--- 1/draft-ietf-mmusic-sdp-mux-attributes-00.txt 2014-02-14 12:14:44.921639917 -0800 +++ 2/draft-ietf-mmusic-sdp-mux-attributes-01.txt 2014-02-14 12:14:45.049643047 -0800 @@ -1,30 +1,30 @@ Network Working Group S. Nandakumar Internet-Draft Cisco -Intended status: Standards Track December 11, 2013 -Expires: June 14, 2014 +Intended status: Standards Track February 14, 2014 +Expires: August 18, 2014 A Framework for SDP Attributes when Multiplexing - draft-ietf-mmusic-sdp-mux-attributes-00 + draft-ietf-mmusic-sdp-mux-attributes-01 Abstract The Session Description Protocol (SDP) provides mechanisms to describe attributes of multimedia sessions and of individual media streams (e.g., Real-time Transport Protocol (RTP) sessions) within a multimedia session. In the RTCWeb WG, there is a need to use a single 5-tuple for sending and receiving media associated with multiple media descriptions ("m=" lines). Such a requirement has raised concerns over the semantic implications of the SDP attributes - associated with the RTP Sessions multiplexed over a single transport - layer flow. + associated with the RTP Media Streams multiplexed over a single + transport layer flow. The scope of this specification is to provide a framework for analyzing the multiplexing characteristics of SDP attributes. The specification also categorizes existing attributes based on the framework described herein. Status of this Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. @@ -32,25 +32,25 @@ Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." - This Internet-Draft will expire on June 14, 2014. + This Internet-Draft will expire on August 18, 2014. Copyright Notice - Copyright (c) 2013 IETF Trust and the persons identified as the + Copyright (c) 2014 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as @@ -59,121 +59,125 @@ Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 5 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5 3. Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . 5 4. SDP Attribute Analysis Framework . . . . . . . . . . . . . . . 6 5. Analysis of Existing Attributes . . . . . . . . . . . . . . . 9 5.1. RFC4566 - SDP: Session Description Protocol . . . . . . . 10 5.2. RFC4585 - RTP/AVPF . . . . . . . . . . . . . . . . . . . . 11 5.3. RFC5761 - Multiplexing RTP and RTCP . . . . . . . . . . . 11 - 5.4. RFC4574 - SDP Label Attribute . . . . . . . . . . . . . . 11 + 5.4. RFC4574 - SDP Label Attribute . . . . . . . . . . . . . . 12 5.5. RFC5432 - QoS Mechanism Selection in SDP . . . . . . . . . 12 - 5.6. RFC4568 - SDP Security Descriptions . . . . . . . . . . . 12 + 5.6. RFC4568 - SDP Security Descriptions . . . . . . . . . . . 13 5.7. RFC5762 - RTP over DCCP . . . . . . . . . . . . . . . . . 13 5.8. RFC6773 - DCCP-UDP Encapsulation . . . . . . . . . . . . . 14 5.9. RFC5506 - Reduced-Size RTCP in RTP Profile . . . . . . . . 14 5.10. RFC6787 - Media Resource Control Protocol Version 2 . . . 15 5.11. RFC5245 - Interactive Connectivity Establishment (ICE) . . 15 - 5.12. RFC5285 - RTP Header Extensions . . . . . . . . . . . . . 16 + 5.12. RFC5285 - RTP Header Extensions . . . . . . . . . . . . . 17 5.13. RFC3605 - RTCP attribute in SDP . . . . . . . . . . . . . 17 5.14. RFC5576 - Source-Specific SDP Attributes . . . . . . . . . 17 5.15. RFC6236 - Image Attributes in SDP . . . . . . . . . . . . 18 - 5.16. RFC6285 - Rapid Acquisition of Multicast RTP Sessions . . 18 + 5.16. RFC6285 - Rapid Acquisition of Multicast RTP Sessions . . 19 5.17. RFC6230 - Media Control Channel Framework . . . . . . . . 19 5.18. RFC6364 - SDP Elements for FEC Framework . . . . . . . . . 19 5.19. RFC4796 - Content Attribute . . . . . . . . . . . . . . . 20 5.20. RFC3407 - SDP Simple Capability Declaration . . . . . . . 20 5.21. RFC6284 - Port Mapping between Unicast and Multicast RTP Sessions . . . . . . . . . . . . . . . . . . . . . . . 21 5.22. RFC6714 - MSRP-CEMA . . . . . . . . . . . . . . . . . . . 21 - 5.23. RFC4583 - SDP Format for BFCP Streams . . . . . . . . . . 21 + 5.23. RFC4583 - SDP Format for BFCP Streams . . . . . . . . . . 22 5.24. RFC5547 - SDP Offer/Answer for File Transfer . . . . . . . 22 - 5.25. RFC6489 - SDP and RTP Media Loopback Extension . . . . . . 22 + 5.25. RFC6489 - SDP and RTP Media Loopback Extension . . . . . . 23 5.26. RFC5760 - RTCP with Unicast Feedback . . . . . . . . . . . 23 - 5.27. RFC3611 - RTCP XR . . . . . . . . . . . . . . . . . . . . 23 + 5.27. RFC3611 - RTCP XR . . . . . . . . . . . . . . . . . . . . 24 5.28. RFC5939 - SDP Capability Negotiation . . . . . . . . . . . 24 - 5.29. draft-ietf-mmusic-sdp-media-capabilities . . . . . . . . . 24 - 5.30. RFC4567 - Key Management Extensions for SDP and RTSP . . . 25 + 5.29. RFC6781 - SDP Media Capabilities Negotiation . . . . . . . 25 + 5.30. RFC4567 - Key Management Extensions for SDP and RTSP . . . 26 5.31. RFC4572 - Comedia over TLS in SDP . . . . . . . . . . . . 26 - 5.32. RFC4570 - SDP Source Filters . . . . . . . . . . . . . . . 26 + 5.32. RFC4570 - SDP Source Filters . . . . . . . . . . . . . . . 27 5.33. RFC6128 - RTCP Port for Multicast Sessions . . . . . . . . 27 - 5.34. RFC6189 - ZRTP . . . . . . . . . . . . . . . . . . . . . . 27 + 5.34. RFC6189 - ZRTP . . . . . . . . . . . . . . . . . . . . . . 28 5.35. RFC4145 - Connection-Oriented Media . . . . . . . . . . . 28 - 5.36. RFC5159 - OMA BCAST SDP Attributes . . . . . . . . . . . . 28 + 5.36. RFC5159 - OMA BCAST SDP Attributes . . . . . . . . . . . . 29 5.37. RFC6193 - Media Description for IKE in SDP . . . . . . . . 29 5.38. RFC6064 - SDP and RTSP Extensions for 3GPP . . . . . . . . 30 - 5.39. RFC3108 - ATM SDP . . . . . . . . . . . . . . . . . . . . 32 - 5.40. 3GPP TS 24.182 . . . . . . . . . . . . . . . . . . . . . . 33 + 5.39. RFC3108 - ATM SDP . . . . . . . . . . . . . . . . . . . . 33 + 5.40. 3GPP TS 24.182 . . . . . . . . . . . . . . . . . . . . . . 34 5.41. 3GPP TS 24.183 . . . . . . . . . . . . . . . . . . . . . . 34 - 5.42. 3GPP TS 24.229 . . . . . . . . . . . . . . . . . . . . . . 34 - 5.43. ITU T.38 . . . . . . . . . . . . . . . . . . . . . . . . . 35 - 5.44. ITU-T H.248.15 . . . . . . . . . . . . . . . . . . . . . . 35 - 5.45. RFC4975 - The Message Session Relay Protocol . . . . . . . 36 - 5.46. Historical . . . . . . . . . . . . . . . . . . . . . . . . 37 - 6. bwtype Attribute Analysis . . . . . . . . . . . . . . . . . . 37 - 6.1. RFC4566 - SDP: Session Description Protocol . . . . . . . 37 - 6.2. RFC3556 - SDP Bandwidth Modifiers for RTCP Bandwidth . . . 38 - 6.3. RFC3890 - Bandwidth Modifier for SDP . . . . . . . . . . . 39 - 7. rtcp-fb Attribute Analysis . . . . . . . . . . . . . . . . . . 39 - 7.1. RFC4585 - RTP/AVPF . . . . . . . . . . . . . . . . . . . . 39 - 7.2. RFC5104 - Codec Control Messages in AVPF . . . . . . . . . 40 - 7.3. RFC6285 - Unicast-Based RAMS . . . . . . . . . . . . . . . 41 - 7.4. RFC6679 - ECN for RTP over UDP/IP . . . . . . . . . . . . 41 - 7.5. RFC6642 - Third-Party Loss Report . . . . . . . . . . . . 41 - 7.6. RFC5104 - Codec Control Messages in AVPF . . . . . . . . . 42 - 8. group Attribute Analysis . . . . . . . . . . . . . . . . . . . 42 - 8.1. RFC5888 - SDP Grouping Framework . . . . . . . . . . . . . 42 + 5.42. 3GPP TS 24.229 . . . . . . . . . . . . . . . . . . . . . . 35 + 5.43. ITU T.38 . . . . . . . . . . . . . . . . . . . . . . . . . 36 + 5.44. ITU-T H.248.15 . . . . . . . . . . . . . . . . . . . . . . 36 + 5.45. RFC4975 - The Message Session Relay Protocol . . . . . . . 37 + 5.46. Historical . . . . . . . . . . . . . . . . . . . . . . . . 38 + 6. bwtype Attribute Analysis . . . . . . . . . . . . . . . . . . 38 + 6.1. RFC4566 - SDP: Session Description Protocol . . . . . . . 39 + 6.2. RFC3556 - SDP Bandwidth Modifiers for RTCP Bandwidth . . . 39 + 6.3. RFC3890 - Bandwidth Modifier for SDP . . . . . . . . . . . 40 + 7. rtcp-fb Attribute Analysis . . . . . . . . . . . . . . . . . . 40 + 7.1. RFC4585 - RTP/AVPF . . . . . . . . . . . . . . . . . . . . 41 + 7.2. RFC5104 - Codec Control Messages in AVPF . . . . . . . . . 41 + 7.3. RFC6285 - Unicast-Based RAMS . . . . . . . . . . . . . . . 42 + 7.4. RFC6679 - ECN for RTP over UDP/IP . . . . . . . . . . . . 42 + 7.5. RFC6642 - Third-Party Loss Report . . . . . . . . . . . . 43 + 7.6. RFC5104 - Codec Control Messages in AVPF . . . . . . . . . 43 + 8. group Attribute Analysis . . . . . . . . . . . . . . . . . . . 44 + 8.1. RFC5888 - SDP Grouping Framework . . . . . . . . . . . . . 44 8.2. RFC3524 - Mapping Media Streams to Resource - Reservation Flows . . . . . . . . . . . . . . . . . . . . 43 - 8.3. RFC4091 - ANAT Semantics . . . . . . . . . . . . . . . . . 43 - 8.4. RFC5956 - FEC Grouping Semantics in SDP . . . . . . . . . 44 - 8.5. RFC5583 - Signaling Media Decoding Dependency in SDP . . . 44 - 9. ssrc-group Attribute Analysis . . . . . . . . . . . . . . . . 45 - 9.1. RFC5576 - Source-Specific SDP Attributes . . . . . . . . . 45 - 10. QoS Mechanism Token Analysis . . . . . . . . . . . . . . . . . 45 - 10.1. RFC5432 - QoS Mechanism Selection in SDP . . . . . . . . . 45 - 11. k= Attribute Analysis . . . . . . . . . . . . . . . . . . . . 45 - 11.1. RFC4566 SDP: Session Description Protocol . . . . . . . . 46 - 12. content Atribute Analysis . . . . . . . . . . . . . . . . . . 46 - 12.1. RFC4796 - MSRP Relays . . . . . . . . . . . . . . . . . . 46 - 13. Payload Formats . . . . . . . . . . . . . . . . . . . . . . . 46 - 13.1. RFC5109 - RTP Payload Format for Generic FEC . . . . . . . 46 - 14. Multiplexing Media Streams and DSCP Markings . . . . . . . . . 47 - 14.1. Option A . . . . . . . . . . . . . . . . . . . . . . . . . 47 - 14.2. Option B . . . . . . . . . . . . . . . . . . . . . . . . . 48 + Reservation Flows . . . . . . . . . . . . . . . . . . . . 44 + 8.3. RFC4091 - ANAT Semantics . . . . . . . . . . . . . . . . . 44 + 8.4. RFC5956 - FEC Grouping Semantics in SDP . . . . . . . . . 45 + 8.5. RFC5583 - Signaling Media Decoding Dependency in SDP . . . 45 + 9. ssrc-group Attribute Analysis . . . . . . . . . . . . . . . . 46 + 9.1. RFC5576 - Source-Specific SDP Attributes . . . . . . . . . 46 + 10. QoS Mechanism Token Analysis . . . . . . . . . . . . . . . . . 46 + 10.1. RFC5432 - QoS Mechanism Selection in SDP . . . . . . . . . 46 + 11. k= Attribute Analysis . . . . . . . . . . . . . . . . . . . . 47 + 11.1. RFC4566 SDP: Session Description Protocol . . . . . . . . 47 + 12. content Atribute Analysis . . . . . . . . . . . . . . . . . . 47 + 12.1. RFC4796 . . . . . . . . . . . . . . . . . . . . . . . . . 47 + 13. Payload Formats . . . . . . . . . . . . . . . . . . . . . . . 47 + 13.1. RFC5109 - RTP Payload Format for Generic FEC . . . . . . . 47 + 14. Multiplexing Media Streams and DSCP Markings . . . . . . . . . 48 + 14.1. Option A . . . . . . . . . . . . . . . . . . . . . . . . . 48 + 14.2. Option B . . . . . . . . . . . . . . . . . . . . . . . . . 49 - 15. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 48 - 16. Security Considerations . . . . . . . . . . . . . . . . . . . 48 - 17. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 48 - 18. Change Log . . . . . . . . . . . . . . . . . . . . . . . . . . 49 - 19. References . . . . . . . . . . . . . . . . . . . . . . . . . . 50 - 19.1. Normative References . . . . . . . . . . . . . . . . . . . 50 - 19.2. Informative References . . . . . . . . . . . . . . . . . . 50 - Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 56 + 15. Multiplexing Considerations for Encapsulating Attributes . . . 49 + 16. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 52 + 17. Security Considerations . . . . . . . . . . . . . . . . . . . 53 + 18. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 53 + 19. Change Log . . . . . . . . . . . . . . . . . . . . . . . . . . 53 + 20. References . . . . . . . . . . . . . . . . . . . . . . . . . . 54 + 20.1. Normative References . . . . . . . . . . . . . . . . . . . 54 + 20.2. Informative References . . . . . . . . . . . . . . . . . . 54 + Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 60 1. Introduction Real-Time Communication Web (RTCWeb) framework requires Real-time - Transport Protocol 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 multi-media communication sessions. SDP defines several attributes for capturing characteristics that apply to the individual media descriptions (described by "m=" lines") and the overall multimedia session. Typically different media types (audio, video etc) described using different media descriptions represent separate RTP Sessions that are carried over individual - transport layer flows. However, in the RTCWeb WG, a requirement has - arisen to multiplex several RTP Sessions over a single transport - layer flow. This in turn has made necessary to understand the - interpretation and usage of the SDP attributes defined for the + transport layer flows. However in the IETF RTCWEB WG, a need to use + a single 5-tuple for sending and receiving media associated with + multiple SDP media descriptions ("m=" lines) has been identified. + This would e.g. allow the usage of a single set of Interactive + Connectivity Establishment (ICE) [RFC5245] candidates for multiple + media descriptions. This in turn has made necessary to understand + the interpretation and usage of the SDP attributes defined for the multiplexed media descriptions. Given the number of SDP attributes registered with the IANA [IANA] and possibility of new attributes being defined in the future, there is need for generic future-proof framework to analyze these attributes for their applicability in the transport multiplexing use- cases. The document starts with providing the motivation for requiring such a framework. This is followed by introduction to the SDP attribute @@ -187,30 +191,31 @@ "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119]. 3. Motivation The time and complications of setting up ICE [RFC5245] and DTLS-SRTP [RFC5763] transports for use by RTP, and conservation of ports, forms an requirement to try and reduce the number of transport level flows needed. This has resulted in the definition of ways, such as, [I-D.ietf-mmusic-sdp-bundle-negotiation] and + [I-D.ietf-avt-multiplexing-rtp] to multiplex RTP over a single transport flow in order to preserve network resources such as port numbers. This imposes further restrictions on applicability of these SDP attributes as they are defined today. The specific problem is that there are attribute combinations which make sense when specified on independent m-lines -- as with classical SDP -- that do not make sense when those m-lines are then multiplexed over the same transport. To give an obvious example, ICE permits - each m-mline to have an independently specified ice-ufrag attribute. + each m=line to have an independently specified ice-ufrag attribute. However, if the media from multiple m-lines is multiplexed over the same ICE component, then the meaning of media-level ice-ufrag attributes becomes muddled. As of today there are close to 250 SDP attributes registered with the IANA [IANA] and more will be added in the future. There is no clearly defined procedure to establish the validity/applicability of these attribute when used with transport multiplexing. 4. SDP Attribute Analysis Framework @@ -246,51 +251,50 @@ t=0 0 m=audio 49172 RTP/AVP 99 a=sendonly a=label:1 a=rtpmap:99 iLBC/8000 m=video 49172 RTP/AVP 31 a=recvonly a=label:2 a=rtpmap:31 H261/90000 - NOT RECOMMENDED Attributes where multiplexing is not recommended if - these attributes are in use in the SDP since doing so MAY result - in incorrect behaviors + NOT RECOMMENDED Attributes that are recommended against multiplexing + since their usage under multiplexing might lead to incorrect + behavior. Example: Multiplexing media descriptions having attribute zrtp- hash defined with the media descriptions lacking it, would either - complicate the handling of multiplexed stream or fail - multiplexing. + complicate the handling of multiplexed streams or might fail + multiplexing altogether. v=0 o=bob 2890844527 2890844527 IN IP4 client.biloxi.example.com s= c=IN IP4 client.biloxi.example.com t=0 0 m=audio 3456 RTP/AVP 97 // with zrtp a=rtpmap:97 iLBC/8000 a=zrtp-hash:1.10 fe30efd02423cb054e50efd0248742ac7a52c8f91bc2 df881ae642c371ba46df m=video 34567 RTP/AVP 31 //without zrtp a=rtpmap:31 H261/90000 IDENTICAL Attributes that MUST be identical across all the media descriptions being multiplexed. Attributes such as rtcp-mux fall into this category. Since RTCP - reporting is done per RTP Session, there is no way to receive RTCP - control data for the video m=line in the example below. Hence - rtcp-mux MUST be repeated for the video m=line as well, when - multiplexed. + 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 o=bob 2890844527 2890844527 IN IP4 client.biloxi.example.com s= c=IN IP4 client.biloxi.example.com t=0 0 m=audio 34567 RTP/AVP 97 a=rtcp-mux m=video 34567 RTP/AVP 31 a=rtpmap:31 H261/90000 @@ -422,47 +426,52 @@ RFC4566 Attribute Analysis 5.2. RFC4585 - RTP/AVPF RFC4585 [RFC4585] defines an extension to the Audio-visual Profile (AVP) that enables receivers to provide, statistically, more immediate feedback to the senders and thus allows for short-term adaptation and efficient feedback-based repair mechanisms to be implemented. - +----------+-----------------------------------+-------+------------+ + +----------+-------------------------------------+-------+----------+ | Attr | Notes | Level | Category | | Name | | | | - +----------+-----------------------------------+-------+------------+ - | rtcp-fb | Repeated if the | M | IDENTICAL | - | | Codec-Configuration is same | | | - | | across all the bundled m=lines. | | | + +----------+-------------------------------------+-------+----------+ + | rtcp-fb | The combination of a particular | M | NORMAL | + | | Payload Type along with the m=line | | | + | | identify the scope and | | | + | | applicability of a given RTCP | | | + | | feedback to a particular RTP | | | + | | Stream. | | | | | | | | - +----------+-----------------------------------+-------+------------+ + +----------+-------------------------------------+-------+----------+ RFC4585 Attribute Analysis - OPEN ISSUE:Codec-Configuration needs to be defined. + Since RTCP feedback attributes are Payload Type (PT) scoped, the + usage of identical Payload Type values across multiplexed m=lines is + described in [I-D.ietf-mmusic-sdp-bundle-negotiation]. 5.3. RFC5761 - Multiplexing RTP and RTCP RFC5761 [RFC5761] discusses issues that arise when multiplexing RTP data packets and RTP Control Protocol (RTCP) packets on a single UDP port. It describes when such multiplexing is and is not appropriate, and it explains how the Session Description Protocol (SDP) can be used to signal multiplexed sessions. +-----------+----------------------------------+-------+------------+ | Name | Notes | Level | Category | +-----------+----------------------------------+-------+------------+ - | rtcp-mux | RTCP muxing should be repeated | M | IDENTICAL | - | | across all the m=lines | | | + | rtcp-mux | RTP and RTCP Multiplexing affect | M | IDENTICAL | + | | the entire RTP Session | | | | | | | | +-----------+----------------------------------+-------+------------+ RFC5761 Attribute Analysis 5.4. RFC4574 - SDP Label Attribute RFC4574 [RFC4574] defines a new Session Description Protocol (SDP) media-level attribute: "label". The "label" attribute carries a pointer to a media stream in the context of an arbitrary network @@ -481,91 +490,87 @@ RFC4574 Attribute Analysis 5.5. RFC5432 - QoS Mechanism Selection in SDP RFC5432 [RFC5432] defines procedures to negotiate QOS mechanisms using the Session Description Protocol (SDP) offer/answer model. +----------------+-------------------------------+-------+----------+ | Name | Notes | Level | Category | +----------------+-------------------------------+-------+----------+ - | qos-mech-send | Since QOS mechanism are | B | NORMAL | - | | signaled per flow, | | | - | | multiplexing multiple m=lines | | | - | | has no impact on per m=line | | | - | | QOS mechanism. | | | + | qos-mech-send | A single DSCP code point per | B | NORMAL | + | | flow being multiplexed | | | + | | doesn't impact multiplexing | | | + | | since QOS mechanisms are | | | + | | signaled/scoped per flow. | | | | | | | | - | qos-mech-recv | Since QOS mechanism are | B | NORMAL | - | | signaled per flow, | | | - | | multiplexing multiple m=lines | | | - | | has no impact on per m=line | | | - | | QOS mechanism. | | | + | qos-mech-recv | A single DSCP code point per | B | NORMAL | + | | flow being multiplexed | | | + | | doesn't impact multiplexing | | | + | | since QOS mechanisms are | | | + | | signaled/scoped per flow. | | | | | | | | +----------------+-------------------------------+-------+----------+ RFC5432 Attribute Analysis + Multiplexing consideration when multiple DSCP code points are defined + per flow can be found in Section 14 + 5.6. RFC4568 - SDP Security Descriptions RFC4568 [RFC4568] defines a Session Description Protocol (SDP) cryptographic attribute for unicast media streams. The attribute describes a cryptographic key and other parameters that serve to configure security for a unicast media stream in either a single message or a roundtrip exchange. - +---------+----------------------------------+-------+--------------+ + +--------+---------------------------------------+-------+----------+ | Name | Notes | Level | Category | - +---------+----------------------------------+-------+--------------+ - | crypto | The multiplexing scheme MUST | M | TRANSPORT | - | | ensure unique SSRCs across all | | | - | | the media lines multiplexed. In | | | - | | that case, cryptographic keys | | | - | | corresponding to the underlying | | | - | | transport is used. | | | - | | | | | - | crypto | If the multiplexing scheme | M | NOT | - | | cannot ensure unique SSRCs | | RECOMMENDED | - | | across all the media lines, | | | - | | multiplexing MUST NOT be | | | - | | performed. | | | + +--------+---------------------------------------+-------+----------+ + | crypto | Refer to section 6.2.5 of | M | SPECIAL | + | | [I-D.ietf-mmusic-sdp-bundle-negotiati | | | + | | on] | | | | | | | | - +---------+----------------------------------+-------+--------------+ + +--------+---------------------------------------+-------+----------+ RFC4568 Attribute Analysis + If the multiplexing scheme cannot ensure unique SSRCs across all the + media lines, multiplexing MUST NOT be performed. + 5.7. RFC5762 - RTP over DCCP The Real-time Transport Protocol (RTP) is a widely used transport for real-time multimedia on IP networks. The Datagram Congestion Control Protocol (DCCP) is a transport protocol that provides desirable services for real-time applications. RFC5762 [RFC5762] specifies a mapping of RTP onto DCCP, along with associated signaling, such that real-time applications can make use of the services provided by DCCP +--------------------+---------------------+---------+--------------+ | Name | Notes | Current | Category | +--------------------+---------------------+---------+--------------+ | dccp-service-code | If RFC 6773 is not | M | NOT | | | being used in | | RECOMMENDED | - | | addition to RFC | | | - | | 5762, the port in | | | - | | the m= line is a | | | + | | addition to | | | + | | RFC5762, the port | | | + | | in the m= line is a | | | | | DCCP port. DCCP | | | | | being a connection | | | | | oriented protocol, | | | | | does not allow | | | | | multiple | | | | | connections on the | | | | | same 5-tuple. | | | | | | | | +--------------------+---------------------+---------+--------------+ - RFC5762 Attribute Analysis If RFC 6773 is being used in addition to RFC 5762 and provided that DCCP-in-UDP layer has additional demultiplexing, then it may be possible to use different DCCP service codes for each DCCP flow, given each uses a different DCCP port. Although doing so might conflict with the media type of the m= line. None of this is standardized yet and it wouldn't work as explained. Hence multiplexing MUST NOT be performed even in this alternate scenario. @@ -584,32 +589,43 @@ | | performed due to potential | | RECOMMENDED | | | conflict between the port | | | | | used for DCCP | | | | | en/decapsulation and the | | | | | RTP. | | | | | | | | +------------+-------------------------------+-------+--------------+ RFC6773 Attribute Analysis + Since RFC6773 is about tunnelling DCCP in UDP, with the UDP port + being the port of the DCCP en-/de-capsulation service. This + encapsulation allows arbitrary DCCP packets to be encapsulated and + the DCCP port choosen MAY conflict with the port chosen for the RTP + traffic. + + For multiplexing several DCCP-in-UDP encapsulations on the same UDP + port, with no RTP traffic on the same port implies collapsing several + DCCP port spaces together. This MAY or MAY NOT work depending on the + nature of DCCP encapsulations and ports choses thus rendering it to + be very application dependant. + 5.9. RFC5506 - Reduced-Size RTCP in RTP Profile RFC5506 [RFC5506] discusses benefits and issues that arise when allowing Real-time Transport Protocol (RTCP) packets to be transmitted with reduced size. +-------------+--------------------------------+-------+------------+ | Name | Notes | Level | Category | +-------------+--------------------------------+-------+------------+ - | rtcp-rsize | RTCP reduced size MUST be | M | IDENTICAL | - | | repeated across all the | | | - | | m=lines | | | + | rtcp-rsize | Reduced size RTCP affects the | M | IDENTICAL | + | | entire RTP Session | | | | | | | | +-------------+--------------------------------+-------+------------+ RFC5506 Attribute Analysis 5.10. RFC6787 - Media Resource Control Protocol Version 2 The Media Resource Control Protocol Version 2 (MRCPv2) allows client hosts to control media service resources such as speech synthesizers, recognizers, verifiers, and identifiers residing in servers on the @@ -625,22 +641,20 @@ speech resource server. RFC6787 [RFC6787] defines attributes for this purpose. +-----------+---------------+-------+----------+ | Name | Notes | Level | Category | +-----------+---------------+-------+----------+ | resource | Not Impacted | M | NORMAL | | | | | | | channel | Not Impacted | M | NORMAL | | | | | | - | | Not Impacted | M | NORMAL | - | | | | | +-----------+---------------+-------+----------+ RFC6787 Attribute Analysis 5.11. RFC5245 - Interactive Connectivity Establishment (ICE) RFC5245 [RFC5245] describes a protocol for Network Address Translator(NAT) traversal for UDP-based multimedia sessions established with the offer/answer model. This protocol is called Interactive Connectivity Establishment (ICE). ICE makes use of the @@ -649,39 +663,49 @@ protocol utilizing the offer/answer model, such as the Session Initiation Protocol (SIP). +--------------------+-------------------------+-------+------------+ | Name | Notes | Level | Category | +--------------------+-------------------------+-------+------------+ | ice-lite | Not Impacted | S | NORMAL | | | | | | | ice-options | Not Impacted | S | NORMAL | | | | | | - | ice-pwd | Per media-level | B | TRANSPORT | - | | attribute MUST be used | | | - | | per underlying | | | - | | transport flow | | | + | ice-pwd | ice-pwd MUST be the one | B | TRANSPORT | + | | that corresponds to the | | | + | | m=line chosen for | | | + | | setting up the | | | + | | underlying transport | | | + | | flow | | | | | | | | - | ice-ufrag | Per media-level | B | TRANSPORT | - | | attribute MUST be used | | | - | | per underlying | | | - | | transport flow | | | + | ice-ufrag | ice-ufrag MUST be the | B | TRANSPORT | + | | one that corresponds to | | | + | | the m=line chosen for | | | + | | setting up the | | | + | | underlying transport | | | + | | flow | | | | | | | | - | candidate | Per media-level | M | TRANSPORT | - | | attribute MUST be used | | | - | | per underlying | | | - | | transport flow | | | + | candidate | ice candidate MUST be | M | TRANSPORT | + | | the one that | | | + | | corresponds to the | | | + | | m=line chosen for | | | + | | setting up the | | | + | | underlying transport | | | + | | flow | | | | | | | | - | remote-candidates | Per media-level | M | TRANSPORT | - | | attribute MUST be used | | | - | | per underlying | | | - | | transport flow | | | + | remote-candidates | ice remote candidate | M | TRANSPORT | + | | MUST be the one that | | | + | | corresponds to the | | | + | | m=line chosen for | | | + | | setting up the | | | + | | underlying transport | | | + | | flow | | | | | | | | +--------------------+-------------------------+-------+------------+ RFC5245 Attribute Analysis 5.12. RFC5285 - RTP Header Extensions RFC5285 [RFC5285] provides a general mechanism to use the header extension feature of RTP (the Real-Time Transport Protocol). It provides the option to use a small number of small extensions in each @@ -700,66 +725,64 @@ 5.13. RFC3605 - RTCP attribute in SDP Originally, SDP assumed that RTP and RTCP were carried on consecutive ports. However, this is not always true when NATs are involved. [RFC3605] specifies an early mechanism to indicate the RTCP port. +-------+--------------------------------------+-------+------------+ | Name | Notes | Level | Category | +-------+--------------------------------------+-------+------------+ - | rtcp | Case1:Same RTCP port is repeated | M | TRANSPORT | - | | across the m=lines. Case2:Different | | | - | | RTCP ports renders multiplexing | | | - | | impossible | | | + | rtcp | Identical attribute value MUST be | M | IDENTICAL | + | | used since the RTCP port affects the | | | + | | entire RTP session. | | | | | | | | +-------+--------------------------------------+-------+------------+ RFC3605 Attribute Analysis 5.14. RFC5576 - Source-Specific SDP Attributes RFC5576 [RFC5576] defines a mechanism to describe RTP media sources, which are identified by their synchronization source (SSRC) identifiers, in SDP, to associate attributes with these sources, and to express relationships among sources. It also defines several source-level attributes that can be used to describe properties of media sources. - +----------------+---------------------------+-------+--------------+ + +----------------+-------------------------------+-------+----------+ | Name | Notes | Level | Category | - +----------------+---------------------------+-------+--------------+ - | ssrc | | M | NOT | - | | | | RECOMMENDED | + +----------------+-------------------------------+-------+----------+ + | ssrc | Refer to Notes below | M | SPECIAL | | | | | | - | ssrc-group | Refer to section | M | SPECIAL | - | | Section 9 for specific | | | - | | analysis of the grouping | | | - | | semantics | | | + | ssrc-group | Refer to section Section 9 | M | SPECIAL | + | | for specific analysis of the | | | + | | grouping semantics | | | | | | | | - | cname | Not Impacted [Open | SR | NORMAL | - | | Issues: what are the | | | - | | rules for CNAME | | | + | cname | Not Impacted [Open Issues: | SR | NORMAL | + | | what are the rules for CNAME | | | | | duplication across | | | | | sessions?] | | | | | | | | - | previous-ssrc | SSSRCs,if repeated across | SR | NOT | - | | bundled m=lines, it MUST | | RECOMMENDED | - | | represent the same | | | - | | underlying RTP stream | | | + | previous-ssrc | Refer to notes below | SR | SPECIAL | | | | | | | fmtp | Not Impacted | SR | NORMAL | | | | | | - +----------------+---------------------------+-------+--------------+ + +----------------+-------------------------------+-------+----------+ RFC5576 Attribute Analysis + If SSRCs are repeated across m=lines being multiplexed, they MUST all + represent the same underlying RTP Source. For more details on + implications of SSRC values with in the context of multiplexing + please refer to [I-D.ietf-mmusic-sdp-bundle-negotiation] + 5.15. RFC6236 - Image Attributes in SDP RFC6236 [RFC6236] proposes a new generic session setup attribute to 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 hand-held terminal to display video without the need to rescale the image,something that may consume large amounts of memory and processing power. The document also helps to maintain an optimal bitrate for video as only the image size that is desired by the receiver is transmitted. @@ -853,38 +877,34 @@ +----------+---------------+-------+----------+ RFC4796 Attribute Analysis 5.20. RFC3407 - SDP Simple Capability Declaration RFC3407 [RFC3407] defines a set of Session Description Protocol (SDP) attributes that enables SDP to provide a minimal and backwards compatible capability declaration mechanism. - +----------+-------------------------------------+-------+----------+ + +----------+----------------------+-------+----------+ | Name | Notes | Level | Category | - +----------+-------------------------------------+-------+----------+ + +----------+----------------------+-------+----------+ | sqn | Not Impacted | B | NORMAL | | | | | | - | csdc | Mismatch in the offered capability | B | TBD | - | | description MAY fail multiplexing. | | | + | csdc | Not Impacted. | B | NORMAL | | | | | | - | cpar | Mismatch in the offered capability | B | TBD | - | | parameters MAY fail multiplexing. | | | + | cpar | Refer to Section 15 | B | SPECIAL | | | | | | - | cparmin | Mismatch in the offered capability | B | TBD | - | | parameters MAY fail multiplexing. | | | + | cparmin | Refer to Section 15 | B | SPECIAL | | | | | | - | cparmax | Mismatch in the offered capability | B | TBD | - | | parameters MAY fail multiplexing. | | | + | cparmax | Refer to Section 15 | B | SPECIAL | | | | | | - +----------+-------------------------------------+-------+----------+ + +----------+----------------------+-------+----------+ RFC3407 Attribute Analysis 5.21. RFC6284 - Port Mapping between Unicast and Multicast RTP Sessions RFC6284 [RFC6284] presents a port mapping solution that allows RTP receivers to choose their own ports for an auxiliary unicast session in RTP applications using both unicast and multicast services. The solution provides protection against denial-of-service or packet amplification attacks that could be used to cause one or more RTP @@ -922,60 +942,58 @@ +------------+---------------+-------+----------+ RFC6714 Attribute Analysis 5.23. RFC4583 - SDP Format for BFCP Streams RFC4583 [RFC4583] document specifies how to describe Binary Floor Control Protocol (BFCP) streams in Session Description Protocol (SDP) descriptions. User agents using the offer/answer model to establish BFCP streams use this format in their offers and answers - +------------+-------------------------------+-------+--------------+ + + +------------+---------------------------------+-------+------------+ | Name | Notes | Level | Category | - +------------+-------------------------------+-------+--------------+ - | floorctrl | Must be repeated across all | M | IDENTICAL | - | | the multiplexed m=lines | | | + +------------+---------------------------------+-------+------------+ + | floorctrl | Must be repeated across all the | M | IDENTICAL | + | | multiplexed m=lines | | | | | | | | | confid | Not Impacted | M | NORMAL | | | | | | | userid | Not Impacted | M | NORMAL | | | | | | - | floorid | The floorid MUST be unique | M | NOT | - | | across the multiplexed | | RECOMMENDED | - | | m=lines | | | + | floorid | The floorid MUST be globally | M | NORMAL | + | | unique | | | | | | | | - +------------+-------------------------------+-------+--------------+ + +------------+---------------------------------+-------+------------+ RFC4583 Attribute Analysis 5.24. RFC5547 - SDP Offer/Answer for File Transfer RFC5547 [RFC5547] provides a mechanism to negotiate the transfer of one or more files between two endpoints by using the Session Description Protocol (SDP) offer/answer model specified in [RFC3264]. - +--------------------------------+---------------+-------+----------+ + +----------------------+---------------+-------+----------+ | Name | Notes | Level | Category | - +--------------------------------+---------------+-------+----------+ + +----------------------+---------------+-------+----------+ | file-selector | Not Impacted | M | NORMAL | | | | | | | file-transfer-id | Not Impacted | M | NORMAL | | | | | | | file-disposition | Not Impacted | M | NORMAL | | | | | | - | file-date,file-iconfile-range | Not Impacted | M | NORMAL | - | | | | | - | file-iconfile-range | Not Impacted | M | NORMAL | + | file-date | Not Impacted | M | NORMAL | | | | | | | file-iconfile-range | Not Impacted | M | NORMAL | | | | | | - +--------------------------------+---------------+-------+----------+ + +----------------------+---------------+-------+----------+ RFC5547 Attribute Analysis 5.25. RFC6489 - SDP and RTP Media Loopback Extension [MEDIA_LOOPBACK] adds new SDP media types and attributes, which enable establishment of media sessions where the media is looped back to the transmitter. Such media sessions will serve as monitoring and troubleshooting tools by providing the means for measurement of more advanced VoIP, Real-time Text and Video over IP performance metrics. @@ -1016,88 +1034,81 @@ RFC5760 Attribute Analysis 5.27. RFC3611 - RTCP XR RFC3611 [RFC3611] defines the Extended Report (XR) packet type for the RTP Control Protocol (RTCP), and defines how the use of XR packets can be signaled by an application if it employs the Session Description Protocol (SDP). - +----------+-----------------------------------+-------+------------+ + +----------+---------------+-------+----------+ | Name | Notes | Level | Category | - +----------+-----------------------------------+-------+------------+ - | rtcp-xr | The attribute MUST be reported | B | IDENTICAL | - | | across all m=lines multiplexed | | | + +----------+---------------+-------+----------+ + | rtcp-xr | Not Impacted | B | NORMAL | | | | | | - +----------+-----------------------------------+-------+------------+ + +----------+---------------+-------+----------+ RFC3611 Attribute Analysis 5.28. RFC5939 - SDP Capability Negotiation RFC5939 [RFC5939] defines a general SDP Capability Negotiation framework. It also specifies how to provide attributes and transport protocols as capabilities and negotiate them using the framework. Extensions for other types of capabilities (e.g., media types and media formats) may be provided in other documents. - +-------+--------------------------------------+-------+------------+ + +-------+-------------------------------+-------+----------+ | Name | Notes | Level | Category | - +-------+--------------------------------------+-------+------------+ - | pcfg | Depends on capability being | M | SPECIAL | - | | negotiated | | | + +-------+-------------------------------+-------+----------+ + | pcfg | Refer to section Section 15 | M | SPECIAL | | | | | | - | acfg | Depends on capability being | M | SPECIAL | - | | negotiated | | | + | acfg | Refer to section Section 15 | M | SPECIAL | | | | | | - | csup | Depends on capability being | B | SPECIAL | - | | negotiated | | | + | csup | Not Impacted | B | NORMAL | | | | | | - | creq | Depends on capability being | B | SPECIAL | - | | negotiateds | | | + | creq | Not Impacted | B | NORMAL | | | | | | - | acap | Depends on capability being | B | SPECIAL | - | | negotiated | | | + | acap | Refer to section Section 15 | B | SPECIAL | | | | | | - | tcap | Repeat transport capability across | B | IDENTICAL | - | | all m= lines | | | + | tcap | Refer to section Section 15 | B | SPECIAL | | | | | | - +-------+--------------------------------------+-------+------------+ + +-------+-------------------------------+-------+----------+ RFC5939 Attribute Analysis -5.29. draft-ietf-mmusic-sdp-media-capabilities +5.29. RFC6781 - SDP Media Capabilities Negotiation Session Description Protocol (SDP) capability negotiation provides a general framework for indicating and negotiating capabilities in SDP. The base framework defines only capabilities for negotiating - transport protocols and attributes. [MEDIA_CAP] extends the - framework by defining media capabilities that can be used to - negotiate media types and their associated parameters. + transport protocols and attributes. [RFC6781] extends the framework + by defining media capabilities that can be used to negotiate media + types and their associated parameters. - +--------+---------------+-------+----------+ + +---------+------------------------------+-------+----------+ | Name | Notes | Level | Category | - +--------+---------------+-------+----------+ + +---------+------------------------------+-------+----------+ | rmcap | Not Impacted | B | NORMAL | | | | | | | omcap | Not Impacted | B | NORMAL | | | | | | | mfcap | Not Impacted | B | NORMAL | | | | | | - | mscap | Not Impacted | B | NORMAL | + | mscap | Refer to section Section 15 | B | SPECIAL | | | | | | - | lcfg | Not Impacted | B | NORMAL | + | lcfg | Refer to section Section 15 | B | SPECIAL | | | | | | - | secap | Not Impacted | S | NORMAL | + | sescap | Not Impacted | S | NORMAL | | | | | | - +--------+---------------+-------+----------+ + +---------+------------------------------+-------+----------+ draft-ietf-mmusic-sdp-media-capabilities Attribute Analysis 5.30. RFC4567 - Key Management Extensions for SDP and RTSP RFC4567 [RFC4567] defines general extensions for Session Description Protocol (SDP) and Real Time Streaming Protocol (RTSP) to carry messages, as specified by a key management protocol, in order 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 @@ -1123,43 +1134,44 @@ defines a new SDP protocol identifier, 'TCP/TLS'. It also defines the syntax and semantics for an SDP 'fingerprint' attribute that identifies the certificate that will be presented for the TLS session. This mechanism allows media transport over TLS connections to be established securely, so long as the integrity of session descriptions is assured. +--------------+-------------------------------+-------+------------+ | Name | Notes | Level | Category | +--------------+-------------------------------+-------+------------+ - | fingerprint | Fingerprint value MUST be | B | IDENTICAL | - | | identical across all the | | | - | | m=lines | | | + | fingerprint | Fingerprint value from the | B | TRANSPORT | + | | m=line defining the | | | + | | underlying transport is | | | + | | chosen | | | | | | | | +--------------+-------------------------------+-------+------------+ RFC4572 Attribute Analysis 5.32. RFC4570 - SDP Source Filters RFC4570 [RFC4570] describes how to adapt the Session Description Protocol (SDP) to express one or more source addresses as a source filter for one or more destination "connection" addresses. It defines the syntax and semantics for an SDP "source-filter" attribute that may reference either IPv4 or IPv6 address(es) as either an inclusive or exclusive source list for either multicast or unicast destinations. In particular, an inclusive source-filter can be used to specify a Source-Specific Multicast (SSM) session +----------------+-----------------------------+-------+------------+ | Name | Notes | Level | Category | +----------------+-----------------------------+-------+------------+ - | source-filter | he attribute MUST be | B | IDENTICAL | + | source-filter | The attribute MUST be | B | IDENTICAL | | | repeated across all m=lines | | | | | multiplexed | | | | | | | | +----------------+-----------------------------+-------+------------+ RFC4570 Attribute Analysis 5.33. RFC6128 - RTCP Port for Multicast Sessions The Session Description Protocol (SDP) has an attribute that allows @@ -1226,48 +1238,48 @@ RFC4145 [RFC4145] describes how to express media transport over TCP using the Session Description Protocol (SDP). It defines the SDP 'TCP' protocol identifier, the SDP 'setup' attribute, which describes the connection setup procedure, and the SDP 'connection' attribute, which handles connection reestablishment. +-------------+--------------------------------+-------+------------+ | Name | Notes | Level | Category | +-------------+--------------------------------+-------+------------+ - | setup | Should be identical across all | B | IDENTICAL | + | setup | MUST be identical across all | B | IDENTICAL | | | m=lines | | | | | | | | - | connection | Should be identical across all | B | IDENTICAL | + | connection | MUST be identical across all | B | IDENTICAL | | | m=lines | | | | | | | | +-------------+--------------------------------+-------+------------+ RFC4145 Attribute Analysis 5.36. RFC5159 - OMA BCAST SDP Attributes RFC5159 [RFC5159] provides descriptions of Session Description Protocol (SDP) attributes used by the Open Mobile Alliance's Broadcast Service and Content Protection specification. - +---------------------+-------+-------+----------+ + +---------------------+---------------+-------+----------+ | Name | Notes | Level | Category | - +---------------------+-------+-------+----------+ - | bcastversion | | S | TBD | + +---------------------+---------------+-------+----------+ + | bcastversion | Not Impacted | S | NORMAL | | | | | | - | stkmstream | | B | TBD | + | stkmstream | Not Impacted | B | NORMAL | | | | | | - | SRTPAuthentication | | M | TBD | + | SRTPAuthentication | Not Impacted | M | NORMAL | | | | | | - | SRTPROCTxRate | | M | TBD | + | SRTPROCTxRate | Not Impacted | M | NORMAL | | | | | | - +---------------------+-------+-------+----------+ + +---------------------+---------------+-------+----------+ RFC5159 Attribute Analysis 5.37. RFC6193 - Media Description for IKE in SDP RFC6193 [RFC6193] specifies how to establish a media session that represents a virtual private network using the Session Initiation Protocol for the purpose of on-demand media/application sharing between peers. It extends the protocol identifier of the Session Description Protocol (SDP) so that it can negotiate use of the @@ -1301,157 +1313,186 @@ m=lines will use only one IPSec association for all of the m= lines. 5.38. RFC6064 - SDP and RTSP Extensions for 3GPP The Packet-switched Streaming Service (PSS) and the Multimedia Broadcast/Multicast Service (MBMS) defined by 3GPP use the Session Description Protocol (SDP) and Real Time Streaming Protocol (RTSP) with some extensions. RFC6064 [RFC6064] provides information about these extensions and registers the RTSP and SDP extensions with IANA. - +-----------------------+----------------------+------+-------------+ - | Name | Notes | Leve | Category | - | | | l | | - +-----------------------+----------------------+------+-------------+ - | X-predecbufsize | Case1:Aggregate | M | NOT | - | | total when video | | RECOMMENDED | - | | m-lines are | | | - | | muxed Case2:Multiple | | | - | | xing with audio | | | - | | m=lines is invalid | | | + +-------------------------------+------------+-------+--------------+ + | Name | Notes | Level | Category | + +-------------------------------+------------+-------+--------------+ + | X-predecbufsize | Refer to | M | NOT | + | | notes | | RECOMMENDED | + | | below | | | | | | | | - | X-initpredecbufperiod | Case1:Aggregate | M | NOT | - | | total when video | | RECOMMENDED | - | | m-lines are | | | - | | muxed Case2:Multiple | | | - | | xing with audio | | | - | | m=lines is invalid | | | + | X-initpredecbufperiod | Refer to | M | NOT | + | | notes | | RECOMMENDED | + | | below | | | | | | | | - | X-initpostdecbufperio | Case1:Aggregate | M | NOT | - | d | total when video | | RECOMMENDED | - | | m-lines are | | | - | | muxed Case2:Multiple | | | - | | xing with audio | | | - | | m=lines is invalid | | | + | X-initpostdecbufperiod | Refer to | M | NOT | + | | notes | | RECOMMENDED | + | | below | | | | | | | | - | X-decbyterate | Case1:Aggregate | M | NOT | - | | total when video | | RECOMMENDED | - | | m-lines are | | | - | | muxed Case2:Multiple | | | - | | xing with audio | | | - | | m=lines is invalid | | | + | X-decbyterate | Refer to | M | NOT | + | | notes | | RECOMMENDED | + | | below | | | | | | | | - | 3gpp-videopostdecbufs | Case1:Aggregate | M | NOT | - | ize | total when video | | RECOMMENDED | - | | m-lines are muxed. | | | - | | Case2:Multiplexing | | | - | | with audio m=lines | | | - | | is invalid | | | + | 3gpp-videopostdecbufsize | Refer to | M | NOT | + | | notes | | RECOMMENDED | + | | below | | | | | | | | - | framesize | Not Impacted | M | NORMAL | + | framesize | Refer to | M | NOT | + | | notes | | RECOMMENDED | + | | below | | | | | | | | - | 3GPP-Integrity-Key | Not Impacted | S | NORMAL | + | 3GPP-Integrity-Key | Refer to | S | NOT | + | | notes | | RECOMMENDED | + | | below | | | | | | | | - | 3GPP-SRTP-Config | Same config SHALL | M | NORMAL | - | | apply to all the | | | - | | m=lines multiplexed | | | + | 3GPP-SRTP-Config | Refer to | M | NOT | + | | notes | | RECOMMENDED | + | | below | | | | | | | | - | alt,alt-default-id | Specifying alternate | M | TBD | - | | m=lines when session | | | - | | with mulitple | | | - | | m=lines of different | | | - | | types cannot be | | | - | | clearly specified | | | + | alt,alt-default-id | Refer to | M | NOT | + | | notes | | RECOMMENDED | + | | below | | | | | | | | - | alt-group | Complicates | M | TBD | - | | selection of | | | - | | alternate m=lines | | | - | | grouped with | | | - | | alt-group on | | | - | | mulitplexing | | | + | alt-group | Refer to | M | NOT | + | | notes | | RECOMMENDED | + | | below | | | | | | | | - | 3GPP-Adaptation-Suppo | | M | TBD | - | rt | | | | + | 3GPP-Adaptation-Support | Refer to | M | NOT | + | | notes | | RECOMMENDED | + | | below | | | | | | | | - | 3GPP-QoE-Metricsn | | B | TBD | + | 3GPP-Asset-Informatio | Refer to | B | NOT | + | | notes | | RECOMMENDED | + | | below | | | | | | | | - | 3GPP-Asset-Informatio | | B | TBD | + | mbms-mode | Refer to | B | NOT | + | | notes | | RECOMMENDED | + | | below | | | | | | | | + | mbms-flowid | MRefer to | M | NOT | + | | notes | | RECOMMENDED | + | | below | | | | | | | | - | mbms-mode | | B | TBD | + | mbms-repair | Refer to | B | NOT | + | | notes | | RECOMMENDED | + | | below | | | | | | | | - | mbms-flowid | Multiplexing | M | TBD | - | | multiple m=lines | | | - | | complicates FEC | | | - | | mappings to the | | | - | | transport | | | - | | addresses. | | | + | 3GPP-QoE-Metrics:Corruption | Refer to | M | NOT | + | duration | notes | | RECOMMENDED | + | | below | | | | | | | | - | mbms-repair | | B | TBD | + | 3GPP-QoE-Metrics:Rebuffering | Refer to | M | NOT | + | duration | notes | | RECOMMENDED | + | | below | | | | | | | | - +-----------------------+----------------------+------+-------------+ + | 3GPP-QoE-Metrics:Initial | Refer to | M | NOT | + | buffering duration | notes | | RECOMMENDED | + | | below | | | + | | | | | + | 3GPP-QoE-Metrics:Successive | Refer to | M | NOT | + | loss of RTP packets | notes | | RECOMMENDED | + | | below | | | + | | | | | + | 3GPP-QoE-Metrics:Frame rate | Refer to | M | NOT | + | deviation | notes | | RECOMMENDED | + | | below | | | + | | | | | + | 3GPP-QoE-Metrics:Jitter | Refer to | M | NOT | + | duration | notes | | RECOMMENDED | + | | 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] defines SDP attributes that are applicable in the + declarative usage of SDP alone. For purposes of this document, only + the Offer/Answer usage of SDP is considered as mandated by + + [I-D.ietf-mmusic-sdp-bundle-negotiation]. + 5.39. RFC3108 - ATM SDP RFC3108 [RFC3108] describes conventions for using the Session Description Protocol (SDP) described for controlling ATM Bearer Connections, and any associated ATM Adaptation Layer (AAL) +------------------------+--------------+-------+----------+ | Name | Notes | Level | Category | +------------------------+--------------+-------+----------+ - | aalType | NOT IMPACTED | B | NORMAL | - | eecid | NOT IMPACTED | B | NORMAL | - | aalType | NOT IMPACTED | B | NORMAL | - | capability | NOT IMPACTED | B | NORMAL | - | qosClass | NOT IMPACTED | B | NORMAL | - | bcob | NOT IMPACTED | B | NORMAL | - | stc | NOT IMPACTED | B | NORMAL | - | upcc | NOT IMPACTED | B | NORMAL | - | atmQOSparms | NOT IMPACTED | B | NORMAL | - | atmTrfcDesc | NOT IMPACTED | B | NORMAL | - | abrParms | NOT IMPACTED | B | NORMAL | - | abrSetup | NOT IMPACTED | B | NORMAL | - | bearerType | NOT IMPACTED | B | NORMAL | - | lij | NOT IMPACTED | B | NORMAL | - | anycast | NOT IMPACTED | B | NORMAL | - | cache | NOT IMPACTED | B | NORMAL | - | bearerSigIE | NOT IMPACTED | B | NORMAL | - | aalApp | NOT IMPACTED | B | NORMAL | - | cbrRate | NOT IMPACTED | B | NORMAL | - | sbc | NOT IMPACTED | B | NORMAL | - | clkrec | NOT IMPACTED | B | NORMAL | - | fec | NOT IMPACTED | B | NORMAL | - | prtfl | NOT IMPACTED | B | NORMAL | - | structure | NOT IMPACTED | B | NORMAL | - | cpsSDUsize | NOT IMPACTED | B | NORMAL | - | aal2CPS | NOT IMPACTED | B | NORMAL | - | aal2CPSSDUrate | NOT IMPACTED | B | NORMAL | - | aal2sscs3661unassured | NOT IMPACTED | B | NORMAL | - | aal2sscs3661assured | NOT IMPACTED | B | NORMAL | - | aal2sscs3662 | NOT IMPACTED | B | NORMAL | - | aal5sscop | NOT IMPACTED | B | NORMAL | - | atmmap | NOT IMPACTED | B | NORMAL | - | silenceSupp | NOT IMPACTED | B | NORMAL | - | ecan | NOT IMPACTED | B | NORMAL | - | gc | NOT IMPACTED | B | NORMAL | - | profileDesc | NOT IMPACTED | B | NORMAL | - | vsel | NOT IMPACTED | B | NORMAL | - | dsel | NOT IMPACTED | B | NORMAL | - | fsel | NOT IMPACTED | B | NORMAL | - | onewaySel | NOT IMPACTED | B | NORMAL | - | codecconfig | NOT IMPACTED | B | NORMAL | - | isup_usi | NOT IMPACTED | B | NORMAL | - | isup_usi | NOT IMPACTED | B | NORMAL | - | chain | NOT IMPACTED | B | NORMAL | + | aalType | Not Impacted | B | NORMAL | + | eecid | Not Impacted | B | NORMAL | + | aalType | Not Impacted | B | NORMAL | + | capability | Not Impacted | B | NORMAL | + | qosClass | Not Impacted | B | NORMAL | + | bcob | Not Impacted | B | NORMAL | + | stc | Not Impacted | B | NORMAL | + | upcc | Not Impacted | B | NORMAL | + | atmQOSparms | Not Impacted | B | NORMAL | + | atmTrfcDesc | Not Impacted | B | NORMAL | + | abrParms | Not Impacted | B | NORMAL | + | abrSetup | Not Impacted | B | NORMAL | + | bearerType | Not Impacted | B | NORMAL | + | lij | Not Impacted | B | NORMAL | + | anycast | Not Impacted | B | NORMAL | + | cache | Not Impacted | B | NORMAL | + | bearerSigIE | Not Impacted | B | NORMAL | + | aalApp | Not Impacted | B | NORMAL | + | cbrRate | Not Impacted | B | NORMAL | + | sbc | Not Impacted | B | NORMAL | + | clkrec | Not Impacted | B | NORMAL | + | fec | Not Impacted | B | NORMAL | + | prtfl | Not Impacted | B | NORMAL | + | structure | Not Impacted | B | NORMAL | + | cpsSDUsize | Not Impacted | B | NORMAL | + | aal2CPS | Not Impacted | B | NORMAL | + | aal2CPSSDUrate | Not Impacted | B | NORMAL | + | aal2sscs3661unassured | Not Impacted | B | NORMAL | + | aal2sscs3661assured | Not Impacted | B | NORMAL | + | aal2sscs3662 | Not Impacted | B | NORMAL | + | aal5sscop | Not Impacted | B | NORMAL | + | atmmap | Not Impacted | B | NORMAL | + | silenceSupp | Not Impacted | B | NORMAL | + | ecan | Not Impacted | B | NORMAL | + | gc | Not Impacted | B | NORMAL | + | profileDesc | Not Impacted | B | NORMAL | + | vsel | Not Impacted | B | NORMAL | + | dsel | Not Impacted | B | NORMAL | + | fsel | Not Impacted | B | NORMAL | + | onewaySel | Not Impacted | B | NORMAL | + | codecconfig | Not Impacted | B | NORMAL | + | isup_usi | Not Impacted | B | NORMAL | + | isup_usi | Not Impacted | B | NORMAL | + | chain | Not Impacted | B | NORMAL | | | | | | +------------------------+--------------+-------+----------+ RFC3108 Attribute Analysis RFC3108 describes conventions for using the Session Description Protocol (SDP) for characterizing ATM bearer connections using an AAL1, AAL2 or AAL5 adaptation layers. For AAL1, AAL2 and AAL5, bearer connections can be used to transport single media streams. In addition, for AAL1 and AAL2, multiple media streams may be @@ -1613,87 +1653,93 @@ | path | Not Impacted | M | NORMAL | | | | | | +-----------------------+---------------+-------+----------+ RFC4975 Attribute Analysis 5.46. Historical This section specifies analysis for the attributes that are included for historic usage alone by the [IANA]. - +---------------------+-----------------+---------------+----------+ + +---------------------+--------------+---------------+--------------+ | Name | Notes | Level | Category | - +---------------------+-----------------+---------------+----------+ - | rtpred1 | Not Applicable | Not-Applcable | TBD | + +---------------------+--------------+---------------+--------------+ + | rtpred1 | Historic | Not-Applcable | NOT | + | | attributes. | | RECOMMENDED | | | | | | - | rtpred2 | Not Applicable | Not-Applcable | TBD | + | rtpred2 | Historic | Not-Applcable | NOT | + | | attributes. | | RECOMMENDED | | | | | | - | PSCid | Not Applicable | Not-Applcable | TBD | + | PSCid | Not | Not-Applcable | TBD | + | | Applicable | | | | | | | | - | bc_service | Not Applicable | Not-Applcable | TBD | + | bc_service | Not | Not-Applcable | TBD | + | | Applicable | | | | | | | | - | bc_program | Not Applicable | Not-Applcable | TBD | + | bc_program | Not | Not-Applcable | TBD | + | | Applicable | | | | | | | | - | bc_service_package | Not Applicable | Not-Applcable | TBD | + | bc_service_package | Not | Not-Applcable | TBD | + | | Applicable | | | | | | | | - +---------------------+-----------------+---------------+----------+ + +---------------------+--------------+---------------+--------------+ Unknowns Attribute Analysis 6. bwtype Attribute Analysis This section specifies handling of specific bandwidth attributes when used in multiplexing scenarios. 6.1. RFC4566 - SDP: Session Description Protocol +------------+-----------------------------------+-------+----------+ | Name | Notes | Level | Category | +------------+-----------------------------------+-------+----------+ | bwtype:CT | Aggregate bandwidth for the | S | NORMAL | | | conference | | | | | | | | - | bwtype:AS | There are 2 interpretations for | B | NORMAL, | - | | this attribute As a session | | SUM | - | | attribute, it specifies the | | | - | | session aggregate unless | | | - | | media-level b=RR and/or b=RS | | | - | | attributes are used. Under this | | | - | | interpretation the multiplexing | | | - | | scheme has no impact and belongs | | | - | | to NORMAL category. For the | | | - | | media level usage, the aggregate | | | - | | of individual bandwidth values is | | | - | | considered. | | | + | bwtype:AS | As a session attribute, it | B | NORMAL | + | | specifies the session aggregate | | | + | | unless media-level b=RR and/or | | | + | | b=RS attributes are used. Under | | | + | | this interpretation the | | | + | | multiplexing scheme has no impact | | | + | | and thus NORMAL category | | | + | | applies. | | | + | | | | | + | bwtype:AS | For the media level usage,the | B | SUM | + | | aggregate of individual bandwidth | | | + | | values is considered. | | | | | | | | +------------+-----------------------------------+-------+----------+ RFC4566 bwtype Analysis 6.2. RFC3556 - SDP Bandwidth Modifiers for RTCP Bandwidth RFC3556 [RFC3556] defines an extension to the Session Description Protocol (SDP) to specify two additional modifiers for the bandwidth attribute. These modifiers may be used to specify the bandwidth allowed for RTP Control Protocol (RTCP) packets in a Real-time Transport Protocol (RTP) session +------------+--------------------------------+-------+-------------+ | Name | Notes | Level | Category | +------------+--------------------------------+-------+-------------+ - | bwtype:RS | S level usage represents | B | NORMAL,SUM | + | bwtype:RS | Session level usage represents | B | NORMAL,SUM | | | session aggregate and media | | | | | level usage indicates SUM of | | | | | the individual values while | | | | | multiplexing | | | | | | | | - | bwtype:RR | S level usage represents | B | NORMAL,SUM | + | bwtype:RR | Session level usage represents | B | NORMAL,SUM | | | session aggregate and media | | | | | level usage indicates SUM of | | | | | the individual values while | | | | | multiplexing | | | | | | | | +------------+--------------------------------+-------+-------------+ RFC3556 bwtype Analysis 6.3. RFC3890 - Bandwidth Modifier for SDP @@ -1702,25 +1748,25 @@ Transport Independent Application Specific Maximum (TIAS) bandwidth modifier that does not include transport overhead; instead an additional packet rate attribute is defined. The transport independent bit-rate value together with the maximum packet rate can then be used to calculate the real bit-rate over the transport actually used. +--------------+---------------------------------+-------+----------+ | Name | Notes | Level | Category | +--------------+---------------------------------+-------+----------+ - | bwtype:TIAS | The usage of TIAS is not | B | TBD | + | bwtype:TIAS | The usage of TIAS is not | B | SPECIAL | | | clearly defined Offer/Answer | | | | | usage. | | | | | | | | - | maxprate | The usage of TIAS and maxprate | B | TBD | + | maxprate | The usage of TIAS and maxprate | B | SPECIAL | | | is not well defined under | | | | | multiplexing | | | | | | | | +--------------+---------------------------------+-------+----------+ RFC3890 bwtype Analysis The intention of TIAS is that the media level bit-rate is multiplied with the known per-packet overhead for the selected transport and the maxprate value to determine the worst case bit-rate from the @@ -1911,26 +1958,27 @@ RFC3524 Attribute Analysis 8.3. RFC4091 - ANAT Semantics RFC4091 [RFC4091] defines the Alternative Network Address Types (ANAT) semantics for the Session Description Protocol (SDP) grouping framework. The ANAT semantics allow alternative types of network addresses to establish a particular media stream. - +-------------+----------------+-------+------------------+ + +-------------+---------------------------+-------+-----------------+ | Name | Notes | Level | Category | - +-------------+----------------+-------+------------------+ - | group:ANAT | Not Impacted | S | NOT RECOMMENDED | + +-------------+---------------------------+-------+-----------------+ + | group:ANAT | ANAT semantics is | S | NOT | + | | obseleted | | RECOMMENDED | | | | | | - +-------------+----------------+-------+------------------+ + +-------------+---------------------------+-------+-----------------+ RFC4091 Attribute Analysis 8.4. RFC5956 - FEC Grouping Semantics in SDP RFC5956 [RFC5956] defines the semantics for grouping the associated source and FEC-based (Forward Error Correction) repair flows in the Session Description Protocol (SDP). The semantics defined in the document are to be used with the SDP Grouping Framework (RFC 5888). These semantics allow the description of grouping relationships @@ -1951,33 +1999,33 @@ 8.5. RFC5583 - Signaling Media Decoding Dependency in SDP RFC5583 [RFC5583] defines semantics that allow for signaling the decoding dependency of different media descriptions with the same media type in the Session Description Protocol (SDP). This is required, for example, if media data is separated and transported in different network streams as a result of the use of a layered or multiple descriptive media coding process. - +-------------+---------------+-------+----------+ + +-------------+----------------+-------+----------+ | Name | Notes | Level | Category | - +-------------+---------------+-------+----------+ + +-------------+----------------+-------+----------+ | depend lay | Not Impacted | M | NORMAL | | | | | | | depend mdc | Not Impacted | M | NORMAL | | | | | | - +-------------+---------------+-------+----------+ + +-------------+----------------+-------+----------+ RFC5583 Attribute Analysis - If the Payload Type is not unique across the bundled m=lines, it MUST - represent the same Codec-Configuration. + The usage of identical Payload Type values across multiplexed m=lines + is described in [I-D.ietf-mmusic-sdp-bundle-negotiation]. 9. ssrc-group Attribute Analysis This section analyzes "ssrc-group" semantics [SSRC-GROUP]. 9.1. RFC5576 - Source-Specific SDP Attributes +---------+---------------+-------+----------+ | Name | Notes | Level | Category | +---------+---------------+-------+----------+ @@ -2018,21 +2067,21 @@ +------+------------------------------------+-------+---------------+ | k= | It is NOT recommended to use this | S | NOT | | | attribute | | RECOMMENDED | | | | | | +------+------------------------------------+-------+---------------+ RFC4566 Attribute Analysis 12. content Atribute Analysis -12.1. RFC4796 - MSRP Relays +12.1. RFC4796 +------------------+---------------+-------+----------+ | Name | Notes | Level | Category | +------------------+---------------+-------+----------+ | content:slides | Not Impacted | M | NORMAL | | | | | | | content:speaker | Not Impacted | M | NORMAL | | | | | | | content:main | Not Impacted | M | NORMAL | | | | | | @@ -2091,88 +2140,249 @@ a proposal to the WG. There are two options being proposed, A and B. The authors suggest A. 14.1. Option A This section provides two rules for multiplexing multiple media streams with DSCP markings over a single 5-tuple. Rule 1: Media Streams with markings from different service classes MUST NOT be multiplexed. For example, a media stream with DSCP Marking EF MUST NOT be multiplexed with a media stream marked with - AF class. Likewise, a media stream with DSCP marking AF3X MUST - NOT be multiplexed with a media stream marked with AF4X. + AF class. Likewise, a media stream with DSCP marking AF3x MUST + NOT be multiplexed with a media stream marked with AF4x. + Rule 2: Media Streams that belong to the same service class, even with different drop precedence, MAY be multiplexed. Thus media streams that all belong to the EF group or all that belong to the AF4X class can be multiplexed. For WebRTC applications following the advice in [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. 14.2. Option B - Media Streams MAY be multiplexed regardless of their DSCP service - class markings. + Media Streams MAY be multiplexed regardless of what the setting of + the DSCP Per Hop Behavior group (PHB). -15. IANA Considerations +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 + multiplexing charactersitics of the SDP attributes that encaspsulate + other SDP attributes. Such attributes as of today, for example, are + defined in [RFC3407], [RFC5939] and [RFC6781] as part of a generic + framework for indicating and negotiating transport, media and media + format related capabilities in the SDP. + + The behavior of such attributes under multiplexing is in turn defined + by the multiplexing behavior of the attributes they encapsulate which + are made known once the negotiation process is completed. + + 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]. + + v=0 + o=- 25678 753849 IN IP4 192.0.2.1 + s= + t=0 0 + c=IN IP4 192.0.2.1 + m=audio 3456 RTP/AVP 98 + a=tcap:1 RTP/SAVPF + a=rtpmap:98 OPUS/48000/2 + a=pcfg:1 t=1 + + m=video 51372 RTP/AVP 101 + a=rtpmap:101 H264/90000 + a=tcap:2 RTP/SAVPF RTP/AVPF + a=pcfg:2 t=2|3 + + ANSWER - 1 + ----------- + v=0 + o=- 24351 621814 IN IP4 192.0.2.2 + s= + m=audio 3456 RTP/SAVPF 98 + a=rtpmap:98 OPUS/48000/2 + a=acfg:1 t=1 + + m=video 51372 RTP/SAVPF 101 + a=rtpmap:101 H264/90000 + a=acfg:2 t=2 + + ANSWER - 2 + ----------- + v=0 + o=- 24351 621814 IN IP4 192.0.2.2 + s= + m=audio 3456 RTP/SAVPF 98 + a=rtpmap:98 OPUS/48000/2 + a=acfg:1 t=1 + + m=video 51372 RTP/AVPF 101 + a=rtpmap:101 H264/90000 + 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 IANA shall register categories from this specification by expanding the Session Description Protocol (SDP) Parameters table with a column listing categories against each SDP parameter. +---------------------+ | Category | +---------------------+ | NORMAL | +---------------------+ | NOT RECOMMENDED | +---------------------+ | IDENTICAL | +---------------------+ | TRANSPORT | +---------------------+ | SPECIAL | ---------------------- -16. Security Considerations +17. Security Considerations 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. -17. Acknowledgments +18. Acknowledgments I would like to thank Cullen Jennings for suggesting the categories, - contributing text and helping review 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 helping improve the document readability. I would like also to thank following experts on their inputs and - reviews as listed - Rohan Mahy(5.45), Eric Burger(5.22), Christian - Huitema(5.13), Christer Holmberg(5.22,5.40,5.41), Richard Ejzak - (5.36,5.42,5.43,5.44,), Colin Perkins(5.7,5.8), Magnus - westerlund(5.3,5.9,6.1,6.2,6.3,8.3,5.2,7,8,9), 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 - Begen(5.1,5.16,5.18,5.21,5.33,8.2,13.1,10.4,15.1), Bo Burman - (7.2,7.6), Charles Eckel(5.14,5.23,5.24,10.5), Paul Kyzivat(5.24), - Ian Johansson (5.11), Saravanan Shanmugham(5.10), Paul E Jones(5.25), + 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 + 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, + 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 + 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 + 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 - Zanaty(5.4,5.19,10.1,10.5), David Black (14) + Zanaty(5.4,5.19,8.1,8.3,8.5,12.1), Christian Huitema (5.13), Qin Wu + (5.38 PM-Dir review). -18. Change Log +19. Change Log [RFC EDITOR NOTE: Please remove this section when publishing] + Changes from draft-ietf-mmusic-sdp-mux-attributes-00 + o Added Section 15 to provide recommendations on multiplexing SDP + encapsulating attributes. Also updated sections 5.20, 5.28, 5.29 + to refer to Section 15. + o Updated Section 5.38 to incorporate PM-dir review inputs from Qin + Wu + o Updated Sections 5.2,5.14,8.5 to refer to BUNDLE draft for more + clarity. + o Fixed few nits regarding sentence clarity and fill-in the NOTES + section where information was lacking. + Changes from draft-nandakumar-mmusic-mux-attributes-05 o Renamed the document to be a WG document. o Added Section 14. + o Updated Open Issues based on IETF88 discussions. Changes from draft-nandakumar-mmusic-mux-attributes-04 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, 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 category explanation on suggestions form Dan Wing. o Grouped all the rtcp-fb attribute analysis under a single section as suggested by Magnus/ @@ -2186,30 +2396,31 @@ the inputs from the respective RFC Authors. Changes from draft-nandakumar-mmusic-mux-attributes-01 o Replaced Category BAD with NOT RECOMMENDED. o Added Category TBD. o Updated IANA Consideration Section. Changes from draft-nandakumar-mmusic-mux-attributes-00 o Added new section for dealing with FEC payload types. -19. References -19.1. Normative References +20. References + +20.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session Description Protocol", RFC 4566, July 2006. -19.2. Informative References +20.2. Informative References [ACK-NACK] "S Description Protocol (SDP) RTCP ACK/NACK Feedback attributes", . [CCM] "S Description Protocol (SDP) RTCP-FB Codec Control Messages", . @@ -2238,26 +2449,20 @@ Holmberg, C., Alvestrand, H., and C. Jennings, "Multiplexing Negotiation Using Session Description Protocol (SDP) Port Numbers", draft-ietf-mmusic-sdp-bundle-negotiation-03 (work in progress), February 2013. [IANA] "S Description Protocol (SDP) Parameters", . - [MEDIA_CAP] - Kaplan, H., Hedayat, K., and N. Venna, "S Description - Protocol (SDP) Media Capabilities Negotiation", - draft-ietf-mmusic-sdp-media-capabilities-17 (work in - progress), January 2013. - [MEDIA_LOOPBACK] Kaplan, H., Hedayat, K., Venna, N., Jones, P., and N. Stratton, "An Extension to the Session Description Protocol (SDP) and Real-time Transport Protocol (RTP) for Media Loopback", Internet-Draft 6489, January 2013. [QOS] "S Description Protocol (SDP) QoS Mechanism Tokens", . @@ -2461,20 +2666,24 @@ for RTP over UDP", RFC 6679, August 2012. [RFC6714] Holmberg, C., Blau, S., and E. Burger, "Connection Establishment for Media Anchoring (CEMA) for the Message Session Relay Protocol (MSRP)", RFC 6714, August 2012. [RFC6773] Phelan, T., Fairhurst, G., and C. Perkins, "DCCP-UDP: A Datagram Congestion Control Protocol UDP Encapsulation for 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 Protocol Version 2 (MRCPv2)", RFC 6787, November 2012. [RTCP-FB] "S Description Protocol (SDP) RTCP Feedback attributes", < http://www.iana.org/assignments/sdp-parameters/ sdp-parameters.xml#sdp-parameters-14>. [SSRC-GROUP] "S Description Protocol (SDP) "ssrc-group" semantics",