated to confirm connectivity. Two unidirectional links MUST be associated to confirm
bidirectional connectivity, a process often known as "backlink bidirectional connectivity, a process often known as "backlink
check". As part of the check, both Node TIEs MUST contain the check". As part of the check, both Node TIEs MUST contain the
correct System IDs *and* expected levels. correct System IDs *and* expected levels.
The default route found when crossing an E-W link SHOULD be used if The default route found when crossing an E-W link SHOULD be used if
and only if: and only if:
1. the node itself does *not* have any northbound adjacencies *and* 1. the node itself does *not* have any northbound adjacencies *and*
skipping to change at line 3565 skipping to change at line 3525
That is, the E-W link can be used as a gateway of last resort for a That is, the E-W link can be used as a gateway of last resort for a
specific prefix only. Using south prefixes across an E-W link can be specific prefix only. Using south prefixes across an E-W link can be
beneficial, e.g., on automatic disaggregation in pathological fabric beneficial, e.g., on automatic disaggregation in pathological fabric
partitioning scenarios. partitioning scenarios.
A detailed example can be found in Appendix B.4. A detailed example can be found in Appendix B.4.
6.4.2. Southbound Reachability SPF 6.4.2. Southbound Reachability SPF
S-SPF MUST use the southbound adjacencies in the Node South TIEs S-SPF MUST use the southbound adjacencies in the South Node TIEs
exclusively, i.e., progresses towards nodes at lower levels. Observe exclusively, i.e., progresses towards nodes at lower levels. Observe
that E-W adjacencies are NEVER used in this computation. This that E-W adjacencies are NEVER used in this computation. This
enforces the requirement that a packet traversing in a southbound enforces the requirement that a packet traversing in a southbound
direction must never change its direction. direction must never change its direction.
S-SPF MUST use northbound adjacencies in node North TIEs to verify S-SPF MUST use northbound adjacencies in North Node TIEs to verify
backlink connectivity by checking for the presence of the link beside backlink connectivity by checking for the presence of the link beside
the correct System ID and level. the correct System ID and level.
6.4.3. East-West Forwarding Within a Non-ToF Level 6.4.3. East-West Forwarding Within a Non-ToF Level
Using south prefixes over horizontal links MAY occur if the N-SPF Using south prefixes over horizontal links MAY occur if the N-SPF
includes East-West adjacencies in computation. It can protect includes East-West adjacencies in computation. It can protect
against pathological fabric partitioning cases that leave only paths against pathological fabric partitioning cases that leave only paths
to destinations that would necessitate multiple changes of the to destinations that would necessitate multiple changes of forwarding
forwarding direction between north and south. direction between north and south.
6.4.4. East-West Links Within a ToF Level 6.4.4. East-West Links Within a ToF Level
E-W ToF links behave in terms of flooding scopes defined in E-W ToF links behave in terms of flooding scopes defined in
Section 6.3.4 like northbound links and MUST be used exclusively for Section 6.3.4 like northbound links and MUST be used exclusively for
control plane information flooding. Even though a ToF node could be control plane information flooding. Even though a ToF node could be
tempted to use those links during southbound SPF and carry traffic tempted to use those links during southbound SPF and carry traffic
over them, this MUST NOT be attempted since it may, in anycast cases, over them, this MUST NOT be attempted since it may, in anycast cases,
lead to routing loops. An implementation MAY try to resolve the lead to routing loops. An implementation MAY try to resolve the
looping problem by following on the ring strictly tie-broken looping problem by following on the ring strictly tie-broken
skipping to change at line 3628 skipping to change at line 3588
node or link failures can lead to several independent instances of node or link failures can lead to several independent instances of
positive disaggregation necessary to prevent looping or bow-tying the positive disaggregation necessary to prevent looping or bow-tying the
fabric. fabric.
A node determines the set of prefixes needing disaggregation using A node determines the set of prefixes needing disaggregation using
the following steps: the following steps:
1. A DAG computation in the southern direction is performed first. 1. A DAG computation in the southern direction is performed first.
The North TIEs are used to find all of the prefixes it can reach The North TIEs are used to find all of the prefixes it can reach
and the set of next hops in the lower level for each of them. and the set of next hops in the lower level for each of them.
Such a computation can be easily performed on a Fat Tree by Such a computation can be easily performed on a fat tree by
setting all link costs in the southern direction to 1 and all setting all link costs in the southern direction to 1 and all
northern directions to infinity. The set of those prefixes is northern directions to infinity. The set of those prefixes is
referred to as |R; for each prefix r in |R, its set of next hops referred to as |R; for each prefix r in |R, its set of next hops
is |H(r). is referred to as |H(r).
2. The node uses reflected South TIEs to find all nodes at the same 2. The node uses reflected South TIEs to find all nodes at the same
level in the same PoD and the set of southbound adjacencies for level in the same PoD and the set of southbound adjacencies for
each. The set of nodes at the same level is termed |N, and for each. The set of nodes at the same level is termed |N, and for
each node, n, in |N, its set of southbound adjacencies is defined each node, n, in |N, its set of southbound adjacencies is defined
to be |A(n). to be |A(n).
3. For a given r, if the intersection of |H(r) and |A(n), for any n, 3. For a given r, if the intersection of |H(r) and |A(n), for any n,
is empty, then that prefix r must be explicitly advertised by the is empty, then that prefix r must be explicitly advertised by the
node in a South TIE. node in a South TIE.
skipping to change at line 3741 skipping to change at line 3701
the algorithms to keep them more tractable: the algorithms to keep them more tractable:
1. All neighbor relationships MUST perform backlink checks. 1. All neighbor relationships MUST perform backlink checks.
2. The overload flag as introduced in Section 6.8.2 and carried in 2. The overload flag as introduced in Section 6.8.2 and carried in
the _overload_ schema element has to be respected during the the _overload_ schema element has to be respected during the
computation. Nodes advertising themselves as overloaded MUST NOT computation. Nodes advertising themselves as overloaded MUST NOT
be transited in reachability computation but MUST be used as be transited in reachability computation but MUST be used as
terminal nodes with prefixes they advertise being reachable. terminal nodes with prefixes they advertise being reachable.
3. All the lower-level nodes are flooded to the same disaggregated 3. All the lower-level nodes are flooded the same disaggregated
prefixes since RIFT does not build a South TIE per node, which prefixes since RIFT does not build a South TIE per node, which
would complicate things unnecessarily. The lower-level node that would complicate things unnecessarily. The lower-level node that
can compute a southbound route to the prefix will prefer it to can compute a southbound route to the prefix will prefer it to
the disaggregated route anyway based on route preference rules. the disaggregated route anyway based on route preference rules.
4. Positively disaggregated prefixes do *not* have to propagate to 4. Positively disaggregated prefixes do *not* have to propagate to
lower levels. With that, the disturbance in terms of new lower levels. With that, the disturbance in terms of new
flooding is contained to a single level experiencing failures. flooding is contained to a single level experiencing failures.
5. Disaggregated Prefix South TIEs are not "reflected" by the lower 5. Disaggregated South Prefix TIEs are not "reflected" by the lower
level. Nodes within the same level do *not* need to be aware of level. Nodes within the same level do *not* need to be aware of
which node computed the need for disaggregation. which node computed the need for disaggregation.
6. The fabric is still supporting maximum load balancing properties 6. The fabric is still supporting maximum load balancing properties
while not trying to send traffic northbound unless necessary. while not trying to send traffic northbound unless necessary.
In case positive disaggregation is triggered and due to the very In case positive disaggregation is triggered and due to the very
stable but unsynchronized nature of the algorithm, the nodes may stable but unsynchronized nature of the algorithm, the nodes may
issue the necessary disaggregated prefixes at different points in issue the necessary disaggregated prefixes at different points in
time. For a short time, this can lead to an "incast" behavior where time. For a short time, this can lead to an "incast" behavior where
the first advertising router based on the nature of the longest the first advertising router based on the nature of the longest
prefix match will attract all the traffic. Different implementation prefix match will attract all the traffic. Different implementation
strategies can be used to lessen that effect, but those are outside strategies can be used to lessen that effect, but those are outside
the scope of this specification. the scope of this specification.
It is worth observing that, in a single plane ToF, this It is worth observing that, in a single-plane ToF, this
disaggregation prevents traffic loss up to (K_LEAF * P) link failures disaggregation prevents traffic loss up to (K_LEAF * P) link failures
in terms of Section 5.2 or, in other terms, it takes at minimum that in terms of Section 5.2 or, in other terms, it takes at minimum that
many link failures to partition the ToF into multiple planes. many link failures to partition the ToF into multiple planes.
6.5.2. Negative, Transitive Disaggregation for Fallen Leaves 6.5.2. Negative, Transitive Disaggregation for Fallen Leaves
As explained in Section 5.3, failures in multi-plane ToF or more than As explained in Section 5.3, failures in multi-plane ToF or more than
(K_LEAF * P) links failing in single plane design can generate fallen (K_LEAF * P) links failing in single-plane design can generate fallen
leaves. Such scenario cannot be addressed by positive disaggregation leaves. Such scenario cannot be addressed by positive disaggregation
only and needs a further mechanism. only and needs a further mechanism.
6.5.2.1. Cabling of Multiple ToF Planes 6.5.2.1. Cabling of Multiple ToF Planes
Returning in this section to designs with multiple planes as shown Returning in this section to designs with multiple planes as shown
originally in Figure 3, Figure 18 highlights how the ToF is cabled in originally in Figure 3, Figure 18 highlights how the ToF is cabled in
case of two planes by the means of dual-rings to distribute all the case of two planes by the means of dual-rings to distribute all the
North TIEs within both planes. North TIEs within both planes.
____________________________________________________________________________ _______________________________________________________________________
| [Plane A] . [Plane B] . [Plane C] . [Plane D] | | [Plane A] . [Plane B] . [Plane C] . [Plane D] |
|..........................................................................| |.....................................................................|
| +-------------------------------------------------------------+ | | +------------------------------------------------------------+ |
| | +---+ . +---+ . +---+ . +---+ | | | | +---+ . +---+ . +---+ . +---+ | |
| +-+ n +-------------+ n +-------------+ n +-------------+ n +-+ | | +-+ n +-------------+ n +-------------+ n +------------+ n +-+ |
| +--++ . +-+++ . +-+++ . +--++ | | +--++ . +-+++ . +-+++ . +--++ |
| || . || . || . || | | || . || . || . || |
| +---------||---------------||----------------||---------------+ || | | +---------||---------------||----------------||--------------+ || |
| | +---+ || . +---+ || . +---+ || . +---+ | || | | | +---+ || . +---+ || . +---+ || . +---+ | || |
| +-+ 1 +---||--------+ 1 +--||---------+ 1 +--||---------+ 1 +-+ || | | +-+ 1 +---||--------+ 1 +--||---------+ 1 +--||--------+ 1 +-+ || |
| +--++ || . +-+++ || . +-+++ || . +-+++ || | | +--++ || . +-+++ || . +-+++ || . +-+++ || |
| || || . || || . || || . || || | | || || . || || . || || . || || |
| || || . || || . || || . || || | | || || . || || . || || . || || |
Figure 18: Topologically Connected Planes Figure 18: Topologically Connected Planes
Section 5.3 already describes how failures in multi-plane fabrics can Section 5.3 already describes how failures in multi-plane fabrics can
lead to traffic loss that normal positive disaggregation cannot fix. lead to traffic loss that normal positive disaggregation cannot fix.
The mechanism of negative, transitive disaggregation incorporated in The mechanism of negative, transitive disaggregation incorporated in
RIFT provides the corresponding solution, and the next section RIFT provides the corresponding solution, and the next section
explains the involved mechanisms in more detail. explains the involved mechanisms in more detail.
6.5.2.2. Transitive Advertisement of Negative Disaggregates 6.5.2.2. Transitive Advertisement of Negative Disaggregates
A ToF node discovering that it cannot reach a fallen leaf SHOULD A ToF node discovering that it cannot reach a fallen leaf SHOULD
disaggregate all the prefixes of that leaf. For that purpose, it disaggregate all the prefixes of that leaf. For that purpose, it
uses negative prefix South TIEs that are, as usual, flooded uses negative South Prefix TIEs that are, as usual, flooded
southwards with the scope defined in Section 6.3.4. southwards with the scope defined in Section 6.3.4.
Transitively, a node explicitly loses connectivity to a prefix when Transitively, a node explicitly loses connectivity to a prefix when
none of its children advertises it and when the prefix is negatively none of its children advertises it and when the prefix is negatively
disaggregated by all of its parents. When that happens, the node disaggregated by all of its parents. When that happens, the node
originates the negative prefix further down south. Since the originates the negative prefix further down south. Since the
mechanism applies recursively south, the negative prefix may mechanism applies recursively south, the negative prefix may
propagate transitively all the way down to the leaf. This is propagate transitively all the way down to the leaf. This is
necessary since leaves connected to multiple planes by means of necessary since leaves connected to multiple planes by means of
disjointed paths may have to choose the correct plane at the very disjointed paths may have to choose the correct plane at the very
skipping to change at line 3837 skipping to change at line 3797
When connectivity is restored, a node that disaggregated a prefix When connectivity is restored, a node that disaggregated a prefix
withdraws the negative disaggregation by the usual mechanism of re- withdraws the negative disaggregation by the usual mechanism of re-
advertising TIEs omitting the negative prefix. advertising TIEs omitting the negative prefix.
6.5.2.3. Computation of Negative Disaggregates 6.5.2.3. Computation of Negative Disaggregates
Negative prefixes can in fact be advertised due to two different Negative prefixes can in fact be advertised due to two different
triggers. This will be described consecutively. triggers. This will be described consecutively.
The first origination reason is a computation that uses all the node The first origination reason is a computation that uses all the North
North TIEs to build the set of all reachable nodes by reachability Node TIEs to build the set of all reachable nodes by reachability
computation over the complete graph, including horizontal ToF links. computation over the complete graph, including horizontal ToF links.
The computation uses the node itself as the root. This is compared The computation uses the node itself as the root. This is compared
with the result of the normal southbound SPF as described in with the result of the normal southbound SPF as described in
Section 6.4.2. The differences are the fallen leaves and all their Section 6.4.2. The differences are the fallen leaves and all their
attached prefixes are advertised as negative prefixes southbound if attached prefixes are advertised as negative prefixes southbound if
the node does not consider the prefix to be reachable within the the node does not consider the prefix to be reachable within the
southbound SPF. southbound SPF.
The second origination reason hinges on the understanding of how the The second origination reason hinges on the understanding of how the
negative prefixes are used within the computation as described in negative prefixes are used within the computation as described in
skipping to change at line 3875 skipping to change at line 3835
that node's next-hop set and a distance equal to the prefix's cost that node's next-hop set and a distance equal to the prefix's cost
plus the node's minimized path distance. The RIFT route database, a plus the node's minimized path distance. The RIFT route database, a
set of (prefix, prefix-type, attributes, path_distance, next-hop set of (prefix, prefix-type, attributes, path_distance, next-hop
set), accumulates these results. set), accumulates these results.
N-SPF prefixes from each South TIE need to also be added to the RIFT N-SPF prefixes from each South TIE need to also be added to the RIFT
route database. The N-SPF is really just a stub so the computing route database. The N-SPF is really just a stub so the computing
node simply needs to determine, for each prefix in a South TIE that node simply needs to determine, for each prefix in a South TIE that
originated from adjacent node, what next hops to use to reach that originated from adjacent node, what next hops to use to reach that
node. Since there may be parallel links, the next hops to use can be node. Since there may be parallel links, the next hops to use can be
a set; the presence of the computing node in the associated Node a set; the presence of the computing node in the associated South
South TIE is sufficient to verify that at least one link has Node TIE is sufficient to verify that at least one link has
bidirectional connectivity. The set of minimum cost next hops from bidirectional connectivity. The set of minimum cost next hops from
the computing node X to the originating adjacent node is determined. the computing node X to the originating adjacent node is determined.
Each prefix has its cost adjusted before being added into the RIFT Each prefix has its cost adjusted before being added into the RIFT
route database. The cost of the prefix is set to the cost received route database. The cost of the prefix is set to the cost received
plus the cost of the minimum distance next hop to that neighbor while plus the cost of the minimum distance next hop to that neighbor while
considering its attributes such as mobility per Section 6.8.4. Then considering its attributes such as mobility per Section 6.8.4. Then
each prefix can be added into the RIFT route database with the next- each prefix can be added into the RIFT route database with the next-
hop set; ties are broken based upon type first and then distance and hop set; ties are broken based upon type first and then distance and
further on _PrefixAttributes_. Only the best combination is used for further on _PrefixAttributes_. Only the best combination is used for
skipping to change at line 3930 skipping to change at line 3890
end for end for
end for end for
Figure 19: Adding Routes from South TIE Positive and Negative Figure 19: Adding Routes from South TIE Positive and Negative
Prefixes Prefixes
After the positive prefixes are attached and tie-broken, negative After the positive prefixes are attached and tie-broken, negative
prefixes are attached and used in case of northbound computation, prefixes are attached and used in case of northbound computation,
ideally from the shortest length to the longest. The next-hop ideally from the shortest length to the longest. The next-hop
adjacencies for a negative prefix are inherited from the longest adjacencies for a negative prefix are inherited from the longest
positive prefix that aggregates it, and subsequently adjacencies to positive prefix that aggregates it; subsequently, adjacencies to
nodes that advertised negative for this prefix are removed. nodes that advertised negative disaggregation for this prefix are
removed.
The rule of inheritance MUST be maintained when the next-hop list for The rule of inheritance MUST be maintained when the next-hop list for
a prefix is modified, as the modification may affect the entries for a prefix is modified, as the modification may affect the entries for
matching negative prefixes of immediate longer prefix length. For matching negative prefixes of immediate longer prefix length. For
instance, if a next hop is added, then by inheritance, it must be instance, if a next hop is added, then by inheritance, it must be
added to all the negative routes of immediate longer prefixes length added to all the negative routes of immediate longer prefixes length
unless it is pruned due to a negative advertisement for the same next unless it is pruned due to a negative advertisement for the same next
hop. Similarly, if a next hop is deleted for a given prefix, then it hop. Similarly, if a next hop is deleted for a given prefix, then it
is deleted for all the immediately aggregated negative routes. This is deleted for all the immediately aggregated negative routes. This
will recurse in the case of nested negative prefix aggregations. will recurse in the case of nested negative prefix aggregations.
skipping to change at line 4199 skipping to change at line 4160
+---> | Via S4 | +---> | Via S4 | +---> | Via S4 | +---> | Via S4 | +---> | Via S4 | +---> | Via S4 |
+--------+ +--------+ +--------+ +--------+ +--------+ +--------+
Figure 27: Abstract FIB After Negative 2001:db8:2::/48 from S4 Figure 27: Abstract FIB After Negative 2001:db8:2::/48 from S4
6.7. Optional Zero Touch Provisioning (RIFT ZTP) 6.7. Optional Zero Touch Provisioning (RIFT ZTP)
Each RIFT node can operate in Zero Touch Provisioning (ZTP) mode, Each RIFT node can operate in Zero Touch Provisioning (ZTP) mode,
i.e., it has no RIFT-specific configuration (unless it is a ToF or it i.e., it has no RIFT-specific configuration (unless it is a ToF or it
is explicitly configured to operate in the overall topology as a leaf is explicitly configured to operate in the overall topology as a leaf
and/or support leaf-to-leaf procedures), and it will fully, and/or support L2L procedures), and it will fully, automatically
automatically derive necessary RIFT parameters itself after being derive necessary RIFT parameters itself after being attached to the
attached to the topology. Manually configured nodes and nodes topology. Manually configured nodes and nodes operating using RIFT
operating using RIFT ZTP can be mixed freely and will form a valid ZTP can be mixed freely and will form a valid topology if achievable.
topology if achievable.
The derivation of the level of each node happens based on offers The derivation of the level of each node happens based on offers
received from its neighbors, whereas each node (with the possible received from its neighbors, whereas each node (with the possible
exception of nodes configured as leaves) tries to attach at the exception of nodes configured as leaves) tries to attach at the
highest possible point in the fabric. This guarantees that even if highest possible point in the fabric. This guarantees that even if
the diffusion front of offers reaches a node from "below" faster than the diffusion front of offers reaches a node from "below" faster than
from "above", it will greedily abandon an already negotiated level from "above", it will greedily abandon an already negotiated level
derived from nodes topologically below it and properly peer with derived from nodes topologically below it and properly peer with
nodes above. nodes above.
skipping to change at line 4393 skipping to change at line 4353
1. It advertises its LEVEL_VALUE on all LIEs (observe that this can 1. It advertises its LEVEL_VALUE on all LIEs (observe that this can
be UNDEFINED_LEVEL, which in terms of the schema, is simply an be UNDEFINED_LEVEL, which in terms of the schema, is simply an
omitted optional value). omitted optional value).
2. It computes HAL as the numerically highest available level in all 2. It computes HAL as the numerically highest available level in all
VOLs. VOLs.
3. Then, it chooses MAX(HAL-1,0) as its DERIVED_LEVEL. The node 3. Then, it chooses MAX(HAL-1,0) as its DERIVED_LEVEL. The node
then starts to advertise this derived level. then starts to advertise this derived level.
4. A node that lost all adjacencies with the HAL value MUST hold 4. A node that lost all adjacencies with the HAL value MUST holddown
down computation of the new DERIVED_LEVEL for at least one second computation of the new DERIVED_LEVEL for at least one second
unless it has no VOLs from southbound adjacencies. After the unless it has no VOLs from southbound adjacencies. After the
holddown timer expired, it MUST discard all received offers, holddown timer expired, it MUST discard all received offers,
recompute DERIVED_LEVEL, and announce it to all neighbors. recompute DERIVED_LEVEL, and announce it to all neighbors.
5. A node MUST reset any adjacency that has changed the level it is 5. A node MUST reset any adjacency that has changed the level it is
offering and is in _ThreeWay_ state. offering and is in _ThreeWay_ state.
6. A node that changed its defined level value MUST re-advertise its 6. A node that changed its defined level value MUST re-advertise its
own TIEs (since the new _PacketHeader_ will contain a different own TIEs (since the new _PacketHeader_ will contain a different
level than before). The sequence number of each TIE MUST be level than before). The sequence number of each TIE MUST be
increased. increased.
7. After a level has been derived, the node MUST set the 7. After a level has been derived, the node MUST set the
_not_a_ztp_offer_ on LIEs towards all systems offering a VOL for _not_a_ztp_offer_ on LIEs towards all systems offering a VOL for
HAL. HAL.
8. A node that changed its level SHOULD flush TIEs of all other 8. A node that changed its level SHOULD flush TIEs of all other
nodes from its link state database; otherwise, stale information nodes from its LSDB; otherwise, stale information may persist on
may persist on "direction reversal", i.e., nodes that seemed "direction reversal", i.e., nodes that seemed south are now north
south are now north or east-west. This will not prevent the or east-west. This will not prevent the correct operation of the
correct operation of the protocol but could be slightly confusing protocol but could be slightly confusing operationally.
operationally.
A node starting with LEVEL_VALUE being 0 (i.e., it assumes a leaf A node starting with LEVEL_VALUE being 0 (i.e., it assumes a leaf
function by being configured with the appropriate flags or has a function by being configured with the appropriate flags or has a
CONFIGURED_LEVEL of 0) MUST follow this additional procedure: CONFIGURED_LEVEL of 0) MUST follow this additional procedure:
1. It computes HAT per the procedures above but does *not* use it to 1. It computes HAT per the procedures above but does *not* use it to
compute DERIVED_LEVEL. HAT is used to limit adjacency formation compute DERIVED_LEVEL. HAT is used to limit adjacency formation
per Section 6.2. per Section 6.2.
It MAY also follow this modified procedure: It MAY also follow this modified procedure:
skipping to change at line 4879 skipping to change at line 4838
optional sequence number field. In case of a negatively distributed optional sequence number field. In case of a negatively distributed
prefix, this attribute MUST NOT be included by the originator and it prefix, this attribute MUST NOT be included by the originator and it
MUST be ignored by all nodes during computation. When this attribute MUST be ignored by all nodes during computation. When this attribute
is present (observe that per data schema, the attribute itself is is present (observe that per data schema, the attribute itself is
optional, but in case it is included, the "timestamp" field is optional, but in case it is included, the "timestamp" field is
required): required):
* The leaf node MAY advertise a timestamp of the latest sighting of * The leaf node MAY advertise a timestamp of the latest sighting of
a prefix, e.g., by snooping IP protocols or the node using the a prefix, e.g., by snooping IP protocols or the node using the
time at which it advertised the prefix. RIFT transports the time at which it advertised the prefix. RIFT transports the
timestamp within the desired Prefix North TIEs as the timestamp within the desired North Prefix TIEs as the
[IEEEstd1588] timestamp. [IEEEstd1588] timestamp.
* RIFT MAY interoperate with "Registration Extensions for 6LoWPAN * RIFT MAY interoperate with "Registration Extensions for 6LoWPAN
Neighbor Discovery" [RFC8505], which provides a method for Neighbor Discovery" [RFC8505], which provides a method for
registering a prefix with a sequence number called a Transaction registering a prefix with a sequence number called a Transaction
ID (TID). In such cases, RIFT SHOULD transport the derived TID ID (TID). In such cases, RIFT SHOULD transport the derived TID
without modification. without modification.
* RIFT also defines an abstract negative clock (ASNC) (also called * RIFT also defines an abstract negative clock (ASNC) (also called
an "undefined" clock). The ASNC MUST be considered older than any an "undefined" clock). The ASNC MUST be considered older than any
other defined clock. By default, when a node receives a Prefix other defined clock. By default, when a node receives a North
North TIE that does not contain a 'PrefixSequenceType' attribute, Prefix TIE that does not contain a 'PrefixSequenceType' attribute,
it MUST interpret the absence as the ASNC. it MUST interpret the absence as the ASNC.
* Any prefix present on the fabric in multiple nodes that have the * Any prefix present on the fabric in multiple nodes that have the
*same* clock is considered as anycast. *same* clock is considered as anycast.
* The RIFT specification assumes that all nodes are being * The RIFT specification assumes that all nodes are being
synchronized within at least 200 milliseconds or less. This is synchronized within at least 200 milliseconds or less. This is
achievable through the use of NTP [RFC5905]. An implementation achievable through the use of NTP [RFC5905]. An implementation
MAY provide a way to reconfigure a domain to a different value and MAY provide a way to reconfigure a domain to a different value and
provides a variable called MAXIMUM_CLOCK_DELTA for this purpose. provides a variable called MAXIMUM_CLOCK_DELTA for this purpose.
6.8.4.1. Clock Comparison 6.8.4.1. Clock Comparison
All monotonic clock values MUST be compared to each other using the All monotonic clock values MUST be compared to each other using the
following rules: following rules:
1. The ASNC is older than any other value except ASNC, 1. The ASNC is older than any other value except ASNC *and*
2. Clocks with timestamps differing by more than MAXIMUM_CLOCK_DELTA 2. Clocks with timestamps differing by more than MAXIMUM_CLOCK_DELTA
are comparable by using the timestamps only, are comparable by using the timestamps only *and*
3. Clocks with timestamps differing by less than MAXIMUM_CLOCK_DELTA 3. Clocks with timestamps differing by less than MAXIMUM_CLOCK_DELTA
are comparable by using their TIDs only, *and* are comparable by using their TIDs only, *and*
4. An undefined TID is always older than any other TID, *and* 4. An undefined TID is always older than any other TID, *and*
5. TIDs are compared using rules of [RFC8505]. 5. TIDs are compared using rules of [RFC8505].
6.8.4.2. Interaction Between Timestamps and Sequence Counters 6.8.4.2. Interaction Between Timestamps and Sequence Counters
For attachment changes that occur less frequently (e.g., once per For attachment changes that occur less frequently (e.g., once per
second), the timestamp that the RIFT infrastructure captures should second), the timestamp that the RIFT infrastructure captures should
be enough to determine the most current discovery. If the point of be enough to determine the most current discovery. If the point of
attachment changes faster than the maximum drift of the timestamping attachment changes faster than the maximum drift of the timestamping
mechanism (i.e., MAXIMUM_CLOCK_DELTA), then a sequence number SHOULD mechanism (i.e., MAXIMUM_CLOCK_DELTA), then a sequence number SHOULD
be used to enable necessary precision to determine currency. be used to enable necessary precision to determine currency.
The sequence counter in [RFC8505] is encoded as one octet and wraps The sequence counter in [RFC8505] is encoded as one octet and wraps
around using Appendix A. around using the arithmetic defined in Appendix A.
Within the resolution of MAXIMUM_CLOCK_DELTA, sequence counter values Within the resolution of MAXIMUM_CLOCK_DELTA, sequence counter values
captured during 2 sequential iterations of the same timestamp SHOULD captured during 2 sequential iterations of the same timestamp SHOULD
be comparable. This means that with default values, a node may move be comparable. This means that with default values, a node may move
up to 127 times in a 200-millisecond period and the clocks will up to 127 times in a 200-millisecond period and the clocks will
remain comparable. This allows the RIFT infrastructure to explicitly remain comparable. This allows the RIFT infrastructure to explicitly
assert the most up-to-date advertisement. assert the most up-to-date advertisement.
6.8.4.3. Anycast vs. Unicast 6.8.4.3. Anycast vs. Unicast
skipping to change at line 5031 skipping to change at line 4990
[RFC5881] to react quickly to link failures. In such case, the [RFC5881] to react quickly to link failures. In such case, the
following procedures are introduced: following procedures are introduced:
1. After RIFT _ThreeWay_ hello adjacency convergence, a BFD session 1. After RIFT _ThreeWay_ hello adjacency convergence, a BFD session
MAY be formed automatically between the RIFT endpoints without MAY be formed automatically between the RIFT endpoints without
further configuration using the exchanged discriminators that are further configuration using the exchanged discriminators that are
equal to the _local_id_ in the _LIEPacket_. The capability of the equal to the _local_id_ in the _LIEPacket_. The capability of the
remote side to support BFD is carried in the LIEs in remote side to support BFD is carried in the LIEs in
_LinkCapabilities_. _LinkCapabilities_.
2. In case an established BFD session goes down after it was up, 2. In case an established BFD session goes Down after it was Up,
RIFT adjacency SHOULD be re-initialized and subsequently started RIFT adjacency SHOULD be re-initialized and subsequently started
from Init after it receives a consecutive BFD Up. from Init after it receives a consecutive BFD Up.
3. In case of parallel links between nodes, each link MAY run its 3. In case of parallel links between nodes, each link MAY run its
own independent BFD session or they MAY share a session. The own independent BFD session or they MAY share a session. The
specific manner in which this is implemented is outside the scope specific manner in which this is implemented is outside the scope
of this document. of this document.
4. If link identifiers or BFD capabilities change, both the LIE and 4. If link identifiers or BFD capabilities change, both the LIE and
any BFD sessions SHOULD be brought down and back up again. In any BFD sessions SHOULD be brought down and back up again. In
skipping to change at line 5111 skipping to change at line 5070
Spine 111, and as a result, Leaf 111 wants to forward more traffic Spine 111, and as a result, Leaf 111 wants to forward more traffic
towards Spine 112. Additionally, it includes an uplink failure on towards Spine 112. Additionally, it includes an uplink failure on
Spine 111. Spine 111.
The local modification of the received default route distance from The local modification of the received default route distance from
the upper level is achieved by running a relatively simple algorithm the upper level is achieved by running a relatively simple algorithm
where the bandwidth is weighted exponentially, while the distance on where the bandwidth is weighted exponentially, while the distance on
the default route represents a multiplier for the bandwidth weight the default route represents a multiplier for the bandwidth weight
for easy operational adjustments. for easy operational adjustments.
On a node, L, use Node TIEs to compute from each non-overloaded On a node, L, use Node TIEs to compute 3 values from each non-
northbound neighbor N to compute 3 values: overloaded northbound neighbor, N:
1. L_N_u: sum of the bandwidth available from L to N (to account for 1. L_N_u: sum of the bandwidth available from L to N (to account for
parallel links) parallel links)
2. N_u: sum of the uplink bandwidth available on N 2. N_u: sum of the uplink bandwidth available on N
3. T_N_u: L_N_u * OVERSUBSCRIPTION_CONSTANT + N_u 3. T_N_u: L_N_u * OVERSUBSCRIPTION_CONSTANT + N_u
For all T_N_u, determine the corresponding M_N_u as For all T_N_u, determine the corresponding M_N_u as
log_2(next_power_2(T_N_u)) and determine MAX_M_N_u as the maximum log_2(next_power_2(T_N_u)) and determine MAX_M_N_u as the maximum
skipping to change at line 5184 skipping to change at line 5143
packet continues to flow southbound, it will take some viable, loop- packet continues to flow southbound, it will take some viable, loop-
free path to reach its destination. free path to reach its destination.
6.8.8. Label Binding 6.8.8. Label Binding
In its LIEs, a node MAY advertise a locally significant, downstream- In its LIEs, a node MAY advertise a locally significant, downstream-
assigned, interface-specific label. One use of such a label is a assigned, interface-specific label. One use of such a label is a
hop-by-hop encapsulation allowing forwarding planes to be easily hop-by-hop encapsulation allowing forwarding planes to be easily
distinguished among multiple RIFT instances. distinguished among multiple RIFT instances.
6.8.9. Leaf-to-Leaf Procedures 6.8.9. L2L Procedures
RIFT implementations SHOULD support special East-West adjacencies RIFT implementations SHOULD support special East-West adjacencies
between leaf nodes. Leaf nodes supporting these procedures MUST: between leaf nodes. Leaf nodes supporting these procedures MUST:
1. advertise the LEAF_2_LEAF flag in its node capabilities, 1. advertise the LEAF_2_LEAF flag in its node capabilities,
2. set the overload flag on all leaf's Node TIEs, 2. set the overload flag on all leaf's Node TIEs,
3. flood only a node's own North and South TIEs over E-W leaf 3. flood only a node's own North and South TIEs over E-W leaf
adjacencies, adjacencies,
4. always use E-W leaf adjacency in all SPF computations, 4. always use E-W leaf adjacency in all SPF computations,
5. install a discard route for any advertised aggregate routes in a 5. install a discard route for any advertised aggregate routes in a
leaf's TIE, *and* leaf's TIE, *and*
6. never form southbound adjacencies. 6. never form southbound adjacencies.
This will allow the E-W leaf nodes to exchange traffic strictly for This will allow the E-W leaf nodes to exchange traffic strictly for
the prefixes advertised in each other's north prefix TIEs since the the prefixes advertised in each other's North Prefix TIEs since the
southbound computation will find the reverse direction in the other southbound computation will find the reverse direction in the other
node's TIE and install its north prefixes. node's TIE and install its north prefixes.
6.8.10. Address Family and Multi-Topology Considerations 6.8.10. Address Family and Multi-Topology Considerations
Multi-Topology (MT) [RFC5120] and Multi-Instance (MI) [RFC8202] Multi-Topology (MT) [RFC5120] and Multi-Instance (MI) [RFC8202]
concepts are used today in link-state routing protocols to support concepts are used today in link-state routing protocols to support
several domains on the same physical topology. RIFT supports this several domains on the same physical topology. RIFT supports this
capability by carrying transport ports in the LIE protocol exchanges. capability by carrying transport ports in the LIE protocol exchanges.
Multiplexing of LIEs can be achieved by either choosing varying Multiplexing of LIEs can be achieved by either choosing varying
skipping to change at line 5341 skipping to change at line 5300
* message integrity, * message integrity,
* the prevention of replay attacks, * the prevention of replay attacks,
* low processing overhead, and * low processing overhead, and
* efficient messaging * efficient messaging
unless no security is deployed by means of using unless no security is deployed by means of using
'undefined_securitykey_id' as key identifiers. 'undefined_securitykey_id' as key identifiers (key ID).
Message confidentiality is a non-goal. Message confidentiality is a non-goal.
The model in the previous section allows a range of security key The model in the previous section allows a range of security key
types that are analogous to the various security association models. types that are analogous to the various security association models.
PAM and NAM allow security associations at the port or node level PAM and NAM allow security associations at the port or node level
using symmetric or asymmetric keys that are preinstalled. FAM argues using symmetric or asymmetric keys that are preinstalled. FAM argues
for security associations to be applied only at a group level or to for security associations to be applied only at a group level or to
be refined once the topology has been established. RIFT does not be refined once the topology has been established. RIFT does not
specify how security keys are installed or updated, though it does specify how security keys are installed or updated, though it does
skipping to change at line 5364 skipping to change at line 5323
The protocol has provisions for "weak" nonces to prevent replay The protocol has provisions for "weak" nonces to prevent replay
attacks and includes authentication mechanisms comparable to those attacks and includes authentication mechanisms comparable to those
described in [RFC5709] and [RFC7987]. described in [RFC5709] and [RFC7987].
6.9.3. Security Envelope 6.9.3. Security Envelope
A serialized schema _ProtocolPacket_ MUST be carried in a secure A serialized schema _ProtocolPacket_ MUST be carried in a secure
envelope as illustrated in Figure 34. The _ProtocolPacket_ MUST be envelope as illustrated in Figure 34. The _ProtocolPacket_ MUST be
serialized using the default Thrift's binary protocol. Any value in serialized using the default Thrift's binary protocol. Any value in
the packet following a security fingerprint MUST be used by a the packet following a security fingerprint MUST be used by a
receiver only after the fingerprint generated based on acceptable, receiver only after the fingerprint generated based on an acceptable,
advertised key ID has been validated against the data covered by it advertised key ID has been validated against the data covered by the
bare exceptions arising from operational exigencies where, based on bare exceptions arising from operational exigencies. Based on local
local configuration, a node MAY allow for the envelope's integrity configuration, a node MAY allow for the envelope's integrity checks
checks to be skipped and for behavior specified in Section 6.9.6. to be skipped and for the procedure specified in Section 6.9.6 to be
This means that for all packets, in case the node is configured to implemented. This means that for all packets, in case the node is
validate the outer fingerprint based on a key ID, an unexpected key configured to validate the outer fingerprint based on a key ID, an
ID or fingerprint not validating against the expected key ID will unexpected key ID or fingerprint not validating against the expected
lead to packet rejection. Further, in case of reception of a TIE and key ID will lead to packet rejection. Further, in case of reception
the receiver being configured to validate the originator by checking of a TIE and the receiver being configured to validate the originator
the TIE Origin Security Envelope Header fingerprint against a key ID, by checking the TIE Origin Security Envelope Header fingerprint
an incorrect key ID or inner fingerprint not validating against the against a key ID, an incorrect key ID or inner fingerprint not
key ID will lead to the rejection of the packet. validating against the key ID will lead to the rejection of the
packet.
For reasons of clarity, it is important to observe that the For reasons of clarity, it is important to observe that the
specification uses the words "fingerprint" and "signature" specification uses the words "fingerprint" and "signature"
interchangeably since the specific properties of the fingerprint part interchangeably since the specific properties of the fingerprint part
of the envelope depend on the algorithms used to insure the payload of the envelope depend on the algorithms used to insure the payload
integrity. Moreover, any security chosen never implies encryption integrity. Moreover, any security chosen never implies encryption
due to performance impact involved but only fingerprint or signature due to performance impact involved but only fingerprint or signature
generation and validation. generation and validation.
An implementation MUST implement at least both sending and receiving An implementation MUST implement at least both sending and receiving
skipping to change at line 5624 skipping to change at line 5584
adjacency back up. Obviously, an implementation MAY choose to stop adjacency back up. Obviously, an implementation MAY choose to stop
verifying the security envelope for the duration of the algorithm verifying the security envelope for the duration of the algorithm
change to keep the adjacency up, but since this introduces a security change to keep the adjacency up, but since this introduces a security
vulnerability window, such rollover SHOULD NOT be recommended. Other vulnerability window, such rollover SHOULD NOT be recommended. Other
approaches, such as accepting multiple algorithms for same key ID for approaches, such as accepting multiple algorithms for same key ID for
a configured time window, are possible but in the realm of a configured time window, are possible but in the realm of
implementation choices rather than protocol specification. implementation choices rather than protocol specification.
7. Information Elements Schema 7. Information Elements Schema
This section introduces the schema for information elements. The IDL This section introduces the schema for information elements. The
is Thrift [thrift]. Interface Description Language (IDL) is Thrift [thrift].
On schema changes that On schema changes that
1. change field numbers, 1. change field numbers *or*
2. add new *required* fields, 2. add new *required* fields *or*
3. remove any fields. 3. remove any fields *or*
4. change lists into sets and unions into structures, 4. change lists into sets, unions into structures *or*
5. change the multiplicity of fields, 5. change multiplicity of fields *or*
6. change the type or name of any field, 6. changes type or name of any field *or*
7. change data types of the type of any field, 7. change data types of the type of any field *or*
8. add, change, or remove a default value of any *existing* field, 8. adds, changes or removes a default value of any *existing* field
*or*
9. remove or change any defined constant or constant value, 9. removes or changes any defined constant or constant value *or*
10. change any enumeration type except extending 10. changes any enumeration type except extending
'common.TIETypeType' (use of enumeration types is generally `common.TIETypeType` (use of enumeration types is generally
discouraged), or discouraged) *or*
11. add a new TIE type to _TIETypeType_ with the flooding scope 11. adds new TIE type to _TIETypeType_ with flooding scope different
different from the prefix TIE flooding scope from prefix TIE flooding scope
the major version of the schema MUST increase. All other changes the major version of the schema MUST increase. All other changes
MUST increase the minor version within the same major. MUST increase the minor version within the same major.
Introducing an optional field does not cause a major version increase Introducing an optional field does not cause a major version increase
even if the fields inside the structure are optional with defaults. even if the fields inside the structure are optional with defaults.
All signed integers, as forced by Thrift [thrift] support, must be All signed integers, as forced by Thrift [thrift] support, must be
cast for internal purposes to equivalent unsigned values without cast for internal purposes to equivalent unsigned values without
discarding the signedness bit. An implementation SHOULD try to avoid discarding the signedness bit. An implementation SHOULD try to avoid
skipping to change at line 5717 skipping to change at line 5678
To support new TIE types without increasing the major version To support new TIE types without increasing the major version
enumeration, _TIEElement_ can be extended with new optional elements enumeration, _TIEElement_ can be extended with new optional elements
for new 'common.TIETypeType' values as long the scope of the new TIE for new 'common.TIETypeType' values as long the scope of the new TIE
matches the prefix TIE scope. In case it is necessary to understand matches the prefix TIE scope. In case it is necessary to understand
whether all nodes can parse the new TIE type, a node capability MUST whether all nodes can parse the new TIE type, a node capability MUST
be added in _NodeCapabilities_ to prevent a non-homogenous network. be added in _NodeCapabilities_ to prevent a non-homogenous network.
7.2. common.thrift 7.2. common.thrift
This schema references [RFC5837], [RFC5880], and [RFC6550].
/** /**
Thrift file with common definitions for RIFT Thrift file with common definitions for RIFT
*/ */
namespace py common namespace py common
/** @note MUST be interpreted in implementation as unsigned 64 bits. /** @note MUST be interpreted in implementation as unsigned 64 bits.
*/ */
typedef i64 SystemIDType typedef i64 SystemIDType
typedef i32 IPv4Address typedef i32 IPv4Address
skipping to change at line 5790 skipping to change at line 5753
value MUST be interpreted in implementation as unsigned */ value MUST be interpreted in implementation as unsigned */
typedef i8 PrefixTransactionIDType typedef i8 PrefixTransactionIDType
/** Timestamp per IEEE 802.1AS, all values MUST be interpreted in /** Timestamp per IEEE 802.1AS, all values MUST be interpreted in
implementation as unsigned. */ implementation as unsigned. */
struct IEEE802_1ASTimeStampType { struct IEEE802_1ASTimeStampType {
1: required i64 AS_sec; 1: required i64 AS_sec;
2: optional i32 AS_nsec; 2: optional i32 AS_nsec;
} }
/** generic counter type */ /** generic counter type */
typedef i64 CounterType typedef i64 CounterType
/** Platform Interface Index type, i.e., index of interface on hardware, /** Platform Interface Index type, i.e., index of interface on
can be used, e.g., with RFC 5837 */ hardware, can be used, e.g., with RFC 5837 */
typedef i32 PlatformInterfaceIndex typedef i32 PlatformInterfaceIndex
/** Flags indicating node configuration in case of ZTP. /** Flags indicating node configuration in case of ZTP.
*/ */
enum HierarchyIndications { enum HierarchyIndications {
/** forces level to 'leaf_level' and enables according procedures */ /** forces level to 'leaf_level' and enables
according procedures */
leaf_only = 0, leaf_only = 0,
/** forces level to 'leaf_level' and enables according procedures */ /** forces level to 'leaf_level' and enables
according procedures */
leaf_only_and_leaf_2_leaf_procedures = 1, leaf_only_and_leaf_2_leaf_procedures = 1,
/** forces level to 'top_of_fabric' and enables according /** forces level to 'top_of_fabric' and enables according
procedures */ procedures */
top_of_fabric = 2, top_of_fabric = 2,
} }
const PacketNumberType undefined_packet_number = 0 const PacketNumberType undefined_packet_number = 0
/** used when node is configured as top of fabric in ZTP.*/ /** used when node is configured as top of fabric in ZTP.*/
const LevelType top_of_fabric_level = 24 const LevelType top_of_fabric_level = 24
/** default bandwidth on a link */ /** default bandwidth on a link */
skipping to change at line 5831 skipping to change at line 5796
/** any distance larger than this will be considered infinity */ /** any distance larger than this will be considered infinity */
const MetricType infinite_distance = 0x7FFFFFFF const MetricType infinite_distance = 0x7FFFFFFF
/** represents invalid distance */ /** represents invalid distance */
const MetricType invalid_distance = 0 const MetricType invalid_distance = 0
const bool overload_default = false const bool overload_default = false
const bool flood_reduction_default = true const bool flood_reduction_default = true
/** default LIE FSM LIE TX interval time */ /** default LIE FSM LIE TX interval time */
const TimeIntervalInSecType default_lie_tx_interval = 1 const TimeIntervalInSecType default_lie_tx_interval = 1
/** default LIE FSM holddown time */ /** default LIE FSM holddown time */
const TimeIntervalInSecType default_lie_holdtime = 3 const TimeIntervalInSecType default_lie_holdtime = 3
/** multipler for default_lie_holdtime to hold down multiple neighbors */ /** multiplier for default_lie_holdtime to
const i8 multiple_neighbors_lie_holdtime_multipler = 4 holddown multiple neighbors */
const i8 multiple_neighbors_lie_holdtime_multiplier = 4
/** default ZTP FSM holddown time */ /** default ZTP FSM holddown time */
const TimeIntervalInSecType default_ztp_holdtime = 1 const TimeIntervalInSecType default_ztp_holdtime = 1
/** by default LIE levels are ZTP offers */ /** by default LIE levels are ZTP offers */
const bool default_not_a_ztp_offer = false const bool default_not_a_ztp_offer = false
/** by default everyone is repeating flooding */ /** by default everyone is repeating flooding */
const bool default_you_are_flood_repeater = true const bool default_you_are_flood_repeater = true
/** 0 is illegal for System IDs */ /** 0 is illegal for System IDs */
const SystemIDType IllegalSystemID = 0 const SystemIDType IllegalSystemID = 0
/** empty set of nodes */ /** empty set of nodes */
const set<SystemIDType> empty_set_of_nodeids = {} const set<SystemIDType> empty_set_of_nodeids = {}
/** default lifetime of TIE is one week */ /** default lifetime of TIE is one week */
const LifeTimeInSecType default_lifetime = 604800 const LifeTimeInSecType default_lifetime = 604800
/** default lifetime when TIEs are purged is 5 minutes */ /** default lifetime when TIEs are purged is 5 minutes */
const LifeTimeInSecType purge_lifetime = 300 const LifeTimeInSecType purge_lifetime = 300
/** optional round down interval when TIEs are sent with security signatures /** optional round down interval when
to prevent excessive computation. **/ * TIEs are sent with security signatures
* to prevent excessive computation.
*/
const LifeTimeInSecType rounddown_lifetime_interval = 60 const LifeTimeInSecType rounddown_lifetime_interval = 60
/** any 'TieHeader' that has a smaller lifetime difference /** any 'TieHeader' that has a smaller lifetime difference
than this constant is equal (if other fields equal). */ than this constant is equal (if other fields equal). */
const LifeTimeInSecType lifetime_diff2ignore = 400 const LifeTimeInSecType lifetime_diff2ignore = 400
/** default UDP port to run LIEs on */ /** default UDP port to run LIEs on */
const UDPPortType default_lie_udp_port = 914 const UDPPortType default_lie_udp_port = 914
/** default UDP port to receive TIEs on, which can be peer specific */ /** default UDP port to receive TIEs on,
which can be peer specific */
const UDPPortType default_tie_udp_flood_port = 915 const UDPPortType default_tie_udp_flood_port = 915
/** default MTU link size to use */ /** default MTU link size to use */
const MTUSizeType default_mtu_size = 1400 const MTUSizeType default_mtu_size = 1400
/** default link being BFD capable */ /** default link being BFD capable */
const bool bfd_default = true const bool bfd_default = true
/** type used to target nodes with key value */ /** type used to target nodes with key value */
typedef i64 KeyValueTargetType typedef i64 KeyValueTargetType
/** default target for key value are all nodes. */ /** default target for key value are all nodes. */
const KeyValueTargetType keyvaluetarget_default = 0 const KeyValueTargetType keyvaluetarget_default = 0
/** value for _all leaves_ addressing. Represented by all bits set. */ /** value for _all leaves_ addressing.
Represented by all bits set. */
const KeyValueTargetType keyvaluetarget_all_south_leaves = -1 const KeyValueTargetType keyvaluetarget_all_south_leaves = -1
/** undefined nonce, equivalent to missing nonce */ /** undefined nonce, equivalent to missing nonce */
const NonceType undefined_nonce = 0; const NonceType undefined_nonce = 0;
/** outer security key ID, MUST be interpreted as in implementation /** outer security key ID, MUST be interpreted as in implementation
as unsigned */ as unsigned */
typedef i8 OuterSecurityKeyID typedef i8 OuterSecurityKeyID
/** security key ID, MUST be interpreted as in implementation /** security key ID, MUST be interpreted as in implementation
as unsigned */ as unsigned */
typedef i32 TIESecurityKeyID typedef i32 TIESecurityKeyID
skipping to change at line 6060 skipping to change at line 6030
/** Capabilities the node supports. */ /** Capabilities the node supports. */
struct NodeCapabilities { struct NodeCapabilities {
/** Must advertise supported minor version dialect that way. */ /** Must advertise supported minor version dialect that way. */
1: required common.MinorVersionType protocol_minor_version = 1: required common.MinorVersionType protocol_minor_version =
protocol_minor_version; protocol_minor_version;
/** indicates that node supports flood reduction. */ /** indicates that node supports flood reduction. */
2: optional bool flood_reduction = 2: optional bool flood_reduction =
common.flood_reduction_default; common.flood_reduction_default;
/** indicates place in hierarchy, i.e., top of fabric or /** indicates place in hierarchy, i.e., top of fabric or
leaf only (in ZTP) or support for leaf-to-leaf leaf only (in ZTP) or support for L2L
procedures. */ procedures. */
3: optional common.HierarchyIndications hierarchy_indications; 3: optional common.HierarchyIndications hierarchy_indications;
} }
/** Link capabilities. */ /** Link capabilities. */
struct LinkCapabilities { struct LinkCapabilities {
/** Indicates that the link is supporting BFD. */ /** Indicates that the link is supporting BFD. */
1: optional bool bfd = 1: optional bool bfd =
common.bfd_default; common.bfd_default;
/** Indicates whether the interface will support IPv4 /** Indicates whether the interface will support IPv4
skipping to change at line 6375 skipping to change at line 6345
the leaf routes in their own PoD to prevent traffic loss. the leaf routes in their own PoD to prevent traffic loss.
2. Leaf nodes only hold their own North TIEs and the South TIEs of 2. Leaf nodes only hold their own North TIEs and the South TIEs of
level 1 nodes they are connected to. level 1 nodes they are connected to.
3. Leaf nodes do not have to support any type of disaggregation 3. Leaf nodes do not have to support any type of disaggregation
computation or propagation. computation or propagation.
4. Leaf nodes are not required to support the overload flag. 4. Leaf nodes are not required to support the overload flag.
5. Leaf nodes do not need to originate S-TIEs unless optional leaf- 5. Leaf nodes do not need to originate S-TIEs unless optional L2L
to-leaf features are desired. features are desired.
8.2. Considerations for Spine Implementation 8.2. Considerations for Spine Implementation
Nodes that do not act as ToF are not required to discover fallen Nodes that do not act as ToF are not required to discover fallen
leaves by comparing reachable destinations with peers and therefore leaves by comparing reachable destinations with peers and therefore
do not need to run the computation of disaggregated routes based on do not need to run the computation of disaggregated routes based on
that discovery. On the other hand, non-ToF nodes need to respect that discovery. On the other hand, non-ToF nodes need to respect
disaggregated routes advertised from the north. In the case of disaggregated routes advertised from the north. In the case of
negative disaggregation, spines nodes need to generate southbound negative disaggregation, spines nodes need to generate southbound
disaggregated routes when all parents are lost for a fallen leaf. disaggregated routes when all parents are lost for a fallen leaf.
skipping to change at line 6512 skipping to change at line 6482
combination must match the ongoing exchange and is then limited to combination must match the ongoing exchange and is then limited to
only a single flap since both nodes will advance their nonces in case only a single flap since both nodes will advance their nonces in case
the adjacency state changed. Even in the most unlikely case, the the adjacency state changed. Even in the most unlikely case, the
attack length is limited due to both sides periodically increasing attack length is limited due to both sides periodically increasing
their nonces. their nonces.
Generally, since weak nonces are not changed on every packet for Generally, since weak nonces are not changed on every packet for
performance reasons, a conceivable attack vector by a man in the performance reasons, a conceivable attack vector by a man in the
middle is to flood a receiving node with the maximum bandwidth of middle is to flood a receiving node with the maximum bandwidth of
recently observed packets, both LIEs as well as TIEs. In a scenario recently observed packets, both LIEs as well as TIEs. In a scenario
where such attacks are likely, _maximum_valid_nonce_delta_ can be where such attacks are likely, _maximum_valid_nonce_delta_ and
implemented as configurable, small value and _nonce_regeneration_interval_ can be implemented as configurable and
_nonce_regeneration_interval_ configured to very small value as well. set to small values. This will likely present a significant
This will likely present a significant computational load on large computational load on large fabrics under normal operation.
fabrics under normal operation.
9.8. TIE Origin Fingerprint DoS Attacks 9.8. TIE Origin Fingerprint DoS Attacks
Even when a mechanism in Section 10.2 is enabled to generate inner Even when a mechanism in Section 10.2 is enabled to generate inner
fingerprints or signatures, further attack considerations apply. fingerprints or signatures, further attack considerations apply.
In case the inner fingerprint could be generated by a compromised In case the inner fingerprint could be generated by a compromised
node in the network other than the originator based on shared node in the network other than the originator based on shared
secrets, the deployment must fall back on use of signatures that can secrets, the deployment must fall back on use of signatures that can
be validated but not generated by any other node except the be validated but not generated by any other node except the
originator. originator.
A compromised node in the network can attempt to brute force "fake A compromised node in the network can attempt to brute force "fake
TIEs" using other nodes' TIE origin key identifiers without TIEs" using other nodes' TIE origin key ID without possessing the
possessing the necessary secrets. Albeit the ultimate validation of necessary secrets. Albeit the ultimate validation of the origin
the origin signature will fail in such scenarios and not progress signature will fail in such scenarios and not progress further than
further than immediately peering nodes, the resulting DoS attack immediately peering nodes, the resulting DoS attack seems unavoidable
seems unavoidable since the TIE origin key ID is only protected by since the TIE origin key ID is only protected by the (here assumed to
the (here assumed to be compromised) node. be compromised) node.
9.9. Host Implementations 9.9. Host Implementations
It can be reasonably expected that the proliferation of RotH servers, It can be reasonably expected that the proliferation of RotH servers,
rather than dedicated networking devices, will represent a rather than dedicated networking devices, will represent a
significant amount of RIFT devices. Given their normally far wider significant amount of RIFT devices. Given their normally far wider
software envelope and access granted to them, such servers are also software envelope and access granted to them, such servers are also
far more likely to be compromised and present an attack vector on the far more likely to be compromised and present an attack vector on the
protocol. Hijacking of prefixes to attract traffic is a trust protocol. Hijacking of prefixes to attract traffic is a trust
problem and cannot be easily addressed within the protocol if the problem and cannot be easily addressed within the protocol if the
skipping to change at line 6560 skipping to change at line 6529
attempting similar resource overrun attacks. A prudent attempting similar resource overrun attacks. A prudent
implementation forming adjacencies to leaves should implement implementation forming adjacencies to leaves should implement
threshold mechanisms and raise warnings when, e.g., a leaf is threshold mechanisms and raise warnings when, e.g., a leaf is
advertising an excess number of TIEs or prefixes. Additionally, such advertising an excess number of TIEs or prefixes. Additionally, such
implementation could refuse any topology information except the implementation could refuse any topology information except the
node's own TIEs and authenticated, reflected South Node TIEs at their node's own TIEs and authenticated, reflected South Node TIEs at their
own level. own level.
To isolate possible attack vectors on the leaf to the largest To isolate possible attack vectors on the leaf to the largest
possible extent, a dedicated leaf-only implementation could run possible extent, a dedicated leaf-only implementation could run
without any configuration by hard-coding a well-known adjacency key without any configuration by:
(which can be always rolled over by the means of, e.g., a well-known
key value distributed from the top of the fabric), leaf level value * hard-coding a well-known adjacency key (which can be always rolled
and always setting overload flag. All other values can be derived by over by means of, e.g., a well-known key-value distributed from
automatic means as described above. top of the fabric),
* hard-coding a leaf level value, and
* always setting the overload flag
9.9.1. IPv4 Broadcast and IPv6 All-Routers Multicast Implementations 9.9.1. IPv4 Broadcast and IPv6 All-Routers Multicast Implementations
Section 6.2 describes an optional implementation that supports LIE Section 6.2 describes an optional implementation that supports LIE
exchange over IPv4 broadcast addresses and/or the IPv6 all-routers exchange over IPv4 broadcast addresses and/or the IPv6 all-routers
multicast address. It is important to consider that if an multicast address. It is important to consider that if an
implementation supports this, the attack surface widens as LIEs may implementation supports this, the attack surface widens as LIEs may
be propagated to devices outside of the intended RIFT topology. This be propagated to devices outside of the intended RIFT topology. This
may leave RIFT nodes more susceptible to the various attack vectors may leave RIFT nodes more susceptible to the various attack vectors
already described in this section. already described in this section.
skipping to change at line 6607 skipping to change at line 6580
Description: Routing in Fat Trees Link Information Element Description: Routing in Fat Trees Link Information Element
Assignee: IESG (iesg@ietf.org) Assignee: IESG (iesg@ietf.org)
Contact: IETF Chair (chair@ietf.org) Contact: IETF Chair (chair@ietf.org)
Reference: RFC 9692 Reference: RFC 9692
_RIFT TIE Port_ _RIFT TIE Port_
Service Name: rift-ties Service Name: rift-ties
Port Number: 915 Port Number: 915
Transport Protocol: udp Transport Protocol: udp
Description: Routing in Fat Trees Topology Information Element
Assignee: IESG (iesg@ietf.org) Assignee: IESG (iesg@ietf.org)
Contact: IETF Chair (chair@ietf.org) Contact: IETF Chair (chair@ietf.org)
Description: Routing in Fat Trees Topology Information Element
Reference: RFC 9692 Reference: RFC 9692
10.2. Registry for RIFT Security Algorithms 10.2. Registry for RIFT Security Algorithms
A new registry has been created to hold the allowed RIFT security A new registry has been created to hold the allowed RIFT security
algorithms. No particular enumeration values are necessary since algorithms. No particular enumeration values are necessary since
RIFT uses a key ID abstraction on packets without disclosing any RIFT uses a key ID abstraction on packets without disclosing any
information about the algorithm or secrets used and only carries the information about the algorithm or secrets used and only carries the
resulting fingerprint or signature protecting the integrity of the resulting fingerprint or signature protecting the integrity of the
data. data.
The registry applies the "Specification Required" policy per The registry applies the "Specification Required" policy per
[RFC8126]. The designated expert should ensure that the algorithms [RFC8126]. The designated expert should ensure that the algorithms
suggested represent the state of the art at a given point in time and suggested represent the state of the art at a given point in time and
avoid introducing algorithms that do not represent enhanced security avoid introducing algorithms that do not represent enhanced security
properties or ensure such properties at a lower cost as compared to properties or ensure such properties at a lower cost as compared to
existing registry entries. existing registry entries.
+==========================+============+==========================+ +==========================+==========================+============+
| Name | Reference | Recommendation | | Name | Recommendation | Reference |
+==========================+============+==========================+ +==========================+==========================+============+
| HMAC-SHA256 | [SHA-2] | Simplest way to ensure | | HMAC-SHA256 | Simplest way to ensure | [SHA-2] |
| | and | integrity of | | | integrity of | and |
| | [RFC2104] | transmissions across | | | transmissions across | [RFC2104] |
| | | adjacencies when used as | | | adjacencies when used as | |
| | | outer key and integrity | | | outer keys and integrity | |
| | | of TIEs when used as | | | of TIEs when used as | |
| | | inner keys. Recommended | | | inner keys. Recommended | |
| | | for most interoperable | | | for most interoperable | |
| | | security protection. | | | security protection. | |
+--------------------------+------------+--------------------------+ +--------------------------+--------------------------+------------+
| HMAC-SHA512 | [SHA-2] | Same as HMAC-SHA256 with | | HMAC-SHA512 | Same as HMAC-SHA256 with | [SHA-2] |
| | and | stronger protection. | | | stronger protection. | and |
| | [RFC2104] | | | | | [RFC2104] |
+--------------------------+------------+--------------------------+ +--------------------------+--------------------------+------------+
| SHA256-RSASSA-PKCS1-v1_5 | [RFC8017], | Recommended for high | | SHA256-RSASSA-PKCS1-v1_5 | Recommended for high | [RFC8017], |
| | Section | security applications | | | security applications | Section |
| | 8.2 | where private keys are | | | where private keys are | 8.2 |
| | | protected by according | | | protected by according | |
| | | nodes. Recommended as | | | nodes. Recommended as | |
| | | well in case not only | | | well in case not only | |
| | | integrity but origin | | | integrity but origin | |
| | | validation is necessary | | | validation is necessary | |
| | | for TIEs. Recommended | | | for TIEs. Recommended | |
| | | when adjacencies must be | | | when adjacencies must be | |
| | | protected without | | | protected without | |
| | | disclosing the secrets | | | disclosing the secrets | |
| | | on both sides of the | | | on both sides of the | |
| | | adjacency. | | | adjacency. | |
+--------------------------+------------+--------------------------+ +--------------------------+--------------------------+------------+
| SHA512-RSASSA-PKCS1-v1_5 | [RFC8017] | Same as SHA256-RSASSA- | | SHA512-RSASSA-PKCS1-v1_5 | Same as SHA256-RSASSA- | [RFC8017] |
| | | PKCS1-v1_5 with stronger | | | PKCS1-v1_5 with stronger | |
| | | protection. | | | protection. | |
+--------------------------+------------+--------------------------+ +--------------------------+--------------------------+------------+
Table 7 Table 7: RIFT Security Algorithms
10.3. Registries with Assigned Values for Schema Values 10.3. Registries with Assigned Values for Schema Values
This section requests registries that help govern the schema via the This section requests registries that help govern the schema via the
usual IANA registry procedures. The registry group "Routing in Fat usual IANA registry procedures. The registry group "Routing in Fat
Trees (RIFT)" holds the following registries. Registry values are Trees (RIFT)" holds the following registries. Registry values are
stored with their minimum and maximum version in which they are stored with their minimum and maximum version in which they are
available. All values not provided are to be considered available. All values not provided are to be considered
"Unassigned". The range of every registry is a 16-bit integer. "Unassigned". The range of every registry is a 16-bit integer.
Allocation of new values is performed via "Expert Review" action only Allocation of new values is performed via "Expert Review" action only
skipping to change at line 6727 skipping to change at line 6700
+-------+-----------------------+-------------+---------+---------+ +-------+-----------------------+-------------+---------+---------+
| 4 | AddressFamilyMaxValue | 8.0 | | | | 4 | AddressFamilyMaxValue | 8.0 | | |
+-------+-----------------------+-------------+---------+---------+ +-------+-----------------------+-------------+---------+---------+
Table 9: Address Family Type Table 9: Address Family Type
10.3.3. RIFTCommonHierarchyIndications Registry 10.3.3. RIFTCommonHierarchyIndications Registry
This registry has the following initial values. This registry has the following initial values.
+====================================+=====+=======+=======+=======+ +=====+====================================+=======+=======+=======+
|Name |Value|Min. |Max. |Comment| |Value|Name |Min. |Max. |Comment|
| | |Schema |Schema | | | | |Schema |Schema | |
| | |Version|Version| | | | |Version|Version| |
+====================================+=====+=======+=======+=======+ +=====+====================================+=======+=======+=======+
|leaf_only |0 |8.0 | | | |0 |leaf_only |8.0 | | |
+------------------------------------+-----+-------+-------+-------+ +-----+------------------------------------+-------+-------+-------+
|leaf_only_and_leaf_2_leaf_procedures|1 |8.0 | | | |1 |leaf_only_and_leaf_2_leaf_procedures|8.0 | | |
+------------------------------------+-----+-------+-------+-------+ +-----+------------------------------------+-------+-------+-------+
|top_of_fabric |2 |8.0 | | | |2 |top_of_fabric |8.0 | | |
+------------------------------------+-----+-------+-------+-------+ +-----+------------------------------------+-------+-------+-------+
Table 10: Flags Indicating Node Configuration in Case of ZTP Table 10: Flags Indicating Node Configuration in Case of ZTP
10.3.4. RIFTCommonIEEE8021ASTimeStampType Registry 10.3.4. RIFTCommonIEEE8021ASTimeStampType Registry
This registry has the following initial values. This registry has the following initial values.
The timestamp is per IEEE 802.1AS; all values MUST be interpreted in The timestamp is per IEEE 802.1AS; all values MUST be interpreted in
implementation as unsigned. implementation as unsigned.
+==========+=======+=====================+=============+=========+ +=======+==========+=====================+=============+=========+
| Name | Value | Min. Schema Version | Max. Schema | Comment | | Value | Name | Min. Schema Version | Max. Schema | Comment |
| | | | Version | | | | | | Version | |
+==========+=======+=====================+=============+=========+ +=======+==========+=====================+=============+=========+
| Reserved | 0 | 8.0 | All | | | 0 | Reserved | 8.0 | All | |
| | | | Versions | | | | | | Versions | |
+----------+-------+---------------------+-------------+---------+ +-------+----------+---------------------+-------------+---------+
| AS_sec | 1 | 8.0 | | | | 1 | AS_sec | 8.0 | | |
+----------+-------+---------------------+-------------+---------+ +-------+----------+---------------------+-------------+---------+
| AS_nsec | 2 | 8.0 | | | | 2 | AS_nsec | 8.0 | | |
+----------+-------+---------------------+-------------+---------+ +-------+----------+---------------------+-------------+---------+
Table 11 Table 11
10.3.5. RIFTCommonIPAddressType Registry 10.3.5. RIFTCommonIPAddressType Registry
This registry has the following initial values. This registry has the following initial values.
+=============+=======+=====================+=============+=========+ +=======+=============+=====================+=============+=========+
| Name | Value | Min. Schema | Max. Schema | Comment | | Value | Name | Min. Schema | Max. Schema | Comment |
| | | Version | Version | | | | | Version | Version | |
+=============+=======+=====================+=============+=========+ +=======+=============+=====================+=============+=========+
| Reserved | 0 | 8.0 | All | | | 0 | Reserved | 8.0 | All | |
| | | | Versions | | | | | | Versions | |
+-------------+-------+---------------------+-------------+---------+ +-------+-------------+---------------------+-------------+---------+
| ipv4address | 1 | 8.0 | | Content | | 1 | ipv4address | 8.0 | | Content |
| | | | | is IPv4 | | | | | | is IPv4 |
+-------------+-------+---------------------+-------------+---------+ +-------+-------------+---------------------+-------------+---------+
| ipv6address | 2 | 8.0 | | Content | | 2 | ipv6address | 8.0 | | Content |
| | | | | is IPv6 | | | | | | is IPv6 |
+-------------+-------+---------------------+-------------+---------+ +-------+-------------+---------------------+-------------+---------+
Table 12: IP Address Type Table 12: IP Address Type
10.3.6. RIFTCommonIPPrefixType Registry 10.3.6. RIFTCommonIPPrefixType Registry
This registry has the following initial values. This registry has the following initial values.
Note: For interface addresses, the protocol can propagate the address | Note: For interface addresses the protocol can propagate the
part beyond the subnet mask and on reachability computation that has | address part beyond the subnet mask and on reachability
to be normalized. The non-significant bits can be used for | computation the non-significant bits have to be normalized.
operational purposes. | Those bits can be used for operational purposes.
+============+=======+=====================+=============+=========+ +=======+============+=====================+=============+=========+
| Name | Value | Min. Schema Version | Max. Schema | Comment | | Value | Name | Min. Schema Version | Max. Schema | Comment |
| | | | Version | | | | | | Version | |
+============+=======+=====================+=============+=========+ +=======+============+=====================+=============+=========+
| Reserved | 0 | 8.0 | All | | | 0 | Reserved | 8.0 | All | |
| | | | Versions | | | | | | Versions | |
+------------+-------+---------------------+-------------+---------+ +-------+------------+---------------------+-------------+---------+
| ipv4prefix | 1 | 8.0 | | | | 1 | ipv4prefix | 8.0 | | |
+------------+-------+---------------------+-------------+---------+ +-------+------------+---------------------+-------------+---------+
| ipv6prefix | 2 | 8.0 | | | | 2 | ipv6prefix | 8.0 | | |
+------------+-------+---------------------+-------------+---------+ +-------+------------+---------------------+-------------+---------+
Table 13: Prefix Advertisement Table 13: Prefix Advertisement
10.3.7. RIFTCommonIPv4PrefixType Registry 10.3.7. RIFTCommonIPv4PrefixType Registry
This registry has the following initial values. This registry has the following initial values.
+===========+=======+=====================+=============+=========+ +=======+===========+=====================+=============+=========+
| Name | Value | Min. Schema Version | Max. Schema | Comment | | Value | Name | Min. Schema Version | Max. Schema | Comment |
| | | | Version | | | | | | Version | |
+===========+=======+=====================+=============+=========+ +=======+===========+=====================+=============+=========+
| Reserved | 0 | 8.0 | All | | | 0 | Reserved | 8.0 | All | |
| | | | Versions | | | | | | Versions | |
+-----------+-------+---------------------+-------------+---------+ +-------+-----------+---------------------+-------------+---------+
| address | 1 | 8.0 | | | | 1 | address | 8.0 | | |
+-----------+-------+---------------------+-------------+---------+ +-------+-----------+---------------------+-------------+---------+
| prefixlen | 2 | 8.0 | | | | 2 | prefixlen | 8.0 | | |
+-----------+-------+---------------------+-------------+---------+ +-------+-----------+---------------------+-------------+---------+
Table 14: IPv4 Prefix Type Table 14: IPv4 Prefix Type
10.3.8. RIFTCommonIPv6PrefixType Registry 10.3.8. RIFTCommonIPv6PrefixType Registry
This registry has the following initial values. This registry has the following initial values.
+===========+=======+=====================+=============+=========+ +=======+===========+=====================+=============+=========+
| Name | Value | Min. Schema Version | Max. Schema | Comment | | Value | Name | Min. Schema Version | Max. Schema | Comment |
| | | | Version | | | | | | Version | |
+===========+=======+=====================+=============+=========+ +=======+===========+=====================+=============+=========+
| Reserved | 0 | 8.0 | All | | | 0 | Reserved | 8.0 | All | |
| | | | Versions | | | | | | Versions | |
+-----------+-------+---------------------+-------------+---------+ +-------+-----------+---------------------+-------------+---------+
| address | 1 | 8.0 | | | | 1 | address | 8.0 | | |
+-----------+-------+---------------------+-------------+---------+ +-------+-----------+---------------------+-------------+---------+
| prefixlen | 2 | 8.0 | | | | 2 | prefixlen | 8.0 | | |
+-----------+-------+---------------------+-------------+---------+ +-------+-----------+---------------------+-------------+---------+
Table 15: IPv6 Prefix Type Table 15: IPv6 Prefix Type
10.3.9. RIFTCommonKVTypes Registry 10.3.9. RIFTCommonKVTypes Registry
This registry has the following initial values. This registry has the following initial values.
+==============+=======+=============+=============+=========+ +=======+==============+=============+=============+=========+
| Name | Value | Min. Schema | Max. Schema | Comment | | Value | Name | Min. Schema | Max. Schema | Comment |
| | | Version | Version | | | | | Version | Version | |
+==============+=======+=============+=============+=========+ +=======+==============+=============+=============+=========+
| Unassigned | 0 | | | | | 0 | Unassigned | | | |
+--------------+-------+-------------+-------------+---------+ +-------+--------------+-------------+-------------+---------+
| Experimental | 1 | 8.0 | | | | 1 | Experimental | 8.0 | | |
+--------------+-------+-------------+-------------+---------+ +-------+--------------+-------------+-------------+---------+
| WellKnown | 2 | 8.0 | | | | 2 | WellKnown | 8.0 | | |
+--------------+-------+-------------+-------------+---------+ +-------+--------------+-------------+-------------+---------+
| OUI | 3 | 8.0 | | | | 3 | OUI | 8.0 | | |
+--------------+-------+-------------+-------------+---------+ +-------+--------------+-------------+-------------+---------+
Table 16 Table 16
10.3.10. RIFTCommonPrefixSequenceType Registry 10.3.10. RIFTCommonPrefixSequenceType Registry
This registry has the following initial values. This registry has the following initial values.
+===============+=======+=========+==========+===================+ +=======+===============+=========+==========+===================+
| Name | Value | Min. | Max. | Comment | | Value | Name | Min. | Max. | Comment |
| | | Schema | Schema | | | | | Schema | Schema | |
| | | Version | Version | | | | | Version | Version | |
+===============+=======+=========+==========+===================+ +=======+===============+=========+==========+===================+
| Reserved | 0 | 8.0 | All | | | 0 | Reserved | 8.0 | All | |
| | | | Versions | | | | | | Versions | |
+---------------+-------+---------+----------+-------------------+ +-------+---------------+---------+----------+-------------------+
| timestamp | 1 | 8.0 | | | | 1 | timestamp | 8.0 | | |
+---------------+-------+---------+----------+-------------------+ +-------+---------------+---------+----------+-------------------+
| transactionid | 2 | 8.0 | | Transaction ID | | 2 | transactionid | 8.0 | | Transaction ID |
| | | | | set by client in, | | | | | | set by client in, |
| | | | | e.g., 6LoWPAN. | | | | | | e.g., 6LoWPAN. |
+---------------+-------+---------+----------+-------------------+ +-------+---------------+---------+----------+-------------------+
Table 17: Sequence of a Prefix in Case of Move Table 17: Sequence of a Prefix in Case of Move
10.3.11. RIFTCommonRouteType Registry 10.3.11. RIFTCommonRouteType Registry
This registry has the following initial values. This registry has the following initial values.
Note: The only purpose of these values is to introduce an ordering, | Note: The only purpose of these values is to introduce an
whereas an implementation can internally choose any other values as | ordering, whereas an implementation can internally choose any
long the ordering is preserved. | other values as long the ordering is preserved.
+=====================+=======+=============+=============+=========+ +=======+=====================+=============+=============+=========+
| Name | Value | Min. Schema | Max. | Comment | | Value | Name | Min. Schema | Max. | Comment |
| | | Version | Schema | | | | | Version | Schema | |
| | | | Version | | | | | | Version | |
+=====================+=======+=============+=============+=========+ +=======+=====================+=============+=============+=========+
| Illegal | 0 | 8.0 | | | | 0 | Illegal | 8.0 | | |
+---------------------+-------+-------------+-------------+---------+ +-------+---------------------+-------------+-------------+---------+
| RouteTypeMinValue | 1 | 8.0 | | | | 1 | RouteTypeMinValue | 8.0 | | |
+---------------------+-------+-------------+-------------+---------+ +-------+---------------------+-------------+-------------+---------+
| Discard | 2 | 8.0 | | | | 2 | Discard | 8.0 | | |
+---------------------+-------+-------------+-------------+---------+ +-------+---------------------+-------------+-------------+---------+
| LocalPrefix | 3 | 8.0 | | | | 3 | LocalPrefix | 8.0 | | |
+---------------------+-------+-------------+-------------+---------+ +-------+---------------------+-------------+-------------+---------+
| SouthPGPPrefix | 4 | 8.0 | | | | 4 | SouthPGPPrefix | 8.0 | | |
+---------------------+-------+-------------+-------------+---------+ +-------+---------------------+-------------+-------------+---------+
| NorthPGPPrefix | 5 | 8.0 | | | | 5 | NorthPGPPrefix | 8.0 | | |
+---------------------+-------+-------------+-------------+---------+ +-------+---------------------+-------------+-------------+---------+
| NorthPrefix | 6 | 8.0 | | | | 6 | NorthPrefix | 8.0 | | |
+---------------------+-------+-------------+-------------+---------+ +-------+---------------------+-------------+-------------+---------+
| NorthExternalPrefix | 7 | 8.0 | | | | 7 | NorthExternalPrefix | 8.0 | | |
+---------------------+-------+-------------+-------------+---------+ +-------+---------------------+-------------+-------------+---------+
| SouthPrefix | 8 | 8.0 | | | | 8 | SouthPrefix | 8.0 | | |
+---------------------+-------+-------------+-------------+---------+ +-------+---------------------+-------------+-------------+---------+
| SouthExternalPrefix | 9 | 8.0 | | | | 9 | SouthExternalPrefix | 8.0 | | |
+---------------------+-------+-------------+-------------+---------+ +-------+---------------------+-------------+-------------+---------+
| NegativeSouthPrefix | 10 | 8.0 | | | | 10 | NegativeSouthPrefix | 8.0 | | |
+---------------------+-------+-------------+-------------+---------+ +-------+---------------------+-------------+-------------+---------+
| RouteTypeMaxValue | 11 | 8.0 | | | | 11 | RouteTypeMaxValue | 8.0 | | |
+---------------------+-------+-------------+-------------+---------+ +-------+---------------------+-------------+-------------+---------+
Table 18: RIFT Route Types Table 18: RIFT Route Types
10.3.12. RIFTCommonTIETypeType Registry 10.3.12. RIFTCommonTIETypeType Registry
This registry has the following initial values. This registry has the following initial values.
+===================================+=====+=======+=======+=======+ +=====+===========================================+=======+=======+=======+
|Name |Value|Min. |Max. |Comment| |Value|Name |Min. |Max. |Comment|
| | |Schema |Schema | | | | |Schema |Schema | |
| | |Version|Version| | | | |Version|Version| |
+===================================+=====+=======+=======+=======+ +=====+===========================================+=======+=======+=======+
|Illegal |0 |8.0 | | | |0 |Illegal |8.0 | | |
+-----------------------------------+-----+-------+-------+-------+ +-----+-------------------------------------------+-------+-------+-------+
|TIETypeMinValue |1 |8.0 | | | |1 |TIETypeMinValue |8.0 | | |
+-----------------------------------+-----+-------+-------+-------+ +-----+-------------------------------------------+-------+-------+-------+
|NodeTIEType |2 |8.0 | | | |2 |NodeTIEType |8.0 | | |
+-----------------------------------+-----+-------+-------+-------+ +-----+-------------------------------------------+-------+-------+-------+
|PrefixTIEType |3 |8.0 | | | |3 |PrefixTIEType |8.0 | | |
+-----------------------------------+-----+-------+-------+-------+ +-----+-------------------------------------------+-------+-------+-------+
|PositiveDisaggregationPrefixTIEType|4 |8.0 | | | |4 |PositiveDisaggregationPrefixTIEType |8.0 | | |
+-----------------------------------+-----+-------+-------+-------+ +-----+-------------------------------------------+-------+-------+-------+
|NegativeDisaggregationPrefixTIEType|5 |8.0 | | | |5 |NegativeDisaggregationPrefixTIEType |8.0 | | |
+-----------------------------------+-----+-------+-------+-------+ +-----+-------------------------------------------+-------+-------+-------+
|PGPrefixTIEType |6 |8.0 | | | |6 |PGPrefixTIEType |8.0 | | |
+-----------------------------------+-----+-------+-------+-------+ +-----+-------------------------------------------+-------+-------+-------+
|KeyValueTIEType |7 |8.0 | | | |7 |KeyValueTIEType |8.0 | | |
+-----------------------------------+-----+-------+-------+-------+ +-----+-------------------------------------------+-------+-------+-------+
|ExternalPrefixTIEType |8 |8.0 | | | |8 |ExternalPrefixTIEType |8.0 | | |
+-----------------------------------+-----+-------+-------+-------+ +-----+-------------------------------------------+-------+-------+-------+
|PositiveExternalDisaggregation |9 |8.0 | | | |9 |PositiveExternalDisaggregationPrefixTIEType|8.0 | | |
|PrefixTIEType | | | | | +-----+-------------------------------------------+-------+-------+-------+
+-----------------------------------+-----+-------+-------+-------+ |10 |TIETypeMaxValue |8.0 | | |
|TIETypeMaxValue |10 |8.0 | | | +-----+-------------------------------------------+-------+-------+-------+
+-----------------------------------+-----+-------+-------+-------+
Table 19: Type of TIE Table 19: Type of TIE
10.3.13. RIFTCommonTieDirectionType Registry 10.3.13. RIFTCommonTieDirectionType Registry
This registry has the following initial values. This registry has the following initial values.
+===================+=======+=============+=============+=========+ +=======+===================+=============+=============+=========+
| Name | Value | Min. Schema | Max. Schema | Comment | | Value | Name | Min. Schema | Max. Schema | Comment |
| | | Version | Version | | | | | Version | Version | |
+===================+=======+=============+=============+=========+ +=======+===================+=============+=============+=========+
| Illegal | 0 | 8.0 | | | | 0 | Illegal | 8.0 | | |
+-------------------+-------+-------------+-------------+---------+ +-------+-------------------+-------------+-------------+---------+
| South | 1 | 8.0 | | | | 1 | South | 8.0 | | |
+-------------------+-------+-------------+-------------+---------+ +-------+-------------------+-------------+-------------+---------+
| North | 2 | 8.0 | | | | 2 | North | 8.0 | | |
+-------------------+-------+-------------+-------------+---------+ +-------+-------------------+-------------+-------------+---------+
| DirectionMaxValue | 3 | 8.0 | | | | 3 | DirectionMaxValue | 8.0 | | |
+-------------------+-------+-------------+-------------+---------+ +-------+-------------------+-------------+-------------+---------+
Table 20: Direction of TIEs Table 20: Direction of TIEs
10.3.14. RIFTEncodingCommunity Registry 10.3.14. RIFTEncodingCommunity Registry
This registry has the following initial values. This registry has the following initial values.
+==========+=======+=====================+=============+============+ +=======+==========+=====================+=============+============+
| Name | Value | Min. Schema | Max. Schema | Comment | | Value | Name | Min. Schema | Max. Schema | Comment |
| | | Version | Version | | | | | Version | Version | |
+==========+=======+=====================+=============+============+ +=======+==========+=====================+=============+============+
| Reserved | 0 | 8.0 | All | | | 0 | Reserved | 8.0 | All | |
| | | | Versions | | | | | | Versions | |
+----------+-------+---------------------+-------------+------------+ +-------+----------+---------------------+-------------+------------+
| top | 1 | 8.0 | | Higher | | 1 | top | 8.0 | | Higher |
| | | | | order bits | | | | | | order bits |
+----------+-------+---------------------+-------------+------------+ +-------+----------+---------------------+-------------+------------+
| bottom | 2 | 8.0 | | Lower | | 2 | bottom | 8.0 | | Lower |
| | | | | order bits | | | | | | order bits |
+----------+-------+---------------------+-------------+------------+ +-------+----------+---------------------+-------------+------------+
Table 21: Prefix Community Table 21: Prefix Community
10.3.15. RIFTEncodingKeyValueTIEElement Registry 10.3.15. RIFTEncodingKeyValueTIEElement Registry
This registry has the following initial values. This registry has the following initial values.
+===========+=======+=====================+=============+=========+ +=======+===========+=====================+=============+=========+
| Name | Value | Min. Schema Version | Max. Schema | Comment | | Value | Name | Min. Schema Version | Max. Schema | Comment |
| | | | Version | | | | | | Version | |
+===========+=======+=====================+=============+=========+ +=======+===========+=====================+=============+=========+
| Reserved | 0 | 8.0 | All | | | 0 | Reserved | 8.0 | All | |
| | | | Versions | | | | | | Versions | |
+-----------+-------+---------------------+-------------+---------+ +-------+-----------+---------------------+-------------+---------+
| keyvalues | 1 | 8.0 | | | | 1 | keyvalues | 8.0 | | |
+-----------+-------+---------------------+-------------+---------+ +-------+-----------+---------------------+-------------+---------+
Table 22: Generic Key Value Pairs Table 22: Generic Key Value Pairs
10.3.16. RIFTEncodingKeyValueTIEElementContent Registry 10.3.16. RIFTEncodingKeyValueTIEElementContent Registry
This registry has the following initial values. It defines the This registry has the following initial values. It defines the
targeted nodes and the value carried. targeted nodes and the value carried.
+==========+=======+=====================+=============+=========+ +=======+==========+=====================+=============+=========+
| Name | Value | Min. Schema Version | Max. Schema | Comment | | Value | Name | Min. Schema Version | Max. Schema | Comment |
| | | | Version | | | | | | Version | |
+==========+=======+=====================+=============+=========+ +=======+==========+=====================+=============+=========+
| Reserved | 0 | 8.0 | All | | | 0 | Reserved | 8.0 | All | |
| | | | Versions | | | | | | Versions | |
+----------+-------+---------------------+-------------+---------+ +-------+----------+---------------------+-------------+---------+
| targets | 1 | 8.0 | | | | 1 | targets | 8.0 | | |
+----------+-------+---------------------+-------------+---------+ +-------+----------+---------------------+-------------+---------+
| value | 2 | 8.0 | | | | 2 | value | 8.0 | | |
+----------+-------+---------------------+-------------+---------+ +-------+----------+---------------------+-------------+---------+
Table 23 Table 23
10.3.17. RIFTEncodingLIEPacket Registry 10.3.17. RIFTEncodingLIEPacket Registry
This registry has the following initial values. This registry has the following initial values.
Note: This node's level is already included on the packet header. | Note: This node's level is already included on the packet
| header.
+=============================+=====+=======+========+==============+ +=====+=============================+=======+========+==============+
| Name |Value|Min. |Max. |Comment | |Value| Name |Min. |Max. |Comment |
| | |Schema |Schema | | | | |Schema |Schema | |
| | |Version|Version | | | | |Version|Version | |
+=============================+=====+=======+========+==============+ +=====+=============================+=======+========+==============+
| Reserved |0 |8.0 |All | | |0 | Reserved |8.0 |All | |
| | | |Versions| | | | | |Versions| |
+-----------------------------+-----+-------+--------+--------------+ +-----+-----------------------------+-------+--------+--------------+
| name |1 |8.0 | |Node or | |1 | name |8.0 | |Node or |
| | | | |adjacency | | | | | |adjacency |
| | | | |name. | | | | | |name. |
+-----------------------------+-----+-------+--------+--------------+ +-----+-----------------------------+-------+--------+--------------+
| local_id |2 |8.0 | |Local link | |2 | local_id |8.0 | |Local link |
| | | | |ID. | | | | | |ID. |
+-----------------------------+-----+-------+--------+--------------+ +-----+-----------------------------+-------+--------+--------------+
| flood_port |3 |8.0 | |UDP port to | |3 | flood_port |8.0 | |UDP port to |
| | | | |which we can | | | | | |which we can |
| | | | |receive | | | | | |receive |
| | | | |flooded ties. | | | | | |flooded ties. |
+-----------------------------+-----+-------+--------+--------------+ +-----+-----------------------------+-------+--------+--------------+
| link_mtu_size |4 |8.0 | |Layer 2 MTU, | |4 | link_mtu_size |8.0 | |Layer 2 MTU, |
| | | | |used to | | | | | |used to |
| | | | |discover | | | | | |discover |
| | | | |mismatch. | | | | | |mismatch. |
+-----------------------------+-----+-------+--------+--------------+ +-----+-----------------------------+-------+--------+--------------+
| link_bandwidth |5 |8.0 | |Local link | |5 | link_bandwidth |8.0 | |Local link |
| | | | |bandwidth on | | | | | |bandwidth on |
| | | | |the | | | | | |the |
| | | | |interface. | | | | | |interface. |
+-----------------------------+-----+-------+--------+--------------+ +-----+-----------------------------+-------+--------+--------------+
| neighbor |6 |8.0 | |Reflects the | |6 | neighbor |8.0 | |Reflects the |
| | | | |neighbor once | | | | | |neighbor once |
| | | | |received to | | | | | |received to |
| | | | |provide 3-way | | | | | |provide 3-way |
| | | | |connectivity. | | | | | |connectivity. |
+-----------------------------+-----+-------+--------+--------------+ +-----+-----------------------------+-------+--------+--------------+
| pod |7 |8.0 | |Node's PoD. | |7 | pod |8.0 | |Node's PoD. |
+-----------------------------+-----+-------+--------+--------------+ +-----+-----------------------------+-------+--------+--------------+
| node_capabilities |10 |8.0 | |Node | |10 | node_capabilities |8.0 | |Node |
| | | | |capabilities | | | | | |capabilities |
| | | | |supported. | | | | | |supported. |
+-----------------------------+-----+-------+--------+--------------+ +-----+-----------------------------+-------+--------+--------------+
| link_capabilities |11 |8.0 | |Capabilities | |11 | link_capabilities |8.0 | |Capabilities |
| | | | |of this link. | | | | | |of this link. |
+-----------------------------+-----+-------+--------+--------------+ +-----+-----------------------------+-------+--------+--------------+
| holdtime |12 |8.0 | |Required | |12 | holdtime |8.0 | |Required |
| | | | |holdtime of | | | | | |holdtime of |
| | | | |the | | | | | |the |
| | | | |adjacency, | | | | | |adjacency, |
| | | | |i.e., for how | | | | | |i.e., for how |
| | | | |long a period | | | | | |long a period |
| | | | |adjacency | | | | | |adjacency |
| | | | |should be | | | | | |should be |
| | | | |kept up | | | | | |kept up |
| | | | |without valid | | | | | |without valid |
| | | | |LIE | | | | | |LIE |
| | | | |reception. | | | | | |reception. |
+-----------------------------+-----+-------+--------+--------------+ +-----+-----------------------------+-------+--------+--------------+
| label |13 |8.0 | |Optional, | |13 | label |8.0 | |Optional, |
| | | | |unsolicited, | | | | | |unsolicited, |
| | | | |downstream | | | | | |downstream |
| | | | |assigned | | | | | |assigned |
| | | | |locally | | | | | |locally |
| | | | |significant | | | | | |significant |
| | | | |label value | | | | | |label value |
| | | | |for the | | | | | |for the |
| | | | |adjacency. | | | | | |adjacency. |
+-----------------------------+-----+-------+--------+--------------+ +-----+-----------------------------+-------+--------+--------------+
| not_a_ztp_offer |21 |8.0 | |Indicates | |21 | not_a_ztp_offer |8.0 | |Indicates |
| | | | |that the | | | | | |that the |
| | | | |level on the | | | | | |level on the |
| | | | |lie must not | | | | | |LIE must not |
| | | | |be used to | | | | | |be used to |
| | | | |derive a ZTP | | | | | |derive a ZTP |
| | | | |level by the | | | | | |level by the |
| | | | |receiving | | | | | |receiving |
| | | | |node. | | | | | |node. |
+-----------------------------+-----+-------+--------+--------------+ +-----+-----------------------------+-------+--------+--------------+
| you_are_flood_repeater |22 |8.0 | |Indicates to | |22 | you_are_flood_repeater |8.0 | |Indicates to |
| | | | |the | | | | | |the |
| | | | |northbound | | | | | |northbound |
| | | | |neighbor that | | | | | |neighbor that |
| | | | |it should be | | | | | |it should be |
| | | | |reflooding | | | | | |reflooding |
| | | | |ties received | | | | | |TIEs received |
| | | | |from this | | | | | |from this |
| | | | |node to | | | | | |node to |
| | | | |achieve flood | | | | | |achieve flood |
| | | | |reduction and | | | | | |reduction and |
| | | | |balancing for | | | | | |balancing for |
| | | | |northbound | | | | | |northbound |
| | | | |flooding. | | | | | |flooding. |
+-----------------------------+-----+-------+--------+--------------+ +-----+-----------------------------+-------+--------+--------------+
| you_are_sending_too_quickly |23 |8.0 | |Indicates to | |23 | you_are_sending_too_quickly |8.0 | |Indicates to |
| | | | |the neighbor | | | | | |the neighbor |
| | | | |to flood node | | | | | |to flood node |
| | | | |ties only and | | | | | |ties only and |
| | | | |slow down all | | | | | |slow down all |
| | | | |other ties. | | | | | |other ties. |
| | | | |Ignored when | | | | | |Ignored when |
| | | | |received from | | | | | |received from |
| | | | |the | | | | | |the |
| | | | |southbound | | | | | |southbound |
| | | | |neighbor. | | | | | |neighbor. |
+-----------------------------+-----+-------+--------+--------------+ +-----+-----------------------------+-------+--------+--------------+
| instance_name |24 |8.0 | |Instance name | |24 | instance_name |8.0 | |Instance name |
| | | | |in case | | | | | |in case |
| | | | |multiple rift | | | | | |multiple RIFT |
| | | | |instances | | | | | |instances are |
| | | | |running on | | | | | |running on |
| | | | |same | | | | | |the same |
| | | | |interface. | | | | | |interface. |
+-----------------------------+-----+-------+--------+--------------+ +-----+-----------------------------+-------+--------+--------------+
| fabric_id |35 |8.0 | |It provides | |35 | fabric_id |8.0 | |It provides |
| | | | |the optional | | | | | |the optional |
| | | | |ID of the | | | | | |ID of the |
| | | | |fabric | | | | | |fabric |
| | | | |configured. | | | | | |configured. |
| | | | |This must | | | | | |This must |
| | | | |match the | | | | | |match the |
| | | | |information | | | | | |information |
| | | | |advertised on | | | | | |advertised on |
| | | | |the node | | | | | |the node |
| | | | |element. | | | | | |element. |
+-----------------------------+-----+-------+--------+--------------+ +-----+-----------------------------+-------+--------+--------------+
Table 24: RIFT LIE Packet Table 24: RIFT LIE Packet
10.3.18. RIFTEncodingLinkCapabilities Registry 10.3.18. RIFTEncodingLinkCapabilities Registry
This registry has the following initial values. This registry has the following initial values.
+=========================+=====+=========+==========+==============+ +=====+=========================+=========+==========+==============+
| Name |Value| Min. | Max. | Comment | |Value| Name | Min. | Max. | Comment |
| | | Schema | Schema | | | | | Schema | Schema | |
| | | Version | Version | | | | | Version | Version | |
+=========================+=====+=========+==========+==============+ +=====+=========================+=========+==========+==============+
| Reserved |0 | 8.0 | All | | |0 | Reserved | 8.0 | All | |
| | | | Versions | | | | | | Versions | |
+-------------------------+-----+---------+----------+--------------+ +-----+-------------------------+---------+----------+--------------+
| bfd |1 | 8.0 | | Indicates | |1 | bfd | 8.0 | | Indicates |
| | | | | that the | | | | | | that the |
| | | | | link is | | | | | | link is |
| | | | | supporting | | | | | | supporting |
| | | | | BFD. | | | | | | BFD. |
+-------------------------+-----+---------+----------+--------------+ +-----+-------------------------+---------+----------+--------------+
| ipv4_forwarding_capable |2 | 8.0 | | Indicates | |2 | ipv4_forwarding_capable | 8.0 | | Indicates |
| | | | | whether the | | | | | | whether the |
| | | | | interface | | | | | | interface |
| | | | | will | | | | | | will |
| | | | | support | | | | | | support |
| | | | | IPv4 | | | | | | IPv4 |
| | | | | forwarding. | | | | | | forwarding. |
+-------------------------+-----+---------+----------+--------------+ +-----+-------------------------+---------+----------+--------------+
Table 25: Link Capabilities Table 25: Link Capabilities
10.3.19. RIFTEncodingLinkIDPair Registry 10.3.19. RIFTEncodingLinkIDPair Registry
The LinkID pair describes one of the parallel links between two The LinkID pair describes one of the parallel links between two
nodes. nodes.
This registry has the following initial values. This registry has the following initial values.
+============================+=====+=======+========+==============+ +=====+============================+=======+========+==============+
| Name |Value|Min. |Max. | Comment | |Value| Name |Min. |Max. | Comment |
| | |Schema |Schema | | | | |Schema |Schema | |
| | |Version|Version | | | | |Version|Version | |
+============================+=====+=======+========+==============+ +=====+============================+=======+========+==============+
| Reserved |0 |8.0 |All | | |0 | Reserved |8.0 |All | |
| | | |Versions| | | | | |Versions| |
+----------------------------+-----+-------+--------+--------------+ +-----+----------------------------+-------+--------+--------------+
| local_id |1 |8.0 | | Node-wide | |1 | local_id |8.0 | | Node-wide |
| | | | | unique value | | | | | | unique value |
| | | | | for the | | | | | | for the |
| | | | | local link. | | | | | | local link. |
+----------------------------+-----+-------+--------+--------------+ +-----+----------------------------+-------+--------+--------------+
| remote_id |2 |8.0 | | Received the | |2 | remote_id |8.0 | | Received the |
| | | | | remote link | | | | | | remote link |
| | | | | ID for this | | | | | | ID for this |
| | | | | link. | | | | | | link. |
+----------------------------+-----+-------+--------+--------------+ +-----+----------------------------+-------+--------+--------------+
| platform_interface_index |10 |8.0 | | Describes | |10 | platform_interface_index |8.0 | | Describes |
| | | | | the local | | | | | | the local |
| | | | | interface | | | | | | interface |
| | | | | index of the | | | | | | index of the |
| | | | | link. | | | | | | link. |
+----------------------------+-----+-------+--------+--------------+ +-----+----------------------------+-------+--------+--------------+
| platform_interface_name |11 |8.0 | | Describes | |11 | platform_interface_name |8.0 | | Describes |
| | | | | the local | | | | | | the local |
| | | | | interface | | | | | | interface |
| | | | | name. | | | | | | name. |
+----------------------------+-----+-------+--------+--------------+ +-----+----------------------------+-------+--------+--------------+
| trusted_outer_security_key |12 |8.0 | | Indicates | |12 | trusted_outer_security_key |8.0 | | Indicates |
| | | | | whether the | | | | | | whether the |
| | | | | link is | | | | | | link is |
| | | | | secured, | | | | | | secured, |
| | | | | i.e., | | | | | | i.e., |
| | | | | protected by | | | | | | protected by |
| | | | | outer key, | | | | | | outer key, |
| | | | | absence of | | | | | | absence of |
| | | | | this element | | | | | | this element |
| | | | | means no | | | | | | means no |
| | | | | indication, | | | | | | indication, |
| | | | | undefined | | | | | | undefined |
| | | | | outer key | | | | | | outer key |
| | | | | means not | | | | | | means not |
| | | | | secured. | | | | | | secured. |
+----------------------------+-----+-------+--------+--------------+ +-----+----------------------------+-------+--------+--------------+
| bfd_up |13 |8.0 | | Indicates | |13 | bfd_up |8.0 | | Indicates |
| | | | | whether the | | | | | | whether the |
| | | | | link is | | | | | | link is |
| | | | | protected by | | | | | | protected by |
| | | | | an | | | | | | an |
| | | | | established | | | | | | established |
| | | | | BFD session. | | | | | | BFD session. |
+----------------------------+-----+-------+--------+--------------+ +-----+----------------------------+-------+--------+--------------+
| address_families |14 |8.0 | | Optional | |14 | address_families |8.0 | | Optional |
| | | | | indication | | | | | | indication |
| | | | | that address | | | | | | that address |
| | | | | families are | | | | | | families are |
| | | | | up on the | | | | | | up on the |
| | | | | interface. | | | | | | interface. |
+----------------------------+-----+-------+--------+--------------+ +-----+----------------------------+-------+--------+--------------+
Table 26 Table 26
10.3.20. RIFTEncodingNeighbor Registry 10.3.20. RIFTEncodingNeighbor Registry
This registry has the following initial values. This registry has the following initial values.
+============+=======+=============+=============+=================+ +=======+============+=============+=============+=================+
| Name | Value | Min. Schema | Max. Schema | Comment | | Value | Name | Min. Schema | Max. Schema | Comment |
| | | Version | Version | | | | | Version | Version | |
+============+=======+=============+=============+=================+ +=======+============+=============+=============+=================+
| Reserved | 0 | 8.0 | All | | | 0 | Reserved | 8.0 | All | |
| | | | Versions | | | | | | Versions | |
+------------+-------+-------------+-------------+-----------------+ +-------+------------+-------------+-------------+-----------------+
| originator | 1 | 8.0 | | System ID of | | 1 | originator | 8.0 | | System ID of |
| | | | | the originator. | | | | | | the originator. |
+------------+-------+-------------+-------------+-----------------+ +-------+------------+-------------+-------------+-----------------+
| remote_id | 2 | 8.0 | | ID of remote | | 2 | remote_id | 8.0 | | ID of remote |
| | | | | side of the | | | | | | side of the |
| | | | | link. | | | | | | link. |
+------------+-------+-------------+-------------+-----------------+ +-------+------------+-------------+-------------+-----------------+
Table 27: Neighbor Structure Table 27: Neighbor Structure
10.3.21. RIFTEncodingNodeCapabilities Registry 10.3.21. RIFTEncodingNodeCapabilities Registry
This registry has the following initial values. This registry has the following initial values.
+========================+=====+=========+==========+==============+ +=====+========================+=========+==========+==============+
| Name |Value| Min. | Max. | Comment | |Value| Name | Min. | Max. | Comment |
| | | Schema | Schema | | | | | Schema | Schema | |
| | | Version | Version | | | | | Version | Version | |
+========================+=====+=========+==========+==============+ +=====+========================+=========+==========+==============+
| Reserved |0 | 8.0 | All | | |0 | Reserved | 8.0 | All | |
| | | | Versions | | | | | | Versions | |
+------------------------+-----+---------+----------+--------------+ +-----+------------------------+---------+----------+--------------+
| protocol_minor_version |1 | 8.0 | | Must | |1 | protocol_minor_version | 8.0 | | Must |
| | | | | advertise | | | | | | advertise |
| | | | | supported | | | | | | supported |
| | | | | minor | | | | | | minor |
| | | | | version | | | | | | version |
| | | | | dialect that | | | | | | dialect that |
| | | | | way. | | | | | | way. |
+------------------------+-----+---------+----------+--------------+ +-----+------------------------+---------+----------+--------------+
| flood_reduction |2 | 8.0 | | Indicates | |2 | flood_reduction | 8.0 | | Indicates |
| | | | | that node | | | | | | that node |
| | | | | supports | | | | | | supports |
| | | | | flood | | | | | | flood |
| | | | | reduction. | | | | | | reduction. |
+------------------------+-----+---------+----------+--------------+ +-----+------------------------+---------+----------+--------------+
| hierarchy_indications |3 | 8.0 | | Indicates | |3 | hierarchy_indications | 8.0 | | Indicates |
| | | | | place in | | | | | | place in |
| | | | | hierarchy, | | | | | | hierarchy, |
| | | | | i.e., top of | | | | | | i.e., top of |
| | | | | fabric or | | | | | | fabric or |
| | | | | leaf only | | | | | | leaf only |
| | | | | (in ZTP) or | | | | | | (in ZTP) or |
| | | | | support for | | | | | | support for |
| | | | | leaf-to-leaf | | | | | | L2L |
| | | | | procedures. | | | | | | procedures. |
+------------------------+-----+---------+----------+--------------+ +-----+------------------------+---------+----------+--------------+
Table 28: Capabilities the Node Supports Table 28: Capabilities the Node Supports
10.3.22. RIFTEncodingNodeFlags Registry 10.3.22. RIFTEncodingNodeFlags Registry
This registry has the following initial values. This registry has the following initial values.
+==========+=======+=========+==========+===========================+ +=======+==========+=========+==========+===========================+
| Name | Value | Min. | Max. | Comment | | Value | Name | Min. | Max. | Comment |
| | | Schema | Schema | | | | | Schema | Schema | |
| | | Version | Version | | | | | Version | Version | |
+==========+=======+=========+==========+===========================+ +=======+==========+=========+==========+===========================+
| Reserved | 0 | 8.0 | All | | | 0 | Reserved | 8.0 | All | |
| | | | Versions | | | | | | Versions | |
+----------+-------+---------+----------+---------------------------+ +-------+----------+---------+----------+---------------------------+
| overload | 1 | 8.0 | | Indicates that node | | 1 | overload | 8.0 | | Indicates that node |
| | | | | is in overload; do | | | | | | is in overload; do |
| | | | | not transit traffic | | | | | | not transit traffic |
| | | | | through it. | | | | | | through it. |
+----------+-------+---------+----------+---------------------------+ +-------+----------+---------+----------+---------------------------+
Table 29: Indication Flags of the Node Table 29: Indication Flags of the Node
10.3.23. RIFTEncodingNodeNeighborsTIEElement Registry 10.3.23. RIFTEncodingNodeNeighborsTIEElement Registry
This registry has the following initial values. This registry has the following initial values.
+===========+=======+=========+==========+======================+ +=======+===========+=========+==========+======================+
| Name | Value | Min. | Max. | Comment | | Value | Name | Min. | Max. | Comment |
| | | Schema | Schema | | | | | Schema | Schema | |
| | | Version | Version | | | | | Version | Version | |
+===========+=======+=========+==========+======================+ +=======+===========+=========+==========+======================+
| Reserved | 0 | 8.0 | All | | | 0 | Reserved | 8.0 | All | |
| | | | Versions | | | | | | Versions | |
+-----------+-------+---------+----------+----------------------+ +-------+-----------+---------+----------+----------------------+
| level | 1 | 8.0 | | Level of neighbor. | | 1 | level | 8.0 | | Level of neighbor. |
+-----------+-------+---------+----------+----------------------+ +-------+-----------+---------+----------+----------------------+
| cost | 3 | 8.0 | | Cost to neighbor. | | 3 | cost | 8.0 | | Cost to neighbor. |
| | | | | Ignore anything | | | | | | Ignore anything |
| | | | | equal or larger than | | | | | | equal or larger than |
| | | | | 'infinite_distance' | | | | | | 'infinite_distance' |
| | | | | and equal to | | | | | | and equal to |
| | | | | 'invalid_distance'. | | | | | | 'invalid_distance'. |
+-----------+-------+---------+----------+----------------------+ +-------+-----------+---------+----------+----------------------+
| link_ids | 4 | 8.0 | | Carries description | | 4 | link_ids | 8.0 | | Carries description |
| | | | | of multiple parallel | | | | | | of multiple parallel |
| | | | | links in a tie. | | | | | | links in a tie. |
+-----------+-------+---------+----------+----------------------+ +-------+-----------+---------+----------+----------------------+
| bandwidth | 5 | 8.0 | | Total bandwidth to | | 5 | bandwidth | 8.0 | | Total bandwidth to |
| | | | | neighbor as sum of | | | | | | neighbor as sum of |
| | | | | all parallel links. | | | | | | all parallel links. |
+-----------+-------+---------+----------+----------------------+ +-------+-----------+---------+----------+----------------------+
Table 30: Neighbor of a Node Table 30: Neighbor of a Node
10.3.24. RIFTEncodingNodeTIEElement Registry 10.3.24. RIFTEncodingNodeTIEElement Registry
This registry has the following initial values. This registry has the following initial values.
+=================+=======+=========+==========+====================+ +=======+=================+=========+==========+====================+
| Name | Value | Min. | Max. | Comment | | Value | Name | Min. | Max. | Comment |
| | | Schema | Schema | | | | | Schema | Schema | |
| | | Version | Version | | | | | Version | Version | |
+=================+=======+=========+==========+====================+ +=======+=================+=========+==========+====================+
| Reserved | 0 | 8.0 | All | | | 0 | Reserved | 8.0 | All | |
| | | | Versions | | | | | | Versions | |
+-----------------+-------+---------+----------+--------------------+ +-------+-----------------+---------+----------+--------------------+
| level | 1 | 8.0 | | Level of the | | 1 | level | 8.0 | | Level of the |
| | | | | node. | | | | | | node. |
+-----------------+-------+---------+----------+--------------------+ +-------+-----------------+---------+----------+--------------------+
| neighbors | 2 | 8.0 | | Node's neighbors. | | 2 | neighbors | 8.0 | | Node's neighbors. |
| | | | | Multiple node | | | | | | Multiple node |
| | | | | ties can carry | | | | | | ties can carry |
| | | | | disjoint sets of | | | | | | disjoint sets of |
| | | | | neighbors. | | | | | | neighbors. |
+-----------------+-------+---------+----------+--------------------+ +-------+-----------------+---------+----------+--------------------+
| capabilities | 3 | 8.0 | | Capabilities of | | 3 | capabilities | 8.0 | | Capabilities of |
| | | | | the node. | | | | | | the node. |
+-----------------+-------+---------+----------+--------------------+ +-------+-----------------+---------+----------+--------------------+
| flags | 4 | 8.0 | | Flags of the | | 4 | flags | 8.0 | | Flags of the |
| | | | | node. | | | | | | node. |
+-----------------+-------+---------+----------+--------------------+ +-------+-----------------+---------+----------+--------------------+
| name | 5 | 8.0 | | Optional node | | 5 | name | 8.0 | | Optional node |
| | | | | name for easier | | | | | | name for easier |
| | | | | operations. | | | | | | operations. |
+-----------------+-------+---------+----------+--------------------+ +-------+-----------------+---------+----------+--------------------+
| pod | 6 | 8.0 | | Pod to which the | | 6 | pod | 8.0 | | Pod to which the |
| | | | | node belongs. | | | | | | node belongs. |
+-----------------+-------+---------+----------+--------------------+ +-------+-----------------+---------+----------+--------------------+
| startup_time | 7 | 8.0 | | Optional startup | | 7 | startup_time | 8.0 | | Optional startup |
| | | | | time of the node. | | | | | | time of the node. |
+-----------------+-------+---------+----------+--------------------+ +-------+-----------------+---------+----------+--------------------+
| miscabled_links | 10 | 8.0 | | If any local | | 10 | miscabled_links | 8.0 | | If any local |
| | | | | links are | | | | | | links are |
| | | | | miscabled, this | | | | | | miscabled, this |
| | | | | indication is | | | | | | indication is |
| | | | | flooded. | | | | | | flooded. |
+-----------------+-------+---------+----------+--------------------+ +-------+-----------------+---------+----------+--------------------+
| same_plane_tofs | 12 | 8.0 | | ToFs in the same | | 12 | same_plane_tofs | 8.0 | | ToFs in the same |
| | | | | plane. Only | | | | | | plane. Only |
| | | | | carried by ToF. | | | | | | carried by ToF. |
| | | | | Multiple node | | | | | | Multiple node |
| | | | | ties can carry | | | | | | ties can carry |
| | | | | disjoint sets of | | | | | | disjoint sets of |
| | | | | ToFs that must be | | | | | | ToFs that must be |
| | | | | joined to form a | | | | | | joined to form a |
| | | | | single set. | | | | | | single set. |
+-----------------+-------+---------+----------+--------------------+ +-------+-----------------+---------+----------+--------------------+
| fabric_id | 20 | 8.0 | | It provides the | | 20 | fabric_id | 8.0 | | It provides the |
| | | | | optional ID of | | | | | | optional ID of |
| | | | | the fabric | | | | | | the fabric |
| | | | | configured. | | | | | | configured. |
+-----------------+-------+---------+----------+--------------------+ +-------+-----------------+---------+----------+--------------------+
Table 31: Description of a Node Table 31: Description of a Node
10.3.25. RIFTEncodingPacketContent Registry 10.3.25. RIFTEncodingPacketContent Registry
This registry has the following initial values. This registry has the following initial values.
+==========+=======+=====================+=============+=========+ +=======+==========+=====================+=============+=========+
| Name | Value | Min. Schema Version | Max. Schema | Comment | | Value | Name | Min. Schema Version | Max. Schema | Comment |
| | | | Version | | | | | | Version | |
+==========+=======+=====================+=============+=========+ +=======+==========+=====================+=============+=========+
| Reserved | 0 | 8.0 | All | | | 0 | Reserved | 8.0 | All | |
| | | | Versions | | | | | | Versions | |
+----------+-------+---------------------+-------------+---------+ +-------+----------+---------------------+-------------+---------+
| lie | 1 | 8.0 | | | | 1 | lie | 8.0 | | |
+----------+-------+---------------------+-------------+---------+ +-------+----------+---------------------+-------------+---------+
| tide | 2 | 8.0 | | | | 2 | tide | 8.0 | | |
+----------+-------+---------------------+-------------+---------+ +-------+----------+---------------------+-------------+---------+
| tire | 3 | 8.0 | | | | 3 | tire | 8.0 | | |
+----------+-------+---------------------+-------------+---------+ +-------+----------+---------------------+-------------+---------+
| tie | 4 | 8.0 | | | | 4 | tie | 8.0 | | |
+----------+-------+---------------------+-------------+---------+ +-------+----------+---------------------+-------------+---------+
Table 32: Content of a RIFT Packet Table 32: Content of a RIFT Packet
10.3.26. RIFTEncodingPacketHeader Registry 10.3.26. RIFTEncodingPacketHeader Registry
This registry has the following initial values. This registry has the following initial values.
+===============+=======+=========+==========+===================+ +=======+===============+=========+==========+===================+
| Name | Value | Min. | Max. | Comment | | Value | Name | Min. | Max. | Comment |
| | | Schema | Schema | | | | | Schema | Schema | |
| | | Version | Version | | | | | Version | Version | |
+===============+=======+=========+==========+===================+ +=======+===============+=========+==========+===================+
| Reserved | 0 | 8.0 | All | | | 0 | Reserved | 8.0 | All | |
| | | | Versions | | | | | | Versions | |
+---------------+-------+---------+----------+-------------------+ +-------+---------------+---------+----------+-------------------+
| major_version | 1 | 8.0 | | Major version of | | 1 | major_version | 8.0 | | Major version of |
| | | | | protocol. | | | | | | protocol. |
+---------------+-------+---------+----------+-------------------+ +-------+---------------+---------+----------+-------------------+
| minor_version | 2 | 8.0 | | Minor version of | | 2 | minor_version | 8.0 | | Minor version of |
| | | | | protocol. | | | | | | protocol. |
+---------------+-------+---------+----------+-------------------+ +-------+---------------+---------+----------+-------------------+
| sender | 3 | 8.0 | | Node sending the | | 3 | sender | 8.0 | | Node sending the |
| | | | | packet, in case | | | | | | packet, in case |
| | | | | of LIE/TIRE/TIDE | | | | | | of LIE/TIRE/TIDE |
| | | | | also the | | | | | | also the |
| | | | | originator of it. | | | | | | originator of it. |
+---------------+-------+---------+----------+-------------------+ +-------+---------------+---------+----------+-------------------+
| level | 4 | 8.0 | | Level of the node | | 4 | level | 8.0 | | Level of the node |
| | | | | sending the | | | | | | sending the |
| | | | | packet, required | | | | | | packet, required |
| | | | | on everything | | | | | | on everything |
| | | | | except LIEs. | | | | | | except LIEs. |
| | | | | Lack of presence | | | | | | Lack of presence |
| | | | | on LIEs indicates | | | | | | on LIEs indicates |
| | | | | undefined_level | | | | | | undefined_level |
| | | | | and is used in | | | | | | and is used in |
| | | | | ZTP procedures. | | | | | | ZTP procedures. |
+---------------+-------+---------+----------+-------------------+ +-------+---------------+---------+----------+-------------------+
Table 33: Common RIFT Packet Header Table 33: Common RIFT Packet Header
10.3.27. RIFTEncodingPrefixAttributes Registry 10.3.27. RIFTEncodingPrefixAttributes Registry
This registry has the following initial values. This registry has the following initial values.
+===================+=======+=========+==========+==================+ +=======+===================+=========+==========+==================+
| Name | Value | Min. | Max. | Comment | | Value | Name | Min. | Max. | Comment |
| | | Schema | Schema | | | | | Schema | Schema | |
| | | Version | Version | | | | | Version | Version | |
+===================+=======+=========+==========+==================+ +=======+===================+=========+==========+==================+
| Reserved | 0 | 8.0 | All | | | 0 | Reserved | 8.0 | All | |
| | | | Versions | | | | | | Versions | |
+-------------------+-------+---------+----------+------------------+ +-------+-------------------+---------+----------+------------------+
| metric | 2 | 8.0 | | Distance of the | | 2 | metric | 8.0 | | Distance of the |
| | | | | prefix. | | | | | | prefix. |
+-------------------+-------+---------+----------+------------------+ +-------+-------------------+---------+----------+------------------+
| tags | 3 | 8.0 | | Generic | | 3 | tags | 8.0 | | Generic |
| | | | | unordered set | | | | | | unordered set |
| | | | | of route tags, | | | | | | of route tags, |
| | | | | can be | | | | | | can be |
| | | | | redistributed | | | | | | redistributed |
| | | | | to other | | | | | | to other |
| | | | | protocols or | | | | | | protocols or |
| | | | | used within the | | | | | | used within the |
| | | | | context of real | | | | | | context of real |
| | | | | time analytics. | | | | | | time analytics. |
+-------------------+-------+---------+----------+------------------+ +-------+-------------------+---------+----------+------------------+
| monotonic_clock | 4 | 8.0 | | Monotonic clock | | 4 | monotonic_clock | 8.0 | | Monotonic clock |
| | | | | for mobile | | | | | | for mobile |
| | | | | addresses. | | | | | | addresses. |
+-------------------+-------+---------+----------+------------------+ +-------+-------------------+---------+----------+------------------+
| loopback | 6 | 8.0 | | Indicates if | | 6 | loopback | 8.0 | | Indicates if |
| | | | | the prefix is a | | | | | | the prefix is a |
| | | | | node loopback. | | | | | | node loopback. |
+-------------------+-------+---------+----------+------------------+ +-------+-------------------+---------+----------+------------------+
| directly_attached | 7 | 8.0 | | Indicates that | | 7 | directly_attached | 8.0 | | Indicates that |
| | | | | the prefix is | | | | | | the prefix is |
| | | | | directly | | | | | | directly |
| | | | | attached. | | | | | | attached. |
+-------------------+-------+---------+----------+------------------+ +-------+-------------------+---------+----------+------------------+
| from_link | 10 | 8.0 | | Link to which | | 10 | from_link | 8.0 | | Link to which |
| | | | | the address | | | | | | the address |
| | | | | belongs to. | | | | | | belongs to. |
+-------------------+-------+---------+----------+------------------+ +-------+-------------------+---------+----------+------------------+
| label | 12 | 8.0 | | Optional, per- | | 12 | label | 8.0 | | Optional, per- |
| | | | | prefix | | | | | | prefix |
| | | | | significant | | | | | | significant |
| | | | | label. | | | | | | label. |
+-------------------+-------+---------+----------+------------------+ +-------+-------------------+---------+----------+------------------+
Table 34: Attributes of a Prefix Table 34: Attributes of a Prefix
10.3.28. RIFTEncodingPrefixTIEElement Registry 10.3.28. RIFTEncodingPrefixTIEElement Registry
This registry has the following initial values. This registry has the following initial values.
+==========+=======+=============+=============+================+ +=======+==========+=============+=============+================+
| Name | Value | Min. Schema | Max. Schema | Comment | | Value | Name | Min. Schema | Max. Schema | Comment |
| | | Version | Version | | | | | Version | Version | |
+==========+=======+=============+=============+================+ +=======+==========+=============+=============+================+
| Reserved | 0 | 8.0 | All | | | 0 | Reserved | 8.0 | All | |
| | | | Versions | | | | | | Versions | |
+----------+-------+-------------+-------------+----------------+ +-------+----------+-------------+-------------+----------------+
| prefixes | 1 | 8.0 | | Prefixes with | | 1 | prefixes | 8.0 | | Prefixes with |
| | | | | the associated | | | | | | the associated |
| | | | | attributes. | | | | | | attributes. |
+----------+-------+-------------+-------------+----------------+ +-------+----------+-------------+-------------+----------------+
Table 35: TIE Carrying Prefixes Table 35: TIE Carrying Prefixes
10.3.29. RIFTEncodingProtocolPacket Registry 10.3.29. RIFTEncodingProtocolPacket Registry
This registry has the following initial values. This registry has the following initial values.
+==========+=======+=====================+=============+=========+ +=======+==========+=====================+=============+=========+
| Name | Value | Min. Schema Version | Max. Schema | Comment | | Value | Name | Min. Schema Version | Max. Schema | Comment |
| | | | Version | | | | | | Version | |
+==========+=======+=====================+=============+=========+ +=======+==========+=====================+=============+=========+
| Reserved | 0 | 8.0 | All | | | 0 | Reserved | 8.0 | All | |
| | | | Versions | | | | | | Versions | |
+----------+-------+---------------------+-------------+---------+ +-------+----------+---------------------+-------------+---------+
| header | 1 | 8.0 | | | | 1 | header | 8.0 | | |
+----------+-------+---------------------+-------------+---------+ +-------+----------+---------------------+-------------+---------+
| content | 2 | 8.0 | | | | 2 | content | 8.0 | | |
+----------+-------+---------------------+-------------+---------+ +-------+----------+---------------------+-------------+---------+
Table 36: RIFT Packet Structure Table 36: RIFT Packet Structure
10.3.30. RIFTEncodingTIDEPacket Registry 10.3.30. RIFTEncodingTIDEPacket Registry
This registry has the following initial values. This registry has the following initial values.
+=============+=======+=============+=============+===============+ +=======+=============+=============+=============+===============+
| Name | Value | Min. Schema | Max. Schema | Comment | | Value | Name | Min. Schema | Max. Schema | Comment |
| | | Version | Version | | | | | Version | Version | |
+=============+=======+=============+=============+===============+ +=======+=============+=============+=============+===============+
| Reserved | 0 | 8.0 | All | | | 0 | Reserved | 8.0 | All | |
| | | | Versions | | | | | | Versions | |
+-------------+-------+-------------+-------------+---------------+ +-------+-------------+-------------+-------------+---------------+
| start_range | 1 | 8.0 | | First TIE | | 1 | start_range | 8.0 | | First TIE |
| | | | | header in the | | | | | | header in the |
| | | | | TIDE packet. | | | | | | TIDE packet. |
+-------------+-------+-------------+-------------+---------------+ +-------+-------------+-------------+-------------+---------------+
| end_range | 2 | 8.0 | | Last TIE | | 2 | end_range | 8.0 | | Last TIE |
| | | | | header in the | | | | | | header in the |
| | | | | TIDE packet. | | | | | | TIDE packet. |
+-------------+-------+-------------+-------------+---------------+ +-------+-------------+-------------+-------------+---------------+
| headers | 3 | 8.0 | | _sorted_ list | | 3 | headers | 8.0 | | _sorted_ list |
| | | | | of headers. | | | | | | of headers. |
+-------------+-------+-------------+-------------+---------------+ +-------+-------------+-------------+-------------+---------------+
Table 37: TIDE with Sorted TIE Headers Table 37: TIDE with Sorted TIE Headers
10.3.31. RIFTEncodingTIEElement Registry 10.3.31. RIFTEncodingTIEElement Registry
This registry has the following initial values. This registry has the following initial values.
+========================+=====+=======+========+===================+ +=====+========================+=======+========+===================+
|Name |Value|Min. |Max. |Comment | |Value|Name |Min. |Max. |Comment |
| | |Schema |Schema | | | | |Schema |Schema | |
| | |Version|Version | | | | |Version|Version | |
+========================+=====+=======+========+===================+ +=====+========================+=======+========+===================+
|Reserved |0 |8.0 |All | | |0 |Reserved |8.0 |All | |
| | | |Versions| | | | | |Versions| |
+------------------------+-----+-------+--------+-------------------+ +-----+------------------------+-------+--------+-------------------+
|node |1 |8.0 | |Used in case of | |1 |node |8.0 | |Used in case of |
| | | | |enum | | | | | |enum |
| | | | |common.tietypetype.| | | | | |common.tietypetype.|
| | | | |nodetietype. | | | | | |nodetietype. |
+------------------------+-----+-------+--------+-------------------+ +-----+------------------------+-------+--------+-------------------+
|prefixes |2 |8.0 | |Used in case of | |2 |prefixes |8.0 | |Used in case of |
| | | | |enum | | | | | |enum |
| | | | |common.tietypetype.| | | | | |common.tietypetype.|
| | | | |prefixtietype. | | | | | |prefixtietype. |
+------------------------+-----+-------+--------+-------------------+ +-----+------------------------+-------+--------+-------------------+
|positive_disaggregation_|3 |8.0 | |Positive prefixes | |3 |positive_disaggregation_|8.0 | |Positive prefixes |
|prefixes | | | |(always | | |prefixes | | |(always |
| | | | |southbound). | | | | | |southbound). |
+------------------------+-----+-------+--------+-------------------+ +-----+------------------------+-------+--------+-------------------+
|negative_disaggregation_|5 |8.0 | |Transitive, | |5 |negative_disaggregation_|8.0 | |Transitive, |
|prefixes | | | |negative prefixes | | |prefixes | | |negative prefixes |
| | | | |(always southbound)| | | | | |(always southbound)|
+------------------------+-----+-------+--------+-------------------+ +-----+------------------------+-------+--------+-------------------+
|external_prefixes |6 |8.0 | |Externally | |6 |external_prefixes |8.0 | |Externally |
| | | | |reimported | | | | | |reimported |
| | | | |prefixes. | | | | | |prefixes. |
+------------------------+-----+-------+--------+-------------------+ +-----+------------------------+-------+--------+-------------------+
|positive_external_ |7 |8.0 | |Positive external | |7 |positive_external_ |8.0 | |Positive external |
|disaggregation_prefixes | | | |disaggregated | | |disaggregation_prefixes | | |disaggregated |
| | | | |prefixes | | | | | |prefixes |
| | | | |(always | | | | | |(always |
| | | | |southbound). | | | | | |southbound). |
+------------------------+-----+-------+--------+-------------------+ +-----+------------------------+-------+--------+-------------------+
|keyvalues |9 |8.0 | |Key-value | |9 |keyvalues |8.0 | |Key-value |
| | | | |store elements. | | | | | |store elements. |
+------------------------+-----+-------+--------+-------------------+ +-----+------------------------+-------+--------+-------------------+
Table 38: Single Element in a TIE Table 38: Single Element in a TIE
10.3.32. RIFTEncodingTIEHeader Registry 10.3.32. RIFTEncodingTIEHeader Registry
This registry has the following initial values. This registry has the following initial values.
+======================+=======+=========+==========+==============+ +=======+======================+=========+==========+==============+
| Name | Value | Min. | Max. | Comment | | Value | Name | Min. | Max. | Comment |
| | | Schema | Schema | | | | | Schema | Schema | |
| | | Version | Version | | | | | Version | Version | |
+======================+=======+=========+==========+==============+ +=======+======================+=========+==========+==============+
| Reserved | 0 | 8.0 | All | | | 0 | Reserved | 8.0 | All | |
| | | | Versions | | | | | | Versions | |
+----------------------+-------+---------+----------+--------------+ +-------+----------------------+---------+----------+--------------+
| tieid | 2 | 8.0 | | ID of TIE. | | 2 | tieid | 8.0 | | ID of TIE. |
+----------------------+-------+---------+----------+--------------+ +-------+----------------------+---------+----------+--------------+
| seq_nr | 3 | 8.0 | | Sequence | | 3 | seq_nr | 8.0 | | Sequence |
| | | | | number of | | | | | | number of |
| | | | | TIE. | | | | | | TIE. |
+----------------------+-------+---------+----------+--------------+ +-------+----------------------+---------+----------+--------------+
| origination_time | 10 | 8.0 | | Absolute | | 10 | origination_time | 8.0 | | Absolute |
| | | | | timestamp | | | | | | timestamp |
| | | | | when TIE was | | | | | | when TIE was |
| | | | | generated. | | | | | | generated. |
+----------------------+-------+---------+----------+--------------+ +-------+----------------------+---------+----------+--------------+
| origination_lifetime | 12 | 8.0 | | Original | | 12 | origination_lifetime | 8.0 | | Original |
| | | | | lifetime | | | | | | lifetime |
| | | | | when TIE was | | | | | | when TIE was |
| | | | | generated. | | | | | | generated. |
+----------------------+-------+---------+----------+--------------+ +-------+----------------------+---------+----------+--------------+
Table 39: Header of a TIE Table 39: Header of a TIE
10.3.33. RIFTEncodingTIEHeaderWithLifeTime Registry 10.3.33. RIFTEncodingTIEHeaderWithLifeTime Registry
This registry has the following initial values. This registry has the following initial values.
+====================+=======+=============+==========+===========+ +=======+====================+=============+==========+===========+
| Name | Value | Min. Schema | Max. | Comment | | Value | Name | Min. Schema | Max. | Comment |
| | | Version | Schema | | | | | Version | Schema | |
| | | | Version | | | | | | Version | |
+====================+=======+=============+==========+===========+ +=======+====================+=============+==========+===========+
| Reserved | 0 | 8.0 | All | | | 0 | Reserved | 8.0 | All | |
| | | | Versions | | | | | | Versions | |
+--------------------+-------+-------------+----------+-----------+ +-------+--------------------+-------------+----------+-----------+
| header | 1 | 8.0 | | | | 1 | header | 8.0 | | |
+--------------------+-------+-------------+----------+-----------+ +-------+--------------------+-------------+----------+-----------+
| remaining_lifetime | 2 | 8.0 | | Remaining | | 2 | remaining_lifetime | 8.0 | | Remaining |
| | | | | lifetime. | | | | | | lifetime. |
+--------------------+-------+-------------+----------+-----------+ +-------+--------------------+-------------+----------+-----------+
Table 40: Header of a TIE as Described in TIRE/TIDE Table 40: Header of a TIE as Described in TIRE/TIDE
10.3.34. RIFTEncodingTIEID Registry 10.3.34. RIFTEncodingTIEID Registry
This registry has the following initial values. This registry has the following initial values.
+============+=======+=============+=============+============+ +=======+============+=============+=============+============+
| Name | Value | Min. Schema | Max. Schema | Comment | | Value | Name | Min. Schema | Max. Schema | Comment |
| | | Version | Version | | | | | Version | Version | |
+============+=======+=============+=============+============+ +=======+============+=============+=============+============+
| Reserved | 0 | 8.0 | All | | | 0 | Reserved | 8.0 | All | |
| | | | Versions | | | | | | Versions | |
+------------+-------+-------------+-------------+------------+ +-------+------------+-------------+-------------+------------+
| direction | 1 | 8.0 | | Direction | | 1 | direction | 8.0 | | Direction |
| | | | | of TIE. | | | | | | of TIE. |
+------------+-------+-------------+-------------+------------+ +-------+------------+-------------+-------------+------------+
| originator | 2 | 8.0 | | Indicates | | 2 | originator | 8.0 | | Indicates |
| | | | | originator | | | | | | originator |
| | | | | of TIE. | | | | | | of TIE. |
+------------+-------+-------------+-------------+------------+ +-------+------------+-------------+-------------+------------+
| tietype | 3 | 8.0 | | Type of | | 3 | tietype | 8.0 | | Type of |
| | | | | TIE. | | | | | | TIE. |
+------------+-------+-------------+-------------+------------+ +-------+------------+-------------+-------------+------------+
| tie_nr | 4 | 8.0 | | Number of | | 4 | tie_nr | 8.0 | | Number of |
| | | | | TIE. | | | | | | TIE. |
+------------+-------+-------------+-------------+------------+ +-------+------------+-------------+-------------+------------+
Table 41: Unique ID of a TIE Table 41: Unique ID of a TIE
10.3.35. RIFTEncodingTIEPacket Registry 10.3.35. RIFTEncodingTIEPacket Registry
This registry has the following initial values. This registry has the following initial values.
+==========+=======+=====================+=============+=========+ +=======+==========+=====================+=============+=========+
| Name | Value | Min. Schema Version | Max. Schema | Comment | | Value | Name | Min. Schema Version | Max. Schema | Comment |
| | | | Version | | | | | | Version | |
+==========+=======+=====================+=============+=========+ +=======+==========+=====================+=============+=========+
| Reserved | 0 | 8.0 | All | | | 0 | Reserved | 8.0 | All | |
| | | | Versions | | | | | | Versions | |
+----------+-------+---------------------+-------------+---------+ +-------+----------+---------------------+-------------+---------+
| header | 1 | 8.0 | | | | 1 | header | 8.0 | | |
+----------+-------+---------------------+-------------+---------+ +-------+----------+---------------------+-------------+---------+
| element | 2 | 8.0 | | | | 2 | element | 8.0 | | |
+----------+-------+---------------------+-------------+---------+ +-------+----------+---------------------+-------------+---------+
Table 42: TIE Packet Table 42: TIE Packet
10.3.36. RIFTEncodingTIREPacket Registry 10.3.36. RIFTEncodingTIREPacket Registry
This registry has the following initial values. This registry has the following initial values.
+==========+=======+=====================+=============+=========+ +=======+==========+=====================+=============+=========+
| Name | Value | Min. Schema Version | Max. Schema | Comment | | Value | Name | Min. Schema Version | Max. Schema | Comment |
| | | | Version | | | | | | Version | |
+==========+=======+=====================+=============+=========+ +=======+==========+=====================+=============+=========+
| Reserved | 0 | 8.0 | All | | | 0 | Reserved | 8.0 | All | |
| | | | Versions | | | | | | Versions | |
+----------+-------+---------------------+-------------+---------+ +-------+----------+---------------------+-------------+---------+
| headers | 1 | 8.0 | | | | 1 | headers | 8.0 | | |
+----------+-------+---------------------+-------------+---------+ +-------+----------+---------------------+-------------+---------+
Table 43: TIRE Packet Table 43: TIRE Packet
11. References 11. References
11.1. Normative References 11.1. Normative References
[EUI64] IEEE, "Guidelines for Use of Extended Unique Identifier [EUI64] IEEE, "Guidelines for Use of Extended Unique Identifier
(EUI), Organizationally Unique Identifier (OUI), and (EUI), Organizationally Unique Identifier (OUI), and
Company ID (CID)", <https://standards-support.ieee.org/hc/ Company ID (CID)", <https://standards-support.ieee.org/hc/
skipping to change at line 8155 skipping to change at line 8128
21 and ToF 22. 21 and ToF 22.
Spines hold only North TIEs of level 0 for their PoD, while leaves Spines hold only North TIEs of level 0 for their PoD, while leaves
only hold their own North TIEs while, at this point, both ToF 21 and only hold their own North TIEs while, at this point, both ToF 21 and
ToF 22 (as well as any northbound connected controllers) would have ToF 22 (as well as any northbound connected controllers) would have
the complete network topology. the complete network topology.
ToF 21 and ToF 22 would then originate and flood South TIEs ToF 21 and ToF 22 would then originate and flood South TIEs
containing any established adjacencies and a default IP route to all containing any established adjacencies and a default IP route to all
spines. Spine 111, Spine 112, Spine 121, and Spine 122 will reflect spines. Spine 111, Spine 112, Spine 121, and Spine 122 will reflect
all Node South TIEs received from ToF 21 to ToF 22 and all Node South all South Node TIEs received from ToF 21 to ToF 22 and all South Node
TIEs from ToF 22 to ToF 21. South TIEs will not be re-propagated TIEs from ToF 22 to ToF 21. South TIEs will not be re-propagated
southbound. southbound.
South TIEs containing a default IP route are then originated by both South TIEs containing a default IP route are then originated by both
Spine 111 and Spine 112 towards Leaf 111 and Leaf 112. Similarly, Spine 111 and Spine 112 towards Leaf 111 and Leaf 112. Similarly,
South TIEs containing a default IP route are originated by Spine 121 South TIEs containing a default IP route are originated by Spine 121
and Spine 122 towards Leaf 121 and Leaf 122. and Spine 122 towards Leaf 121 and Leaf 122.
At this point, IP connectivity across the maximum number of viable At this point, IP connectivity across the maximum number of viable
paths has been established for all leaves, with routing information paths has been established for all leaves, with routing information
skipping to change at line 8194 skipping to change at line 8167
+-------+ +-------+ +-------+ +-------+
+ + + +
Prefix111 Prefix112 Prefix111 Prefix112
Figure 36: Single Leaf Link Failure Figure 36: Single Leaf Link Failure
In the event of a link failure between Spine 112 and Leaf 112, both In the event of a link failure between Spine 112 and Leaf 112, both
nodes will originate new Node TIEs that contain their connected nodes will originate new Node TIEs that contain their connected
adjacencies, except for the one that just failed. Leaf 112 will send adjacencies, except for the one that just failed. Leaf 112 will send
a North Node TIE to Spine 111. Spine 112 will send a North Node TIE a North Node TIE to Spine 111. Spine 112 will send a North Node TIE
to ToF 21 and ToF 22 as well as a new Node South TIE to Leaf 111 that to ToF 21 and ToF 22 as well as a new South Node TIE to Leaf 111 that
will be reflected to Spine 111. Necessary SPF recomputation will will be reflected to Spine 111. Necessary SPF recomputation will
occur, resulting in Spine 112 no longer being in the forwarding path occur, resulting in Spine 112 no longer being in the forwarding path
for Prefix 112. for Prefix 112.
Spine 111 will also disaggregate Prefix 112 by sending new Prefix Spine 111 will also disaggregate Prefix 112 by sending new South
South TIE to Leaf 111 and Leaf 112. Though disaggregation is covered Prefix TIE to Leaf 111 and Leaf 112. Though disaggregation is
in more detail in the following section, it is worth mentioning in covered in more detail in the following section, it is worth
this example as it further illustrates RIFT's mechanism to mitigate mentioning in this example as it further illustrates RIFT's mechanism
traffic loss. Consider that Leaf 111 has yet to receive the more to mitigate traffic loss. Consider that Leaf 111 has yet to receive
specific (disaggregated) route from Spine 111. In such a scenario, the more specific (disaggregated) route from Spine 111. In such a
traffic from Leaf 111 towards Prefix 112 may still use Spine 112's scenario, traffic from Leaf 111 towards Prefix 112 may still use
default route, causing it to traverse ToF 21 and ToF 22 back down via Spine 112's default route, causing it to traverse ToF 21 and ToF 22
Spine 111. While this behavior is suboptimal, it is transient in back down via Spine 111. While this behavior is suboptimal, it is
nature and preferred to dropping traffic. transient in nature and preferred to dropping traffic.
B.3. Partitioned Fabric B.3. Partitioned Fabric
+--------+ +--------+ +--------+ +--------+
Level 2 |ToF 21| |ToF 22| Level 2 |ToF 21| |ToF 22|
++-+--+-++ ++-+--+-++ ++-+--+-++ ++-+--+-++
| | | | | | | | | | | | | | | |
| | | | | | | 0/0 | | | | | | | 0/0
| | | | | | | | | | | | | | | |
| | | | | | | | | | | | | | | |
skipping to change at line 8273 skipping to change at line 8246
do not benefit from this information. Spine 111 and Spine 112 are do not benefit from this information. Spine 111 and Spine 112 are
only required to reflect the new South Node TIEs received from ToF 22 only required to reflect the new South Node TIEs received from ToF 22
to ToF 21. In short, only the relevant nodes received the relevant to ToF 21. In short, only the relevant nodes received the relevant
updates, thereby restricting the failure to only the partitioned updates, thereby restricting the failure to only the partitioned
level rather than burdening the whole fabric with the flooding and level rather than burdening the whole fabric with the flooding and
recomputation of the new topology information. recomputation of the new topology information.
To finish this example, the following list shows sets computed by ToF To finish this example, the following list shows sets computed by ToF
22 using notation introduced in Section 6.5: 22 using notation introduced in Section 6.5:
* R = Prefix 111, Prefix 112, Prefix 121, Prefix 122 |R = Prefix 111, Prefix 112, Prefix 121, Prefix 122
* H (for r=Prefix 111) = Spine 111, Spine 112 |H (for r=Prefix 111) = Spine 111, Spine 112
* H (for r=Prefix 112) = Spine 111, Spine 112 |H (for r=Prefix 112) = Spine 111, Spine 112
* H (for r=Prefix 121) = Spine 121, Spine 122 |H (for r=Prefix 121) = Spine 121, Spine 122
* H (for r=Prefix 122) = Spine 121, Spine 122 |H (for r=Prefix 122) = Spine 121, Spine 122
* A (for ToF 21) = Spine 111, Spine 112 |A (for ToF 21) = Spine 111, Spine 112
With that and |H (for r=Prefix 121) and |H (for r=Prefix 122) being With that and |H (for r=Prefix 121) and |H (for r=Prefix 122) being
disjoint from |A (for ToF 21), ToF 22 will originate a South TIE with disjoint from |A (for ToF 21), ToF 22 will originate a South TIE with
Prefix 121 and Prefix 122, which will be flooded to all spines. Prefix 121 and Prefix 122, which will be flooded to all spines.
B.4. Northbound Partitioned Router and Optional East-West Links B.4. Northbound Partitioned Router and Optional East-West Links
+ + + + + +
X N1 | N2 | N3 X N1 | N2 | N3
X | | X | |
skipping to change at line 8396 skipping to change at line 8369
Contributors Contributors
This work is a product of a list of individuals who are all to be This work is a product of a list of individuals who are all to be
considered major contributors, independent of the fact whether or not considered major contributors, independent of the fact whether or not
their name made it to the limited author list. their name made it to the limited author list.
Tony Przygienda, Ed. Tony Przygienda, Ed.
Juniper Juniper
Jordan Head, Ed.
Juniper
Alankar Sharma
Hudson River Trading
Pascal Thubert Pascal Thubert
Cisco Cisco
Bruno Rijsman Bruno Rijsman
Individual Individual
Jordan Head, Ed.
Juniper
Dmitry Afanasiev Dmitry Afanasiev
Individual Individual
Don Fedyk Don Fedyk
LabN LabN
Alia Atlas Alia Atlas
Individual Individual
John Drake John Drake
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