YANG Data Model for IS-IS
SRv6
Huawei
Huawei Bld., No.156 Beiqing Rd.
Beijing
100095
China
huzhibo@huawei.com
Cisco
170 W. Tasman Dr. San Jose,
California
95134
USA
daye@cisco.com
Futurewei Technologies
2330 Central Express Way
Santa Clara
950950
USA
yingzhen.qu@futurewei.com
Huawei
Huawei Bld., No.156 Beiqing Rd.
Beijing
100095
China
gengxuesong@huawei.com
Huawei
101 Software Avenue, Yuhua District
Nanjing
Jiangsu
210012
China
maqiufang1@huawei.com
This document defines a YANG data model that can be used to configure
and manage IS-IS SRv6
.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 .
YANG is
a data definition language used to define the contents of a conceptual
data store that allows networked devices to be managed using
NETCONF . YANG is proving relevant beyond
its initial confines, as bindings to other interfaces (e.g., REST) and
encodings other than XML (e.g., JSON) are being defined. Furthermore,
YANG data models can be used as the basis for implementation of other
interfaces, such as CLI and programmatic APIs.
This document defines a YANG data model that can be used to configure
and manage IS-IS SRv6 and it is an augmentation to the IS-IS YANG data
model.
This document defines a model for IS-IS SRv6 feature. It is an
augmentation of the IS-IS base model.
The IS-IS SRv6 YANG module requires support for the base srv6
module , which defines the
global srv6 configuration independent of any specific routing protocol
configuration, and support of IS-IS base model which defines basic IS-IS
configuration and state. This module uses types defined in . It also references , , , and .
The figure below describes the overall structure of the isis-srv6
YANG module:
/rt:routing/sr:segment-routing
| /srv6:srv6/locators/locator/name
| +--rw persistent-end-x-sid? boolean
+--rw micro-loop-avoidance
+--rw srv6-enable? boolean
+--rw srv6-rib-update-delay? uint16
augment /rt:routing/rt:control-plane-protocols
/rt:control-plane-protocol/isis:isis/isis:fast-reroute:
+--rw srv6-ti-lfa {srv6-ti-lfa}?
+--rw enable? boolean
augment /rt:routing/rt:control-plane-protocols
/rt:control-plane-protocol/isis:isis/isis:database
/isis:levels/isis:lsp/isis:router-capabilities:
+--ro v6-capability
| +--ro flags? bits
+--ro srv6-msd
+--ro max-segments-left? uint8
+--ro max-end-pop? uint8
+--ro max-h-encaps? uint8
+--ro max-end-d? uint8
augment /rt:routing/rt:control-plane-protocols
/rt:control-plane-protocol/isis:isis/isis:database
/isis:levels/isis:lsp/isis:extended-is-neighbor/isis:neighbor:
+--ro srv6-adjacency-sids
+--ro end-x-sid* [sid]
+--ro func-flags? bits
+--ro algorithm? uint8
+--ro weight? uint8
+--ro endpoint-func
| +--ro flags? uint8
| +--ro endpoint-func? identityref
| +--ro undefined-endpoint-func? uint16
+--ro sid srv6-sid-value
+--ro neighbor-id? isis:system-id
+--ro srv6-sid-structure
+--ro lb-length? uint8
+--ro ln-length? uint8
+--ro fun-length? uint8
+--ro arg-length? uint8
augment /rt:routing/rt:control-plane-protocols
/rt:control-plane-protocol/isis:isis/isis:database
/isis:levels/isis:lsp/isis:mt-is-neighbor/isis:neighbor:
+--ro srv6-adjacency-sids
+--ro end-x-sid* [sid]
+--ro func-flags? bits
+--ro algorithm? uint8
+--ro weight? uint8
+--ro endpoint-func
| +--ro flags? uint8
| +--ro endpoint-func? identityref
| +--ro undefined-endpoint-func? uint16
+--ro sid srv6-sid-value
+--ro neighbor-id? isis:system-id
+--ro srv6-sid-structure
+--ro lb-length? uint8
+--ro ln-length? uint8
+--ro fun-length? uint8
+--ro arg-length? uint8
augment /rt:routing/rt:control-plane-protocols
/rt:control-plane-protocol/isis:isis/isis:database
/isis:levels/isis:lsp:
+--ro srv6-locators
+--ro locator* [locator]
+--ro mt-id? uint16
+--ro flags? bits
+--ro metric? uint32
+--ro algorithm? uint8
+--ro loc-size? uint8
+--ro locator inet:ipv6-address-no-zone
+--ro srv6-end-sids
| +--ro end-sid* [sid]
| +--ro flags? uint8
| +--ro endpoint-func
| | +--ro flags? uint8
| | +--ro endpoint-func? identityref
| | +--ro undefined-endpoint-func? uint16
| +--ro sid srv6-sid-value
| +--ro srv6-sid-structure
| +--ro lb-length? uint8
| +--ro ln-length? uint8
| +--ro fun-length? uint8
| +--ro arg-length? uint8
+--ro external-prefix-flag? boolean
+--ro readvertisement-flag? boolean
+--ro node-flag? boolean
+--ro ipv4-source-router-id? inet:ipv4-address
+--ro ipv6-source-router-id? inet:ipv6-address
augment /rt:routing/rt:control-plane-protocols
/rt:control-plane-protocol/isis:isis/isis:interfaces
/isis:interface/isis:adjacencies/isis:adjacency:
+--ro end-x-sid* [value]
+--ro value srv6-sid-value
+--ro weight? uint8
+--ro protection-requested? boolean
+--ro persistent? boolean
+--ro algorithm? uint8
+--ro endpoint-func
+--ro flags? uint8
+--ro endpoint-func? identityref
+--ro undefined-endpoint-func? uint16
]]>
Activation of IS-IS SRv6 is done by setting the "enable" leaf to
true. This triggers advertisement of SRv6 extensions based on the
configuration parameters that have been setup using the base SRv6
module.
The basic SRv6 module defines the related locator leafs. When the
IS-IS SRv6 module is enabled, set the locator by using the following
strategy: firstly, it is reasonable to check whether the default
locator is used, if not, to use the specified locator. The strategy is
realized by adding the leaf "default-locator", "locator-name" .
IS-IS SRv6 model augments the fast-reroute container. It brings the
ability to activate ipv6 TI-LFA (topology independent LFA).
IS-IS SRv6 model augments the micro-loop-avoidance container, this
container including the leaf "srv6-enable" brings the ability to
activate SRv6 avoid-microloop.
file "ietf-isis-srv6@2022-03-26.yang"
module ietf-isis-srv6 {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:"
+ "yang:ietf-isis-srv6";
prefix isis-srv6;
import ietf-routing {
prefix "rt";
reference "RFC8349: A YANG Data Model for
Routing Management (NMDA Version)";
}
import ietf-isis {
prefix "isis";
reference "draft-ietf-isis-yang-isis-cfg: YANG
Data Model for IS-IS Protocol";
}
import ietf-inet-types {
prefix "inet";
reference "RFC 6991:Common YANG Data Types";
}
import ietf-segment-routing {
prefix sr;
reference "RFC 9020: YANG Data Model for Segment
Routing";
}
import ietf-srv6-base {
prefix "srv6";
reference "draft-ietf-spring-srv6-yang: YANG Data
Model for SRv6 Base and Static";
}
organization
"IETF LSR Working Group";
contact
"WG List:
Author: Zhibo Hu
Author: Dan Ye
Author: Yingzhen Qu
Author: Qiufang Ma
";
description
"The YANG module defines the configuration and operatioanl state
for IS-IS extension to support Segment Routing over IPv6 data
plane.
This YANG model conforms to the Network Management
Datastore Architecture (NDMA) as described in RFC 8342.
Copyright (c) 2022 IETF Trust and the persons identified as
authors of the code. All rights reserved.
Redistribution and use in source and binary forms, with or
without modification, is permitted pursuant to, and subject
to the license terms contained in, the Simplified BSD License
set forth in Section 4.c of the IETF Trust's Legal Provisions
Relating to IETF Documents
(http://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC XXXX
(https://www.rfc-editor.org/info/rfcXXXX); see the RFC itself
for full legal notices.
The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL
NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'NOT RECOMMENDED',
'MAY', and 'OPTIONAL' in this document are to be interpreted as
described in BCP 14 (RFC 2119) (RFC 8174) when, and only when,
they appear in all capitals, as shown here.";
revision 2022-03-26 {
description
"Initial revision.";
reference "draft-ietf-lsr-isis-srv6-extensions-08";
}
/* Identities */
identity SRV6_END_FUNC_TYPE {
description
"Base identity type for srv6 endpoint function code points.";
}
identity SRV6_END_FUNC_PSP_USP_USD {
base "SRV6_END_FUNC_TYPE";
description
"End (May support PSP, USP, USD).";
}
identity SRV6_END_X_FUNC_PSP_USP_USD {
base "SRV6_END_FUNC_TYPE";
description
"End.X(May support PSP, USP, USD)";
}
identity SRV6_END_T_FUNC_PSP_USP_USD {
base "SRV6_END_FUNC_TYPE";
description
"END (May support PSP, USP, USD)";
}
identity SRV6_END_FUNC_DX6 {
base "SRV6_END_FUNC_TYPE";
description
"End.DX6.";
}
identity SRV6_END_FUNC_DX4 {
base "SRV6_END_FUNC_TYPE";
description
"End.DX4.";
}
identity SRV6_END_FUNC_DT6 {
base "SRV6_END_FUNC_TYPE";
description
"End.DT6.";
}
identity SRV6_END_FUNC_DT4 {
base "SRV6_END_FUNC_TYPE";
description
"End.DT4.";
}
identity SRV6_END_FUNC_DT64 {
base "SRV6_END_FUNC_TYPE";
description
"End.DT64.";
}
identity SRV6_END_FUNC_OP {
base "SRV6_END_FUNC_TYPE";
description
"END.OP .";
}
identity SRV6_END_FUNC_OTP {
base "SRV6_END_FUNC_TYPE";
description
"END.OTP .";
}
/* typedef */
typedef srv6-sid-value {
type inet:ipv6-address-no-zone;
description
"16 Octets encoded sid value.";
}
/* Features */
feature srv6-ti-lfa {
description
"Enhance SRv6 FRR with ti-lfa
support";
}
/* Groupings */
grouping srv6-msds {
description
"means to advertise to advertise node/link specific
values for Maxium Sid Depths(MSD) of various types";
container srv6-msd {
description
"Maximum SRv6 SID Depths.";
leaf max-segments-left {
type uint8;
description
"The Maximum Segments Left MSD Type specifies
the maximum value of the 'SL' field in the SRH
of a received packet before applying the
Endpoint behavior associated with a SID.";
}
leaf max-end-pop {
type uint8;
description
"The Maximum End Pop MSD Type specifies the maximum
number of SIDs in the SRH to which the router can
apply 'PSP' or 'USP' behavior, as defined in flavors.";
}
leaf max-h-encaps {
type uint8;
description
"The Maximum H.Encaps MSD Type specifies the maximum number
of SIDs that can be included as part of the 'H.Encaps'
behavior";
}
leaf max-end-d {
type uint8;
description
"The maximum number of SIDs in an SRH when performing
decapsulation associated with 'End.Dx' functions
(e.g., 'End.DX6' and 'End.DT6').";
}
}
}
grouping srv6-sid-structures {
description
"This group defines SRv6 SID Structure sub-sub-TLV.";
container srv6-sid-structure {
description
"SRv6 SID Structure sub-sub-TLV is used to advertise
the length of each individual part of the SRv6 SID
as defined in [I-D.ietf-spring-srv6-network-programming]";
leaf lb-length {
type uint8;
description
"SRv6 SID Locator Block length in bits.";
}
leaf ln-length {
type uint8;
description
"SRv6 SID Locator Node length in bits.";
}
leaf fun-length {
type uint8;
description
"SRv6 SID Function length in bits.";
}
leaf arg-length {
type uint8;
description
"SRv6 SID Argument length in bits.";
}
}
}
grouping srv6-capability {
description
"SRV6 capability grouping.";
container v6-capability {
description
"SRv6 capability.";
leaf flags {
type bits {
bit o-flag {
position 1;
description
"If set, then the router is able to
use of the O-bit in the Segment Routing Header(SRH)
as defined in [draft-ietf-6man-segment-routing-header].";
}
}
description
"Flags.";
}
}
}
grouping srv6-endpoint-func {
description
"This group defines srv6 endpoint function";
container endpoint-func {
description
"Srv6 Endpoint function Descriptor.";
leaf flags {
type uint8;
description
"No flags are currently being defined.";
}
leaf endpoint-func {
type identityref {
base isis-srv6:SRV6_END_FUNC_TYPE;
}
description
"The endpoint function.";
}
leaf undefined-endpoint-func {
type uint16;
description
"Unknown endpoint func value.";
}
}
}
grouping srv6-end-sid {
description
"SRv6 Segment Identifier(SID) with Endpoint functions.";
leaf flags {
type uint8;
description
"NO flags are currently being defined.";
}
uses srv6-endpoint-func;
leaf sid {
type srv6-sid-value;
description
"SRV6 sid value.";
}
// sub-sub-tlvs
uses srv6-sid-structures;
}
grouping srv6-locator {
description
"This group defines srv6 locator tlv.";
leaf mt-id {
type uint16 {
range "0..4095";
}
description
"Multitopology Identifier as defined in [RFC5120].";
}
leaf flags {
type bits {
bit d-flag {
position 0;
description
"When the locator is leaked from level-2 to leve-1,
the d-flag must be set.";
}
}
description
"Flags for srv6 locator tlv.";
}
leaf metric {
type uint32;
description
"Metric value.";
}
leaf algorithm {
type uint8;
description
"Associated algorithm.";
}
leaf loc-size {
type uint8;
description
"Number of bits in the locator field.";
}
leaf locator {
type inet:ipv6-address-no-zone;
description
"Advertised SRV6 locator.";
}
container srv6-end-sids {
description
"This contains list of srv6 end sids.";
list end-sid {
key "sid";
description
"List of SRV6 SRv6 Segment Identifiers (SID)
with Endpoint functions.";
uses srv6-end-sid;
}
}
uses isis:prefix-reachability-attributes;
uses isis:prefix-ipv4-source-router-id;
uses isis:prefix-ipv6-source-router-id;
}
grouping srv6-adjacency-sid {
description
"SRv6 sid associated with an adjacency.";
leaf func-flags {
type bits {
bit b-flag {
position 0;
description
"Backup flag. If set, the End.X sid is
eligible for protection.";
}
bit s-flag {
position 1;
description
"Set flag. When set, the End.X sid refers to
a set of adjacencies (and therefore May be assigned
to other adjacencies as well.";
}
bit p-flag {
position 2;
description
"Persistent flag. When set, the End.X sid is persistently
allocated, i.e., the End.x sid value remains consistent
across router restart and/or interface flap.";
}
}
description
"Flags for srv6 end x sid.";
}
leaf algorithm {
type uint8;
description
"Associated algorithm.";
}
leaf weight {
type uint8;
description
"The value represents the weight of the End.X sid
for the purpose of load balancing.";
}
uses srv6-endpoint-func;
leaf sid {
type srv6-sid-value;
description
"SRV6 sid value.";
}
leaf neighbor-id {
type isis:system-id;
description
"Describes the system ID of the neighbor
associated with the SID value. This is only
used on LAN adjacencies.";
}
// sub-sub-tlvs
uses srv6-sid-structures;
}
grouping srv6-adjacency-state {
description
"This group will extend adjacency state.";
list end-x-sid {
key value;
config false;
leaf value {
type srv6-sid-value;
description
"Value of the Adj-SID.";
}
leaf weight {
type uint8;
description
"Weight associated with
the End.X SID.";
}
leaf protection-requested {
type boolean;
description
"Set to True if the End.X SID
must be protected.";
}
leaf persistent {
type boolean;
description
"Persistent flag. When set, the End.X sid is persistently
allocated, i.e., the End.X sid value remains consistent
across router restart and/or interface flap.";
}
leaf algorithm {
type uint8;
description
"Associated algorithm.";
}
uses srv6-endpoint-func;
description
"List of End.X Segment IDs.";
}
}
/* Cfg */
augment "/rt:routing/" +
"rt:control-plane-protocols/rt:control-plane-protocol"+
"/isis:isis" {
when "/rt:routing/rt:control-plane-protocols/"+
"rt:control-plane-protocol/rt:type = 'isis:isis'" {
description
"This augment ISIS routing protocol when used";
}
description
"This augments ISIS protocol configuration
with SRv6.";
container srv6-cfg{
leaf enable{
type boolean;
default "false";
description
"Enables SRv6
protocol extensions.";
}
leaf default-locator {
type boolean;
default "false";
description
"Enable ISIS segment-routing IPv6 with default Locator.";
}
leaf-list locator-name {
when "../default-locator = 'false'" {
description
"Only applies to non default locator.";
}
type leafref {
path "/rt:routing/sr:segment-routing/srv6:srv6" +
"/srv6:locators/srv6:locator/srv6:name";
}
description
"Enable ISIS segment-routing IPv6 with specified Locator.";
}
leaf persistent-end-x-sid{
type boolean;
default "false";
description
"Enable the persistent nature of End.X sid";
}
description
"Configuration about ISIS segment-routing IPv6.";
}
container micro-loop-avoidance {
leaf srv6-enable {
type boolean;
default "false";
description
"Enable SRv6 avoid-microloop.Depend on SR IPv6 Enable.";
}
leaf srv6-rib-update-delay {
type uint16 {
range "1000..10000";
}
units "ms";
default "5000";
description
"Set the route delivery delay for SRv6 avoid-microloop.
Depend on SR IPv6 Enable.";
}
description
"Enable IS-IS avoid-microloop.";
}
}
augment "/rt:routing/" +
"rt:control-plane-protocols/rt:control-plane-protocol"+
"/isis:isis/isis:fast-reroute"{
when "/rt:routing/rt:control-plane-protocols/"+
"rt:control-plane-protocol/rt:type = 'isis:isis'"{
description
"This augment ISIS routing protocol when used";
}
description
"This augments ISIS IPFRR with IPV6 TILFA.";
container srv6-ti-lfa {
if-feature srv6-ti-lfa;
leaf enable {
type boolean;
description
"Enables SRv6 TI-LFA computation.";
}
description
"SRv6 TILFA configuration.";
}
}
/* Operational states */
augment "/rt:routing/" +
"rt:control-plane-protocols/rt:control-plane-protocol"+
"/isis:isis/isis:database/isis:levels/isis:lsp"+
"/isis:router-capabilities" {
when "/rt:routing/rt:control-plane-protocols/"+
"rt:control-plane-protocol/rt:type = 'isis:isis'" {
description
"This augment ISIS routing protocol when used";
}
description
"This augments ISIS protocol router capability.";
uses srv6-capability;
uses srv6-msds;
}
augment "/rt:routing/" +
"rt:control-plane-protocols/rt:control-plane-protocol"+
"/isis:isis/isis:database/isis:levels/isis:lsp"+
"/isis:extended-is-neighbor/isis:neighbor" {
when "/rt:routing/rt:control-plane-protocols/"+
"rt:control-plane-protocol/rt:type = 'isis:isis'" {
description
"This augment ISIS routing protocol when used.";
}
description
"This augments ISIS protocol neighbor.";
container srv6-adjacency-sids {
description
"This defines svr6 end-x sids for the adjacency.";
list end-x-sid {
key "sid";
uses srv6-adjacency-sid;
description
"List of end-x sids.";
}
}
}
augment "/rt:routing/" +
"rt:control-plane-protocols/rt:control-plane-protocol"+
"/isis:isis/isis:database/isis:levels/isis:lsp"+
"/isis:mt-is-neighbor/isis:neighbor" {
when "/rt:routing/rt:control-plane-protocols/"+
"rt:control-plane-protocol/rt:type = 'isis:isis'" {
description
"This augment ISIS routing protocol when used.";
}
description
"This augments ISIS protocol neighbor.";
container srv6-adjacency-sids {
description
"This defines svr6 end-x sids for the adjacency.";
list end-x-sid {
key "sid";
uses srv6-adjacency-sid;
description
"List of end-x sids.";
}
}
}
augment "/rt:routing/" +
"rt:control-plane-protocols/rt:control-plane-protocol"+
"/isis:isis/isis:database/isis:levels/isis:lsp" {
when "/rt:routing/rt:control-plane-protocols/"+
"rt:control-plane-protocol/rt:type = 'isis:isis'" {
description
"This augment ISIS routing protocol when used.";
}
description
"This augments ISIS protocol LSDB.";
container srv6-locators {
description
"This defines srv6 locator tlvs.";
list locator {
key "locator";
uses srv6-locator;
description
"List of srv6 locators.";
}
}
}
augment "/rt:routing/" +
"rt:control-plane-protocols/rt:control-plane-protocol"+
"/isis:isis/isis:interfaces/isis:interface" +
"/isis:adjacencies/isis:adjacency" {
when "/rt:routing/rt:control-plane-protocols/"+
"rt:control-plane-protocol/rt:type = 'isis:isis'" {
description
"This augment ISIS routing protocol when used.";
}
description
"This augments ISIS protocol operational state
with segment routing.";
uses srv6-adjacency-state;
}
/* Notifications */
}
]]>
Configuration and state data defined in this document are designed to
be accessed via the NETCONF protocol .
As IS-IS is an IGP protocol (critical piece of the network), ensuring
stability and security of the protocol is mandatory for the network
service.
Authors recommends to implement NETCONF access control model ( ) to restrict access to all or part of the
configuration to specific users.
The IANA is requested to assign two new URIs from the IETF XML
registry ( ). Authors are suggesting the
following URI:
This document also requests one new YANG module name in the
YANG Module Names registry ( ) with the following
suggestion :
The following is an XML example using IS-IS SRv6 YANG module.
true
false
DOM0_ALG0
true
true
2000
true
]]>
The following is the corresponding example using JSON format.