draft-ietf-mmusic-sdp-simulcast-13.txt   draft-ietf-mmusic-sdp-simulcast-14.txt 
Network Working Group B. Burman Network Working Group B. Burman
Internet-Draft M. Westerlund Internet-Draft M. Westerlund
Intended status: Standards Track Ericsson Intended status: Standards Track Ericsson
Expires: December 29, 2018 S. Nandakumar Expires: September 6, 2019 S. Nandakumar
M. Zanaty M. Zanaty
Cisco Cisco
June 27, 2018 March 5, 2019
Using Simulcast in SDP and RTP Sessions Using Simulcast in SDP and RTP Sessions
draft-ietf-mmusic-sdp-simulcast-13 draft-ietf-mmusic-sdp-simulcast-14
Abstract Abstract
In some application scenarios it may be desirable to send multiple In some application scenarios it may be desirable to send multiple
differently encoded versions of the same media source in different differently encoded versions of the same media source in different
RTP streams. This is called simulcast. This document describes how RTP streams. This is called simulcast. This document describes how
to accomplish simulcast in RTP and how to signal it in SDP. The to accomplish simulcast in RTP and how to signal it in SDP. The
described solution uses an RTP/RTCP identification method to identify described solution uses an RTP/RTCP identification method to identify
RTP streams belonging to the same media source, and makes an RTP streams belonging to the same media source, and makes an
extension to SDP to relate those RTP streams as being different extension to SDP to relate those RTP streams as being different
skipping to change at page 1, line 42 skipping to change at page 1, line 42
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 https://datatracker.ietf.org/drafts/current/. Drafts is at https://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 December 29, 2018. This Internet-Draft will expire on September 6, 2019.
Copyright Notice Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the Copyright (c) 2019 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
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to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
skipping to change at page 3, line 9 skipping to change at page 3, line 9
8. Limitation . . . . . . . . . . . . . . . . . . . . . . . . . 29 8. Limitation . . . . . . . . . . . . . . . . . . . . . . . . . 29
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 29 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 29
10. Security Considerations . . . . . . . . . . . . . . . . . . . 30 10. Security Considerations . . . . . . . . . . . . . . . . . . . 30
11. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 30 11. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 30
12. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 30 12. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 30
13. References . . . . . . . . . . . . . . . . . . . . . . . . . 30 13. References . . . . . . . . . . . . . . . . . . . . . . . . . 30
13.1. Normative References . . . . . . . . . . . . . . . . . . 31 13.1. Normative References . . . . . . . . . . . . . . . . . . 31
13.2. Informative References . . . . . . . . . . . . . . . . . 32 13.2. Informative References . . . . . . . . . . . . . . . . . 32
Appendix A. Requirements . . . . . . . . . . . . . . . . . . . . 34 Appendix A. Requirements . . . . . . . . . . . . . . . . . . . . 34
Appendix B. Changes From Earlier Versions . . . . . . . . . . . 35 Appendix B. Changes From Earlier Versions . . . . . . . . . . . 35
B.1. Modifications Between WG Version -12 and -13 . . . . . . 35 B.1. Modifications Between WG Version -13 and -14 . . . . . . 35
B.2. Modifications Between WG Version -11 and -12 . . . . . . 36 B.2. Modifications Between WG Version -12 and -13 . . . . . . 36
B.3. Modifications Between WG Version -10 and -11 . . . . . . 36 B.3. Modifications Between WG Version -11 and -12 . . . . . . 36
B.4. Modifications Between WG Version -09 and -10 . . . . . . 37 B.4. Modifications Between WG Version -10 and -11 . . . . . . 36
B.5. Modifications Between WG Version -08 and -09 . . . . . . 37 B.5. Modifications Between WG Version -09 and -10 . . . . . . 37
B.6. Modifications Between WG Version -07 and -08 . . . . . . 37 B.6. Modifications Between WG Version -08 and -09 . . . . . . 37
B.7. Modifications Between WG Version -06 and -07 . . . . . . 38 B.7. Modifications Between WG Version -07 and -08 . . . . . . 37
B.8. Modifications Between WG Version -05 and -06 . . . . . . 38 B.8. Modifications Between WG Version -06 and -07 . . . . . . 38
B.9. Modifications Between WG Version -04 and -05 . . . . . . 38 B.9. Modifications Between WG Version -05 and -06 . . . . . . 38
B.10. Modifications Between WG Version -03 and -04 . . . . . . 39 B.10. Modifications Between WG Version -04 and -05 . . . . . . 38
B.11. Modifications Between WG Version -02 and -03 . . . . . . 39 B.11. Modifications Between WG Version -03 and -04 . . . . . . 39
B.12. Modifications Between WG Version -01 and -02 . . . . . . 40 B.12. Modifications Between WG Version -02 and -03 . . . . . . 39
B.13. Modifications Between WG Version -00 and -01 . . . . . . 40 B.13. Modifications Between WG Version -01 and -02 . . . . . . 40
B.14. Modifications Between Individual Version -00 and WG B.14. Modifications Between WG Version -00 and -01 . . . . . . 40
B.15. Modifications Between Individual Version -00 and WG
Version -00 . . . . . . . . . . . . . . . . . . . . . . . 40 Version -00 . . . . . . . . . . . . . . . . . . . . . . . 40
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 40 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 40
1. Introduction 1. Introduction
Most of today's multiparty video conference solutions make use of Most of today's multiparty video conference solutions make use of
centralized servers to reduce the bandwidth and CPU consumption in centralized servers to reduce the bandwidth and CPU consumption in
the endpoints. Those servers receive RTP streams from each the endpoints. Those servers receive RTP streams from each
participant and send some suitable set of possibly modified RTP participant and send some suitable set of possibly modified RTP
streams to the rest of the participants, which usually have streams to the rest of the participants, which usually have
skipping to change at page 17, line 29 skipping to change at page 17, line 29
a simulcast of 2 video resolutions and frame rates: HD 1280x720p a simulcast of 2 video resolutions and frame rates: HD 1280x720p
30fps and thumbnail 320x180p 15fps. This is defined below using the 30fps and thumbnail 320x180p 15fps. This is defined below using the
"imageattr" [RFC6236]. In this example, only the "pt" "a=rid" "imageattr" [RFC6236]. In this example, only the "pt" "a=rid"
parameter is used, effectively achieving a 1:1 mapping between parameter is used, effectively achieving a 1:1 mapping between
RtpStreamId and media formats (RTP payload types), to describe RtpStreamId and media formats (RTP payload types), to describe
simulcast stream formats. Alice's Offer: simulcast stream formats. Alice's Offer:
v=0 v=0
o=alice 2362969037 2362969040 IN IP4 192.0.2.156 o=alice 2362969037 2362969040 IN IP4 192.0.2.156
s=Simulcast Enabled Client s=Simulcast Enabled Client
t=0 0
c=IN IP4 192.0.2.156 c=IN IP4 192.0.2.156
t=0 0
m=audio 49200 RTP/AVP 0 m=audio 49200 RTP/AVP 0
a=rtpmap:0 PCMU/8000 a=rtpmap:0 PCMU/8000
m=video 49300 RTP/AVP 97 98 m=video 49300 RTP/AVP 97 98
a=rtpmap:97 H264/90000 a=rtpmap:97 H264/90000
a=rtpmap:98 H264/90000 a=rtpmap:98 H264/90000
a=fmtp:97 profile-level-id=42c01f;max-fs=3600;max-mbps=108000 a=fmtp:97 profile-level-id=42c01f;max-fs=3600;max-mbps=108000
a=fmtp:98 profile-level-id=42c00b;max-fs=240;max-mbps=3600 a=fmtp:98 profile-level-id=42c00b;max-fs=240;max-mbps=3600
a=imageattr:97 send [x=1280,y=720] recv [x=1280,y=720] a=imageattr:97 send [x=1280,y=720] recv [x=1280,y=720]
a=imageattr:98 send [x=320,y=180] recv [x=320,y=180] a=imageattr:98 send [x=320,y=180] recv [x=320,y=180]
a=rid:1 send pt=97 a=rid:1 send pt=97
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The Answer from the server indicates that it too is simulcast The Answer from the server indicates that it too is simulcast
capable. Should it not have been simulcast capable, the capable. Should it not have been simulcast capable, the
"a=simulcast" line would not have been present and communication "a=simulcast" line would not have been present and communication
would have started with the media negotiated in the SDP. Also the would have started with the media negotiated in the SDP. Also the
usage of the RtpStreamId RTP header extension is accepted. usage of the RtpStreamId RTP header extension is accepted.
v=0 v=0
o=server 823479283 1209384938 IN IP4 192.0.2.2 o=server 823479283 1209384938 IN IP4 192.0.2.2
s=Answer to Simulcast Enabled Client s=Answer to Simulcast Enabled Client
t=0 0
c=IN IP4 192.0.2.43 c=IN IP4 192.0.2.43
t=0 0
m=audio 49672 RTP/AVP 0 m=audio 49672 RTP/AVP 0
a=rtpmap:0 PCMU/8000 a=rtpmap:0 PCMU/8000
m=video 49674 RTP/AVP 97 98 m=video 49674 RTP/AVP 97 98
a=rtpmap:97 H264/90000 a=rtpmap:97 H264/90000
a=rtpmap:98 H264/90000 a=rtpmap:98 H264/90000
a=fmtp:97 profile-level-id=42c01f;max-fs=3600;max-mbps=108000 a=fmtp:97 profile-level-id=42c01f;max-fs=3600;max-mbps=108000
a=fmtp:98 profile-level-id=42c00b;max-fs=240;max-mbps=3600 a=fmtp:98 profile-level-id=42c00b;max-fs=240;max-mbps=3600
a=imageattr:97 send [x=1280,y=720] recv [x=1280,y=720] a=imageattr:97 send [x=1280,y=720] recv [x=1280,y=720]
a=imageattr:98 send [x=320,y=180] recv [x=320,y=180] a=imageattr:98 send [x=320,y=180] recv [x=320,y=180]
a=rid:1 recv pt=97 a=rid:1 recv pt=97
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of both BUNDLE [I-D.ietf-mmusic-sdp-bundle-negotiation] and "a=rid" of both BUNDLE [I-D.ietf-mmusic-sdp-bundle-negotiation] and "a=rid"
[I-D.ietf-mmusic-rid] recommends using the RTP header extension [I-D.ietf-mmusic-rid] recommends using the RTP header extension
[RFC8285] for carrying these RTP stream identification fields, which [RFC8285] for carrying these RTP stream identification fields, which
is consequently also included in the SDP. Note also that for is consequently also included in the SDP. Note also that for
"a=rid", the corresponding RtpStreamId SDES attribute RTP header "a=rid", the corresponding RtpStreamId SDES attribute RTP header
extension is named rtp-stream-id [I-D.ietf-avtext-rid]. extension is named rtp-stream-id [I-D.ietf-avtext-rid].
v=0 v=0
o=fred 238947129 823479223 IN IP6 2001:db8::c000:27d o=fred 238947129 823479223 IN IP6 2001:db8::c000:27d
s=Offer from Simulcast Enabled Multi-Source Client s=Offer from Simulcast Enabled Multi-Source Client
t=0 0
c=IN IP6 2001:db8::c000:27d c=IN IP6 2001:db8::c000:27d
t=0 0
a=group:BUNDLE foo bar zen a=group:BUNDLE foo bar zen
m=audio 49200 RTP/AVP 99 m=audio 49200 RTP/AVP 99
a=mid:foo a=mid:foo
a=rtpmap:99 G722/8000 a=rtpmap:99 G722/8000
m=video 49600 RTP/AVPF 100 101 103 m=video 49600 RTP/AVPF 100 101 103
a=mid:bar a=mid:bar
a=rtpmap:100 H264-SVC/90000 a=rtpmap:100 H264-SVC/90000
a=rtpmap:101 H264/90000 a=rtpmap:101 H264/90000
a=rtpmap:103 VP8/90000 a=rtpmap:103 VP8/90000
a=fmtp:100 profile-level-id=42400d;max-fs=3600;max-mbps=216000; \ a=fmtp:100 profile-level-id=42400d;max-fs=3600;max-mbps=216000; \
skipping to change at page 22, line 8 skipping to change at page 22, line 8
The video source is offered to be sent as two simulcast streams, both The video source is offered to be sent as two simulcast streams, both
with two alternative simulcast formats. Redundancy and repair are with two alternative simulcast formats. Redundancy and repair are
offered in the form of both Flexible FEC and RTP Retransmission. The offered in the form of both Flexible FEC and RTP Retransmission. The
Flexible FEC is not bound to any particular RTP streams and is Flexible FEC is not bound to any particular RTP streams and is
therefore possible to use across all RTP streams that are being sent therefore possible to use across all RTP streams that are being sent
as part of this media description. as part of this media description.
v=0 v=0
o=fred 238947129 823479223 IN IP6 2001:db8::c000:27d o=fred 238947129 823479223 IN IP6 2001:db8::c000:27d
s=Offer from Simulcast Enabled Client using Redundancy s=Offer from Simulcast Enabled Client using Redundancy
t=0 0
c=IN IP6 2001:db8::c000:27d c=IN IP6 2001:db8::c000:27d
t=0 0
a=group:BUNDLE foo bar a=group:BUNDLE foo bar
m=audio 49200 RTP/AVP 97 98 99 100 101 102 m=audio 49200 RTP/AVP 97 98 99 100 101 102
a=mid:foo a=mid:foo
a=rtpmap:97 G711/8000 a=rtpmap:97 G711/8000
a=rtpmap:98 LPC/8000 a=rtpmap:98 LPC/8000
a=rtpmap:99 OPUS/48000/1 a=rtpmap:99 OPUS/48000/1
a=rtpmap:100 RED/8000/1 a=rtpmap:100 RED/8000/1
a=rtpmap:101 CN/8000 a=rtpmap:101 CN/8000
a=rtpmap:102 telephone-event/8000 a=rtpmap:102 telephone-event/8000
a=fmtp:99 useinbandfec=1;usedtx=0 a=fmtp:99 useinbandfec=1;usedtx=0
skipping to change at page 31, line 19 skipping to change at page 31, line 19
rid-09 (work in progress), October 2016. rid-09 (work in progress), October 2016.
[I-D.ietf-mmusic-rid] [I-D.ietf-mmusic-rid]
Roach, A., "RTP Payload Format Restrictions", draft-ietf- Roach, A., "RTP Payload Format Restrictions", draft-ietf-
mmusic-rid-15 (work in progress), May 2018. mmusic-rid-15 (work in progress), May 2018.
[I-D.ietf-mmusic-sdp-bundle-negotiation] [I-D.ietf-mmusic-sdp-bundle-negotiation]
Holmberg, C., Alvestrand, H., and C. Jennings, Holmberg, C., Alvestrand, H., and C. Jennings,
"Negotiating Media Multiplexing Using the Session "Negotiating Media Multiplexing Using the Session
Description Protocol (SDP)", draft-ietf-mmusic-sdp-bundle- Description Protocol (SDP)", draft-ietf-mmusic-sdp-bundle-
negotiation-52 (work in progress), May 2018. negotiation-54 (work in progress), December 2018.
[I-D.ietf-mmusic-sdp-mux-attributes] [I-D.ietf-mmusic-sdp-mux-attributes]
Nandakumar, S., "A Framework for SDP Attributes when Nandakumar, S., "A Framework for SDP Attributes when
Multiplexing", draft-ietf-mmusic-sdp-mux-attributes-17 Multiplexing", draft-ietf-mmusic-sdp-mux-attributes-17
(work in progress), February 2018. (work in progress), February 2018.
[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, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
skipping to change at page 32, line 13 skipping to change at page 32, line 13
February 2016, <https://www.rfc-editor.org/info/rfc7728>. February 2016, <https://www.rfc-editor.org/info/rfc7728>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>. May 2017, <https://www.rfc-editor.org/info/rfc8174>.
13.2. Informative References 13.2. Informative References
[I-D.ietf-avtcore-multiplex-guidelines] [I-D.ietf-avtcore-multiplex-guidelines]
Westerlund, M., Burman, B., Perkins, C., Alvestrand, H., Westerlund, M., Burman, B., Perkins, C., Alvestrand, H.,
Even, R., and H. Zheng, "Guidelines for using the and R. Even, "Guidelines for using the Multiplexing
Multiplexing Features of RTP to Support Multiple Media Features of RTP to Support Multiple Media Streams", draft-
Streams", draft-ietf-avtcore-multiplex-guidelines-05 (work ietf-avtcore-multiplex-guidelines-08 (work in progress),
in progress), October 2017. December 2018.
[I-D.ietf-payload-flexible-fec-scheme] [I-D.ietf-payload-flexible-fec-scheme]
Zanaty, M., Singh, V., Begen, A., and G. Mandyam, "RTP Zanaty, M., Singh, V., Begen, A., and G. Mandyam, "RTP
Payload Format for Flexible Forward Error Correction Payload Format for Flexible Forward Error Correction
(FEC)", draft-ietf-payload-flexible-fec-scheme-07 (work in (FEC)", draft-ietf-payload-flexible-fec-scheme-17 (work in
progress), March 2018. progress), February 2019.
[RFC2198] Perkins, C., Kouvelas, I., Hodson, O., Hardman, V., [RFC2198] Perkins, C., Kouvelas, I., Hodson, O., Hardman, V.,
Handley, M., Bolot, J., Vega-Garcia, A., and S. Fosse- Handley, M., Bolot, J., Vega-Garcia, A., and S. Fosse-
Parisis, "RTP Payload for Redundant Audio Data", RFC 2198, Parisis, "RTP Payload for Redundant Audio Data", RFC 2198,
DOI 10.17487/RFC2198, September 1997, DOI 10.17487/RFC2198, September 1997,
<https://www.rfc-editor.org/info/rfc2198>. <https://www.rfc-editor.org/info/rfc2198>.
[RFC3264] Rosenberg, J. and H. Schulzrinne, "An Offer/Answer Model [RFC3264] Rosenberg, J. and H. Schulzrinne, "An Offer/Answer Model
with Session Description Protocol (SDP)", RFC 3264, with Session Description Protocol (SDP)", RFC 3264,
DOI 10.17487/RFC3264, June 2002, DOI 10.17487/RFC3264, June 2002,
skipping to change at page 35, line 46 skipping to change at page 35, line 46
REQ-6.1: Interworking with non-simulcast legacy clients using a REQ-6.1: Interworking with non-simulcast legacy clients using a
single media source per media type. single media source per media type.
REQ-6.2: WebRTC environment with a single media source per SDP REQ-6.2: WebRTC environment with a single media source per SDP
media description. media description.
Appendix B. Changes From Earlier Versions Appendix B. Changes From Earlier Versions
NOTE TO RFC EDITOR: Please remove this section prior to publication. NOTE TO RFC EDITOR: Please remove this section prior to publication.
B.1. Modifications Between WG Version -12 and -13 B.1. Modifications Between WG Version -13 and -14
o c= and t= line order corrected in SDP examples
B.2. Modifications Between WG Version -12 and -13
o Examples corrected to follow RID ABNF o Examples corrected to follow RID ABNF
o Example Figure 7 now comments on priority for second media source. o Example Figure 7 now comments on priority for second media source.
o Clarified a SHOULD limitation. o Clarified a SHOULD limitation.
o Added urn:ietf:params:rtp-hdrext:sdes:repaired-rtp-stream-id in o Added urn:ietf:params:rtp-hdrext:sdes:repaired-rtp-stream-id in
examples with RTX. examples with RTX.
o ABNF now uses RFC 7405 to indicate case sensitivity o ABNF now uses RFC 7405 to indicate case sensitivity
o Various minor editorials and nits. o Various minor editorials and nits.
B.2. Modifications Between WG Version -11 and -12 B.3. Modifications Between WG Version -11 and -12
o Modified Normative statement regarding RTP stream duplication in o Modified Normative statement regarding RTP stream duplication in
Section 5.2. Section 5.2.
o Clarified assumption about use of congestion control by o Clarified assumption about use of congestion control by
applications. applications.
o Changed to use RFC 8174 boilerplate instead of RFC 2119. o Changed to use RFC 8174 boilerplate instead of RFC 2119.
o Clarified explanation of syntax for simulcast attribute in o Clarified explanation of syntax for simulcast attribute in
Section 4. Section 4.
o Editorial clarification in Section 5.2 and 5.3.2. o Editorial clarification in Section 5.2 and 5.3.2.
o Various minor editorials and nits. o Various minor editorials and nits.
B.3. Modifications Between WG Version -10 and -11 B.4. Modifications Between WG Version -10 and -11
o Added new SDP example section on Simulcast and Redundancy, o Added new SDP example section on Simulcast and Redundancy,
including both RED (RFC2198), RTP RTX (RFC4588), and FEC (draft- including both RED (RFC2198), RTP RTX (RFC4588), and FEC (draft-
ietf-payload-flexible-fec-scheme). ietf-payload-flexible-fec-scheme).
o Removed restriction that "related" payload formats in an RTP o Removed restriction that "related" payload formats in an RTP
stream (such as CN and DTMF) must not have their own rid-id, since stream (such as CN and DTMF) must not have their own rid-id, since
there is no reason to forbid this and corresponding clarification there is no reason to forbid this and corresponding clarification
is made in draft-ietf-mmusic-rid. is made in draft-ietf-mmusic-rid.
o Removed any mention of source-specific signaling and the reference o Removed any mention of source-specific signaling and the reference
to RFC5576, since draft-ietf-mmusic-rid is not defined for source- to RFC5576, since draft-ietf-mmusic-rid is not defined for source-
specific signaling. specific signaling.
o Changed some SDP examples to use a=rid restrictions instead of o Changed some SDP examples to use a=rid restrictions instead of
a=imageattr. a=imageattr.
o Changed reference from the obsoleted RFC 5285 to RFC 8285. o Changed reference from the obsoleted RFC 5285 to RFC 8285.
B.4. Modifications Between WG Version -09 and -10 B.5. Modifications Between WG Version -09 and -10
o Amended overview section with a bit more explanation on the o Amended overview section with a bit more explanation on the
examples, and added an rid-id alternative for one of the streams. examples, and added an rid-id alternative for one of the streams.
o Removed SCID also from the Terminology section, which was o Removed SCID also from the Terminology section, which was
forgotten in -09 when changing SCID to rid-id. forgotten in -09 when changing SCID to rid-id.
B.5. Modifications Between WG Version -08 and -09 B.6. Modifications Between WG Version -08 and -09
o Changed SCID to rid-id, to align with ietf-draft-mmusic-rid o Changed SCID to rid-id, to align with ietf-draft-mmusic-rid
naming. naming.
o Changed Overview to be based on examples and shortened it. o Changed Overview to be based on examples and shortened it.
o Changed semantics of initially paused rid-id in modified SDP o Changed semantics of initially paused rid-id in modified SDP
offers from requiring it to follow actual RFC 7728 pause state to offers from requiring it to follow actual RFC 7728 pause state to
an informational offerer's opinion at the time of offer creation, an informational offerer's opinion at the time of offer creation,
not in any way overriding or amending RFC 7728 signaling. not in any way overriding or amending RFC 7728 signaling.
skipping to change at page 37, line 37 skipping to change at page 37, line 42
most one "a=simulcast" line is included. most one "a=simulcast" line is included.
o Clarified with a note that, for the case it is clear from the SDP o Clarified with a note that, for the case it is clear from the SDP
that RTP PT uniquely maps to RtpStreamId, an RTP receiver can use that RTP PT uniquely maps to RtpStreamId, an RTP receiver can use
RTP PT to relate simulcast streams. RTP PT to relate simulcast streams.
o Moved Section 4 Requirements to become Appendix A. o Moved Section 4 Requirements to become Appendix A.
o Editorial corrections and clarifications. o Editorial corrections and clarifications.
B.6. Modifications Between WG Version -07 and -08 B.7. Modifications Between WG Version -07 and -08
o Correcting syntax of SDP examples in section 6.6.1, as found by o Correcting syntax of SDP examples in section 6.6.1, as found by
Inaki Baz Castillo. Inaki Baz Castillo.
o Changing ABNF to only define the sc-value, not the SDP attribute o Changing ABNF to only define the sc-value, not the SDP attribute
itself, as suggested by Paul Kyzivat. itself, as suggested by Paul Kyzivat.
o Changing I-D reference to newly published RFC 8108. o Changing I-D reference to newly published RFC 8108.
o Adding list of modifications between -06 and -07. o Adding list of modifications between -06 and -07.
B.7. Modifications Between WG Version -06 and -07 B.8. Modifications Between WG Version -06 and -07
o A scope clarification, as result of the discussion with Roni Even. o A scope clarification, as result of the discussion with Roni Even.
o A reformulation of the identification requirements for simulcast o A reformulation of the identification requirements for simulcast
stream. stream.
o Correcting the statement related to source specific signalling o Correcting the statement related to source specific signalling
(RFC 5576) to address Roni Even's comment. (RFC 5576) to address Roni Even's comment.
o Update of the last paragraph in Section 6.2 regarding simulcast o Update of the last paragraph in Section 6.2 regarding simulcast
stream differences as well as forbidding multiple instances of the stream differences as well as forbidding multiple instances of the
same SCID within a single a=simulcast line. same SCID within a single a=simulcast line.
o Removal of note in Section 6.4 as result of issue raised by Roni o Removal of note in Section 6.4 as result of issue raised by Roni
Even. Even.
o Use of "m=" has been changed to media description and a few other o Use of "m=" has been changed to media description and a few other
editorial improvements and clarifications. editorial improvements and clarifications.
B.8. Modifications Between WG Version -05 and -06 B.9. Modifications Between WG Version -05 and -06
o Added section on RTP Aspects o Added section on RTP Aspects
o Added a requirement (5-4) on that capability exchange must be o Added a requirement (5-4) on that capability exchange must be
capable of handling multi RTP stream cases. capable of handling multi RTP stream cases.
o Added extmap attribute also on first signalling example as it is a o Added extmap attribute also on first signalling example as it is a
recommended to use mechanism. recommended to use mechanism.
o Clarified the definition of the simulcast attribute and how o Clarified the definition of the simulcast attribute and how
simulcast streams relates to simulcast formats and SCIDs. simulcast streams relates to simulcast formats and SCIDs.
o Updated References list and moved around some references between o Updated References list and moved around some references between
informative and normative categories. informative and normative categories.
o Editorial improvements and corrections. o Editorial improvements and corrections.
B.9. Modifications Between WG Version -04 and -05 B.10. Modifications Between WG Version -04 and -05
o Aligned with recent changes in draft-ietf-mmusic-rid and draft- o Aligned with recent changes in draft-ietf-mmusic-rid and draft-
ietf-avtext-rid. ietf-avtext-rid.
o Modified the SDP offer/answer section to follow the generally o Modified the SDP offer/answer section to follow the generally
accepted structure, also adding a brief text on modifying the accepted structure, also adding a brief text on modifying the
session that is aligned with draft-ietf-mmusic-rid. session that is aligned with draft-ietf-mmusic-rid.
o Improved text around simulcast stream identification (as opposed o Improved text around simulcast stream identification (as opposed
to the simulcast stream itself) to consistently use the acronym to the simulcast stream itself) to consistently use the acronym
skipping to change at page 39, line 19 skipping to change at page 39, line 19
o Changed references for RTP-level pause/resume and VP8 payload o Changed references for RTP-level pause/resume and VP8 payload
format that are now published as RFC. format that are now published as RFC.
o Improved IANA registration text. o Improved IANA registration text.
o Removed unused reference to draft-ietf-payload-flexible-fec- o Removed unused reference to draft-ietf-payload-flexible-fec-
scheme. scheme.
o Editorial improvements and corrections. o Editorial improvements and corrections.
B.10. Modifications Between WG Version -03 and -04 B.11. Modifications Between WG Version -03 and -04
o Changed to only use RID identification, as was consensus during o Changed to only use RID identification, as was consensus during
IETF 94. IETF 94.
o ABNF improvements. o ABNF improvements.
o Clarified offer-answer rules for initially paused streams. o Clarified offer-answer rules for initially paused streams.
o Changed references for RTP topologies and RTP taxonomy documents o Changed references for RTP topologies and RTP taxonomy documents
that are now published as RFC. that are now published as RFC.
o Added reference to the new RID draft in AVTEXT. o Added reference to the new RID draft in AVTEXT.
o Re-structured section 6 to provide an easy reference by the o Re-structured section 6 to provide an easy reference by the
updated IANA section. updated IANA section.
o Added a sub-section 7.1 with a discussion of bitrate adaptation. o Added a sub-section 7.1 with a discussion of bitrate adaptation.
o Editorial improvements. o Editorial improvements.
B.11. Modifications Between WG Version -02 and -03 B.12. Modifications Between WG Version -02 and -03
o Removed text on multicast / broadcast from use cases, since it is o Removed text on multicast / broadcast from use cases, since it is
not supported by the solution. not supported by the solution.
o Removed explicit references to unified plan draft. o Removed explicit references to unified plan draft.
o Added possibility to initiate simulcast streams in paused mode. o Added possibility to initiate simulcast streams in paused mode.
o Enabled an offerer to offer multiple stream identification (pt or o Enabled an offerer to offer multiple stream identification (pt or
rid) methods and have the answerer choose which to use. rid) methods and have the answerer choose which to use.
o Added a preference indication also in send direction offers. o Added a preference indication also in send direction offers.
o Added a section on limitations of the current proposal, including o Added a section on limitations of the current proposal, including
identification method specific limitations. identification method specific limitations.
B.12. Modifications Between WG Version -01 and -02 B.13. Modifications Between WG Version -01 and -02
o Relying on the new RID solution for codec constraints and o Relying on the new RID solution for codec constraints and
configuration identification. This has resulted in changes in configuration identification. This has resulted in changes in
syntax to identify if pt or RID is used to describe the simulcast syntax to identify if pt or RID is used to describe the simulcast
stream. stream.
o Renamed simulcast version and simulcast version alternative to o Renamed simulcast version and simulcast version alternative to
simulcast stream and simulcast format respectively, and improved simulcast stream and simulcast format respectively, and improved
definitions for them. definitions for them.
o Clarification that it is possible to switch between simulcast o Clarification that it is possible to switch between simulcast
version alternatives, but that only a single one be used at any version alternatives, but that only a single one be used at any
point in time. point in time.
o Changed the definition so that ordering of simulcast formats for a o Changed the definition so that ordering of simulcast formats for a
specific simulcast stream do have a preference order. specific simulcast stream do have a preference order.
B.13. Modifications Between WG Version -00 and -01 B.14. Modifications Between WG Version -00 and -01
o No changes. Only preventing expiry. o No changes. Only preventing expiry.
B.14. Modifications Between Individual Version -00 and WG Version -00 B.15. Modifications Between Individual Version -00 and WG Version -00
o Added this appendix. o Added this appendix.
Authors' Addresses Authors' Addresses
Bo Burman Bo Burman
Ericsson Ericsson
Gronlandsgatan 31 Gronlandsgatan 31
SE-164 60 Stockholm SE-164 60 Stockholm
Sweden Sweden
Email: bo.burman@ericsson.com Email: bo.burman@ericsson.com
Magnus Westerlund Magnus Westerlund
Ericsson Ericsson
Farogatan 2 Torshamnsgatan 23
SE-164 80 Stockholm SE-164 83 Stockholm
Sweden Sweden
Phone: +46 10 714 82 87 Phone: +46 10 714 82 87
Email: magnus.westerlund@ericsson.com Email: magnus.westerlund@ericsson.com
Suhas Nandakumar Suhas Nandakumar
Cisco Cisco
170 West Tasman Drive 170 West Tasman Drive
San Jose, CA 95134 San Jose, CA 95134
USA USA
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