Reliable Multicast Transport (rmt) ---------------------------------- Charter Last Modified: 2008-04-23 Current Status: Active Working Group Chair(s): Lorenzo Vicisano Brian Adamson Transport Area Director(s): Magnus Westerlund Lars Eggert Transport Area Advisor: Magnus Westerlund 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 ------ ------- -------------------------------------------- Jul 2005 Jul 2008 Layered Coding Transport (LCT) Building Block Jul 2005 Jul 2008 Basic Forward Error Correction (FEC) Schemes Oct 2005 Jul 2008 Multicast Negative-Acknowledgment (NACK) Building Blocks Mar 2006 Nov 2007 Reed-Solomon Forward Error Correction (FEC) Schemes Jul 2007 Jul 2008 Security and Reliable Multicast Transport Protocols: Discussions and Guidelines 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