draft-ietf-mmusic-duplication-grouping-02.txt   draft-ietf-mmusic-duplication-grouping-03.txt 
MMUSIC A. Begen MMUSIC A. Begen
Internet-Draft Cisco Internet-Draft Cisco
Intended status: Standards Track Y. Cai Intended status: Standards Track Y. Cai
Expires: November 28, 2013 Microsoft Expires: January 12, 2014 Microsoft
H. Ou H. Ou
Cisco Cisco
May 27, 2013 July 11, 2013
Duplication Grouping Semantics in the Session Description Protocol Duplication Grouping Semantics in the Session Description Protocol
draft-ietf-mmusic-duplication-grouping-02 draft-ietf-mmusic-duplication-grouping-03
Abstract Abstract
Packet loss is undesirable for real-time multimedia sessions, but can Packet loss is undesirable for real-time multimedia sessions, but can
occur due to congestion, or other unplanned network outages. This is occur due to congestion, or other unplanned network outages. This is
especially true for IP multicast networks, where packet loss patterns especially true for IP multicast networks, where packet loss patterns
can vary greatly between receivers. One technique that can be used can vary greatly between receivers. One technique that can be used
to recover from packet loss without incurring unbounded delay for all to recover from packet loss without incurring unbounded delay for all
the receivers is to duplicate the packets and send them in separate the receivers is to duplicate the packets and send them in separate
redundant streams. This document defines the semantics for grouping redundant streams. This document defines the semantics for grouping
redundant streams in the Session Description Protocol (SDP). The redundant streams in the Session Description Protocol (SDP). The
semantics defined in this document are to be used with the SDP semantics defined in this document are to be used with the SDP
Grouping Framework [RFC5888]. SSRC-level (Synchronization Source) Grouping Framework. SSRC-level (Synchronization Source) grouping
grouping semantics are also defined in this document for RTP streams semantics are also defined in this document for RTP streams using
using SSRC multiplexing. SSRC multiplexing.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
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 November 28, 2013. This Internet-Draft will expire on January 12, 2014.
Copyright Notice Copyright Notice
Copyright (c) 2013 IETF Trust and the persons identified as the Copyright (c) 2013 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
skipping to change at page 3, line 30 skipping to change at page 3, line 30
[RFC2119]. [RFC2119].
3. Duplication Grouping 3. Duplication Grouping
3.1. "DUP" Grouping Semantics 3.1. "DUP" Grouping Semantics
Each "a=group" line is used to indicate an association relationship Each "a=group" line is used to indicate an association relationship
between the redundant streams. The streams included in one "a=group" between the redundant streams. The streams included in one "a=group"
line are called a Duplication Group. line are called a Duplication Group.
Using the framework in [RFC5888], this document defines "DUP" as the Using the SDP Grouping Framework in [RFC5888], this document defines
grouping semantics for redundant streams. "DUP" as the grouping semantics for redundant streams.
The "a=group:DUP" semantics MUST be used to group the redundant The "a=group:DUP" semantics MUST be used to group the redundant
streams except when the streams are specified in the same media streams except when the streams are specified in the same media
description, i.e., in the same "m" line (See Section 3.2). In an description, i.e., in the same "m" line (See Section 3.2). In an
"a=group:DUP" line, the order of the listed redundant streams does "a=group:DUP" line, the order of the listed redundant streams does
not strictly indicate the order of transmission, although it is not strictly indicate the order of transmission, although it is
RECOMMENDED that the stream listed first is sent first, with the RECOMMENDED that the stream listed first is sent first, with the
other stream(s) being the (time-delayed) duplicate(s). other stream(s) being the (time-delayed) duplicate(s).
3.2. Duplication Grouping for SSRC-Multiplexed RTP Streams 3.2. Duplication Grouping for SSRC-Multiplexed RTP Streams
skipping to change at page 5, line 4 skipping to change at page 5, line 4
In this example, the redundant streams use the same IP destination In this example, the redundant streams use the same IP destination
address (232.252.0.1) but they are sourced from different addresses address (232.252.0.1) but they are sourced from different addresses
(198.51.100.1 and 198.51.100.2). Thus, the receiving host needs to (198.51.100.1 and 198.51.100.2). Thus, the receiving host needs to
join both source-specific multicast (SSM) sessions separately. join both source-specific multicast (SSM) sessions separately.
v=0 v=0
o=ali 1122334455 1122334466 IN IP4 dup.example.com o=ali 1122334455 1122334466 IN IP4 dup.example.com
s=DUP Grouping Semantics s=DUP Grouping Semantics
t=0 0 t=0 0
m=video 30000 RTP/AVP 100 m=video 30000 RTP/AVP 100
c=IN IP4 232.252.0.1/127 c=IN IP4 233.252.0.1/127
a=source-filter:incl IN IP4 232.252.0.1 198.51.100.1 198.51.100.2 a=source-filter:incl IN IP4 233.252.0.1 198.51.100.1 198.51.100.2
a=rtpmap:100 MP2T/90000 a=rtpmap:100 MP2T/90000
a=ssrc:1000 cname:ch1@example.com a=ssrc:1000 cname:ch1@example.com
a=ssrc:1010 cname:ch1@example.com a=ssrc:1010 cname:ch1@example.com
a=ssrc-group:DUP 1000 1010 a=ssrc-group:DUP 1000 1010
a=mid:Ch1 a=mid:Ch1
Note that in actual use, SSRC values, which are random 32-bit Note that in actual use, SSRC values, which are random 32-bit
numbers, can be much larger than the ones shown in this example. numbers, can be much larger than the ones shown in this example.
Also note that this SDP description does not use the 'duplication- Also note that this SDP description does not use the 'duplication-
delay' attribute (defined in [I-D.ietf-mmusic-delayed-duplication]) delay' attribute (defined in [I-D.ietf-mmusic-delayed-duplication])
skipping to change at page 8, line 9 skipping to change at page 8, line 9
Media Attributes in the Session Description Protocol Media Attributes in the Session Description Protocol
(SDP)", RFC 5576, June 2009. (SDP)", RFC 5576, June 2009.
[RFC5888] Camarillo, G. and H. Schulzrinne, "The Session Description [RFC5888] Camarillo, G. and H. Schulzrinne, "The Session Description
Protocol (SDP) Grouping Framework", RFC 5888, June 2010. Protocol (SDP) Grouping Framework", RFC 5888, June 2010.
8.2. Informative References 8.2. Informative References
[I-D.ietf-avtext-rtp-duplication] [I-D.ietf-avtext-rtp-duplication]
Begen, A. and C. Perkins, "Duplicating RTP Streams", Begen, A. and C. Perkins, "Duplicating RTP Streams",
draft-ietf-avtext-rtp-duplication-01 (work in progress), draft-ietf-avtext-rtp-duplication-02 (work in progress),
December 2012. March 2013.
[I-D.ietf-mmusic-delayed-duplication] [I-D.ietf-mmusic-delayed-duplication]
Begen, A., Cai, Y., and H. Ou, "Delayed Duplication Begen, A., Cai, Y., and H. Ou, "Delayed Duplication
Attribute in the Session Description Protocol", draft- Attribute in the Session Description Protocol", draft-
ietf-mmusic-delayed-duplication-01 (work in progress), ietf-mmusic-delayed-duplication-02 (work in progress), May
March 2013. 2013.
[IC2011] Evans, J., Begen, A., Greengrass, J., and C. Filsfils, [IC2011] Evans, J., Begen, A., Greengrass, J., and C. Filsfils,
"Toward Lossless Video Transport (to appear in IEEE "Toward Lossless Video Transport (to appear in IEEE
Internet Computing)", November 2011. Internet Computing)", November 2011.
[RFC2354] Perkins, C. and O. Hodson, "Options for Repair of [RFC2354] Perkins, C. and O. Hodson, "Options for Repair of
Streaming Media", RFC 2354, June 1998. Streaming Media", RFC 2354, June 1998.
[RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, May 2000. [RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, May 2000.
 End of changes. 9 change blocks. 
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