draft-ietf-mmusic-sdp-mux-attributes-01.txt   draft-ietf-mmusic-sdp-mux-attributes-02.txt 
Network Working Group S. Nandakumar Network Working Group S. Nandakumar
Internet-Draft Cisco Internet-Draft Cisco
Intended status: Standards Track February 14, 2014 Intended status: Standards Track July 03, 2014
Expires: August 18, 2014 Expires: January 4, 2015
A Framework for SDP Attributes when Multiplexing A Framework for SDP Attributes when Multiplexing
draft-ietf-mmusic-sdp-mux-attributes-01 draft-ietf-mmusic-sdp-mux-attributes-02
Abstract Abstract
The Session Description Protocol (SDP) provides mechanisms to The Session Description Protocol (SDP) provides mechanisms to
describe attributes of multimedia sessions and of individual media describe attributes of multimedia sessions and of individual media
streams (e.g., Real-time Transport Protocol (RTP) sessions) within a streams (e.g., Real-time Transport Protocol (RTP) sessions) within a
multimedia session. In the RTCWeb WG, there is a need to use a multimedia session. In the RTCWeb WG, there is a need to use a
single 5-tuple for sending and receiving media associated with single 5-tuple for sending and receiving media associated with
multiple media descriptions ("m=" lines). Such a requirement has multiple media descriptions ("m=" lines). Such a requirement has
raised concerns over the semantic implications of the SDP attributes raised concerns over the semantic implications of the SDP attributes
associated with the RTP Media Streams multiplexed over a single associated with the RTP Media Streams multiplexed over a single
transport layer flow. transport layer flow.
The scope of this specification is to provide a framework for The scope of this specification is to provide a framework for
analyzing the multiplexing characteristics of SDP attributes. The analyzing the multiplexing characteristics of SDP attributes. The
specification also categorizes existing attributes based on the specification also categorizes existing attributes based on the
framework described herein. framework described herein.
Status of this Memo Status of This Memo
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provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 5 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . 5 3. Motivation . . . . . . . . . . . . . . . . . . . . . . . . . 5
4. SDP Attribute Analysis Framework . . . . . . . . . . . . . . . 6 4. SDP Attribute Analysis Framework . . . . . . . . . . . . . . 6
5. Analysis of Existing Attributes . . . . . . . . . . . . . . . 9 4.1. Category: NORMAL . . . . . . . . . . . . . . . . . . . . 6
5.1. RFC4566 - SDP: Session Description Protocol . . . . . . . 10 4.2. Category: NOT RECOMMENDED . . . . . . . . . . . . . . . . 7
5.2. RFC4585 - RTP/AVPF . . . . . . . . . . . . . . . . . . . . 11 4.3. Category: IDENTICAL . . . . . . . . . . . . . . . . . . . 7
5.3. RFC5761 - Multiplexing RTP and RTCP . . . . . . . . . . . 11 4.4. Category: SUM . . . . . . . . . . . . . . . . . . . . . . 8
5.4. RFC4574 - SDP Label Attribute . . . . . . . . . . . . . . 12 4.5. Category: TRANSPORT . . . . . . . . . . . . . . . . . . . 8
5.5. RFC5432 - QoS Mechanism Selection in SDP . . . . . . . . . 12 4.6. Category: INHERIT . . . . . . . . . . . . . . . . . . . . 9
5.6. RFC4568 - SDP Security Descriptions . . . . . . . . . . . 13 4.7. Category: IDENTICAL-PER-PT . . . . . . . . . . . . . . . 10
5.7. RFC5762 - RTP over DCCP . . . . . . . . . . . . . . . . . 13 4.8. Category: SPECIAL . . . . . . . . . . . . . . . . . . . . 10
5.8. RFC6773 - DCCP-UDP Encapsulation . . . . . . . . . . . . . 14 5. Analysis of Existing Attributes . . . . . . . . . . . . . . . 11
5.9. RFC5506 - Reduced-Size RTCP in RTP Profile . . . . . . . . 14 5.1. RFC4566 - SDP: Session Description Protocol . . . . . . . 11
5.10. RFC6787 - Media Resource Control Protocol Version 2 . . . 15 5.2. RFC4585 - RTP/AVPF . . . . . . . . . . . . . . . . . . . 12
5.11. RFC5245 - Interactive Connectivity Establishment (ICE) . . 15 5.3. RFC5761 - Multiplexing RTP and RTCP . . . . . . . . . . . 13
5.12. RFC5285 - RTP Header Extensions . . . . . . . . . . . . . 17 5.4. RFC4574 - SDP Label Attribute . . . . . . . . . . . . . . 13
5.13. RFC3605 - RTCP attribute in SDP . . . . . . . . . . . . . 17 5.5. RFC5432 - QoS Mechanism Selection in SDP . . . . . . . . 13
5.14. RFC5576 - Source-Specific SDP Attributes . . . . . . . . . 17 5.6. RFC4568 - SDP Security Descriptions . . . . . . . . . . . 14
5.15. RFC6236 - Image Attributes in SDP . . . . . . . . . . . . 18 5.7. RFC5762 - RTP over DCCP . . . . . . . . . . . . . . . . . 14
5.16. RFC6285 - Rapid Acquisition of Multicast RTP Sessions . . 19 5.8. RFC6773 - DCCP-UDP Encapsulation . . . . . . . . . . . . 15
5.17. RFC6230 - Media Control Channel Framework . . . . . . . . 19 5.9. RFC5506 - Reduced-Size RTCP in RTP Profile . . . . . . . 16
5.18. RFC6364 - SDP Elements for FEC Framework . . . . . . . . . 19 5.10. RFC6787 - Media Resource Control Protocol Version 2 . . . 16
5.19. RFC4796 - Content Attribute . . . . . . . . . . . . . . . 20 5.11. RFC5245 - Interactive Connectivity Establishment (ICE) . 17
5.20. RFC3407 - SDP Simple Capability Declaration . . . . . . . 20 5.12. RFC5285 - RTP Header Extensions . . . . . . . . . . . . . 18
5.21. RFC6284 - Port Mapping between Unicast and Multicast 5.13. RFC3605 - RTCP attribute in SDP . . . . . . . . . . . . . 19
RTP Sessions . . . . . . . . . . . . . . . . . . . . . . . 21 5.14. RFC5576 - Source-Specific SDP Attributes . . . . . . . . 19
5.22. RFC6714 - MSRP-CEMA . . . . . . . . . . . . . . . . . . . 21 5.15. RFC6236 - Image Attributes in SDP . . . . . . . . . . . . 20
5.23. RFC4583 - SDP Format for BFCP Streams . . . . . . . . . . 22 5.16. RFC6285 - Rapid Acquisition of Multicast RTP Sessions . . 21
5.24. RFC5547 - SDP Offer/Answer for File Transfer . . . . . . . 22 5.17. RFC6230 - Media Control Channel Framework . . . . . . . . 21
5.25. RFC6489 - SDP and RTP Media Loopback Extension . . . . . . 23 5.18. RFC6364 - SDP Elements for FEC Framework . . . . . . . . 22
5.26. RFC5760 - RTCP with Unicast Feedback . . . . . . . . . . . 23 5.19. RFC4796 - Content Attribute . . . . . . . . . . . . . . . 22
5.27. RFC3611 - RTCP XR . . . . . . . . . . . . . . . . . . . . 24 5.20. RFC3407 - SDP Simple Capability Declaration . . . . . . . 23
5.28. RFC5939 - SDP Capability Negotiation . . . . . . . . . . . 24 5.21. RFC6284 - Port Mapping between Unicast and Multicast RTP
5.29. RFC6781 - SDP Media Capabilities Negotiation . . . . . . . 25 Sessions . . . . . . . . . . . . . . . . . . . . . . . . 23
5.30. RFC4567 - Key Management Extensions for SDP and RTSP . . . 26 5.22. RFC6714 - MSRP-CEMA . . . . . . . . . . . . . . . . . . . 24
5.31. RFC4572 - Comedia over TLS in SDP . . . . . . . . . . . . 26 5.23. RFC4583 - SDP Format for BFCP Streams . . . . . . . . . . 24
5.32. RFC4570 - SDP Source Filters . . . . . . . . . . . . . . . 27 5.24. RFC5547 - SDP Offer/Answer for File Transfer . . . . . . 25
5.33. RFC6128 - RTCP Port for Multicast Sessions . . . . . . . . 27 5.25. RFC6489 - SDP and RTP Media Loopback Extension . . . . . 25
5.34. RFC6189 - ZRTP . . . . . . . . . . . . . . . . . . . . . . 28 5.26. RFC5760 - RTCP with Unicast Feedback . . . . . . . . . . 26
5.35. RFC4145 - Connection-Oriented Media . . . . . . . . . . . 28 5.27. RFC3611 - RTCP XR . . . . . . . . . . . . . . . . . . . . 26
5.36. RFC5159 - OMA BCAST SDP Attributes . . . . . . . . . . . . 29 5.28. RFC5939 - SDP Capability Negotiation . . . . . . . . . . 27
5.37. RFC6193 - Media Description for IKE in SDP . . . . . . . . 29 5.29. RFC6871- SDP Media Capabilities Negotiation . . . . . . . 27
5.38. RFC6064 - SDP and RTSP Extensions for 3GPP . . . . . . . . 30 5.30. RFC4567 - Key Management Extensions for SDP and RTSP . . 28
5.39. RFC3108 - ATM SDP . . . . . . . . . . . . . . . . . . . . 33 5.31. RFC4572 - Comedia over TLS in SDP . . . . . . . . . . . . 28
5.40. 3GPP TS 24.182 . . . . . . . . . . . . . . . . . . . . . . 34 5.32. RFC4570 - SDP Source Filters . . . . . . . . . . . . . . 29
5.41. 3GPP TS 24.183 . . . . . . . . . . . . . . . . . . . . . . 34 5.33. RFC6128 - RTCP Port for Multicast Sessions . . . . . . . 29
5.42. 3GPP TS 24.229 . . . . . . . . . . . . . . . . . . . . . . 35 5.34. RFC6189 - ZRTP . . . . . . . . . . . . . . . . . . . . . 30
5.43. ITU T.38 . . . . . . . . . . . . . . . . . . . . . . . . . 36 5.35. RFC4145 - Connection-Oriented Media . . . . . . . . . . . 31
5.44. ITU-T H.248.15 . . . . . . . . . . . . . . . . . . . . . . 36 5.36. RFC5159 - OMA BCAST SDP Attributes . . . . . . . . . . . 31
5.45. RFC4975 - The Message Session Relay Protocol . . . . . . . 37 5.37. RFC6193 - Media Description for IKE in SDP . . . . . . . 32
5.46. Historical . . . . . . . . . . . . . . . . . . . . . . . . 38 5.38. RFC6064 - SDP and RTSP Extensions for 3GPP . . . . . . . 33
6. bwtype Attribute Analysis . . . . . . . . . . . . . . . . . . 38 5.39. RFC3108 - ATM SDP . . . . . . . . . . . . . . . . . . . . 35
6.1. RFC4566 - SDP: Session Description Protocol . . . . . . . 39 5.40. 3GPP TS 24.182 . . . . . . . . . . . . . . . . . . . . . 36
6.2. RFC3556 - SDP Bandwidth Modifiers for RTCP Bandwidth . . . 39 5.41. 3GPP TS 24.183 . . . . . . . . . . . . . . . . . . . . . 37
6.3. RFC3890 - Bandwidth Modifier for SDP . . . . . . . . . . . 40 5.42. 3GPP TS 24.229 . . . . . . . . . . . . . . . . . . . . . 37
7. rtcp-fb Attribute Analysis . . . . . . . . . . . . . . . . . . 40 5.43. ITU T.38 . . . . . . . . . . . . . . . . . . . . . . . . 38
7.1. RFC4585 - RTP/AVPF . . . . . . . . . . . . . . . . . . . . 41 5.44. ITU-T H.248.15 . . . . . . . . . . . . . . . . . . . . . 39
7.2. RFC5104 - Codec Control Messages in AVPF . . . . . . . . . 41 5.45. RFC4975 - The Message Session Relay Protocol . . . . . . 40
7.3. RFC6285 - Unicast-Based RAMS . . . . . . . . . . . . . . . 42 5.46. Historical . . . . . . . . . . . . . . . . . . . . . . . 41
7.4. RFC6679 - ECN for RTP over UDP/IP . . . . . . . . . . . . 42 6. bwtype Attribute Analysis . . . . . . . . . . . . . . . . . . 42
7.5. RFC6642 - Third-Party Loss Report . . . . . . . . . . . . 43 6.1. RFC4566 - SDP: Session Description Protocol . . . . . . . 42
7.6. RFC5104 - Codec Control Messages in AVPF . . . . . . . . . 43 6.2. RFC3556 - SDP Bandwidth Modifiers for RTCP Bandwidth . . 42
8. group Attribute Analysis . . . . . . . . . . . . . . . . . . . 44 6.3. RFC3890 - Bandwidth Modifier for SDP . . . . . . . . . . 43
8.1. RFC5888 - SDP Grouping Framework . . . . . . . . . . . . . 44 7. rtcp-fb Attribute Analysis . . . . . . . . . . . . . . . . . 44
8.2. RFC3524 - Mapping Media Streams to Resource 7.1. RFC4585 - RTP/AVPF . . . . . . . . . . . . . . . . . . . 44
Reservation Flows . . . . . . . . . . . . . . . . . . . . 44 7.2. RFC5104 - Codec Control Messages in AVPF . . . . . . . . 45
8.3. RFC4091 - ANAT Semantics . . . . . . . . . . . . . . . . . 44 7.3. RFC6285 - Unicast-Based RAMS . . . . . . . . . . . . . . 45
8.4. RFC5956 - FEC Grouping Semantics in SDP . . . . . . . . . 45 7.4. RFC6679 - ECN for RTP over UDP/IP . . . . . . . . . . . . 45
8.5. RFC5583 - Signaling Media Decoding Dependency in SDP . . . 45 7.5. RFC6642 - Third-Party Loss Report . . . . . . . . . . . . 46
9. ssrc-group Attribute Analysis . . . . . . . . . . . . . . . . 46 7.6. RFC5104 - Codec Control Messages in AVPF . . . . . . . . 46
9.1. RFC5576 - Source-Specific SDP Attributes . . . . . . . . . 46 8. group Attribute Analysis . . . . . . . . . . . . . . . . . . 47
10. QoS Mechanism Token Analysis . . . . . . . . . . . . . . . . . 46 8.1. RFC5888 - SDP Grouping Framework . . . . . . . . . . . . 47
10.1. RFC5432 - QoS Mechanism Selection in SDP . . . . . . . . . 46 8.2. RFC3524 - Mapping Media Streams to Resource Reservation
11. k= Attribute Analysis . . . . . . . . . . . . . . . . . . . . 47 Flows . . . . . . . . . . . . . . . . . . . . . . . . . . 47
11.1. RFC4566 SDP: Session Description Protocol . . . . . . . . 47 8.3. RFC4091 - ANAT Semantics . . . . . . . . . . . . . . . . 48
12. content Atribute Analysis . . . . . . . . . . . . . . . . . . 47 8.4. RFC5956 - FEC Grouping Semantics in SDP . . . . . . . . . 48
12.1. RFC4796 . . . . . . . . . . . . . . . . . . . . . . . . . 47 8.5. RFC5583 - Signaling Media Decoding Dependency in SDP . . 49
13. Payload Formats . . . . . . . . . . . . . . . . . . . . . . . 47 9. ssrc-group Attribute Analysis . . . . . . . . . . . . . . . . 49
13.1. RFC5109 - RTP Payload Format for Generic FEC . . . . . . . 47 9.1. RFC5576 - Source-Specific SDP Attributes . . . . . . . . 49
14. Multiplexing Media Streams and DSCP Markings . . . . . . . . . 48 10. QoS Mechanism Token Analysis . . . . . . . . . . . . . . . . 50
14.1. Option A . . . . . . . . . . . . . . . . . . . . . . . . . 48 10.1. RFC5432 - QoS Mechanism Selection in SDP . . . . . . . . 50
14.2. Option B . . . . . . . . . . . . . . . . . . . . . . . . . 49 11. k= Attribute Analysis . . . . . . . . . . . . . . . . . . . . 50
11.1. RFC4566 SDP: Session Description Protocol . . . . . . . 50
15. Multiplexing Considerations for Encapsulating Attributes . . . 49 12. content Atribute Analysis . . . . . . . . . . . . . . . . . . 50
16. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 52 12.1. RFC4796 . . . . . . . . . . . . . . . . . . . . . . . . 50
17. Security Considerations . . . . . . . . . . . . . . . . . . . 53 13. Payload Formats . . . . . . . . . . . . . . . . . . . . . . . 51
18. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 53 13.1. RFC5109 - RTP Payload Format for Generic FEC . . . . . . 51
19. Change Log . . . . . . . . . . . . . . . . . . . . . . . . . . 53 14. Multiplexing Media Streams and DSCP Markings . . . . . . . . 52
20. References . . . . . . . . . . . . . . . . . . . . . . . . . . 54 14.1. Option A . . . . . . . . . . . . . . . . . . . . . . . . 52
20.1. Normative References . . . . . . . . . . . . . . . . . . . 54 14.2. Option B . . . . . . . . . . . . . . . . . . . . . . . . 53
20.2. Informative References . . . . . . . . . . . . . . . . . . 54 15. Multiplexing Considerations for Encapsulating Attributes . . 53
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 60 15.1. RFC3407 - cpar Attribute Analysis . . . . . . . . . . . 53
15.2. RFC5939 Analysis . . . . . . . . . . . . . . . . . . . . 54
15.2.1. Recommendations . . . . . . . . . . . . . . . . . . 54
15.2.1.1. Recommendation-1: Transport Capability Analysis 55
15.2.1.2. Recommendation-2: Attribute Capability Analysis 55
15.2.1.3. Recommendation-3: Sescap Attribute Analysis . . 56
15.2.1.4. Recommendation-4: Capability Extension
Attributes . . . . . . . . . . . . . . . . . . . 56
15.3. RFC6871 Analysis . . . . . . . . . . . . . . . . . . . . 56
15.3.1. Recommendation-5: Attribute Capability Under Shared
Payload Type . . . . . . . . . . . . . . . . . . . . 56
15.4. Recommendation-6: Offer/Answer Negotiation Expectations 57
16. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 59
17. Security Considerations . . . . . . . . . . . . . . . . . . . 60
18. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 60
19. Change Log . . . . . . . . . . . . . . . . . . . . . . . . . 61
20. References . . . . . . . . . . . . . . . . . . . . . . . . . 62
20.1. Normative References . . . . . . . . . . . . . . . . . . 62
20.2. Informative References . . . . . . . . . . . . . . . . . 62
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 68
1. Introduction 1. Introduction
Real-Time Communication Web (RTCWeb) framework requires Real-time Real-Time Communication Web (RTCWeb) framework requires Real-time
Transport Protocol (RTP) as the media transport protocol and Session Transport Protocol (RTP) as the media transport protocol and Session
Description Protocol (SDP) [RFC4566] for describing and negotiating Description Protocol (SDP) [RFC4566] for describing and negotiating
multi-media communication sessions. multi-media communication sessions.
SDP defines several attributes for capturing characteristics that SDP defines several attributes for capturing characteristics that
apply to the individual media descriptions (described by "m=" lines") apply to the individual media descriptions (described by "m=" lines")
skipping to change at page 6, line 32 skipping to change at page 6, line 13
these attribute when used with transport multiplexing. these attribute when used with transport multiplexing.
4. SDP Attribute Analysis Framework 4. SDP Attribute Analysis Framework
Attributes in an SDP session description can be defined at the Attributes in an SDP session description can be defined at the
session-level and media-level. These attributes could be session-level and media-level. These attributes could be
semantically grouped as noted below. semantically grouped as noted below.
o Attributes related to media content such as media type, encoding o Attributes related to media content such as media type, encoding
schemes, payload types. schemes, payload types.
o Attributes specifying media transport characteristics like RTP/ o Attributes specifying media transport characteristics like RTP/
RTCP port numbers, network addresses, QOS. RTCP port numbers, network addresses, QOS.
o Metadata description attributes capturing session timing and o Metadata description attributes capturing session timing and
origin information. origin information.
o Attributes establishing relationships between media streams such o Attributes establishing relationships between media streams such
as grouping framework as grouping framework
With the above semantic grouping as the reference, the proposed With the above semantic grouping as the reference, the proposed
framework classifies each attribute into one of the following framework classifies each attribute into one of the following
categories: categories:
NORMAL Attributes that can be independently specified when
multiplexing and retain their original semantics.
In the example given below, the direction and label attributes are 4.1. Category: NORMAL
independently specified for audio and video m=lines. These
attributes are not impacted by multiplexing these media streams Attributes that can be independently specified when multiplexing and
over a single transport layer flow. retain their original semantics.
In the example given below, the direction and label attributes are
independently specified for audio and video m=lines. These
attributes are not impacted by multiplexing these media streams over
a single transport layer flow.
v=0 v=0
o=alice 2890844526 2890844527 IN IP4 host.atlanta.example.com o=alice 2890844526 2890844527 IN IP4 host.atlanta.example.com
s= s=
c=IN IP4 host.atlanta.example.com c=IN IP4 host.atlanta.example.com
t=0 0 t=0 0
m=audio 49172 RTP/AVP 99 m=audio 49172 RTP/AVP 99
a=sendonly a=sendonly
a=label:1 a=label:1
a=rtpmap:99 iLBC/8000 a=rtpmap:99 iLBC/8000
m=video 49172 RTP/AVP 31 m=video 49172 RTP/AVP 31
a=recvonly a=recvonly
a=label:2 a=label:2
a=rtpmap:31 H261/90000 a=rtpmap:31 H261/90000
NOT RECOMMENDED Attributes that are recommended against multiplexing 4.2. Category: NOT RECOMMENDED
since their usage under multiplexing might lead to incorrect
behavior.
Example: Multiplexing media descriptions having attribute zrtp- Attributes that are recommended against multiplexing since their
hash defined with the media descriptions lacking it, would either usage under multiplexing might lead to incorrect behavior.
complicate the handling of multiplexed streams or might fail
multiplexing altogether. Example: Multiplexing media descriptions having attribute zrtp-hash
defined with the media descriptions lacking it, would either
complicate the handling of multiplexed streams or might fail
multiplexing altogether.
v=0 v=0
o=bob 2890844527 2890844527 IN IP4 client.biloxi.example.com o=bob 2890844527 2890844527 IN IP4 client.biloxi.example.com
s= s=
c=IN IP4 client.biloxi.example.com c=IN IP4 client.biloxi.example.com
t=0 0 t=0 0
m=audio 3456 RTP/AVP 97 // with zrtp m=audio 3456 RTP/AVP 97 // with zrtp
a=rtpmap:97 iLBC/8000 a=rtpmap:97 iLBC/8000
<allOneLine> <allOneLine>
a=zrtp-hash:1.10 fe30efd02423cb054e50efd0248742ac7a52c8f91bc2 a=zrtp-hash:1.10 fe30efd02423cb054e50efd0248742ac7a52c8f91bc2
df881ae642c371ba46df df881ae642c371ba46df
</allOneLine> </allOneLine>
m=video 34567 RTP/AVP 31 //without zrtp m=video 34567 RTP/AVP 31 //without zrtp
a=rtpmap:31 H261/90000 a=rtpmap:31 H261/90000
IDENTICAL Attributes that MUST be identical across all the media 4.3. Category: IDENTICAL
descriptions being multiplexed.
Attributes such as rtcp-mux fall into this category. Since RTCP Attributes that MUST be identical across all the media descriptions
reporting is done per RTP Session, RTCP Multiplexing MUST to being multiplexed.
enabled for both the audio and video m=lines in the example below
if they are transported over a single 5-tuple. Attributes such as rtcp-mux fall into this category. Since RTCP
reporting is done per RTP Session, RTCP Multiplexing MUST to enabled
for both the audio and video m=lines in the example below if they are
transported over a single 5-tuple.
v=0 v=0
o=bob 2890844527 2890844527 IN IP4 client.biloxi.example.com o=bob 2890844527 2890844527 IN IP4 client.biloxi.example.com
s= s=
c=IN IP4 client.biloxi.example.com c=IN IP4 client.biloxi.example.com
t=0 0 t=0 0
m=audio 34567 RTP/AVP 97 m=audio 34567 RTP/AVP 97
a=rtcp-mux a=rtcp-mux
m=video 34567 RTP/AVP 31 m=video 34567 RTP/AVP 31
a=rtpmap:31 H261/90000 a=rtpmap:31 H261/90000
a=rtcp-mux a=rtcp-mux
SUM Attributes can be set as they are normally used but software 4.4. Category: SUM
using them in a multiplex case, MUST apply the sum of all the
attributes being multiplexed instead of trying to use each one.
This is typically used for bandwidth or other rate limiting
attributes to the underlining transport.
The software parsing the SDP sample below, should use the Attributes can be set as they are normally used but software using
aggregate Application Specific (AS) bandwidth value from the them in a multiplex case, MUST apply the sum of all the attributes
individual media descriptions to determine the AS value for the being multiplexed instead of trying to use each one. This is
multiplexed session. Thus the calculated AS value would be 256+64 typically used for bandwidth or other rate limiting attributes to the
bytes for the given example. underlining transport.
The software parsing the SDP sample below, should use the aggregate
Application Specific (AS) bandwidth value from the individual media
descriptions to determine the AS value for the multiplexed session.
Thus the calculated AS value would be 256+64 bytes for the given
example.
v=0 v=0
o=mhandley 2890844526 2890842807 IN IP4 126.16.64.4 o=mhandley 2890844526 2890842807 IN IP4 126.16.64.4
c=IN IP4 client.biloxi.example.com c=IN IP4 client.biloxi.example.com
t=0 0 t=0 0
m=audio 49170 RTP/AVP 0 m=audio 49170 RTP/AVP 0
b=AS:64 b=AS:64
m=video 51372 RTP/AVP 31 m=video 51372 RTP/AVP 31
b=AS:256 b=AS:256
TRANSPORT Attributes that can be set normally for multiple items in 4.5. Category: TRANSPORT
a multiplexed group but the software MUST pick just one of the
attribute of the given type for use. The one chosen is the
attribute associated with the "m=" line that represents the
information being used for the transport of the RTP.
In the example below, "a=crypto" attribute is defined for both the Attributes that can be set normally for multiple items in a
audio and the video m=lines. The video media line's a=crypto multiplexed group but the software MUST pick just one of the
attribute is chosen since its mid value (bar) appears first in the attribute of the given type for use. The one chosen is the attribute
a=group:BUNDLE line. This is due to BUNDLE grouping semantic associated with the "m=" line that represents the information being
[I-D.ietf-mmusic-sdp-bundle-negotiation] which mandates the values used for the transport of the RTP.
from m=line corresponding to the mid appearing first on the
a=group:BUNDLE line to be considered for setting up the RTP In the example below, "a=crypto" attribute is defined for both the
Transport. audio and the video m=lines. The video media line's a=crypto
attribute is chosen since its mid value (bar) appears first in the
a=group:BUNDLE line. This is due to BUNDLE grouping semantic
[I-D.ietf-mmusic-sdp-bundle-negotiation] which mandates the values
from m=line corresponding to the mid appearing first on the
a=group:BUNDLE line to be considered for setting up the RTP
Transport.
v=0 v=0
o=alice 2890844526 2890844527 IN IP4 host.atlanta.example.com o=alice 2890844526 2890844527 IN IP4 host.atlanta.example.com
s= s=
c=IN IP4 host.atlanta.example.com c=IN IP4 host.atlanta.example.com
t=0 0 t=0 0
a=group:BUNDLE bar foo a=group:BUNDLE bar foo
m=audio 49172 RTP/AVP 99 m=audio 49172 RTP/AVP 99
a=mid:foo a=mid:foo
a=crypto:1 AES_CM_128_HMAC_SHA1_80 a=crypto:1 AES_CM_128_HMAC_SHA1_80
inline:d0RmdmcmVCspeEc3QGZiNWpVLFJhQX1cfHAwJSoj|2^20|1:32 inline:d0RmdmcmVCspeEc3QGZiNWpVLFJhQX1cfHAwJSoj|2^20|1:32
a=rtpmap:99 iLBC/8000 a=rtpmap:99 iLBC/8000
m=video 51374 RTP/AVP 31 m=video 51374 RTP/AVP 31
a=mid:bar a=mid:bar
a=crypto:1 AES_CM_128_HMAC_SHA1_80 a=crypto:1 AES_CM_128_HMAC_SHA1_80
inline:EcGZiNWpFJhQXdspcl1ekcmVCNWpVLcfHAwJSoj|2^20|1:32 inline:EcGZiNWpFJhQXdspcl1ekcmVCNWpVLcfHAwJSoj|2^20|1:32
a=rtpmap:96 H261/90000 a=rtpmap:96 H261/90000
SPECIAL Attributes where the text in the source draft must be 4.6. Category: INHERIT
consulted for further handling when multiplexed.
As an example, for the attribute extmap, the specification Attributes that encapsulate other SDP attributes and their
defining the extension MUST be referred to understand the multiplexing characteristics are inherited from the attributes they
multiplexing implications. encapsulate. Such attributes as of today, are defined in [RFC3407],
[RFC5939] and [RFC6871] as part of a generic framework for indicating
and negotiating transport, media and media format related
capabilities in the SDP.
TBD This category defines attributes that need more information to v=0
assign an appropriate category. o=alice 2890844526 2890844527 IN IP4 host.atlanta.example.com
s=
c=IN IP4 host.atlanta.example.com
t=0 0
m=video 3456 RTP/AVP 100
a=rtpmap:100 VP8/90000
a=fmtp:100 max-fr=30;max-fs=8040
a=sqn: 0
a=cdsc: 1 video RTP/AVP 100
a=cpar: a=rtcp-mux
m=video 3456 RTP/AVP 101
a=rtpmap:101 VP8/90000
a=fmtp:100 max-fr=15;max-fs=1200
a=cdsc: 2 video RTP/AVP 101
a=cpar: a=rtcp-mux
The idea behind these categories is to provide recommendations for In the above example , the category IDENTICAL is inherited for the
using the attributes under RTP session multiplexing scenarios. cpar encapsulated rtcp-mux attribute.
Section 5 analyzes attributes listed in IANA [IANA] grouped under the 4.7. Category: IDENTICAL-PER-PT
IETF document that defines them. The "Level" column indicates
Attributes that define the RTP payload configuration on per Payload
Type basis and MUST have identical values across all the media
descriptions for a given RTP Payload Type when repeated.
In the SDP example below, Payload Types 96 and 97 are repeated across
all the video m= lines and all the payload specific parameters (ex:
rtpmap, fmtp) are identical.
v=0
o=alice 2890844526 2890844527 IN IP4 host.atlanta.example.com
s=
c=IN IP4 host.atlanta.example.com
t=0 0
a=group:BUNDLE cam1, cam2
m = video 96 97
a=mid:cam1
a=rtpmap:96 H264/90000
a=fmtp:96 profile-level-id=42400d; max-fs=3600; max-fps=3000;
max-mbps=108000; max-br=1000
a=rtpmap:97 H264/90000
a=fmtp:97 profile-level-id=42400a; max-fs=240; max-fps=3000;
max-mbps=7200; max-br=200
m = video 96 97
a=mid:cam2
a=rtpmap:96 H264/90000
a=fmtp:96 profile-level-id=42400d; max-fs=3600; max-fps=3000;
max-mbps=108000; max-br=1000
a=rtpmap:97 H264/90000
a=fmtp:97 profile-level-id=42400a; max-fs=240; max-fps=3000;
max-mbps=7200; max-br=200
4.8. Category: SPECIAL
Attributes where the text in the source draft must be consulted for
further handling when multiplexed.
As an example, for the attribute extmap, the specification defining
the extension MUST be referred to understand the multiplexing
implications.
5. Analysis of Existing Attributes
This section analyzes attributes listed in IANA [IANA] grouped under
the IETF document that defines them. The "Level" column indicates
whether the attribute is currently specified as: whether the attribute is currently specified as:
o S -- Session level o S -- Session level
o M -- Media level o M -- Media level
o B -- Both o B -- Both
o SR -- Source-level (for a single SSRC) o SR -- Source-level (for a single SSRC)
5. Analysis of Existing Attributes
5.1. RFC4566 - SDP: Session Description Protocol 5.1. RFC4566 - SDP: Session Description Protocol
RFC4566 [RFC4566] defines the Session Description Protocol (SDP) that RFC4566 [RFC4566] defines the Session Description Protocol (SDP) that
is intended for describing multimedia sessions for the purposes of is intended for describing multimedia sessions for the purposes of
session announcement, session invitation, and other forms of session announcement, session invitation, and other forms of
multimedia session initiation multimedia session initiation
+------------+----------------+-------+----------+ +------------+--------------------------+-------+-------------------+
| Attr Name | Notes | Level | Category | | Attr Name | Notes | Level | Category |
+------------+----------------+-------+----------+ +------------+--------------------------+-------+-------------------+
| sendrecv | Not impacted | B | NORMAL | | sendrecv | Not impacted | B | NORMAL |
| | | | | | | | | |
| sendonly | Not impacted | B | NORMAL | | sendonly | Not impacted | B | NORMAL |
| | | | | | | | | |
| recvonly | Not impacted | B | NORMAL | | recvonly | Not impacted | B | NORMAL |
| | | | | | | | | |
| inactive | Not impacted | B | NORMAL | | inactive | Not impacted | B | NORMAL |
| | | | | | | | | |
| cat | Not impacted | S | NORMAL | | cat | Not impacted | S | NORMAL |
| | | | | | | | | |
| ptime | Not Impacted | M | NORMAL | | ptime | The attribute value must | M | IDENTICAL-PER-PT |
| | | | | | | be same for a given | | |
| maxptime | Not Impacted | M | NORMAL | | | codec configuration | | |
| | | | | | | | | |
| orient | Not Impacted | M | NORMAL | | maxptime | The attribute value must | M | IDENTICAL-PER-PT |
| | | | | | | be same for a given | | |
| framerate | Not Impacted | M | NORMAL | | | codec configuration | | |
| | | | | | | | | |
| quality | Not Impacted | M | NORMAL | | orient | Not Impacted | M | NORMAL |
| | | | | | | | | |
| rtpmap | Not Impacted | M | NORMAL | | framerate | The attribute value must | M | IDENTICAL-PER-PT |
| | | | | | | be same for a given | | |
| fmtp | Not Impacted | M | NORMAL | | | codec configuration | | |
| | | | | | | | | |
| keywds | Not impacted | S | NORMAL | | quality | Not Impacted | M | NORMAL |
| | | | | | | | | |
| type | Not Impacted | S | NORMAL | | rtpmap | The attribute value must | M | IDENTICAL-PER-PT |
| | | | | | | be same for a given | | |
| tool | Not Impacted | S | NORMAL | | | codec configuration | | |
| | | | | | | | | |
| charset | Not Impacted | S | NORMAL | | fmtp | The attribute value must | M | IDENTICAL-PER-PT |
| | | | | | | be same for a given | | |
| sdplang | Not Impacted | B | NORMAL | | | codec configuration | | |
| | | | | | | | | |
| lang | Not Impacted | B | NORMAL | | keywds | Not impacted | S | NORMAL |
| | | | | | | | | |
+------------+----------------+-------+----------+ | type | Not Impacted | S | NORMAL |
| | | | |
| tool | Not Impacted | S | NORMAL |
| | | | |
| charset | Not Impacted | S | NORMAL |
| | | | |
| sdplang | Not Impacted | B | NORMAL |
| | | | |
| lang | Not Impacted | B | NORMAL |
| | | | |
+------------+--------------------------+-------+-------------------+
RFC4566 Attribute Analysis RFC4566 Attribute Analysis
5.2. RFC4585 - RTP/AVPF 5.2. RFC4585 - RTP/AVPF
RFC4585 [RFC4585] defines an extension to the Audio-visual Profile RFC4585 [RFC4585] defines an extension to the Audio-visual Profile
(AVP) that enables receivers to provide, statistically, more (AVP) that enables receivers to provide, statistically, more
immediate feedback to the senders and thus allows for short-term immediate feedback to the senders and thus allows for short-term
adaptation and efficient feedback-based repair mechanisms to be adaptation and efficient feedback-based repair mechanisms to be
implemented. implemented.
skipping to change at page 13, line 16 skipping to change at page 14, line 38
RFC4568 [RFC4568] defines a Session Description Protocol (SDP) RFC4568 [RFC4568] defines a Session Description Protocol (SDP)
cryptographic attribute for unicast media streams. The attribute cryptographic attribute for unicast media streams. The attribute
describes a cryptographic key and other parameters that serve to describes a cryptographic key and other parameters that serve to
configure security for a unicast media stream in either a single configure security for a unicast media stream in either a single
message or a roundtrip exchange. message or a roundtrip exchange.
+--------+---------------------------------------+-------+----------+ +--------+---------------------------------------+-------+----------+
| Name | Notes | Level | Category | | Name | Notes | Level | Category |
+--------+---------------------------------------+-------+----------+ +--------+---------------------------------------+-------+----------+
| crypto | Refer to section 6.2.5 of | M | SPECIAL | | crypto | Refer to section 6.2.5 of [I-D.ietf-m | M | SPECIAL |
| | [I-D.ietf-mmusic-sdp-bundle-negotiati | | | | | music-sdp-bundle-negotiation] | | |
| | on] | | |
| | | | | | | | | |
+--------+---------------------------------------+-------+----------+ +--------+---------------------------------------+-------+----------+
RFC4568 Attribute Analysis RFC4568 Attribute Analysis
If the multiplexing scheme cannot ensure unique SSRCs across all the If the multiplexing scheme cannot ensure unique SSRCs across all the
media lines, multiplexing MUST NOT be performed. media lines, multiplexing MUST NOT be performed.
5.7. RFC5762 - RTP over DCCP 5.7. RFC5762 - RTP over DCCP
skipping to change at page 13, line 44 skipping to change at page 15, line 16
real-time applications can make use of the services provided by DCCP real-time applications can make use of the services provided by DCCP
+--------------------+---------------------+---------+--------------+ +--------------------+---------------------+---------+--------------+
| Name | Notes | Current | Category | | Name | Notes | Current | Category |
+--------------------+---------------------+---------+--------------+ +--------------------+---------------------+---------+--------------+
| dccp-service-code | If RFC6773 is not | M | NOT | | dccp-service-code | If RFC6773 is not | M | NOT |
| | being used in | | RECOMMENDED | | | being used in | | RECOMMENDED |
| | addition to | | | | | addition to | | |
| | RFC5762, the port | | | | | RFC5762, the port | | |
| | in the m= line is a | | | | | in the m= line is a | | |
| | DCCP port. DCCP | | | | | DCCP port. DCCP | | |
| | being a connection | | | | | being a connection | | |
| | oriented protocol, | | | | | oriented protocol, | | |
| | does not allow | | | | | does not allow | | |
| | multiple | | | | | multiple | | |
| | connections on the | | | | | connections on the | | |
| | same 5-tuple. | | | | | same 5-tuple. | | |
| | | | | | | | | |
+--------------------+---------------------+---------+--------------+ +--------------------+---------------------+---------+--------------+
RFC5762 Attribute Analysis RFC5762 Attribute Analysis
If RFC6773 is being used in addition to RFC5762 and provided that If RFC6773 is being used in addition to RFC5762 and provided that
DCCP-in-UDP layer has additional demultiplexing, then it may be DCCP-in-UDP layer has additional demultiplexing, then it may be
possible to use different DCCP service codes for each DCCP flow, possible to use different DCCP service codes for each DCCP flow,
given each uses a different DCCP port. Although doing so might given each uses a different DCCP port. Although doing so might
conflict with the media type of the m= line. None of this is conflict with the media type of the m= line. None of this is
standardized yet and it wouldn't work as explained. Hence standardized yet and it wouldn't work as explained. Hence
multiplexing MUST NOT be performed even in this alternate scenario. multiplexing MUST NOT be performed even in this alternate scenario.
skipping to change at page 14, line 21 skipping to change at page 16, line 4
standardized yet and it wouldn't work as explained. Hence standardized yet and it wouldn't work as explained. Hence
multiplexing MUST NOT be performed even in this alternate scenario. multiplexing MUST NOT be performed even in this alternate scenario.
5.8. RFC6773 - DCCP-UDP Encapsulation 5.8. RFC6773 - DCCP-UDP Encapsulation
RFC6773 [RFC6773] document specifies an alternative encapsulation of RFC6773 [RFC6773] document specifies an alternative encapsulation of
the Datagram Congestion Control Protocol (DCCP), referred to as DCCP- the Datagram Congestion Control Protocol (DCCP), referred to as DCCP-
UDP. This encapsulation allows DCCP to be carried through the UDP. This encapsulation allows DCCP to be carried through the
current generation of Network Address Translation (NAT) middle boxes current generation of Network Address Translation (NAT) middle boxes
without modification of those middle boxes without modification of those middle boxes
+------------+-------------------------------+-------+--------------+ +------------+-------------------------------+-------+--------------+
| Name | Notes | Level | Category | | Name | Notes | Level | Category |
+------------+-------------------------------+-------+--------------+ +------------+-------------------------------+-------+--------------+
| dccp-port | Multiplexing MUST NOT be | M | NOT | | dccp-port | Multiplexing MUST NOT be | M | NOT |
| | performed due to potential | | RECOMMENDED | | | performed due to potential | | RECOMMENDED |
| | conflict between the port | | | | | conflict between the port | | |
| | used for DCCP | | | | | used for DCCP | | |
| | en/decapsulation and the | | | | | en/decapsulation and the RTP. | | |
| | RTP. | | |
| | | | | | | | | |
+------------+-------------------------------+-------+--------------+ +------------+-------------------------------+-------+--------------+
RFC6773 Attribute Analysis RFC6773 Attribute Analysis
Since RFC6773 is about tunnelling DCCP in UDP, with the UDP port Since RFC6773 is about tunnelling DCCP in UDP, with the UDP port
being the port of the DCCP en-/de-capsulation service. This being the port of the DCCP en-/de-capsulation service. This
encapsulation allows arbitrary DCCP packets to be encapsulated and encapsulation allows arbitrary DCCP packets to be encapsulated and
the DCCP port choosen MAY conflict with the port chosen for the RTP the DCCP port choosen MAY conflict with the port chosen for the RTP
traffic. traffic.
skipping to change at page 18, line 5 skipping to change at page 20, line 5
5.14. RFC5576 - Source-Specific SDP Attributes 5.14. RFC5576 - Source-Specific SDP Attributes
RFC5576 [RFC5576] defines a mechanism to describe RTP media sources, RFC5576 [RFC5576] defines a mechanism to describe RTP media sources,
which are identified by their synchronization source (SSRC) which are identified by their synchronization source (SSRC)
identifiers, in SDP, to associate attributes with these sources, and identifiers, in SDP, to associate attributes with these sources, and
to express relationships among sources. It also defines several to express relationships among sources. It also defines several
source-level attributes that can be used to describe properties of source-level attributes that can be used to describe properties of
media sources. media sources.
+----------------+-------------------------------+-------+----------+ +----------------+----------------------+-------+-------------------+
| Name | Notes | Level | Category | | Name | Notes | Level | Category |
+----------------+-------------------------------+-------+----------+ +----------------+----------------------+-------+-------------------+
| ssrc | Refer to Notes below | M | SPECIAL | | ssrc | Refer to Notes below | M | NORMAL |
| | | | | | | | | |
| ssrc-group | Refer to section Section 9 | M | SPECIAL | | ssrc-group | Refer to section | M | SPECIAL |
| | for specific analysis of the | | | | | Section 9 for | | |
| | grouping semantics | | | | | specific analysis of | | |
| | | | | | | the grouping | | |
| cname | Not Impacted [Open Issues: | SR | NORMAL | | | semantics | | |
| | what are the rules for CNAME | | | | | | | |
| | duplication across | | | | cname | Not Impacted [Open | SR | NORMAL |
| | sessions?] | | | | | Issues: what are the | | |
| | | | | | | rules for CNAME | | |
| previous-ssrc | Refer to notes below | SR | SPECIAL | | | duplication across | | |
| | | | | | | sessions?] | | |
| fmtp | Not Impacted | SR | NORMAL | | | | | |
| | | | | | previous-ssrc | Refer to notes below | SR | NORMAL |
+----------------+-------------------------------+-------+----------+ | | | | |
| fmtp | The attribute value | SR | IDENTICAL-PER-PT |
| | must be same for a | | |
| | given codec | | |
| | configuration | | |
| | | | |
+----------------+----------------------+-------+-------------------+
RFC5576 Attribute Analysis RFC5576 Attribute Analysis
If SSRCs are repeated across m=lines being multiplexed, they MUST all If SSRCs are repeated across m=lines being multiplexed, they MUST all
represent the same underlying RTP Source. For more details on represent the same underlying RTP Source. For more details on
implications of SSRC values with in the context of multiplexing implications of SSRC values with in the context of multiplexing
please refer to [I-D.ietf-mmusic-sdp-bundle-negotiation] please refer to [I-D.ietf-mmusic-sdp-bundle-negotiation]
5.15. RFC6236 - Image Attributes in SDP 5.15. RFC6236 - Image Attributes in SDP
RFC6236 [RFC6236] proposes a new generic session setup attribute to RFC6236 [RFC6236] proposes a new generic session setup attribute to
make it possible to negotiate different image attributes such as make it possible to negotiate different image attributes such as
image size. A possible use case is to make it possible for a low-end image size. A possible use case is to make it possible for a low-end
hand-held terminal to display video without the need to rescale the hand-held terminal to display video without the need to rescale the
image,something that may consume large amounts of memory and image,something that may consume large amounts of memory and
processing power. The document also helps to maintain an optimal processing power. The document also helps to maintain an optimal
bitrate for video as only the image size that is desired by the bitrate for video as only the image size that is desired by the
receiver is transmitted. receiver is transmitted.
+------------+---------------+-------+----------+ +------------+--------------------------+-------+-------------------+
| Name | Notes | Level | Category | | Name | Notes | Level | Category |
+------------+---------------+-------+----------+ +------------+--------------------------+-------+-------------------+
| imageattr | Not Impacted | M | NORMAL | | imageattr | The attribute value must | M | IDENTICAL-PER-PT |
| | | | | | | be same for a given | | |
+------------+---------------+-------+----------+ | | codec configuration | | |
| | | | |
+------------+--------------------------+-------+-------------------+
RFC6236 Attribute Analysis RFC6236 Attribute Analysis
5.16. RFC6285 - Rapid Acquisition of Multicast RTP Sessions 5.16. RFC6285 - Rapid Acquisition of Multicast RTP Sessions
RFC6285 [RFC6285] describes a method using the existing RTP and RTP RFC6285 [RFC6285] describes a method using the existing RTP and RTP
Control Protocol (RTCP) machinery that reduces the acquisition delay. Control Protocol (RTCP) machinery that reduces the acquisition delay.
In this method, an auxiliary unicast RTP session carrying the In this method, an auxiliary unicast RTP session carrying the
Reference Information to the receiver precedes or accompanies the Reference Information to the receiver precedes or accompanies the
multicast stream. This unicast RTP flow can be transmitted at a multicast stream. This unicast RTP flow can be transmitted at a
skipping to change at page 20, line 6 skipping to change at page 22, line 24
5.18. RFC6364 - SDP Elements for FEC Framework 5.18. RFC6364 - SDP Elements for FEC Framework
RFC6364 [RFC6364] specifies the use of the Session Description RFC6364 [RFC6364] specifies the use of the Session Description
Protocol (SDP) to describe the parameters required to signal the Protocol (SDP) to describe the parameters required to signal the
Forward Error Correction (FEC) Framework Configuration Information Forward Error Correction (FEC) Framework Configuration Information
between the sender(s) and receiver(s). This document also provides between the sender(s) and receiver(s). This document also provides
examples that show the semantics for grouping multiple source and examples that show the semantics for grouping multiple source and
repair flows together for the applications that simultaneously use repair flows together for the applications that simultaneously use
multiple instances of the FEC Framework. multiple instances of the FEC Framework.
+------------------+---------------+-------+----------+ +------------------+-------+-------+----------+
| Name | Notes | Level | Category | | Name | Notes | Level | Category |
+------------------+---------------+-------+----------+ +------------------+-------+-------+----------+
| fec-source-flow | Not Impacted | M | NORMAL | | fec-source-flow | | M | SPECIAL |
| | | | | | | | | |
| fec-repair-flow | Not Impacted | M | NORMAL | | fec-repair-flow | | M | SPECIA: |
| | | | | | | | | |
| repair-window | Not Impacted | M | NORMAL | | repair-window | | M | SPECIAL |
| | | | | | | | | |
+------------------+---------------+-------+----------+ +------------------+-------+-------+----------+
RFC6364 Attribute Analysis RFC6364 Attribute Analysis
5.19. RFC4796 - Content Attribute 5.19. RFC4796 - Content Attribute
RFC4796 [RFC4796] defines a new Session Description Protocol (SDP) RFC4796 [RFC4796] defines a new Session Description Protocol (SDP)
media-level attribute, 'content'. The 'content' attribute defines media-level attribute, 'content'. The 'content' attribute defines
the content of the media stream to a more detailed level than the the content of the media stream to a more detailed level than the
media description line. The sender of an SDP session description can media description line. The sender of an SDP session description can
attach the 'content' attribute to one or more media streams. The attach the 'content' attribute to one or more media streams. The
skipping to change at page 21, line 5 skipping to change at page 23, line 20
+----------+---------------+-------+----------+ +----------+---------------+-------+----------+
RFC4796 Attribute Analysis RFC4796 Attribute Analysis
5.20. RFC3407 - SDP Simple Capability Declaration 5.20. RFC3407 - SDP Simple Capability Declaration
RFC3407 [RFC3407] defines a set of Session Description Protocol (SDP) RFC3407 [RFC3407] defines a set of Session Description Protocol (SDP)
attributes that enables SDP to provide a minimal and backwards attributes that enables SDP to provide a minimal and backwards
compatible capability declaration mechanism. compatible capability declaration mechanism.
+----------+----------------------+-------+----------+ +----------+------------------------+-------+----------+
| Name | Notes | Level | Category | | Name | Notes | Level | Category |
+----------+----------------------+-------+----------+ +----------+------------------------+-------+----------+
| sqn | Not Impacted | B | NORMAL | | sqn | Not Impacted | B | NORMAL |
| | | | | | | | | |
| csdc | Not Impacted. | B | NORMAL | | cdsc | Not Impacted. | B | NORMAL |
| | | | | | | | | |
| cpar | Refer to Section 15 | B | SPECIAL | | cpar | Refer to Section 15 | B | INHERIT |
| | | | | | | | | |
| cparmin | Refer to Section 15 | B | SPECIAL | | cparmin | Refer to notes below | B | SPECIAL |
| | | | | | | | | |
| cparmax | Refer to Section 15 | B | SPECIAL | | cparmax | Refer to notes below | B | SPECIAL |
| | | | | | | | | |
+----------+----------------------+-------+----------+ +----------+------------------------+-------+----------+
RFC3407 Attribute Analysis RFC3407 Attribute Analysis
Since the attributes (a=cparmin and a=cparmax) defines minimum and
maximum numerical values associated with the attributed described in
a=cpar, it is recommended to consult the document defining the
attribute for dealing under media stream multiplexing.
5.21. RFC6284 - Port Mapping between Unicast and Multicast RTP Sessions 5.21. RFC6284 - Port Mapping between Unicast and Multicast RTP Sessions
RFC6284 [RFC6284] presents a port mapping solution that allows RTP RFC6284 [RFC6284] presents a port mapping solution that allows RTP
receivers to choose their own ports for an auxiliary unicast session receivers to choose their own ports for an auxiliary unicast session
in RTP applications using both unicast and multicast services. The in RTP applications using both unicast and multicast services. The
solution provides protection against denial-of-service or packet solution provides protection against denial-of-service or packet
amplification attacks that could be used to cause one or more RTP amplification attacks that could be used to cause one or more RTP
packets to be sent to a victim client packets to be sent to a victim client
+------------------+-------------------------+-------+--------------+ +------------------+-------------------------+-------+--------------+
| Name | Notes | Level | Category | | Name | Notes | Level | Category |
+------------------+-------------------------+-------+--------------+ +------------------+-------------------------+-------+--------------+
| portmapping-req | Not recommended, if | M | NOT | | portmapping-req | Not recommended, if | M | NOT |
| | port mapping is | | RECOMMENDED | | | port mapping is | | RECOMMENDED |
| | required by the | | | | | required by the | | |
| | application | | | | | application | | |
| | | | | | | | | |
+------------------+-------------------------+-------+--------------+ +------------------+-------------------------+-------+--------------+
skipping to change at page 23, line 43 skipping to change at page 26, line 18
| loopback rtp-pkt-loopback | Not Impacted | M | NORMAL | | loopback rtp-pkt-loopback | Not Impacted | M | NORMAL |
| | | | | | | | | |
| loopback rtp-media-loopback | Not Impacted | M | NORMAL | | loopback rtp-media-loopback | Not Impacted | M | NORMAL |
| | | | | | | | | |
| loopback-source | Not Impacted | M | NORMAL | | loopback-source | Not Impacted | M | NORMAL |
| | | | | | | | | |
| loopback-mirror | Not Impacted | M | NORMAL | | loopback-mirror | Not Impacted | M | NORMAL |
| | | | | | | | | |
+------------------------------+----------------+-------+----------+ +------------------------------+----------------+-------+----------+
An Extension to the Session Description Protocol (SDP) An Extension to the Session Description Protocol (SDP) and Real-time
and Real-time Transport Protocol (RTP) for Media Loopback Transport Protocol (RTP) for Media Loopback
5.26. RFC5760 - RTCP with Unicast Feedback 5.26. RFC5760 - RTCP with Unicast Feedback
RFC5760 [RFC5760] specifies an extension to the Real-time Transport RFC5760 [RFC5760] specifies an extension to the Real-time Transport
Control Protocol (RTCP) to use unicast feedback to a multicast Control Protocol (RTCP) to use unicast feedback to a multicast
sender. The proposed extension is useful for single-source multicast sender. The proposed extension is useful for single-source multicast
sessions such as Source-Specific Multicast (SSM) communication where sessions such as Source-Specific Multicast (SSM) communication where
the traditional model of many-to-many group communication is either the traditional model of many-to-many group communication is either
not available or not desired. not available or not desired.
skipping to change at page 25, line 8 skipping to change at page 27, line 25
RFC5939 [RFC5939] defines a general SDP Capability Negotiation RFC5939 [RFC5939] defines a general SDP Capability Negotiation
framework. It also specifies how to provide attributes and transport framework. It also specifies how to provide attributes and transport
protocols as capabilities and negotiate them using the framework. protocols as capabilities and negotiate them using the framework.
Extensions for other types of capabilities (e.g., media types and Extensions for other types of capabilities (e.g., media types and
media formats) may be provided in other documents. media formats) may be provided in other documents.
+-------+-------------------------------+-------+----------+ +-------+-------------------------------+-------+----------+
| Name | Notes | Level | Category | | Name | Notes | Level | Category |
+-------+-------------------------------+-------+----------+ +-------+-------------------------------+-------+----------+
| pcfg | Refer to section Section 15 | M | SPECIAL | | pcfg | Refer to section Section 15 | M | INHERIT |
| | | | | | | | | |
| acfg | Refer to section Section 15 | M | SPECIAL | | acfg | Refer to section Section 15 | M | INHERIT |
| | | | | | | | | |
| csup | Not Impacted | B | NORMAL | | csup | Not Impacted | B | NORMAL |
| | | | | | | | | |
| creq | Not Impacted | B | NORMAL | | creq | Not Impacted | B | NORMAL |
| | | | | | | | | |
| acap | Refer to section Section 15 | B | SPECIAL | | acap | Refer to section Section 15 | B | INHERIT |
| | | | | | | | | |
| tcap | Refer to section Section 15 | B | SPECIAL | | tcap | Refer to section Section 15 | B | INHERIT |
| | | | | | | | | |
+-------+-------------------------------+-------+----------+ +-------+-------------------------------+-------+----------+
RFC5939 Attribute Analysis RFC5939 Attribute Analysis
5.29. RFC6781 - SDP Media Capabilities Negotiation 5.29. RFC6871- SDP Media Capabilities Negotiation
Session Description Protocol (SDP) capability negotiation provides a Session Description Protocol (SDP) capability negotiation provides a
general framework for indicating and negotiating capabilities in SDP. general framework for indicating and negotiating capabilities in SDP.
The base framework defines only capabilities for negotiating The base framework defines only capabilities for negotiating
transport protocols and attributes. [RFC6781] extends the framework transport protocols and attributes. [RFC6871] extends the framework
by defining media capabilities that can be used to negotiate media by defining media capabilities that can be used to negotiate media
types and their associated parameters. types and their associated parameters.
+---------+------------------------------+-------+----------+ +---------+------------------------------+-------+----------+
| Name | Notes | Level | Category | | Name | Notes | Level | Category |
+---------+------------------------------+-------+----------+ +---------+------------------------------+-------+----------+
| rmcap | Not Impacted | B | NORMAL | | rmcap | Refer to section Section 15 | B | INHERIT |
| | | | | | | | | |
| omcap | Not Impacted | B | NORMAL | | omcap | Refer to section Section 15 | B | INHERIT |
| | | | | | | | | |
| mfcap | Not Impacted | B | NORMAL | | mfcap | Refer to section Section 15 | B | INHERIT |
| | | | | | | | | |
| mscap | Refer to section Section 15 | B | SPECIAL | | mscap | Refer to section Section 15 | B | INHERIT |
| | | | | | | | | |
| lcfg | Refer to section Section 15 | B | SPECIAL | | lcfg | Not Impacted | B | NORMAL |
| | | | | | | | | |
| sescap | Not Impacted | S | NORMAL | | sescap | Refer to section Section 15 | S | INHERIT |
| | | | | | | | | |
+---------+------------------------------+-------+----------+ +---------+------------------------------+-------+----------+
draft-ietf-mmusic-sdp-media-capabilities Attribute Analysis Session Description Protocol (SDP) Media Capabilities Negotiation
5.30. RFC4567 - Key Management Extensions for SDP and RTSP 5.30. RFC4567 - Key Management Extensions for SDP and RTSP
RFC4567 [RFC4567] defines general extensions for Session Description RFC4567 [RFC4567] defines general extensions for Session Description
Protocol (SDP) and Real Time Streaming Protocol (RTSP) to carry Protocol (SDP) and Real Time Streaming Protocol (RTSP) to carry
messages, as specified by a key management protocol, in order to messages, as specified by a key management protocol, in order to
secure the media. These extensions are presented as a framework, to secure the media. These extensions are presented as a framework, to
be used by one or more key management protocols. As such, their use be used by one or more key management protocols. As such, their use
is meaningful only when complemented by an appropriate key management is meaningful only when complemented by an appropriate key management
protocol. protocol.
+-----------+----------------------------------+-------+------------+ +-----------+----------------------------------+-------+------------+
| Name | Notes | Level | Category | | Name | Notes | Level | Category |
+-----------+----------------------------------+-------+------------+ +-----------+----------------------------------+-------+------------+
| key-mgmt | Key management protocol MUST be | B | IDENTICAL | | key-mgmt | Key management protocol MUST be | B | IDENTICAL |
| | identical across all the | | | | | identical across all the m=lines | | |
| | m=lines | | |
| | | | | | | | | |
+-----------+----------------------------------+-------+------------+ +-----------+----------------------------------+-------+------------+
RFC4567 Attribute Analysis RFC4567 Attribute Analysis
5.31. RFC4572 - Comedia over TLS in SDP 5.31. RFC4572 - Comedia over TLS in SDP
RFC4572 [RFC4572] specifies how to establish secure connection- RFC4572 [RFC4572] specifies how to establish secure connection-
oriented media transport sessions over the Transport Layer Security oriented media transport sessions over the Transport Layer Security
(TLS) protocol using the Session Description Protocol (SDP). It (TLS) protocol using the Session Description Protocol (SDP). It
skipping to change at page 28, line 17 skipping to change at page 30, line 30
RFC6189 [RFC6189] defines ZRTP, a protocol for media path Diffie- RFC6189 [RFC6189] defines ZRTP, a protocol for media path Diffie-
Hellman exchange to agree on a session key and parameters for Hellman exchange to agree on a session key and parameters for
establishing unicast Secure Real-time Transport Protocol (SRTP) establishing unicast Secure Real-time Transport Protocol (SRTP)
sessions for Voice over IP (VoIP) applications. sessions for Voice over IP (VoIP) applications.
+------------+-------------------------------+-------+--------------+ +------------+-------------------------------+-------+--------------+
| Name | Notes | Level | Category | | Name | Notes | Level | Category |
+------------+-------------------------------+-------+--------------+ +------------+-------------------------------+-------+--------------+
| zrtp-hash | Complicates if all the | M | NOT | | zrtp-hash | Complicates if all the | M | NOT |
| | m=lines are not authenticated | | RECOMMENDED | | | m=lines are not authenticated | | RECOMMENDED |
| | as given in the example | | | | | as given in the example below | | |
| | below | | |
| | | | | | | | | |
+------------+-------------------------------+-------+--------------+ +------------+-------------------------------+-------+--------------+
RFC6189 Attribute Analysis RFC6189 Attribute Analysis
Example: Multiplexing media descriptions having attribute zrtp-hash Example: Multiplexing media descriptions having attribute zrtp-hash
defined with the media descriptions lacking it, would either defined with the media descriptions lacking it, would either
complicate the handling of multiplexed stream or fail multiplexing. complicate the handling of multiplexed stream or fail multiplexing.
v=0 v=0
skipping to change at page 30, line 39 skipping to change at page 33, line 16
m=lines will use only one IPSec association for all of the m= lines. m=lines will use only one IPSec association for all of the m= lines.
5.38. RFC6064 - SDP and RTSP Extensions for 3GPP 5.38. RFC6064 - SDP and RTSP Extensions for 3GPP
The Packet-switched Streaming Service (PSS) and the Multimedia The Packet-switched Streaming Service (PSS) and the Multimedia
Broadcast/Multicast Service (MBMS) defined by 3GPP use the Session Broadcast/Multicast Service (MBMS) defined by 3GPP use the Session
Description Protocol (SDP) and Real Time Streaming Protocol (RTSP) Description Protocol (SDP) and Real Time Streaming Protocol (RTSP)
with some extensions. RFC6064 [RFC6064] provides information about with some extensions. RFC6064 [RFC6064] provides information about
these extensions and registers the RTSP and SDP extensions with IANA. these extensions and registers the RTSP and SDP extensions with IANA.
+-------------------------------+------------+-------+--------------+ +--------------------------+--------------+-------+-----------------+
| Name | Notes | Level | Category | | Name | Notes | Level | Category |
+-------------------------------+------------+-------+--------------+ +--------------------------+--------------+-------+-----------------+
| X-predecbufsize | Refer to | M | NOT | | X-predecbufsize | Refer to | M | NOT RECOMMENDED |
| | notes | | RECOMMENDED | | | notes below | | |
| | below | | | | | | | |
| | | | | | X-initpredecbufperiod | Refer to | M | NOT RECOMMENDED |
| X-initpredecbufperiod | Refer to | M | NOT | | | notes below | | |
| | notes | | RECOMMENDED | | | | | |
| | below | | | | X-initpostdecbufperiod | Refer to | M | NOT RECOMMENDED |
| | | | | | | notes below | | |
| X-initpostdecbufperiod | Refer to | M | NOT | | | | | |
| | notes | | RECOMMENDED | | X-decbyterate | Refer to | M | NOT RECOMMENDED |
| | below | | | | | notes below | | |
| | | | | | | | | |
| X-decbyterate | Refer to | M | NOT | | 3gpp-videopostdecbufsize | Refer to | M | NOT RECOMMENDED |
| | notes | | RECOMMENDED | | | notes below | | |
| | below | | | | | | | |
| | | | | | framesize | The | M | IDENTICAL-PER- |
| 3gpp-videopostdecbufsize | Refer to | M | NOT | | | attribute | | PT |
| | notes | | RECOMMENDED | | | value must | | |
| | below | | | | | be same for | | |
| | | | | | | a given | | |
| framesize | Refer to | M | NOT | | | codec config | | |
| | notes | | RECOMMENDED | | | uration | | |
| | below | | | | | | | |
| | | | | | 3GPP-Integrity-Key | Refer to | S | NOT RECOMMENDED |
| 3GPP-Integrity-Key | Refer to | S | NOT | | | notes below | | |
| | notes | | RECOMMENDED | | | | | |
| | below | | | | 3GPP-SRTP-Config | Refer to | M | NOT RECOMMENDED |
| | | | | | | notes below | | |
| 3GPP-SRTP-Config | Refer to | M | NOT | | | | | |
| | notes | | RECOMMENDED | | alt,alt-default-id | Refer to | M | NOT RECOMMENDED |
| | below | | | | | notes below | | |
| | | | | | | | | |
| alt,alt-default-id | Refer to | M | NOT | | alt-group | Refer to | M | NOT RECOMMENDED |
| | notes | | RECOMMENDED | | | notes below | | |
| | below | | | | | | | |
| | | | | | 3GPP-Adaptation-Support | Refer to | M | NOT RECOMMENDED |
| alt-group | Refer to | M | NOT | | | notes below | | |
| | notes | | RECOMMENDED | | | | | |
| | below | | | | 3GPP-Asset-Informatio | Refer to | B | NOT RECOMMENDED |
| | | | | | | notes below | | |
| 3GPP-Adaptation-Support | Refer to | M | NOT | | | | | |
| | notes | | RECOMMENDED | | mbms-mode | Refer to | B | NOT RECOMMENDED |
| | below | | | | | notes below | | |
| | | | | | | | | |
| 3GPP-Asset-Informatio | Refer to | B | NOT | | mbms-flowid | MRefer to | M | NOT RECOMMENDED |
| | notes | | RECOMMENDED | | | notes below | | |
| | below | | | | | | | |
| | | | | | mbms-repair | Refer to | B | NOT RECOMMENDED |
| mbms-mode | Refer to | B | NOT | | | notes below | | |
| | notes | | RECOMMENDED | | | | | |
| | below | | | | 3GPP-QoE- | Refer to | M | NOT RECOMMENDED |
| | | | | | Metrics:Corruption | notes below | | |
| mbms-flowid | MRefer to | M | NOT | | duration | | | |
| | notes | | RECOMMENDED | | | | | |
| | below | | | | 3GPP-QoE- | Refer to | M | NOT RECOMMENDED |
| | | | | | Metrics:Rebuffering | notes below | | |
| mbms-repair | Refer to | B | NOT | | duration | | | |
| | notes | | RECOMMENDED | | | | | |
| | below | | | | 3GPP-QoE-Metrics:Initial | Refer to | M | NOT RECOMMENDED |
| | | | | | buffering duration | notes below | | |
| 3GPP-QoE-Metrics:Corruption | Refer to | M | NOT | | | | | |
| duration | notes | | RECOMMENDED | | 3GPP-QoE- | Refer to | M | NOT RECOMMENDED |
| | below | | | | Metrics:Successive loss | notes below | | |
| | | | | | of RTP packets | | | |
| 3GPP-QoE-Metrics:Rebuffering | Refer to | M | NOT | | | | | |
| duration | notes | | RECOMMENDED | | 3GPP-QoE-Metrics:Frame | Refer to | M | NOT RECOMMENDED |
| | below | | | | rate deviation | notes below | | |
| | | | | | | | | |
| 3GPP-QoE-Metrics:Initial | Refer to | M | NOT | | 3GPP-QoE-Metrics:Jitter | Refer to | M | NOT RECOMMENDED |
| buffering duration | notes | | RECOMMENDED | | duration | notes below | | |
| | below | | | | | | | |
| | | | | | 3GPP-QoE-Metrics:Content | Refer to | B | NOT RECOMMENDED |
| 3GPP-QoE-Metrics:Successive | Refer to | M | NOT | | Switch Time | notes below | | |
| loss of RTP packets | notes | | RECOMMENDED | | | | | |
| | below | | | | 3GPP-QoE-Metrics:Average | Refer to | M | NOT RECOMMENDED |
| | | | | | Codec Bitrat | notes below | | |
| 3GPP-QoE-Metrics:Frame rate | Refer to | M | NOT | | | | | |
| deviation | notes | | RECOMMENDED | | 3GPP-QoE-Metrics:Codec | Refer to | M | NOT RECOMMENDED |
| | below | | | | Information | notes below | | |
| | | | | | | | | |
| 3GPP-QoE-Metrics:Jitter | Refer to | M | NOT | | 3GPP-QoE-Metrics:Buffer | Refer to | M | NOT RECOMMENDED |
| duration | notes | | RECOMMENDED | | Status | notes below | | |
| | below | | | | | | | |
| | | | | +--------------------------+--------------+-------+-----------------+
| 3GPP-QoE-Metrics:Content | Refer to | B | NOT |
| Switch Time | notes | | RECOMMENDED |
| | below | | |
| | | | |
| 3GPP-QoE-Metrics:Average | Refer to | M | NOT |
| Codec Bitrat | notes | | RECOMMENDED |
| | below | | |
| | | | |
| 3GPP-QoE-Metrics:Codec | Refer to | M | NOT |
| Information | notes | | RECOMMENDED |
| | below | | |
| | | | |
| 3GPP-QoE-Metrics:Buffer | Refer to | M | NOT |
| Status | notes | | RECOMMENDED |
| | below | | |
| | | | |
+-------------------------------+------------+-------+--------------+
RFC6064 Attribute Analysis RFC6064 Attribute Analysis
[RFC6064] defines SDP attributes that are applicable in the [RFC6064] defines SDP attributes that are applicable in the
declarative usage of SDP alone. For purposes of this document, only declarative usage of SDP alone. For purposes of this document, only
the Offer/Answer usage of SDP is considered as mandated by the Offer/Answer usage of SDP is considered as mandated by
[I-D.ietf-mmusic-sdp-bundle-negotiation]. [I-D.ietf-mmusic-sdp-bundle-negotiation].
5.39. RFC3108 - ATM SDP 5.39. RFC3108 - ATM SDP
RFC3108 [RFC3108] describes conventions for using the Session RFC3108 [RFC3108] describes conventions for using the Session
Description Protocol (SDP) described for controlling ATM Bearer Description Protocol (SDP) described for controlling ATM Bearer
Connections, and any associated ATM Adaptation Layer (AAL) Connections, and any associated ATM Adaptation Layer (AAL)
+------------------------+--------------+-------+----------+ +------------------------+--------------+-------+----------+
| Name | Notes | Level | Category | | Name | Notes | Level | Category |
skipping to change at page 37, line 15 skipping to change at page 40, line 15
| Name | Notes | Level | Category | | Name | Notes | Level | Category |
+-----------+------------------------------------+-------+----------+ +-----------+------------------------------------+-------+----------+
| h248item | It is also only applicable for | B | SPECIAL | | h248item | It is also only applicable for | B | SPECIAL |
| | signaling the inclusion of H.248 | | | | | signaling the inclusion of H.248 | | |
| | extension packages to a gateway | | | | | extension packages to a gateway | | |
| | via the local and remote | | | | | via the local and remote | | |
| | descriptors. The attribute itself | | | | | descriptors. The attribute itself | | |
| | is unaffected by multiplexing, but | | | | | is unaffected by multiplexing, but | | |
| | the packaged referenced in a | | | | | the packaged referenced in a | | |
| | specific use of the attribute may | | | | | specific use of the attribute may | | |
| | be impacted. Further analysis of | | | | | be impacted. Further analysis of | | |
| | each package is needed to | | | | | each package is needed to | | |
| | determine if there is an issue. | | | | | determine if there is an issue. | | |
| | This is only a concern in | | | | | This is only a concern in | | |
| | environments using a decomposed | | | | | environments using a decomposed | | |
| | server/gateway with H.248 signaled | | | | | server/gateway with H.248 signaled | | |
| | between them. The ITU-T will need | | | | | between them. The ITU-T will need | | |
| | to do further analysis of various | | | | | to do further analysis of various | | |
| | packages when they specify how to | | | | | packages when they specify how to | | |
| | signal the use of multiplexing to | | | | | signal the use of multiplexing to | | |
| | a gateway. | | | | | a gateway. | | |
skipping to change at page 39, line 19 skipping to change at page 42, line 24
+------------+-----------------------------------+-------+----------+ +------------+-----------------------------------+-------+----------+
| bwtype:CT | Aggregate bandwidth for the | S | NORMAL | | bwtype:CT | Aggregate bandwidth for the | S | NORMAL |
| | conference | | | | | conference | | |
| | | | | | | | | |
| bwtype:AS | As a session attribute, it | B | NORMAL | | bwtype:AS | As a session attribute, it | B | NORMAL |
| | specifies the session aggregate | | | | | specifies the session aggregate | | |
| | unless media-level b=RR and/or | | | | | unless media-level b=RR and/or | | |
| | b=RS attributes are used. Under | | | | | b=RS attributes are used. Under | | |
| | this interpretation the | | | | | this interpretation the | | |
| | multiplexing scheme has no impact | | | | | multiplexing scheme has no impact | | |
| | and thus NORMAL category | | | | | and thus NORMAL category applies. | | |
| | applies. | | |
| | | | | | | | | |
| bwtype:AS | For the media level usage,the | B | SUM | | bwtype:AS | For the media level usage,the | B | SUM |
| | aggregate of individual bandwidth | | | | | aggregate of individual bandwidth | | |
| | values is considered. | | | | | values is considered. | | |
| | | | | | | | | |
+------------+-----------------------------------+-------+----------+ +------------+-----------------------------------+-------+----------+
RFC4566 bwtype Analysis RFC4566 bwtype Analysis
6.2. RFC3556 - SDP Bandwidth Modifiers for RTCP Bandwidth 6.2. RFC3556 - SDP Bandwidth Modifiers for RTCP Bandwidth
skipping to change at page 41, line 17 skipping to change at page 44, line 27
RFC4585 [RFC4585] defines an extension to the Audio-visual Profile RFC4585 [RFC4585] defines an extension to the Audio-visual Profile
(AVP) that enables receivers to provide, statistically, more (AVP) that enables receivers to provide, statistically, more
immediate feedback to the senders and thus allows for short-term immediate feedback to the senders and thus allows for short-term
adaptation and efficient feedback-based repair mechanisms to be adaptation and efficient feedback-based repair mechanisms to be
implemented. implemented.
+----------+-----------------------------------+-------+------------+ +----------+-----------------------------------+-------+------------+
| Attr | Notes | Level | Category | | Attr | Notes | Level | Category |
| Name | | | | | Name | | | |
+----------+-----------------------------------+-------+------------+ +----------+-----------------------------------+-------+------------+
| ack | Not Impacted | M | NORMAL | | ack rpsi | Not Impacted | M | NORMAL |
| rpsi | | | |
| | | | | | | | | |
| ack app | Feedback parameters MUST be | M | SPECIAL | | ack app | Feedback parameters MUST be | M | SPECIAL |
| | handled in the app specific way | | | | | handled in the app specific way | | |
| | when multiplexed | | | | | when multiplexed | | |
| | | | | | | | | |
| nack | Not Impacted | M | NORMAL | | nack | Not Impacted | M | NORMAL |
| | | | | | | | | |
| nack | Not Impacted | M | NORMAL | | nack pli | Not Impacted | M | NORMAL |
| pli | | | |
| | | | | | | | | |
| nack | Not Impacted | M | NORMAL | | nack sli | Not Impacted | M | NORMAL |
| sli | | | |
| | | | | | | | | |
| nack | Not Impacted | M | NORMAL | | nack | Not Impacted | M | NORMAL |
| rpsi | | | | | rpsi | | | |
| | | | | | | | | |
| nack | Feedback parameters MUST be | M | SPECIAL | | nack app | Feedback parameters MUST be | M | SPECIAL |
| app | handled in the app specific way | | | | | handled in the app specific way | | |
| | when multiplexed | | | | | when multiplexed | | |
| | | | | | | | | |
| trr-int | This attribute applies to RTP | M | IDENTICAL | | trr-int | This attribute applies to RTP | M | IDENTICAL |
| | Session as a whole | | | | | Session as a whole | | |
| | | | | | | | | |
+----------+-----------------------------------+-------+------------+ +----------+-----------------------------------+-------+------------+
RFC4585 Attribute Analysis RFC4585 Attribute Analysis
7.2. RFC5104 - Codec Control Messages in AVPF 7.2. RFC5104 - Codec Control Messages in AVPF
skipping to change at page 45, line 8 skipping to change at page 48, line 24
8.3. RFC4091 - ANAT Semantics 8.3. RFC4091 - ANAT Semantics
RFC4091 [RFC4091] defines the Alternative Network Address Types RFC4091 [RFC4091] defines the Alternative Network Address Types
(ANAT) semantics for the Session Description Protocol (SDP) grouping (ANAT) semantics for the Session Description Protocol (SDP) grouping
framework. The ANAT semantics allow alternative types of network framework. The ANAT semantics allow alternative types of network
addresses to establish a particular media stream. addresses to establish a particular media stream.
+-------------+---------------------------+-------+-----------------+ +-------------+---------------------------+-------+-----------------+
| Name | Notes | Level | Category | | Name | Notes | Level | Category |
+-------------+---------------------------+-------+-----------------+ +-------------+---------------------------+-------+-----------------+
| group:ANAT | ANAT semantics is | S | NOT | | group:ANAT | ANAT semantics is | S | NOT RECOMMENDED |
| | obseleted | | RECOMMENDED | | | obseleted | | |
| | | | | | | | | |
+-------------+---------------------------+-------+-----------------+ +-------------+---------------------------+-------+-----------------+
RFC4091 Attribute Analysis RFC4091 Attribute Analysis
8.4. RFC5956 - FEC Grouping Semantics in SDP 8.4. RFC5956 - FEC Grouping Semantics in SDP
RFC5956 [RFC5956] defines the semantics for grouping the associated RFC5956 [RFC5956] defines the semantics for grouping the associated
source and FEC-based (Forward Error Correction) repair flows in the source and FEC-based (Forward Error Correction) repair flows in the
Session Description Protocol (SDP). The semantics defined in the Session Description Protocol (SDP). The semantics defined in the
skipping to change at page 45, line 46 skipping to change at page 49, line 14
8.5. RFC5583 - Signaling Media Decoding Dependency in SDP 8.5. RFC5583 - Signaling Media Decoding Dependency in SDP
RFC5583 [RFC5583] defines semantics that allow for signaling the RFC5583 [RFC5583] defines semantics that allow for signaling the
decoding dependency of different media descriptions with the same decoding dependency of different media descriptions with the same
media type in the Session Description Protocol (SDP). This is media type in the Session Description Protocol (SDP). This is
required, for example, if media data is separated and transported in required, for example, if media data is separated and transported in
different network streams as a result of the use of a layered or different network streams as a result of the use of a layered or
multiple descriptive media coding process. multiple descriptive media coding process.
+-------------+----------------+-------+----------+ +--------+------------------------------+-------+-------------------+
| Name | Notes | Level | Category | | Name | Notes | Level | Category |
+-------------+----------------+-------+----------+ +--------+------------------------------+-------+-------------------+
| depend lay | Not Impacted | M | NORMAL | | depend | The attribute value must be | M | IDENTICAL-PER-PT |
| | | | | | lay | same for a given codec | | |
| depend mdc | Not Impacted | M | NORMAL | | | configuration | | |
| | | | | | | | | |
+-------------+----------------+-------+----------+ | depend | The attribute value must be | M | IDENTICAL-PER-PT |
| mdc | same for a given codec | | |
| | configuration | | |
| | | | |
+--------+------------------------------+-------+-------------------+
RFC5583 Attribute Analysis RFC5583 Attribute Analysis
The usage of identical Payload Type values across multiplexed m=lines The usage of identical Payload Type values across multiplexed m=lines
is described in [I-D.ietf-mmusic-sdp-bundle-negotiation]. is described in [I-D.ietf-mmusic-sdp-bundle-negotiation].
9. ssrc-group Attribute Analysis 9. ssrc-group Attribute Analysis
This section analyzes "ssrc-group" semantics [SSRC-GROUP]. This section analyzes "ssrc-group" semantics [SSRC-GROUP].
skipping to change at page 49, line 21 skipping to change at page 53, line 16
[I-D.dhesikan-tsvwg-rtcweb-qos], the above rules end up allowing the [I-D.dhesikan-tsvwg-rtcweb-qos], the above rules end up allowing the
audio and video to be multiplexed in many, but not all, cases. audio and video to be multiplexed in many, but not all, cases.
14.2. Option B 14.2. Option B
Media Streams MAY be multiplexed regardless of what the setting of Media Streams MAY be multiplexed regardless of what the setting of
the DSCP Per Hop Behavior group (PHB). the DSCP Per Hop Behavior group (PHB).
15. Multiplexing Considerations for Encapsulating Attributes 15. Multiplexing Considerations for Encapsulating Attributes
NOTE: The analysis given below is still Work-In-Progress and will be
updated soon.
This sections deals with recommendations for defining the This sections deals with recommendations for defining the
multiplexing charactersitics of the SDP attributes that encaspsulate multiplexing characteristics of the SDP attributes that encapsulate
other SDP attributes. Such attributes as of today, for example, are other SDP attributes/parameters. Such attributes as of today, for
defined in [RFC3407], [RFC5939] and [RFC6781] as part of a generic example, are defined in [RFC3407], [RFC5939] and [RFC6871] as part of
framework for indicating and negotiating transport, media and media a generic framework for indicating and negotiating transport, media
format related capabilities in the SDP. and media format related capabilities in the SDP.
The behavior of such attributes under multiplexing is in turn defined The behavior of such attributes under multiplexing is in turn defined
by the multiplexing behavior of the attributes they encapsulate which by the multiplexing behavior of the attributes they encapsulate which
are made known once the negotiation process is completed. are made known once the Offer/Answer negotiation process is
completed.
15.1. RFC3407 - cpar Attribute Analysis
RFC3407 capability parameter attribute (a=cpar) encapsulates b=
(bandwidth) or an a= attribute. For bandwidth attribute
encapsulation, the category SUM is inherited. For the case of a=
attribute, the category corresponding to the SDP attribute being
referenced is inherited.
v=0
o=alice 2890844526 2890844527 IN IP4 host.atlanta.example.com
s=
c=IN IP4 host.atlanta.example.com
t=0 0
m=video 3456 RTP/AVP 100
a=rtpmap:100 VP8/90000
a=sqn: 0
a=cdsc: 1 video RTP/AVP 100
a=cpar: a=rtcp-mux
m=video 3456 RTP/AVP 101
a=rtpmap:101 VP8/90000
a=fmtp:100 max-fr=15;max-fs=1200
a=cdsc: 2 video RTP/AVP 101
a=cpar: a=rtcp-mux
In the above example ,the category IDENTICAL is inherited for the
cpar encapsulated rtcp-mux attribute.
15.2. RFC5939 Analysis
[RFC5939] defines a general SDP capability negotiation framework. It
also specifies how to provide transport protocols and SDP attributes
as capabilities and negotiate them using the framework.
For this purpose, [RFC5939] defines the following
o A set of capabilities for the session and its associated media
stream components, supported by each side. The attribute
("a=acap") defines how to list an attribute name and its
associated value (if any) as a capability. The attribute
("a=tcap") that defines how to list transport protocols (e.g.,
"RTP/AVP") as capabilities.
o A set of potential configurations indicating which combinations of
those capabilities can be used for the session and its associated
media stream components. Potential configurations are not ready
for use. Instead, they provide an alternative that may be used,
subject to further negotiation.
o An actual configuration for the session and its associated media
stream components, that specifies which combinations of session
parameters and media stream components can be used currently and
with what parameters. Use of an actual configuration does not
require any further negotiation.
o A negotiation process that takes the set of actual and potential
configurations (combinations of capabilities) as input and
provides the negotiated actual configurations as output.
15.2.1. Recommendations
This section provides recommendations for entities generating and
processing SDP under the generic capability negotiation framework as
defined in [RFC5939] under the context of media stream multiplexing.
These recommendations are provided for the purposes of enabling the
Offerer to make sure that the generated potential configurations
between the multiplexed streams can (easily) be negotiated to be
consistent between those streams.
15.2.1.1. Recommendation-1: Transport Capability Analysis
When a transport capability is proposed as a potential configuration
under a given media description, it is recommended that all the media
descriptions under multiplexing have the same potential configuration
number for the given transport capability.
a=tcap:1 RTP/SAVPF
a=tcap:2 RTP/SAVP
a=group:BUNDLE audio video
m= audio
a=mid:audio
a=pcfg:1 t=1
a=pcfg:2
m= video
a=mid:video
a=pcfg:1 t=1
a=pcfg:2 t=2
In the example above, the potential configurations that Offer
transport protocol capability of RTP/SAVPF has the same configuration
number "1" in both the audio and video media descriptions.
15.2.1.2. Recommendation-2: Attribute Capability Analysis
For attribute capabilities which are offered as potential
configurations that encapsulate attributes whose value MUST be
IDENTICAL under multiplexing, it is recommended that all the media
descriptions under multiplexing have the same potential configuration
number for the given attribute capability.
a=acap:1 a=rtcp-mux
a=acap:2 a=crypto:1 AES_CM_128_HMAC_SHA1_80
inline:EcGZiNWpFJhQXdspcl1ekcmVCNWpVLcfHAwJSoj|2^20|1:32
a=group:BUNDLE audio video
m= audio 49172 RTP/AVP 99
a=mid:audio
a=pcfg:1 a=1
a=pcfg:2
m= video 560024 RTP/AVP 100
a=mid:video
a=pcfg:1 a=1
a=pcfg:2 a=2
In the example above, the potential configuration number 1 is
repeated while referring to attribute capability a=rtcp-mux, since
the behavior is IDENTICAL for the attribute a=rtcp-mux under
multiplexing.
15.2.1.3. Recommendation-3: Sescap Attribute Analysis
It is recommended that any bundled media descriptions/configurations
are also acceptable combinations of media streams/configurations as
specified by "sescap" attribute.
15.2.1.4. Recommendation-4: Capability Extension Attributes
Since it is nearly impossible to define a generic mechanism for
various capability extensions , this document does't provide
procedures for dealing with the capability extension attributes.
However, Section Section 15.3 provide analysis of media capability
extension attributes as defined in [RFC6871].
15.3. RFC6871 Analysis
[RFC6871] extends capability negotiation framework described in
[RFC5939] by defining media capabilities that can be used to indicate
and negotiate media types and their associated format parameters.
Building upon the analysis from the previous section, following
recommendation is provided for dealing with the attributes defined in
[RFC6871] under multiplexing
15.3.1. Recommendation-5: Attribute Capability Under Shared Payload
Type
For attribute capabilities which are offered as potential
configurations that encapsulate attributes whose value MUST be
IDENTICAL-PER-PT under multiplexing, it is recommended that all the
media descriptions under multiplexing have the same potential
configuration number for the given attribute capability
The attributes (a=rmcap, a=mfcap) follow the above recommendations
under mutliplexing
v=0
o=- 25678 753849 IN IP4 192.0.2.1
s=
c=IN IP4 192.0.2.1
t=0 0
a=creq:med-v0
m=audio 54322 RTP/AVP 96
a=rtpmap:96 AMR-WB/16000/1
a=fmtp:96 mode-change-capability=1; max-red=220;
mode-set=0,2,4,7
a=rmcap:1,3 audio AMR-WB/16000/1
a=rmcap:2 audio AMR/8000/1
a=mfcap:1,2 mode-change-capability=1
a=mfcap:3 mode-change-capability=2
a=pcfg:1 m=1 pt=1:96
a=pcfg:2 m=2 pt=2:97
a=pcfg:3 m=3 pt=3:98
m=audio 54322 RTP/AVP 96
a=rtpmap:96 AMR-WB/16000/1
a=fmtp:96 mode-change-capability=1; max-red=220;
mode-set=0,2,4,7
a=rmcap:4 audio AMR/8000/1
a=rmcap:5 audio OPUS/48000/2
a=mfcap:5 minptime=40
a=mfcap:4 mode-change-capability=1
a=pcfg:1 m=4 pt=4:97
a=pcfg:4 m=5 pt=5:101
In the example above, the potential configuration number 1 is
repeated when referring to media and media format capability used for
the Payload Type 97. This implies that both the media capability 2
and 4 along with their media format capabilities MUST refer to the
same Codec configuration , as per the definition of IDENTICAL-PER-PT
15.4. Recommendation-6: Offer/Answer Negotiation Expectations
For attributes encapsulated via "a=acap", "a=omcap", "a=mscap"
capability attributes and presented as part of potential/actual
configurations during the Offer/Answer negotiation prodecure, the
negotiation MUST ensure that the multiplexing behavior of these
capabilities inherit from the behavior of the attribute being
encapsulated.
Example 1: Below SDP example captures the following aspects. Example 1: Below SDP example captures the following aspects.
1. The Offerer offers audio and video streams with several different
RTP profiles (AVP, SAVP, SAVPF) as potential configurations.
2. ANSWER - 1 corresponds to the SDP answer where the Answerer
accepts RTP/SAVPF as the default profile for both the media
streams. In this scenario both the media streams can be
successfully multiplexed.
3. In ANSWER - 2 SDP, the Answerer accepts the profile RTP/SAVPF for
the audio stream and RTP/AVPF for the video stream. This
scenario results in the failure of the multiplexing as defined in
the section 7.2 of the BUNDLE specifcation
[I-D.ietf-mmusic-sdp-bundle-negotiation].
o The Offerer offers audio and video streams with several different
RTP profiles (AVP, SAVP, SAVPF) as potential configurations.
o Valid Answer that corresponds to the SDP answer where the Answerer
accepts RTP/SAVPF as the default profile for both the media
streams. In this scenario both the media streams can be
successfully multiplexed.
o Invalid Answer wherein the Answerer accepts the profile RTP/SAVPF
for the audio stream and RTP/AVPF for the video stream. This
scenario results in the failure of the multiplexing as defined in
the section 7.2 of the BUNDLE specification [I-D.ietf-mmusic-sdp-
bundle-negotiation].
<Offer-SDP>
v=0 v=0
o=- 25678 753849 IN IP4 192.0.2.1 o=- 25678 753849 IN IP4 192.0.2.1
s= s=
t=0 0 t=0 0
c=IN IP4 192.0.2.1 c=IN IP4 192.0.2.1
m=audio 3456 RTP/AVP 98 m=audio 3456 RTP/AVP 98
a=tcap:1 RTP/SAVPF a=tcap:1 RTP/SAVPF
a=rtpmap:98 OPUS/48000/2 a=rtpmap:98 OPUS/48000/2
a=pcfg:1 t=1 a=pcfg:1 t=1
m=video 51372 RTP/AVP 101 m=video 51372 RTP/AVP 101
a=rtpmap:101 H264/90000 a=rtpmap:101 H264/90000
a=tcap:2 RTP/SAVPF RTP/AVPF a=tcap:2 RTP/SAVPF RTP/AVPF
a=pcfg:2 t=2|3 a=pcfg:2 t=2|3
ANSWER - 1 <Valid Answer>
-----------
v=0 v=0
o=- 24351 621814 IN IP4 192.0.2.2 o=- 24351 621814 IN IP4 192.0.2.2
s= s=
m=audio 3456 RTP/SAVPF 98 m=audio 3456 RTP/SAVPF 98
a=rtpmap:98 OPUS/48000/2 a=rtpmap:98 OPUS/48000/2
a=acfg:1 t=1 a=acfg:1 t=1
m=video 51372 RTP/SAVPF 101 m=video 51372 RTP/SAVPF 101
a=rtpmap:101 H264/90000 a=rtpmap:101 H264/90000
a=acfg:2 t=2 a=acfg:2 t=2
ANSWER - 2 <Invalid Answer>
-----------
v=0 v=0
o=- 24351 621814 IN IP4 192.0.2.2 o=- 24351 621814 IN IP4 192.0.2.2
s= s=
m=audio 3456 RTP/SAVPF 98 m=audio 3456 RTP/SAVPF 98
a=rtpmap:98 OPUS/48000/2 a=rtpmap:98 OPUS/48000/2
a=acfg:1 t=1 a=acfg:1 t=1
m=video 51372 RTP/AVPF 101 m=video 51372 RTP/AVPF 101
a=rtpmap:101 H264/90000 a=rtpmap:101 H264/90000
a=acfg:2 t=3 a=acfg:2 t=3
Example 2: Below SDP example captures the following aspects.
1. Offerer offers use of plain RTP and Secure RTP as alternatives.
For the Secure RTP stream, it can be established using either
DTLS-SRTP or SDP security descriptions
2. ANSWER - 1 corresponds to the SDP answer where the Answerer
accepts DTLS based encryption for both the audio and video
streams. This scenario can lead to successfull multiplexing of
the audio and the video streams.
3. In ANSWER - 2 SDP, the Answerer accepts plain RTP for the audio
stream and DTLS based encryption for the video stream. This
scenario results in unsuccesfull multiplexing of the media
streams since the encryption scheme applies to the entire RTP
Session and cannot be applied to video media stream alone when
multiplexed.
OFFER
-----
v=0
o=- 25678 753849 IN IP4 192.0.2.1
s=
t=0 0
c=IN IP4 192.0.2.1
a=acap:1 setup:actpass
a=acap:2 fingerprint: SHA-1 \
4A:AD:B9:B1:3F:82:18:3B:54:02:12:DF:3E:5D:49:6B:19:E5:7C:AB
a=tcap:1 UDP/TLS/RTP/SAVP RTP/SAVP
m=audio 59000 RTP/AVP 98
a=rtpmap:98 AMR/8000
a=acap:3 crypto:1 AES_CM_128_HMAC_SHA1_32
inline:NzB4d1BINUAvLEw6UzF3WSJ+PSdFcGdUJShpX1Zj|2^20|1:32
a=pcfg:1 t=1 a=1,2
a=pcfg:2 t=2 a=3
m=video 59123 RTP/AVP 100
a=rtpmap:100 VP8/90000
a=pcfg:3 t=1 a=1,2
ANSWER - 1
-----------
v=0
o=- 24351 621814 IN IP4 192.0.2.2
s=
t=0 0
c=IN IP4 192.0.2.2
m=audio 54568 UDP/TLS/RTP/SAVP 98
a=rtpmap:98 AMR/8000
a=acfg:1 t=1 a=1,2
m=video 54968 UDP/TLS/RTP/SAVP 100
a=rtpmap:100 VP8/90000
a=acfg:3 t=1 a=1,2
ANSWER - 2
-----------
v=0
o=- 24351 621814 IN IP4 192.0.2.2
s=
t=0 0
c=IN IP4 192.0.2.2
m=audio 54568 RTP/AVP 98
a=rtpmap:98 AMR/8000
m=video 54968 UDP/TLS/RTP/SAVP 100
a=rtpmap:100 VP8/90000
a=setup:active
a=fingerprint: SHA-1 \
FF:FF:FF:B1:3F:82:18:3B:54:02:12:DF:3E:5D:49:6B:19:E5:7C:AB
a=acfg:3 t=1 a=1,2
In conclusion, the mutliplexing behavior of the encapsulating
attributes are defined based on the multiplexing behavior of the
attributes they encapsulate. Thus care should be taken in
determining if certain combinations of these attributes can be used
in the context of transport multplexing.
16. IANA Considerations 16. IANA Considerations
IANA shall register categories from this specification by expanding IANA shall register categories from this specification by expanding
the Session Description Protocol (SDP) Parameters table with a column the Session Description Protocol (SDP) Parameters table with a column
listing categories against each SDP parameter. listing categories against each SDP parameter.
+---------------------+ +---------------------+
| Category | | Category |
+---------------------+ +---------------------+
| NORMAL | | NORMAL |
+---------------------+ +---------------------+
| NOT RECOMMENDED | | NOT RECOMMENDED |
+---------------------+ +---------------------+
| IDENTICAL | | IDENTICAL |
+---------------------+ +---------------------+
| TRANSPORT | | TRANSPORT |
+---------------------+ +---------------------+
| INHERIT |
----------------------+
| IDENTICAL-PER-PT |
+---------------------+
| SPECIAL | | SPECIAL |
---------------------- ----------------------
17. Security Considerations 17. Security Considerations
All the attributes which involve security key needs a careful review All the attributes which involve security key needs a careful review
to ensure two-time pad vulnerability is not created. to ensure two-time pad vulnerability is not created.
18. Acknowledgments 18. Acknowledgments
I would like to thank Cullen Jennings for suggesting the categories, I would like to thank Cullen Jennings for suggesting the categories,
contributing text and reviewing the draft. I would also link to contributing text and reviewing the draft. I would also link to
thank Magnus, Christer and Dan on suggesting structural changes thank Magnus, Christer, Jonathan Lennox, Bo Burman, and Dan on
helping improve the document readability. suggesting structural changes helping improve the document
readability.
I would like also to thank following experts on their inputs and I would like also to thank following experts on their inputs and
reviews as listed - Flemming Andreasen(5.20,5.28,5.29,15), Rohan reviews as listed - Flemming Andreasen(5.20,5.28,5.29,15), Rohan
Mahy(5.45), Eric Burger(5.22),Christian Huitema(5.13), Christer Mahy(5.45), Eric Burger(5.22),Christian Huitema(5.13), Christer
Holmberg(5.17,5.22,5.40,5.41), Richard Ejzak (5.36,5.42,5.43,5.44), Holmberg(5.17,5.22,5.40,5.41), Richard Ejzak (5.36,5.42,5.43,5.44),
Colin Perkins(5.7,5.8), Magnus westerlund(5.2,5.3,5.9,5.26, Colin Perkins(5.7,5.8), Magnus westerlund(5.2,5.3,5.9,5.26,
5.27,6.1,6.2,6.3,8.3,7), Roni Evens(5.12,5.27,8.4), Subha 5.27,6.1,6.2,6.3,8.3,7), Roni Evens(5.12,5.27,8.4), Subha
Dhesikan(5.5,12.1,14), Dan Wing(5.6,5.11,5.30,5.34,5.37), Ali C Dhesikan(5.5,12.1,14), Dan Wing(5.6,5.11,5.30,5.34,5.37), Ali C
Begen(5.1,5.16,5.18,5.21,5.33,8.2,8.4,13.1), Bo Burman (7.2,7.6), Begen(5.1,5.16,5.18,5.21,5.33,8.2,8.4,13.1), Bo Burman (7.2,7.6),
Charles Eckel(5.14,5.23,5.24,9.1,8.5), Paul Kyzivat(5.24), Ian Charles Eckel(5.14,5.23,5.24,9.1,8.5), Paul Kyzivat(5.24), Ian
Johansson(5.15), Saravanan Shanmugham(5.10), Paul E Jones(5.25), Johansson(5.15), Saravanan Shanmugham(5.10), Paul E Jones(5.25),
Rajesh Kumar(5.39), Jonathan Lennox(5.31,5,14,11.1), Mo Rajesh Kumar(5.39), Jonathan Lennox(5.31,5,14,11.1), Mo
Zanaty(5.4,5.19,8.1,8.3,8.5,12.1), Christian Huitema (5.13), Qin Wu Zanaty(5.4,5.19,8.1,8.3,8.5,12.1), Christian Huitema (5.13), Qin Wu
(5.38 PM-Dir review). (5.38 PM-Dir review).
19. Change Log 19. Change Log
[RFC EDITOR NOTE: Please remove this section when publishing] [RFC EDITOR NOTE: Please remove this section when publishing]
Changes from draft-ietf-mmusic-sdp-mux-attributes-01
o Updated section 15 to provide detailed recommendation on dealing
with encapsulating attributes. Also updated sections 5.20, 5.28,
5.29 to refer to Section 15.
o Added new categories IDENTICAL-PER-PT and INHERIT
o Updated Sections 16 to add the new categories.
o Updated Sections 5.1, 5.14, 5.15, 5.38, 8.5 to reflect the
category IDENTICAL-PER-PT.
o Reformatted section 4 to add individual categories to their own
sections.
Changes from draft-ietf-mmusic-sdp-mux-attributes-00 Changes from draft-ietf-mmusic-sdp-mux-attributes-00
o Added Section 15 to provide recommendations on multiplexing SDP o Added Section 15 to provide recommendations on multiplexing SDP
encapsulating attributes. Also updated sections 5.20, 5.28, 5.29 encapsulating attributes. Also updated sections 5.20, 5.28, 5.29
to refer to Section 15. to refer to Section 15.
o Updated Section 5.38 to incorporate PM-dir review inputs from Qin o Updated Section 5.38 to incorporate PM-dir review inputs from Qin
Wu Wu
o Updated Sections 5.2,5.14,8.5 to refer to BUNDLE draft for more o Updated Sections 5.2,5.14,8.5 to refer to BUNDLE draft for more
clarity. clarity.
o Fixed few nits regarding sentence clarity and fill-in the NOTES o Fixed few nits regarding sentence clarity and fill-in the NOTES
section where information was lacking. section where information was lacking.
Changes from draft-nandakumar-mmusic-mux-attributes-05 Changes from draft-nandakumar-mmusic-mux-attributes-05
o Renamed the document to be a WG document. o Renamed the document to be a WG document.
o Added Section 14. o Added Section 14.
o Updated Open Issues based on IETF88 discussions. o Updated Open Issues based on IETF88 discussions.
Changes from draft-nandakumar-mmusic-mux-attributes-04 Changes from draft-nandakumar-mmusic-mux-attributes-04
o Added few OPEN ISSUES that needs to be discussed. o Added few OPEN ISSUES that needs to be discussed.
o Updated sections 5.10,5.23,5,24,5,25,7.2,9.1,5.12,5.27,8.4, o Updated sections 5.10,5.23,5,24,5,25,7.2,9.1,5.12,5.27,8.4,
5.44,5.11,5.4,5.19,10.1,10.5,5.21,10.4,15.1 5.44,5.11,5.4,5.19,10.1,10.5,5.21,10.4,15.1
o Updated Table Column name Current to Level and improved TRANSPORT o Updated Table Column name Current to Level and improved TRANSPORT
category explanation on suggestions form Dan Wing. category explanation on suggestions form Dan Wing.
o Grouped all the rtcp-fb attribute analysis under a single section o Grouped all the rtcp-fb attribute analysis under a single section
as suggested by Magnus/ as suggested by Magnus/
Changes from draft-nandakumar-mmusic-mux-attributes-03 Changes from draft-nandakumar-mmusic-mux-attributes-03
o Maintenance change to clean up grammatical nits and wordings. o Maintenance change to clean up grammatical nits and wordings.
Changes from draft-nandakumar-mmusic-mux-attributes-02 Changes from draft-nandakumar-mmusic-mux-attributes-02
o Updated Sections 5.3,5.5,5.6,5.7,5.9,5.8,5.11,5.13,5.22,5.34, o Updated Sections 5.3,5.5,5.6,5.7,5.9,5.8,5.11,5.13,5.22,5.34,
5.37,5.40,5.41,5.42,5.43,5.44,5.45,6.1,6.2,6.3,8,3,12.1 based on 5.37,5.40,5.41,5.42,5.43,5.44,5.45,6.1,6.2,6.3,8,3,12.1 based on
the inputs from the respective RFC Authors. the inputs from the respective RFC Authors.
Changes from draft-nandakumar-mmusic-mux-attributes-01 Changes from draft-nandakumar-mmusic-mux-attributes-01
o Replaced Category BAD with NOT RECOMMENDED. o Replaced Category BAD with NOT RECOMMENDED.
o Added Category TBD. o Added Category TBD.
o Updated IANA Consideration Section. o Updated IANA Consideration Section.
Changes from draft-nandakumar-mmusic-mux-attributes-00 Changes from draft-nandakumar-mmusic-mux-attributes-00
o Added new section for dealing with FEC payload types. o Added new section for dealing with FEC payload types.
20. References 20. References
20.1. Normative References 20.1. Normative References
[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.
[RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session [RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session
skipping to change at page 54, line 46 skipping to change at page 62, line 50
[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.
[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.
20.2. Informative References 20.2. Informative References
[ACK-NACK] [ACK-NACK]
"S Description Protocol (SDP) RTCP ACK/NACK Feedback "S Description Protocol (SDP) RTCP ACK/NACK Feedback
attributes", <http://www.iana.org/assignments/ attributes", <http://www.iana.org/assignments/sdp-
sdp-parameters/sdp-parameters.xml#sdp-parameters-15>. parameters/sdp-parameters.xml#sdp-parameters-15>.
[CCM] "S Description Protocol (SDP) RTCP-FB Codec Control [CCM] "S Description Protocol (SDP) RTCP-FB Codec Control
Messages", <http://www.iana.org/assignments/ Messages", <http://www.iana.org/assignments/sdp-
sdp-parameters/sdp-parameters.xml#sdp-parameters-19>. parameters/sdp-parameters.xml#sdp-parameters-19>.
[GROUP-SEM] [GROUP-SEM]
"S Description Protocol (SDP) "group" semantics", <http:// "S Description Protocol (SDP) "group" semantics",
www.iana.org/assignments/sdp-parameters/ <http://www.iana.org/assignments/sdp-parameters/
sdp-parameters.xml#sdp-parameters-13>. sdp-parameters.xml#sdp-parameters-13>.
[H.248.15] [H.248.15]
"Gateway control protocol: SDP H.248 package attribute", "Gateway control protocol: SDP H.248 package attribute",
<http://www.itu.int/rec/T-REC-H.248.15>. <http://www.itu.int/rec/T-REC-H.248.15>.
[I-D.dhesikan-tsvwg-rtcweb-qos] [I-D.dhesikan-tsvwg-rtcweb-qos]
Dhesikan, S., Druta, D., Jones, P., and J. Polk, "DSCP and Dhesikan, S., Druta, D., Jones, P., and J. Polk, "DSCP and
other packet markings for RTCWeb QoS", other packet markings for RTCWeb QoS", draft-dhesikan-
draft-dhesikan-tsvwg-rtcweb-qos-02 (work in progress), tsvwg-rtcweb-qos-02 (work in progress), July 2013.
July 2013.
[I-D.ietf-avt-multiplexing-rtp] [I-D.ietf-avt-multiplexing-rtp]
El-Khatib, K., Luo, G., Bochmann, G., and Pinjiang. Feng, El-Khatib, K., Luo, G., Bochmann, G., and Pinjiang. Feng,
"Multiplexing Scheme for RTP Flows between Access "Multiplexing Scheme for RTP Flows between Access
Routers", Internet-Draft http://tools.ietf.org/html/ Routers", http://tools.ietf.org/html/
draft-ietf-avt-multiplexing-rtp-01, October 1999. draft-ietf-avt-multiplexing-rtp-01 (work in progress),
October 1999.
[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,
"Multiplexing Negotiation Using Session Description "Multiplexing Negotiation Using Session Description
Protocol (SDP) Port Numbers", Protocol (SDP) Port Numbers", draft-ietf-mmusic-sdp-
draft-ietf-mmusic-sdp-bundle-negotiation-03 (work in bundle-negotiation-03 (work in progress), February 2013.
progress), February 2013.
[IANA] "S Description Protocol (SDP) Parameters", <http:// [IANA] "S Description Protocol (SDP) Parameters",
www.iana.org/assignments/sdp-parameters/ <http://www.iana.org/assignments/sdp-parameters/
sdp-parameters.xml>. sdp-parameters.xml>.
[MEDIA_LOOPBACK] [MEDIA_LOOPBACK]
Kaplan, H., Hedayat, K., Venna, N., Jones, P., and N. Kaplan, H., Hedayat, K., Venna, N., Jones, P., and N.
Stratton, "An Extension to the Session Description Stratton, "An Extension to the Session Description
Protocol (SDP) and Real-time Transport Protocol (RTP) for Protocol (SDP) and Real-time Transport Protocol (RTP) for
Media Loopback", Internet-Draft 6489, January 2013. Media Loopback", 6489 (work in progress), January 2013.
[QOS] "S Description Protocol (SDP) QoS Mechanism Tokens", <http [QOS] "S Description Protocol (SDP) QoS Mechanism Tokens",
://www.iana.org/assignments/sdp-parameters/ <http://www.iana.org/assignments/sdp-parameters/
sdp-parameters.xml#sdp-parameters-20>. sdp-parameters.xml#sdp-parameters-20>.
[R3GPPTS24.182] [R3GPPTS24.182]
"IP Multimedia Subsystem (IMS) Customized Alerting Tones "IP Multimedia Subsystem (IMS) Customized Alerting Tones
(CAT); Protocol specification", (CAT); Protocol specification",
<http://www.3gpp.org/ftp/Specs/html-info/24182.htm>. <http://www.3gpp.org/ftp/Specs/html-info/24182.htm>.
[R3GPPTS24.183] [R3GPPTS24.183]
"IP Multimedia Subsystem (IMS) Customized Ringing Signal "IP Multimedia Subsystem (IMS) Customized Ringing Signal
(CRS); Protocol specification", (CRS); Protocol specification",
skipping to change at page 56, line 19 skipping to change at page 64, line 26
"IP multimedia call control protocol based on Session "IP multimedia call control protocol based on Session
Initiation Protocol (SIP) and Session Description Protocol Initiation Protocol (SIP) and Session Description Protocol
(SDP);", (SDP);",
<http://www.3gpp.org/ftp/Specs/html-info/24229.htm>. <http://www.3gpp.org/ftp/Specs/html-info/24229.htm>.
[RFC3108] Kumar, R. and M. Mostafa, "Conventions for the use of the [RFC3108] Kumar, R. and M. Mostafa, "Conventions for the use of the
Session Description Protocol (SDP) for ATM Bearer Session Description Protocol (SDP) for ATM Bearer
Connections", RFC 3108, May 2001. Connections", RFC 3108, May 2001.
[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, June
June 2002. 2002.
[RFC3407] Andreasen, F., "S Description Protocol (SDP) Simple [RFC3407] Andreasen, F., "S Description Protocol (SDP) Simple
Capability Declaration", RFC 3407, October 2002. Capability Declaration", RFC 3407, October 2002.
[RFC3524] Camarillo, G. and A. Monrad, "Mapping of Media Streams to [RFC3524] Camarillo, G. and A. Monrad, "Mapping of Media Streams to
Resource Reservation Flows", RFC 3524, April 2003. Resource Reservation Flows", RFC 3524, April 2003.
[RFC3556] Casner, S., "S Description Protocol (SDP) Bandwidth [RFC3556] Casner, S., "S Description Protocol (SDP) Bandwidth
Modifiers for RTP Control Protocol (RTCP) Bandwidth", Modifiers for RTP Control Protocol (RTCP) Bandwidth", RFC
RFC 3556, July 2003. 3556, July 2003.
[RFC3605] Huitema, C., "Real Time Control Protocol (RTCP) attribute [RFC3605] Huitema, C., "Real Time Control Protocol (RTCP) attribute
in Session Description Protocol (SDP)", RFC 3605, in Session Description Protocol (SDP)", RFC 3605, October
October 2003. 2003.
[RFC3611] Friedman, T., Caceres, R., and A. Clark, "RTP Control [RFC3611] Friedman, T., Caceres, R., and A. Clark, "RTP Control
Protocol Extended Reports (RTCP XR)", RFC 3611, Protocol Extended Reports (RTCP XR)", RFC 3611, November
November 2003. 2003.
[RFC3890] Westerlund, M., "A Transport Independent Bandwidth [RFC3890] Westerlund, M., "A Transport Independent Bandwidth
Modifier for the Session Description Protocol (SDP)", Modifier for the Session Description Protocol (SDP)", RFC
RFC 3890, September 2004. 3890, September 2004.
[RFC4091] Camarillo, G. and J. Rosenberg, "The Alternative Network [RFC4091] Camarillo, G. and J. Rosenberg, "The Alternative Network
Address Types (ANAT) Semantics for the Session Description Address Types (ANAT) Semantics for the Session Description
Protocol (SDP) Grouping Framework", RFC 4091, June 2005. Protocol (SDP) Grouping Framework", RFC 4091, June 2005.
[RFC4145] Yon, D. and G. Camarillo, "TCP-Based Media Transport in [RFC4145] Yon, D. and G. Camarillo, "TCP-Based Media Transport in
the Session Description Protocol (SDP)", RFC 4145, the Session Description Protocol (SDP)", RFC 4145,
September 2005. September 2005.
[RFC4567] Arkko, J., Lindholm, F., Naslund, M., Norrman, K., and E. [RFC4567] Arkko, J., Lindholm, F., Naslund, M., Norrman, K., and E.
skipping to change at page 57, line 30 skipping to change at page 65, line 38
[RFC4574] Levin, O. and G. Camarillo, "The Session Description [RFC4574] Levin, O. and G. Camarillo, "The Session Description
Protocol (SDP) Label Attribute", RFC 4574, August 2006. Protocol (SDP) Label Attribute", RFC 4574, August 2006.
[RFC4583] Camarillo, G., "S Description Protocol (SDP) Format for [RFC4583] Camarillo, G., "S Description Protocol (SDP) Format for
Binary Floor Control Protocol (BFCP) Streams", RFC 4583, Binary Floor Control Protocol (BFCP) Streams", RFC 4583,
November 2006. November 2006.
[RFC4585] Ott, J., Wenger, S., Sato, N., Burmeister, C., and J. Rey, [RFC4585] Ott, J., Wenger, S., Sato, N., Burmeister, C., and J. Rey,
"Extended RTP Profile for Real-time Transport Control "Extended RTP Profile for Real-time Transport Control
Protocol (RTCP)-Based Feedback (RTP/AVPF)", RFC 4585, Protocol (RTCP)-Based Feedback (RTP/AVPF)", RFC 4585, July
July 2006. 2006.
[RFC4796] Hautakorpi, J. and G. Camarillo, "The Session Description [RFC4796] Hautakorpi, J. and G. Camarillo, "The Session Description
Protocol (SDP) Content Attribute", RFC 4796, Protocol (SDP) Content Attribute", RFC 4796, February
February 2007. 2007.
[RFC4975] Campbell, B., Mahy, R., and C. Jennings, "The Message [RFC4975] Campbell, B., Mahy, R., and C. Jennings, "The Message
Session Relay Protocol (MSRP)", RFC 4975, September 2007. Session Relay Protocol (MSRP)", RFC 4975, September 2007.
[RFC5104] Wenger, S., Chandra, U., Westerlund, M., and B. Burman, [RFC5104] Wenger, S., Chandra, U., Westerlund, M., and B. Burman,
"Codec Control Messages in the RTP Audio-Visual Profile "Codec Control Messages in the RTP Audio-Visual Profile
with Feedback (AVPF)", RFC 5104, February 2008. with Feedback (AVPF)", RFC 5104, February 2008.
[RFC5109] Li, A., "RTP Payload Format for Generic Forward Error [RFC5109] Li, A., "RTP Payload Format for Generic Forward Error
Correction", RFC 5109, December 2007. Correction", RFC 5109, December 2007.
[RFC5159] Dondeti, L. and A. Jerichow, "S Description Protocol (SDP) [RFC5159] Dondeti, L. and A. Jerichow, "S Description Protocol (SDP)
Attributes for Open Mobile Alliance (OMA) Broadcast Attributes for Open Mobile Alliance (OMA) Broadcast
(BCAST) Service and Content Protection", RFC 5159, (BCAST) Service and Content Protection", RFC 5159, March
March 2008. 2008.
[RFC5245] Rosenberg, J., "Interactive Connectivity Establishment [RFC5245] Rosenberg, J., "Interactive Connectivity Establishment
(ICE): A Protocol for Network Address Translator (NAT) (ICE): A Protocol for Network Address Translator (NAT)
Traversal for Offer/Answer Protocols", RFC 5245, Traversal for Offer/Answer Protocols", RFC 5245, July
July 2006. 2006.
[RFC5285] Singer, D. and H. Desineni, "A General Mechanism for RTP [RFC5285] Singer, D. and H. Desineni, "A General Mechanism for RTP
Header Extensions", RFC 5285, July 2008. Header Extensions", RFC 5285, July 2008.
[RFC5432] Polk, J., Dhesikan, S., and G. Camarillo, "Quality of [RFC5432] Polk, J., Dhesikan, S., and G. Camarillo, "Quality of
Service (QoS) Mechanism Selection in the Session Service (QoS) Mechanism Selection in the Session
Description Protocol (SDP)", RFC 5432, March 2009. Description Protocol (SDP)", RFC 5432, March 2009.
[RFC5506] Johansson, I., "Support for Reduced-Size Real-Time [RFC5506] Johansson, I., "Support for Reduced-Size Real-Time
Transport Control Protocol (RTCP): Opportunities and Transport Control Protocol (RTCP): Opportunities and
skipping to change at page 58, line 29 skipping to change at page 66, line 39
[RFC5547] Garcia-Martin, M., Isomaki, M., Camarillo, G., Loreto, S., [RFC5547] Garcia-Martin, M., Isomaki, M., Camarillo, G., Loreto, S.,
and P. Kyzivat, "A Session Description Protocol (SDP) and P. Kyzivat, "A Session Description Protocol (SDP)
Offer/Answer Mechanism to Enable File Transfer", RFC 5547, Offer/Answer Mechanism to Enable File Transfer", RFC 5547,
May 2009. May 2009.
[RFC5576] Lennox, J., Ott, J., and T. Schierl, "Source-Specific [RFC5576] Lennox, J., Ott, J., and T. Schierl, "Source-Specific
Media Attributes in the Session Description Protocol Media Attributes in the Session Description Protocol
(SDP)", RFC 5576, June 2009. (SDP)", RFC 5576, June 2009.
[RFC5583] Schierl, T. and S. Wenger, "Signaling Media Decoding [RFC5583] Schierl, T. and S. Wenger, "Signaling Media Decoding
Dependency in the Session Description Protocol (SDP)", Dependency in the Session Description Protocol (SDP)", RFC
RFC 5583, July 2009. 5583, July 2009.
[RFC5760] Ott, J., Chesterfield, J., and E. Schooler, "RTP Control [RFC5760] Ott, J., Chesterfield, J., and E. Schooler, "RTP Control
Protocol (RTCP) Extensions for Single-Source Multicast Protocol (RTCP) Extensions for Single-Source Multicast
Sessions with Unicast Feedback", RFC 5760, February 2010. Sessions with Unicast Feedback", RFC 5760, February 2010.
[RFC5761] Perkins, C. and M. Westerlund, "Multiplexing RTP Data and [RFC5761] Perkins, C. and M. Westerlund, "Multiplexing RTP Data and
Control Packets on a Single Port", RFC 5761, April 2010. Control Packets on a Single Port", RFC 5761, April 2010.
[RFC5762] Perkins, C., "RTP and the Datagram Congestion Control [RFC5762] Perkins, C., "RTP and the Datagram Congestion Control
Protocol (DCCP)", RFC 5762, April 2010. Protocol (DCCP)", RFC 5762, April 2010.
skipping to change at page 59, line 6 skipping to change at page 67, line 17
(SRTP) Security Context Using Datagram Transport Layer (SRTP) Security Context Using Datagram Transport Layer
Security (DTLS)", RFC 5763, May 2010. Security (DTLS)", RFC 5763, May 2010.
[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.
[RFC5939] Andreasen, F., "S Description Protocol (SDP) Capability [RFC5939] Andreasen, F., "S Description Protocol (SDP) Capability
Negotiation", RFC 5939, September 2010. Negotiation", RFC 5939, September 2010.
[RFC5956] Begen, A., "Forward Error Correction Grouping Semantics in [RFC5956] Begen, A., "Forward Error Correction Grouping Semantics in
the Session Description Protocol", RFC 5956, the Session Description Protocol", RFC 5956, September
September 2010. 2010.
[RFC6064] Westerlund, M. and P. Frojdh, "SDP and RTSP Extensions [RFC6064] Westerlund, M. and P. Frojdh, "SDP and RTSP Extensions
Defined for 3GPP Packet-Switched Streaming Service and Defined for 3GPP Packet-Switched Streaming Service and
Multimedia Broadcast/Multicast Service", RFC 6064, Multimedia Broadcast/Multicast Service", RFC 6064, January
January 2011. 2011.
[RFC6128] Begen, A., "RTP Control Protocol (RTCP) Port for Source- [RFC6128] Begen, A., "RTP Control Protocol (RTCP) Port for Source-
Specific Multicast (SSM) Sessions", RFC 6128, Specific Multicast (SSM) Sessions", RFC 6128, February
February 2011. 2011.
[RFC6189] Zimmermann, P., Johnston, A., and J. Callas, "ZRTP: Media [RFC6189] Zimmermann, P., Johnston, A., and J. Callas, "ZRTP: Media
Path Key Agreement for Unicast Secure RTP", RFC 6189, Path Key Agreement for Unicast Secure RTP", RFC 6189,
April 2011. April 2011.
[RFC6193] Saito, M., Wing, D., and M. Toyama, "Media Description for [RFC6193] Saito, M., Wing, D., and M. Toyama, "Media Description for
the Internet Key Exchange Protocol (IKE) in the Session the Internet Key Exchange Protocol (IKE) in the Session
Description Protocol (SDP)", RFC 6193, April 2011. Description Protocol (SDP)", RFC 6193, April 2011.
[RFC6230] Boulton, C., Melanchuk, T., and S. McGlashan, "Media [RFC6230] Boulton, C., Melanchuk, T., and S. McGlashan, "Media
Control Channel Framework", RFC 6230, May 2011. Control Channel Framework", RFC 6230, May 2011.
[RFC6236] Johansson, I. and K. Jung, "Negotiation of Generic Image [RFC6236] Johansson, I. and K. Jung, "Negotiation of Generic Image
Attributes in the Session Description Protocol (SDP)", Attributes in the Session Description Protocol (SDP)", RFC
RFC 6236, May 2011. 6236, May 2011.
[RFC6284] Begen, A., Wing, D., and T. Van Caenegem, "Port Mapping [RFC6284] Begen, A., Wing, D., and T. Van Caenegem, "Port Mapping
between Unicast and Multicast RTP Sessions", RFC 6284, between Unicast and Multicast RTP Sessions", RFC 6284,
June 2011. June 2011.
[RFC6285] Ver Steeg, B., Begen, A., Van Caenegem, T., and Z. Vax, [RFC6285] Ver Steeg, B., Begen, A., Van Caenegem, T., and Z. Vax,
"Unicast-Based Rapid Acquisition of Multicast RTP "Unicast-Based Rapid Acquisition of Multicast RTP
Sessions", RFC 6285, June 2011. Sessions", RFC 6285, June 2011.
[RFC6364] Begen, A., "S Description Protocol Elements for the [RFC6364] Begen, A., "S Description Protocol Elements for the
Forward Error Correction (FEC) Framework", RFC 6364, Forward Error Correction (FEC) Framework", RFC 6364,
October 2011. October 2011.
[RFC6642] Wu, Q., Xia, F., and R. Even, "RTP Control Protocol (RTCP) [RFC6642] Wu, Q., Xia, F., and R. Even, "RTP Control Protocol (RTCP)
Extension for a Third-Party Loss Report", RFC 6642, Extension for a Third-Party Loss Report", RFC 6642, June
June 2012. 2012.
[RFC6679] Westerlund, M., Johansson, I., Perkins, C., O'Hanlon, P., [RFC6679] Westerlund, M., Johansson, I., Perkins, C., O'Hanlon, P.,
and K. Carlberg, "Explicit Congestion Notification (ECN) and K. Carlberg, "Explicit Congestion Notification (ECN)
for RTP over UDP", RFC 6679, August 2012. for RTP over UDP", RFC 6679, August 2012.
[RFC6714] Holmberg, C., Blau, S., and E. Burger, "Connection [RFC6714] Holmberg, C., Blau, S., and E. Burger, "Connection
Establishment for Media Anchoring (CEMA) for the Message Establishment for Media Anchoring (CEMA) for the Message
Session Relay Protocol (MSRP)", RFC 6714, August 2012. Session Relay Protocol (MSRP)", RFC 6714, August 2012.
[RFC6773] Phelan, T., Fairhurst, G., and C. Perkins, "DCCP-UDP: A [RFC6773] Phelan, T., Fairhurst, G., and C. Perkins, "DCCP-UDP: A
Datagram Congestion Control Protocol UDP Encapsulation for Datagram Congestion Control Protocol UDP Encapsulation for
NAT Traversal", RFC 6773, November 2012. NAT Traversal", RFC 6773, November 2012.
[RFC6781] Gimlan, R., Evan, R., and F. Andreasen, "Session
Description Protocol (SDP) Media Capabilities
Negotiation", RFC 6781, Febrauary 2013.
[RFC6787] Burnett, D. and S. Shanmugham, "Media Resource Control [RFC6787] Burnett, D. and S. Shanmugham, "Media Resource Control
Protocol Version 2 (MRCPv2)", RFC 6787, November 2012. Protocol Version 2 (MRCPv2)", RFC 6787, November 2012.
[RTCP-FB] "S Description Protocol (SDP) RTCP Feedback attributes", < [RFC6871] Gimlan, R., Evan, R., and F. Andreasen, "Session
http://www.iana.org/assignments/sdp-parameters/ Description Protocol (SDP) Media Capabilities
Negotiation", RFC 6871, Febrauary 2013.
[RTCP-FB] "S Description Protocol (SDP) RTCP Feedback attributes",
<http://www.iana.org/assignments/sdp-parameters/
sdp-parameters.xml#sdp-parameters-14>. sdp-parameters.xml#sdp-parameters-14>.
[SSRC-GROUP] [SSRC-GROUP]
"S Description Protocol (SDP) "ssrc-group" semantics", <ht "S Description Protocol (SDP) "ssrc-group" semantics",
tp://www.iana.org/assignments/sdp-parameters/ <http://www.iana.org/assignments/sdp-parameters/
sdp-parameters.xml#sdp-parameters-17>. sdp-parameters.xml#sdp-parameters-17>.
[T.38] "Procedures for real-time Group 3 facsimile communication [T.38] "Procedures for real-time Group 3 facsimile communication
over IP networks", <http://www.itu.int/rec/T-REC-T.38/e>. over IP networks", <http://www.itu.int/rec/T-REC-T.38/e>.
Author's Address Author's Address
Suhas Nandakumar Suhas Nandakumar
Cisco Cisco
170 West Tasman Drive 170 West Tasman Drive
 End of changes. 121 change blocks. 
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