IETF 82 Proceedings

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FEC Framework (fecframe) (WG)

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Transport Area Director(s):

Transport Area Advisor:

Meeting Slides

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Request for Comments:

Charter (as of 2011-12-09)

The object of this group is to develop specifications for using forward
error correction (FEC) codes with applications in the Internet to
provide protection against packet loss. The group will develop a
protocol framework for application of FEC codes to arbitrary packet
flows over unreliable transport protocols over both IP multicast and
unicast. The application of the FEC codec on an aggregate of multiple
packet flows may be investigated and considered to be included in the

The FECFrame working group will use the building block approach (RFC
3269), especially the FEC Building Block (RFC 3452), developed by the
RMT working group. The FEC Building Block was developed to ensure that
the RMT framework developed can support multiple FEC codes and maintain
independence between FEC codes and protocols based on the framework.
The FECFrame WG may develop new FEC schemes if necessary to provide
substantial performance gains for the intended applications. However
the acceptance of any FEC scheme will require multiple, prior, detailed
reviews of the FEC code by independent experts from both the IETF and
the broader community, since it is likely that the IETF working group
will not include a large enough number of suitable experts in its
working set. If these reviews are positive, then Working Group
acceptance of an FEC scheme work item still needs the approval of the
responsible Area Director.

A primary objective of this framework is to support FEC for real-time
media applications using RTP over UDP, such as on demand streaming and
audio/video broadcast. Other potential usages of the framework may be
brought to the working group for consideration during the development
of the requirements, to enable future support of those usages. The
group will coordinate closely with the AVT and MMUSIC working groups to
ensure that the streaming use-case is fully specified both in terms of
interactions with RTP/RTCP and application layer signalling. The group
will also coordinate with the DCCP working group, at least to consider
that transport protocol's role in streaming media. The interactions of
the framework with existing and used security mechanisms must also be

The group will work with the RMT working group to ensure that the FEC
Building Block defined in RMT supports both the RMT use-cases (object
delivery over multicast) and the more general FEC protection of
flow(s) over unreliable unicast and multicast transport.

Specification of hybrid schemes involving both retransmission and
forward error correction is out of scope of the group.

Goals and Milestones:

Done  Working Group consensus on requirements and their prioritization for the FEC protocol framework
Done  Completed selection of solution to develop and mature
Done  FEC framework requirements WG soft-freeze
Done  FEC Streaming Framework WG soft-freeze
Done  FEC Grouping informational draft submitted to MMUSIC
Done  FEC Streaming Framework submitted as Proposed Standard
Done  Usage of FEC framework with RTP submitted as Proposed Standard
Done  FEC SDP Elements submitted as Proposed Standard
Dec 2011  Transfer open FEC scheme documents to TSVWG