Reliable Multicast Transport (rmt)
----------------------------------

 Charter
 Last Modified: 2008-08-21

 Current Status: Active Working Group

 Chair(s):
     Lorenzo Vicisano  <lorenzo@vicisano.net>
     Brian Adamson  <adamson@itd.nrl.navy.mil>

 Transport Area Director(s):
     Magnus Westerlund  <magnus.westerlund@ericsson.com>
     Lars Eggert  <lars.eggert@nokia.com>

 Transport Area Advisor:
     Magnus Westerlund  <magnus.westerlund@ericsson.com>

 Mailing Lists: 
     General Discussion:rmt@ietf.org
     To Subscribe:      rmt-request@ietf.org
         In Body:       subscribe
     Archive:           http://www.ietf.org/mail-archive/web/rmt/index.html

Description of Working Group:

The purpose of this WG is to standardize reliable multicast transport.


Initial efforts have focused solely on the standardization of the
one-to-many transport of large amounts of data. Due to the large
number of applications that fall into this category, and the sometimes
orthogonal requirements these applications exhibit, it is believed
that a "one size fits all" protocol will be unable to meet the
requirements of all applications. In recognition of this observation,
this working group will standardize two protocol instantiations,
initially as Experimental protocols, and then as warranted, in the
standards track, from the following families:

1) A NACK-based protocol.
2) An "Asynchronous Layered Coding protocol that uses Forward Error
   Correction.

The WG will carry out protocol standardization in general by composing
a a set of RFCs that specify

- building blocks: A set of easily-separable coarse-grained modular
components that are common to multiple protocols along with abstract
APIs that define a building block's access methods and their
arguments.

- protocol instantiations: Specifications that define the necessary
gluing logic and minimal additional functionality required to realize
a working protocol from one or more building blocks. These
specifications will also include an abstract API that defines the
interface between the protocol implementation and an application.

The WG has previously completed work on three documents to assist in
the standardization process. RFC2887 describes the design-space in
which the one-to-many transport protocols will be developed. RFC3048
explains the concepts of building-blocks and protocol
instantiations. RFC3269 provides guidelines to authors of drafts that
specify building-blocks and protocol instantiations.

The WG will generate and submit for standardization drafts of the
following building-blocks for use in the construction of the two
protocols: congestion control, negative acknowledgments, forward error
correction, and to address the RFC 2357 security requirements.

Generic mechanisms for router assist are also considered for an
additional building block. Initial work on the framework for
router-assist has already been performed, the WG will evaluate whether
to complete this task basing on available resource and interest.

The WG will also standardize and generate RFCs for the following two
protocol instantiations: A NACK-based protocol, and an Asynchronous
Layered Coding (ALC) protocol that uses Forward Error Correction.
RFC 3450 is the Experimental RFC of the ALC protocol instantiation.

If new requirements are identified that cannot be satisfied with the
building-blocks and protocol instantiations described above, the Area
Directors in consultation with the IESG may add additional
building-blocks and protocol instantiations to the working group
deliverables.

This working group will work closely with the Internet Research Task
Force (IRTF) groups on Reliable Multicast (RMRG) and
Secure Multicast (SMUG), especially for meeting the congestion control
and security requirements mandated by RFC 2357. This working group may
work with the Area Directors to recharter to standardize reliable
multicast for additional scenarios beyond the one-to-many transport of
bulk data once they are sufficiently well understood.

 Goals and Milestones:

   Done         Submit design-space, building-blocks, and guidelines drafts for 
                publication as Informational RFCs 

   Done         Initial Drafts for the following building blocks: negative 
                acknowledgments, forward error correction, a generic signaling 
                mechanism for router assist, and transport protection 

   Done         Submit Initial Drafts for the two protocol instantiations. 

   Done         Submit Initial Draft for Congestion Control 

   Done         Complete building-block drafts WG Last-Call and submit for 
                publication as Proposed Standard 

   Done         Complete building blocks and protocol instantiations for ALC 
                and submit for publication as Experimental RFC 

   Done         WG Decision on whether to pursue the router-assist building 
                block work. These milestones may have to be modified 
                accordingly 

   Done         Submit WEBRC (congestion control building block) for 
                publication as Experimental 

   Done         Submit NACK building block and protocol instantiation for 
                publication as Experimental 

   Done         Evaluate when and how the RMT Experimental specifications will 
                be submitted for publication as Proposed Standard, and update 
                this charter accordingly 

   Sep 2005       Submit remaining congestion control building blocks (TFMCC, 
                PGMCC) for publication as Experimental 

   Dec 2005       Submit all the RMT Eperimental Specifications published before 
                July 05 for publication as Proposed Standard 

   Apr 2006       Submit all remaining RMT Eperimental Specifications for 
                publication as Proposed Standard 


 Internet-Drafts:

Posted Revised         I-D Title   <Filename>
------ ------- --------------------------------------------
Jul 2005 Jul 2008   <draft-ietf-rmt-bb-lct-revised-07.txt>
                Layered Coding Transport (LCT) Building Block 

Jul 2005 Nov 2008   <draft-ietf-rmt-pi-alc-revised-06.txt>
                Asynchronous Layered Coding (ALC) Protocol Instantiation 

Jul 2005 Oct 2008   <draft-ietf-rmt-bb-fec-basic-schemes-revised-06.txt>
                Basic Forward Error Correction (FEC) Schemes 

Oct 2005 Sep 2008   <draft-ietf-rmt-flute-revised-06.txt>
                FLUTE - File Delivery over Unidirectional Transport 

Oct 2005 Oct 2008   <draft-ietf-rmt-pi-norm-revised-07.txt>
                NACK-Oriented Reliable Multicast Protocol 

Oct 2005 Sep 2008   <draft-ietf-rmt-bb-norm-revised-07.txt>
                Multicast Negative-Acknowledgment (NACK) Building Blocks 

Mar 2006 Nov 2007   <draft-ietf-rmt-bb-fec-rs-05.txt>
                Reed-Solomon Forward Error Correction (FEC) Schemes 

Jul 2007 Nov 2008   <draft-ietf-rmt-sec-discussion-03.txt>
                Security and Reliable Multicast Transport Protocols: 
                Discussions and Guidelines 

Oct 2008 Oct 2008   <draft-ietf-rmt-simple-auth-for-alc-norm-00.txt>
                Simple Authentication Schemes for the ALC and NORM Protocols 

 Request For Comments:

  RFC   Stat Published     Title
------- -- ----------- ------------------------------------
RFC2887 I    Aug 2000    The Reliable Multicast Design Space for Bulk Data 
                       Transfer 

RFC3048 I    Feb 2001    Reliable Multicast Transport Building Blocks for 
                       One-to-Many Bulk-Data Transfer 

RFC3269 I    May 2002    Author Guidelines for RMT Building Blocks and Protocol 
                       Instantiation documents 

RFC3450 E    Dec 2002    Asynchronous Layered Coding protocol instantiation 

RFC3451 E    Dec 2002    Layered Coding Transport (LCT) Building Block 

RFC3452 E    Dec 2002    Forward Error Correction Building Block 

RFC3453 I    Dec 2002    The use of Forward Error Correction in Reliable 
                       Multicast 

RFC3695 E    Feb 2004    Compact Forward Error Correction (FEC) Schemes 

RFC3738 E    Apr 2004    Wave and Equation Based Rate Control building block 

RFC3926 E    Oct 2004    FLUTE - File Delivery over Unidirectional Transport 

RFC3940 E    Nov 2004    NACK-Oriented Reliable Multicast Protocol (NORM) 

RFC3941 E    Nov 2004    NACK-Oriented Reliable Multicast (NORM) Building Blocks 

RFC4654 E    Aug 2006    TCP-Friendly Multicast Congestion Control (TFMCC): 
                       Protocol Specification 

RFC5052 PS   Aug 2007    Forward Error Correction (FEC) Building Block 

RFC5053 PS   Oct 2007    Raptor Forward Error Correction Scheme for Object 
                       Delivery 

RFC5170 PS   Jun 2008    Low Density Parity Check (LDPC) Staircase and Triangle 
                       Forward Error Correction (FEC) Schemes