draft-ietf-fecframe-raptor-05.txt   draft-ietf-fecframe-raptor-06.txt 
FEC Framework M. Watson FEC Framework M. Watson
Internet-Draft Netflix Internet-Draft Netflix
Intended status: Standards Track T. Stockhammer Intended status: Standards Track T. Stockhammer
Expires: March 21, 2012 Nomor Research Expires: May 27, 2012 Nomor Research
M. Luby M. Luby
Qualcomm Incorporated Qualcomm Incorporated
September 18, 2011 November 24, 2011
Raptor FEC Schemes for FECFRAME Raptor FEC Schemes for FECFRAME
draft-ietf-fecframe-raptor-05 draft-ietf-fecframe-raptor-06
Abstract Abstract
This document describes Fully-Specified Forward Error Correction This document describes Fully-Specified Forward Error Correction
(FEC) Schemes for the Raptor and RaptorQ codes and their application (FEC) Schemes for the Raptor and RaptorQ codes and their application
to reliable delivery of media streams in the context of FEC to reliable delivery of media streams in the context of FEC
Framework. The Raptor and RaptorQ codes are systematic codes, where Framework. The Raptor and RaptorQ codes are systematic codes, where
a number of repair symbols are generated from a set of source symbols a number of repair symbols are generated from a set of source symbols
and sent in one or more repair flows in addition to the source and sent in one or more repair flows in addition to the source
symbols that are sent to the receiver(s) within a source flow. The symbols that are sent to the receiver(s) within a source flow. The
skipping to change at page 1, line 46 skipping to change at page 1, line 46
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on March 21, 2012. This Internet-Draft will expire on May 27, 2012.
Copyright Notice Copyright Notice
Copyright (c) 2011 IETF Trust and the persons identified as the Copyright (c) 2011 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
(http://trustee.ietf.org/license-info) in effect on the date of (http://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
skipping to change at page 5, line 7 skipping to change at page 5, line 7
12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 19 12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 19
12.1. Registration of FEC Scheme IDs . . . . . . . . . . . . . . 19 12.1. Registration of FEC Scheme IDs . . . . . . . . . . . . . . 19
13. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 20 13. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 20
14. References . . . . . . . . . . . . . . . . . . . . . . . . . . 20 14. References . . . . . . . . . . . . . . . . . . . . . . . . . . 20
14.1. Normative References . . . . . . . . . . . . . . . . . . . 20 14.1. Normative References . . . . . . . . . . . . . . . . . . . 20
14.2. Informative References . . . . . . . . . . . . . . . . . . 21 14.2. Informative References . . . . . . . . . . . . . . . . . . 21
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 21 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 21
1. Introduction 1. Introduction
The FEC Framework [I-D.ietf-fecframe-framework] describes a framework The FEC Framework [RFC6363] describes a framework for the application
for the application of Forward Error Correction to arbitrary packet of Forward Error Correction to arbitrary packet flows. Modeled after
flows. Modeled after the FEC Building Block developed by the IETF the FEC Building Block developed by the IETF Reliable Multicast
Reliable Multicast Transport working group [RFC5052], the FEC Transport working group [RFC5052], the FEC Framework defines the
Framework defines the concept of FEC Schemes which provide specific concept of FEC Schemes which provide specific Forward Error
Forward Error Correction schemes. This document describes six FEC Correction schemes. This document describes six FEC Schemes which
Schemes which make use of the Raptor and RaptorQ FEC codes as defined make use of the Raptor and RaptorQ FEC codes as defined in [RFC5053]
in [RFC5053] and [RFC6330]. and [RFC6330].
The FEC protection mechanism is independent of the type of the source The FEC protection mechanism is independent of the type of the source
data, which can be an arbitrary sequence of packets, including for data, which can be an arbitrary sequence of packets, including for
example audio or video data. In general, the operation of the example audio or video data. In general, the operation of the
protection mechanism is as follows: protection mechanism is as follows:
o The sender determines a set of source packets (a source block) to o The sender determines a set of source packets (a source block) to
be protected together based on the FEC Framework Configuration be protected together based on the FEC Framework Configuration
Information. Information.
skipping to change at page 5, line 52 skipping to change at page 5, line 52
The operation of the FEC mechanism requires that the receiver can The operation of the FEC mechanism requires that the receiver can
identify the relationships between received source packets and repair identify the relationships between received source packets and repair
packets and in particular which source packets are missing. In many packets and in particular which source packets are missing. In many
cases, data already exists in the source packets which can be used to cases, data already exists in the source packets which can be used to
refer to source packets and to identify which packets are missing. refer to source packets and to identify which packets are missing.
In this case we assume it is possible to derive a "sequence number" In this case we assume it is possible to derive a "sequence number"
directly or indirectly from the source packets and this sequence directly or indirectly from the source packets and this sequence
number can be used within the FEC Scheme. This case is referred to number can be used within the FEC Scheme. This case is referred to
as a "single sequenced flow". In this case the FEC Source Payload ID as a "single sequenced flow". In this case the FEC Source Payload ID
defined in [I-D.ietf-fecframe-framework] is empty and the source defined in [RFC6363] is empty and the source packets are not modified
packets are not modified by the application of FEC, with obvious by the application of FEC, with obvious backwards compatibility
backwards compatibility advantages. advantages.
Otherwise, it is necessary to add data to the source packets for FEC Otherwise, it is necessary to add data to the source packets for FEC
purposes in the form of a non-empty FEC Source Payload ID. This case purposes in the form of a non-empty FEC Source Payload ID. This case
if referred to as the "arbitrary packet flow" case. Accordingly, if referred to as the "arbitrary packet flow" case. Accordingly,
this document defines six FEC Schemes, two for the case of a single this document defines six FEC Schemes, two for the case of a single
sequenced flow and four for the case of arbitrary packet flows. sequenced flow and four for the case of arbitrary packet flows.
2. Document Outline 2. Document Outline
This document is organised as follows: This document is organised as follows:
o Section 5 defines general procedures applicable to the use of the o Section 5 defines general procedures applicable to the use of the
Raptor and RaptorQ codes in the context of the FEC Framework. Raptor and RaptorQ codes in the context of the FEC Framework.
o Section 6defines an FEC Scheme for the case of arbitrary source o Section 6defines an FEC Scheme for the case of arbitrary source
flows and follows the format defined for FEC Schemes in flows and follows the format defined for FEC Schemes in [RFC6363].
[I-D.ietf-fecframe-framework]. When used with Raptor codes, this When used with Raptor codes, this scheme is equivalent to that
scheme is equivalent to that defined in [MBMSTS]. defined in [MBMSTS].
o Section 7 defines an FEC Scheme similar to that defined in o Section 7 defines an FEC Scheme similar to that defined in
Section 6but with optimisations for the case where only limited Section 6but with optimisations for the case where only limited
source block sizes are required. When used with Raptor codes, source block sizes are required. When used with Raptor codes,
this scheme is equivalent to that defined in [dvbts] for arbitrary this scheme is equivalent to that defined in [dvbts] for arbitrary
packet flows. packet flows.
o Section 8 defines an FEC Scheme for the case of a single flow o Section 8 defines an FEC Scheme for the case of a single flow
which is already provided with a source packet sequence number. which is already provided with a source packet sequence number.
When used with Raptor codes, this scheme is equivalent to that When used with Raptor codes, this scheme is equivalent to that
skipping to change at page 7, line 8 skipping to change at page 7, line 8
document are to be interpreted as described in [RFC2119]. document are to be interpreted as described in [RFC2119].
4. Definitions and Abbreviations 4. Definitions and Abbreviations
The definitions, notations and abbreviations commonly used in this The definitions, notations and abbreviations commonly used in this
document are summarized in this section. document are summarized in this section.
4.1. Definitions 4.1. Definitions
This document uses the following definitions. For further This document uses the following definitions. For further
definitions that apply to FEC Framework in general, see definitions that apply to FEC Framework in general, see [RFC6363].
[I-D.ietf-fecframe-framework].
Symbol: A unit of data. Its size, in octets, is referred to as the Symbol: A unit of data. Its size, in octets, is referred to as the
symbol size. symbol size.
FEC Framework Configuration Information: Information that controls FEC Framework Configuration Information: Information that controls
the operation of the FEC Framework. Each FEC Framework instance the operation of the FEC Framework. Each FEC Framework instance
has its own configuration information. has its own configuration information.
4.2. Abbreviations 4.2. Abbreviations
This document uses the following abbreviations. For further This document uses the following abbreviations. For further
abbreviations that apply to FEC Framework in general, see abbreviations that apply to FEC Framework in general, see [RFC6363].
[I-D.ietf-fecframe-framework].
FSSI: FEC-Scheme-Specific Information. FSSI: FEC-Scheme-Specific Information.
SS-FSSI: Sender-Side FEC-Scheme-Specific Information. SS-FSSI: Sender-Side FEC-Scheme-Specific Information.
RS-FSSI: Receiver-Side FEC-Scheme-Specific Information. RS-FSSI: Receiver-Side FEC-Scheme-Specific Information.
ADUI: Application Data Unit Information. ADUI: Application Data Unit Information.
5. General procedures for Raptor FEC Schemes 5. General procedures for Raptor FEC Schemes
This section specifies general procedures which apply to all Raptor This section specifies general procedures which apply to all Raptor
and RaptorQ FEC Schemes, specifically the construction of source and RaptorQ FEC Schemes, specifically the construction of source
symbols from a set of source transport payloads. As described in symbols from a set of source transport payloads. As described in
[I-D.ietf-fecframe-framework] for each Application Data Unit (ADU) in [RFC6363] for each Application Data Unit (ADU) in a source block, the
a source block, the FEC Scheme is provided with: FEC Scheme is provided with:
o A description of the source data flow with which the ADU is o A description of the source data flow with which the ADU is
associated and an integer identifier associated with that flow. associated and an integer identifier associated with that flow.
o The ADU itself. o The ADU itself.
o The length of the ADU. o The length of the ADU.
For each ADU, we define the Application Data Unit Information (ADUI) For each ADU, we define the Application Data Unit Information (ADUI)
as follows: as follows:
skipping to change at page 19, line 8 skipping to change at page 19, line 8
present, and the RTP padding octets, if any. Note that this length present, and the RTP padding octets, if any. Note that this length
is always equal to the UDP payload length of the packet minus 12. is always equal to the UDP payload length of the packet minus 12.
8.3. FEC Code Specification 8.3. FEC Code Specification
See Section 7.4 See Section 7.4
9. Security Considerations 9. Security Considerations
For the general security considerations related to the use of FEC, For the general security considerations related to the use of FEC,
refer to [I-D.ietf-fecframe-framework]. No security considerations refer to [RFC6363]. No security considerations specific to this
specific to this document have been identified. document have been identified.
10. Session Description Protocol (SDP) Signaling 10. Session Description Protocol (SDP) Signaling
This section provides an SDP [RFC4566] example. The syntax follows This section provides an SDP [RFC4566] example. The syntax follows
the definition in [I-D.ietf-fecframe-sdp-elements] .Assume we have the definition in [RFC6364] .Assume we have one source video stream
one source video stream (mid:S1) and one FEC repair stream (mid:R1). (mid:S1) and one FEC repair stream (mid:R1). We form one FEC group
We form one FEC group with the "a=group:FEC-FR S1 R1" line. The with the "a=group:FEC-FR S1 R1" line. The source and repair streams
source and repair streams are sent to the same port on different are sent to the same port on different multicast groups. The repair
multicast groups. The repair window is set to 200 ms. window is set to 200 ms.
v=0 v=0
o=ali 1122334455 1122334466 IN IP4 fec.example.com o=ali 1122334455 1122334466 IN IP4 fec.example.com
s=Raptor FEC Example s=Raptor FEC Example
t=0 0 t=0 0
a=group:FEC-FR S1 R1 a=group:FEC-FR S1 R1
m=video 30000 RTP/AVP 100 m=video 30000 RTP/AVP 100
c=IN IP4 233.252.0.1/127 c=IN IP4 233.252.0.1/127
a=rtpmap:100 MP2T/90000 a=rtpmap:100 MP2T/90000
a=fec-source-flow: id=0 a=fec-source-flow: id=0
a=mid:S1 a=mid:S1
m=application 30000 UDP/FEC m=application 30000 UDP/FEC
c=IN IP4 233.252.0.2/127 c=IN IP4 233.252.0.2/127
a=fec-repair-flow: encoding-id=6; fssi=Kmax:8192,T:128,P:A a=fec-repair-flow: encoding-id=6; fssi=Kmax:8192,T:128,P:A
a=repair-window:200ms a=repair-window:200ms
a=mid:R1 a=mid:R1
11. Congestion Control Considerations 11. Congestion Control Considerations
For the general congestion control considerations related to the use For the general congestion control considerations related to the use
of FEC, refer to [I-D.ietf-fecframe-framework]. of FEC, refer to [RFC6363].
12. IANA Considerations 12. IANA Considerations
12.1. Registration of FEC Scheme IDs 12.1. Registration of FEC Scheme IDs
The value of FEC Scheme IDs is subject to IANA registration. For The value of FEC Scheme IDs is subject to IANA registration. For
general guidelines on IANA considerations as they apply to this general guidelines on IANA considerations as they apply to this
document, refer to [I-D.ietf-fecframe-framework]. document, refer to [RFC6363].
This document registers three values in the FEC Framework (FECFRAME) This document registers three values in the FEC Framework (FECFRAME)
FEC Encoding IDs registry as follows: FEC Encoding IDs registry as follows:
o 1 for the Raptor FEC Scheme for Arbitrary Packet Flows (Section 6 o 1 for the Raptor FEC Scheme for Arbitrary Packet Flows (Section 6
using Raptor [RFC5053]. using Raptor [RFC5053].
o 2 for the Raptor FEC Scheme for Arbitrary Packet Flows (Section 6 o 2 for the Raptor FEC Scheme for Arbitrary Packet Flows (Section 6
using RaptorQ [RFC6330]. using RaptorQ [RFC6330].
skipping to change at page 20, line 33 skipping to change at page 20, line 33
13. Acknowledgements 13. Acknowledgements
Thanks are due to Ali C. Begen for thorough review of earlier draft Thanks are due to Ali C. Begen for thorough review of earlier draft
versions of this document. versions of this document.
14. References 14. References
14.1. Normative References 14.1. Normative References
[I-D.ietf-fecframe-framework] [RFC6363] Watson, M., Begen, A., and V. Roca, "Forward Error
Watson, M., Begen, A., and V. Roca, "Forward Error Correction (FEC) Framework", RFC 6363, October 2011.
Correction (FEC) Framework",
draft-ietf-fecframe-framework-15 (work in progress),
June 2011.
[RFC5053] Luby, M., Shokrollahi, A., Watson, M., and T. Stockhammer, [RFC5053] Luby, M., Shokrollahi, A., Watson, M., and T. Stockhammer,
"Raptor Forward Error Correction Scheme for Object "Raptor Forward Error Correction Scheme for Object
Delivery", RFC 5053, October 2007. Delivery", RFC 5053, October 2007.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC6330] Luby, M., Shokrollahi, A., Watson, M., Stockhammer, T., [RFC6330] Luby, M., Shokrollahi, A., Watson, M., Stockhammer, T.,
and L. Minder, "RaptorQ Forward Error Correction Scheme and L. Minder, "RaptorQ Forward Error Correction Scheme
for Object Delivery", RFC 6330, August 2011. for Object Delivery", RFC 6330, August 2011.
14.2. Informative References 14.2. Informative References
[RFC5052] Watson, M., Luby, M., and L. Vicisano, "Forward Error [RFC5052] Watson, M., Luby, M., and L. Vicisano, "Forward Error
Correction (FEC) Building Block", RFC 5052, August 2007. Correction (FEC) Building Block", RFC 5052, August 2007.
[RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session [RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session
Description Protocol", RFC 4566, July 2006. Description Protocol", RFC 4566, July 2006.
[I-D.ietf-fecframe-sdp-elements] [RFC6364] Begen, A., "Session Description Protocol Elements for the
Begen, A., "Session Description Protocol Elements for FEC Forward Error Correction (FEC) Framework", RFC 6364,
Framework", October 2010. October 2011.
[dvbts] "ETSI TS 102 034 - Digital Video Broadcasting (DVB); [dvbts] "ETSI TS 102 034 - Digital Video Broadcasting (DVB);
Transport of MPEG-2 Based DVB Services over IP Based Transport of MPEG-2 Based DVB Services over IP Based
Networks", March 2005. Networks", March 2005.
[MBMSTS] 3GPP, "Multimedia Broadcast/Multicast Service (MBMS); [MBMSTS] 3GPP, "Multimedia Broadcast/Multicast Service (MBMS);
Protocols and codecs", 3GPP TS 26.346, April 2005. Protocols and codecs", 3GPP TS 26.346, April 2005.
Authors' Addresses Authors' Addresses
 End of changes. 16 change blocks. 
41 lines changed or deleted 36 lines changed or added

This html diff was produced by rfcdiff 1.41. The latest version is available from http://tools.ietf.org/tools/rfcdiff/