draft-ietf-mmusic-sdp-bundle-negotiation-10.txt   draft-ietf-mmusic-sdp-bundle-negotiation-11.txt 
MMUSIC Working Group C. Holmberg MMUSIC Working Group C. Holmberg
Internet-Draft Ericsson Internet-Draft Ericsson
Updates: 3264 (if approved) H. Alvestrand Updates: 3264 (if approved) H. Alvestrand
Intended status: Standards Track Google Intended status: Standards Track Google
Expires: March 14, 2015 C. Jennings Expires: March 26, 2015 C. Jennings
Cisco Cisco
September 10, 2014 September 22, 2014
Negotiating Media Multiplexing Using the Session Description Protocol Negotiating Media Multiplexing Using the Session Description Protocol
(SDP) (SDP)
draft-ietf-mmusic-sdp-bundle-negotiation-10.txt draft-ietf-mmusic-sdp-bundle-negotiation-11.txt
Abstract Abstract
This specification defines a new SDP Grouping Framework extension, This specification defines a new SDP Grouping Framework extension,
'BUNDLE'. The extension can be used with the Session Description 'BUNDLE'. The extension can be used with the Session Description
Protocol (SDP) Offer/Answer mechanism to negotiate the usage of a Protocol (SDP) Offer/Answer mechanism to negotiate the usage of a
single 5-tuple for sending and receiving media associated with single 5-tuple for sending and receiving media associated with
multiple SDP media descriptions ("m="). This is referred to as multiple SDP media descriptions ("m="). This is referred to as
bundled media. This specification also defines a new SDP attribute, bundled media. This specification also defines a new SDP attribute,
'bundle-only', which can be used to request that specific media is 'bundle-only', which can be used to request that specific media is
only used if bundled. only used if bundled.
This specification also updates sections 5.1, 8.1 and 8.2 of RFC This specification also updates sections 5.1, 8.1 and 8.2 of RFC
3264. The update allows an answerer to assign a non-zero port value 3264. The update allows an answerer to assign a non-zero port value
to an "m=" line in an SDP answer, even if the "m=" line in the to an "m=" line in an SDP answer, even if the "m=" line in the
associated SDP offer contained a zero port value. associated SDP offer contained a zero port value.
This specification also defines a new RTP SDES item, and a new RTP
header extension, that can be used to carry a value that associates
RTP/RTCP packets with a specific media description.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on March 26, 2015.
This Internet-Draft will expire on March 14, 2015.
Copyright Notice Copyright Notice
Copyright (c) 2014 IETF Trust and the persons identified as the Copyright (c) 2014 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
skipping to change at page 2, line 26 skipping to change at page 2, line 27
include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 6 3. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 6
4. Applicability Statement . . . . . . . . . . . . . . . . . . . 6 4. Applicability Statement . . . . . . . . . . . . . . . . . . . 6
5. SDP Grouping Framework BUNDLE Extension . . . . . . . . . . . 6 5. SDP Grouping Framework BUNDLE Extension . . . . . . . . . . . 7
5.1. General . . . . . . . . . . . . . . . . . . . . . . . . . 6 5.1. General . . . . . . . . . . . . . . . . . . . . . . . . . 7
6. SDP 'bundle-only' Attribute . . . . . . . . . . . . . . . . . 7 6. SDP 'bundle-only' Attribute . . . . . . . . . . . . . . . . . 7
6.1. General . . . . . . . . . . . . . . . . . . . . . . . . . 7 6.1. General . . . . . . . . . . . . . . . . . . . . . . . . . 7
6.2. Syntax . . . . . . . . . . . . . . . . . . . . . . . . . 7 6.2. Syntax . . . . . . . . . . . . . . . . . . . . . . . . . 8
7. SDP Information Considerations . . . . . . . . . . . . . . . 8 7. SDP Information Considerations . . . . . . . . . . . . . . . 8
7.1. General . . . . . . . . . . . . . . . . . . . . . . . . . 8 7.1. General . . . . . . . . . . . . . . . . . . . . . . . . . 8
7.2. Connection Data (c=) . . . . . . . . . . . . . . . . . . 8 7.2. Connection Data (c=) . . . . . . . . . . . . . . . . . . 8
7.3. Bandwidth (b=) . . . . . . . . . . . . . . . . . . . . . 8 7.3. Bandwidth (b=) . . . . . . . . . . . . . . . . . . . . . 8
7.4. Attributes (a=) . . . . . . . . . . . . . . . . . . . . . 8 7.4. Attributes (a=) . . . . . . . . . . . . . . . . . . . . . 9
8. SDP Offer/Answer Procedures . . . . . . . . . . . . . . . . . 8 8. SDP Offer/Answer Procedures . . . . . . . . . . . . . . . . . 9
8.1. General . . . . . . . . . . . . . . . . . . . . . . . . . 8 8.1. General . . . . . . . . . . . . . . . . . . . . . . . . . 9
8.2. Generating the Initial SDP Offer . . . . . . . . . . . . 9 8.2. Generating the Initial SDP Offer . . . . . . . . . . . . 10
8.2.1. General . . . . . . . . . . . . . . . . . . . . . . . 9 8.2.1. General . . . . . . . . . . . . . . . . . . . . . . . 10
8.2.2. Request offerer BUNDLE address selection . . . . . . 10 8.2.2. Request offerer BUNDLE address selection . . . . . . 10
8.3. Generating the SDP Answer . . . . . . . . . . . . . . . . 10 8.3. Generating the SDP Answer . . . . . . . . . . . . . . . . 10
8.3.1. General . . . . . . . . . . . . . . . . . . . . . . . 10 8.3.1. General . . . . . . . . . . . . . . . . . . . . . . . 10
8.3.2. Answerer Selection of Offerer Bundle Address . . . . 11 8.3.2. Answerer Selection of Offerer Bundle Address . . . . 11
8.3.3. Answerer Selection of Answerer BUNDLE Address . . . . 12 8.3.3. Answerer Selection of Answerer BUNDLE Address . . . . 12
8.3.4. Moving A Media Description Out Of A BUNDLE Group . . 12 8.3.4. Moving A Media Description Out Of A BUNDLE Group . . 12
8.3.5. Rejecting A Media Description In A BUNDLE Group . . . 12 8.3.5. Rejecting A Media Description In A BUNDLE Group . . . 13
8.4. Offerer Processing of the SDP Answer . . . . . . . . . . 13 8.4. Offerer Processing of the SDP Answer . . . . . . . . . . 13
8.4.1. General . . . . . . . . . . . . . . . . . . . . . . . 13 8.4.1. General . . . . . . . . . . . . . . . . . . . . . . . 13
8.4.2. Bundle Address Synchronization (BAS) . . . . . . . . 13 8.4.2. Bundle Address Synchronization (BAS) . . . . . . . . 13
8.5. Modifying the Session . . . . . . . . . . . . . . . . . . 14 8.5. Modifying the Session . . . . . . . . . . . . . . . . . . 14
8.5.1. General . . . . . . . . . . . . . . . . . . . . . . . 14 8.5.1. General . . . . . . . . . . . . . . . . . . . . . . . 14
8.5.2. Request a new offerer BUNDLE address . . . . . . . . 15 8.5.2. Request a new offerer BUNDLE address . . . . . . . . 15
8.5.3. Adding a media description to a BUNDLE group . . . . 15 8.5.3. Adding a media description to a BUNDLE group . . . . 15
8.5.4. Moving A Media Description Out Of A BUNDLE Group . . 16 8.5.4. Moving A Media Description Out Of A BUNDLE Group . . 16
8.5.5. Disabling A Media Description In A BUNDLE Group . . . 16 8.5.5. Disabling A Media Description In A BUNDLE Group . . . 16
9. Protocol Identification . . . . . . . . . . . . . . . . . . . 16 9. Protocol Identification . . . . . . . . . . . . . . . . . . . 17
9.1. General . . . . . . . . . . . . . . . . . . . . . . . . . 16 9.1. General . . . . . . . . . . . . . . . . . . . . . . . . . 17
9.2. STUN, DTLS, SRTP . . . . . . . . . . . . . . . . . . . . 17 9.2. STUN, DTLS, SRTP . . . . . . . . . . . . . . . . . . . . 17
10. RTP Considerations . . . . . . . . . . . . . . . . . . . . . 17 10. RTP Considerations . . . . . . . . . . . . . . . . . . . . . 18
10.1. Single RTP Session . . . . . . . . . . . . . . . . . . . 17 10.1. Single RTP Session . . . . . . . . . . . . . . . . . . . 18
10.1.1. General . . . . . . . . . . . . . . . . . . . . . . 17 10.1.1. General . . . . . . . . . . . . . . . . . . . . . . 18
10.1.2. Payload Type (PT) Value Re-usage . . . . . . . . . . 18 10.1.2. Payload Type (PT) Value Re-usage . . . . . . . . . . 18
10.2. Associating RTP/RTCP Packets With Correct SDP Media 10.2. Associating RTP/RTCP Packets With Correct SDP Media
Description . . . . . . . . . . . . . . . . . . . . . . 18 Description . . . . . . . . . . . . . . . . . . . . . . 19
10.3. RTP/RTCP Multiplexing . . . . . . . . . . . . . . . . . 19 10.3. RTP/RTCP Multiplexing . . . . . . . . . . . . . . . . . 19
10.3.1. General . . . . . . . . . . . . . . . . . . . . . . 19 10.3.1. General . . . . . . . . . . . . . . . . . . . . . . 19
10.3.2. SDP Offer/Answer Procedures . . . . . . . . . . . . 19 10.3.2. SDP Offer/Answer Procedures . . . . . . . . . . . . 20
11. ICE Considerations . . . . . . . . . . . . . . . . . . . . . 21 11. ICE Considerations . . . . . . . . . . . . . . . . . . . . . 21
11.1. General . . . . . . . . . . . . . . . . . . . . . . . . 21 11.1. General . . . . . . . . . . . . . . . . . . . . . . . . 21
11.2. SDP Offer/Answer Procedures . . . . . . . . . . . . . . 21 11.2. SDP Offer/Answer Procedures . . . . . . . . . . . . . . 22
11.2.1. General . . . . . . . . . . . . . . . . . . . . . . 21 11.2.1. General . . . . . . . . . . . . . . . . . . . . . . 22
11.2.2. Generating the Initial SDP Offer . . . . . . . . . . 22 11.2.2. Generating the Initial SDP Offer . . . . . . . . . . 22
11.2.3. Generating the SDP Answer . . . . . . . . . . . . . 22 11.2.3. Generating the SDP Answer . . . . . . . . . . . . . 22
11.2.4. Offerer Processing of the SDP Answer . . . . . . . . 22 11.2.4. Offerer Processing of the SDP Answer . . . . . . . . 22
11.2.5. Modifying the Session . . . . . . . . . . . . . . . 22 11.2.5. Modifying the Session . . . . . . . . . . . . . . . 23
12. Update to RFC 3264 . . . . . . . . . . . . . . . . . . . . . 22 12. Update to RFC 3264 . . . . . . . . . . . . . . . . . . . . . 23
12.1. General . . . . . . . . . . . . . . . . . . . . . . . . 22 12.1. General . . . . . . . . . . . . . . . . . . . . . . . . 23
12.2. Original text of section 5.1 (2nd paragraph) of RFC 3264 22 12.2. Original text of section 5.1 (2nd paragraph) of RFC 3264 23
12.3. New text replacing section 5.1 (2nd paragraph) of RFC 12.3. New text replacing section 5.1 (2nd paragraph) of RFC
3264 . . . . . . . . . . . . . . . . . . . . . . . . . . 23 3264 . . . . . . . . . . . . . . . . . . . . . . . . . . 23
12.4. Original text of section 8.2 (2nd paragraph) of RFC 3264 23 12.4. Original text of section 8.2 (2nd paragraph) of RFC 3264 24
12.5. New text replacing section 8.2 (2nd paragraph) of RFC 12.5. New text replacing section 8.2 (2nd paragraph) of RFC
3264 . . . . . . . . . . . . . . . . . . . . . . . . . . 23 3264 . . . . . . . . . . . . . . . . . . . . . . . . . . 24
12.6. Original text of section 8.4 (6th paragraph) of RFC 3264 23 12.6. Original text of section 8.4 (6th paragraph) of RFC 3264 24
12.7. New text replacing section 8.4 (6th paragraph) of RFC 12.7. New text replacing section 8.4 (6th paragraph) of RFC
3264 . . . . . . . . . . . . . . . . . . . . . . . . . . 24 3264 . . . . . . . . . . . . . . . . . . . . . . . . . . 24
13. RTP/RTCP extensions for mid value transport . . . . . . . . . 24 13. RTP/RTCP extensions for mid value transport . . . . . . . . . 25
13.1. General . . . . . . . . . . . . . . . . . . . . . . . . 24 13.1. General . . . . . . . . . . . . . . . . . . . . . . . . 25
13.2. RTP MID SDES Item . . . . . . . . . . . . . . . . . . . 25 13.2. RTP MID SDES Item . . . . . . . . . . . . . . . . . . . 26
13.3. RTP MID Header Extension . . . . . . . . . . . . . . . . 25 13.3. RTP MID Header Extension . . . . . . . . . . . . . . . . 26
13.4. IANA Considerations . . . . . . . . . . . . . . . . . . 25 14. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 26
14. Security Considerations . . . . . . . . . . . . . . . . . . . 26 14.1. New SDES item . . . . . . . . . . . . . . . . . . . . . 26
15. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 26 14.2. New RTP Header Extension URI . . . . . . . . . . . . . . 27
15.1. Example: Bundle Address Selection . . . . . . . . . . . 26 14.3. New SDP Attribute . . . . . . . . . . . . . . . . . . . 27
15.2. Example: BUNDLE Extension Rejected . . . . . . . . . . . 28 15. Security Considerations . . . . . . . . . . . . . . . . . . . 27
15.3. Example: Offerer Adds A Media Description To A BUNDLE 16. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Group . . . . . . . . . . . . . . . . . . . . . . . . . 29 16.1. Example: Bundle Address Selection . . . . . . . . . . . 27
15.4. Example: Offerer Moves A Media Description Out Of A 16.2. Example: BUNDLE Extension Rejected . . . . . . . . . . . 29
BUNDLE Group . . . . . . . . . . . . . . . . . . . . . . 31 16.3. Example: Offerer Adds A Media Description To A BUNDLE
15.5. Example: Offerer Disables A Media Description Within A Group . . . . . . . . . . . . . . . . . . . . . . . . . 30
BUNDLE Group . . . . . . . . . . . . . . . . . . . . . . 33 16.4. Example: Offerer Moves A Media Description Out Of A
16. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 35 BUNDLE Group . . . . . . . . . . . . . . . . . . . . . . 32
17. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 35 16.5. Example: Offerer Disables A Media Description Within A
18. Change Log . . . . . . . . . . . . . . . . . . . . . . . . . 35 BUNDLE Group . . . . . . . . . . . . . . . . . . . . . . 34
19. References . . . . . . . . . . . . . . . . . . . . . . . . . 38 17. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 36
19.1. Normative References . . . . . . . . . . . . . . . . . . 38 18. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 36
19.2. Informative References . . . . . . . . . . . . . . . . . 38 19. Change Log . . . . . . . . . . . . . . . . . . . . . . . . . 36
Appendix A. Design Considerations . . . . . . . . . . . . . . . 39 20. References . . . . . . . . . . . . . . . . . . . . . . . . . 39
A.1. General . . . . . . . . . . . . . . . . . . . . . . . . . 39 20.1. Normative References . . . . . . . . . . . . . . . . . . 39
A.2. UA Interoperability . . . . . . . . . . . . . . . . . . . 40 20.2. Informative References . . . . . . . . . . . . . . . . . 40
A.3. Usage of port number value zero . . . . . . . . . . . . . 41 Appendix A. Design Considerations . . . . . . . . . . . . . . . 40
A.4. B2BUA And Proxy Interoperability . . . . . . . . . . . . 41 A.1. General . . . . . . . . . . . . . . . . . . . . . . . . . 40
A.4.1. Traffic Policing . . . . . . . . . . . . . . . . . . 42 A.2. UA Interoperability . . . . . . . . . . . . . . . . . . . 41
A.4.2. Bandwidth Allocation . . . . . . . . . . . . . . . . 42 A.3. Usage of port number value zero . . . . . . . . . . . . . 43
A.5. Candidate Gathering . . . . . . . . . . . . . . . . . . . 43 A.4. B2BUA And Proxy Interoperability . . . . . . . . . . . . 43
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 43 A.4.1. Traffic Policing . . . . . . . . . . . . . . . . . . 44
A.4.2. Bandwidth Allocation . . . . . . . . . . . . . . . . 44
A.5. Candidate Gathering . . . . . . . . . . . . . . . . . . . 44
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 44
1. Introduction 1. Introduction
In the IETF RTCWEB WG, a need to use a single 5-tuple for sending and 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=" receiving media associated with multiple SDP media descriptions ("m="
lines) has been identified. This would e.g. allow the usage of a lines) has been identified. This would e.g. allow the usage of a
single set of Interactive Connectivity Establishment (ICE) [RFC5245] single set of Interactive Connectivity Establishment (ICE) [RFC5245]
candidates for multiple media descriptions. candidates for multiple media descriptions.
This specification defines a new SDP Grouping Framework [RFC5888] This specification defines a new SDP Grouping Framework [RFC5888]
skipping to change at page 4, line 44 skipping to change at page 4, line 49
is referred to as bundled media. This specification also defines a is referred to as bundled media. This specification also defines a
new SDP attribute, 'bundle-only', which can be used to request that new SDP attribute, 'bundle-only', which can be used to request that
specific media is only used if bundled. specific media is only used if bundled.
The offerer and answerer [RFC3264] use the BUNDLE extension to The offerer and answerer [RFC3264] use the BUNDLE extension to
negotiate the 5-tuples (BUNDLE addresses), one for the offerer negotiate the 5-tuples (BUNDLE addresses), one for the offerer
(offerer BUNDLE address) and one for the answerer (answerer BUNDLE (offerer BUNDLE address) and one for the answerer (answerer BUNDLE
address) to be used for the bundled media associated with a BUNDLE address) to be used for the bundled media associated with a BUNDLE
group. group.
Once the offerer and the answerer have negotiated a BUNDLE group, and Once the offerer and the answerer have negotiated a BUNDLE group,
the associated BUNDLE addresses, each endpoint can assign its BUNDLE they assign their respective BUNDLE address to each "m=" line in the
address to each "m=" line within, and use the address to send and BUNDLE group. The BUNDLE address is used to send and receive all
receive all media associated with, the BUNDLE group. media associated with the BUNDLE group.
NOTE: As defined in RFC 4566 [RFC4566], the semantics of assigning NOTE: As defined in RFC 4566 [RFC4566], the semantics of assigning
the same port value to multiple "m=" lines are undefined, and there the same port value to multiple "m=" lines are undefined, and there
is no grouping defined by such means. Instead, an explicit grouping is no grouping defined by such means. Instead, an explicit grouping
mechanism needs to be used to express the intended semantics. This mechanism needs to be used to express the intended semantics. This
specification provides such an extension. specification provides such an extension.
This specification also updates sections 5.1, 8.1 and 8.2 of RFC 3264 This specification also updates sections 5.1, 8.1 and 8.2 of RFC 3264
[RFC3264]. The update allows an answerer to assign a non-zero port [RFC3264]. The update allows an answerer to assign a non-zero port
value to an "m=" line in an SDP answer, even if the "m=" line in the value to an "m=" line in an SDP answer, even if the "m=" line in the
associated SDP offer contained a zero port value. associated SDP offer contained a zero port value.
This specification also defines a new RTP SDES item, and a new RTP
header extension, that can be used to carry a value that associates
RTP/RTCP packets with a specific media description.
SDP bodies can contain multiple BUNDLE groups. A given BUNDLE SDP bodies can contain multiple BUNDLE groups. A given BUNDLE
address MUST only be associated with a single BUNDLE group. address MUST only be associated with a single BUNDLE group.
The procedures in this specification apply independently to a given The procedures in this specification apply independently to a given
BUNDLE group. BUNDLE group.
All Real-time Transport Protocol (RTP) [RFC3550] based media flows All Real-time Transport Protocol (RTP) [RFC3550] based media flows
associated with a single BUNDLE group belong to a single RTP session associated with a single BUNDLE group belong to a single RTP session
[RFC3550]. [RFC3550].
skipping to change at page 6, line 6 skipping to change at page 6, line 17
Offerer BUNDLE address: Within a given BUNDLE group, an IP address Offerer BUNDLE address: Within a given BUNDLE group, an IP address
and IP port combination used by an offerer to receive all media and IP port combination used by an offerer to receive all media
associated with each "m=" line within the BUNDLE group. associated with each "m=" line within the BUNDLE group.
Answerer BUNDLE address: Within a given BUNDLE group, an IP address Answerer BUNDLE address: Within a given BUNDLE group, an IP address
and IP port combination used by an answerer to receive all media and IP port combination used by an answerer to receive all media
associated with each "m=" line within the BUNDLE group. associated with each "m=" line within the BUNDLE group.
BUNDLE group: A set of "m=" lines, created using an SDP Offer/Answer BUNDLE group: A set of "m=" lines, created using an SDP Offer/Answer
exchange, for which each endpoint use a single 5-tuple is to send and exchange, for which each endpoint uses a single 5-tuple to send and
receive media. Each endpoint uses its BUNDLE address, associated receive media. Each endpoint uses its BUNDLE address, associated
with the BUNDLE group, to send and receive the media. with the BUNDLE group, to send and receive the media.
Bundled "m=" line: An "m=" line, which SDP 'mid' attribute value is Bundled "m=" line: An "m=" line, whose SDP 'mid' attribute value is
placed in a SDP 'group:BUNDLE' attribute mid value list in an offer placed in a SDP 'group:BUNDLE' attribute mid value list in an offer
or answer. or answer.
Bundle-only "m=" line: A bundled "m=" line with an associated SDP Bundle-only "m=" line: A bundled "m=" line with an associated SDP
'bundle-only' attribute. 'bundle-only' attribute.
Bundled media: All media associated with a given BUNDLE group. Bundled media: All media associated with a given BUNDLE group.
Initial offer: The first offer, within an SDP session, in which the Initial offer: The first offer, within an SDP session, in which the
offerer indicates that it wants to create a given BUNDLE group. offerer indicates that it wants to create a given BUNDLE group.
skipping to change at page 7, line 6 skipping to change at page 7, line 22
negotiate the usage of a single 5-tuple for sending and receiving negotiate the usage of a single 5-tuple for sending and receiving
media, referred to as bundled media, associated with multiple SDP media, referred to as bundled media, associated with multiple SDP
media descriptions ("m=" lines). Within a successfully created media descriptions ("m=" lines). Within a successfully created
BUNDLE group, media described with "m=" lines associated with the BUNDLE group, media described with "m=" lines associated with the
BUNDLE group will be sent and received using a single 5-tuple. BUNDLE group will be sent and received using a single 5-tuple.
The BUNDLE extension is indicated using an SDP 'group' attribute with The BUNDLE extension is indicated using an SDP 'group' attribute with
a "BUNDLE" semantics value [RFC5888]. An SDP "mid" attribute is a "BUNDLE" semantics value [RFC5888]. An SDP "mid" attribute is
assigned to each bundled "m=" line, and the "mid" attribute value is assigned to each bundled "m=" line, and the "mid" attribute value is
listed in the 'group:BUNDLE' attribute mid value list. Each "m=" listed in the 'group:BUNDLE' attribute mid value list. Each "m="
line, which mid value is listed in the mid value list, is associated line, whose mid value is listed in the mid value list, is associated
with a given BUNDLE group. with a given BUNDLE group.
SDP bodies can contain multiple BUNDLE groups. Any given bundled SDP bodies can contain multiple BUNDLE groups. Any given bundled
"m=" line MUST NOT be associated with more than one BUNDLE group. "m=" line MUST NOT be associated with more than one BUNDLE group.
[Section 8] defines the detailed SDP Offer/Answer procedures for the [Section 8] defines the detailed SDP Offer/Answer procedures for the
BUNDLE extension. BUNDLE extension.
6. SDP 'bundle-only' Attribute 6. SDP 'bundle-only' Attribute
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transport protocol represented by a bundled "m=" line. [Section 10] transport protocol represented by a bundled "m=" line. [Section 10]
defines additional considerations for RTP based media. [Section 6] defines additional considerations for RTP based media. [Section 6]
defines additional considerations for the usage of the SDP 'bundle- defines additional considerations for the usage of the SDP 'bundle-
only' attribute. [Section 11] defines additional considerations for only' attribute. [Section 11] defines additional considerations for
the usage of Interactive Connectivity Establishment (ICE) mechanism the usage of Interactive Connectivity Establishment (ICE) mechanism
[RFC5245]. [RFC5245].
The offerer and answerer MUST follow the rules and restrictions The offerer and answerer MUST follow the rules and restrictions
defined in [Section 7] when creating offers and answers. defined in [Section 7] when creating offers and answers.
SDP bodies can contain multiple BUNDLE groups. The procedures in
this section apply independently to a given BUNDLE group.
8.2. Generating the Initial SDP Offer 8.2. Generating the Initial SDP Offer
8.2.1. General 8.2.1. General
When an offerer generates an initial offer, in order to create a When an offerer generates an initial offer, in order to create a
BUNDLE group, it MUST: BUNDLE group, it MUST:
o Assign a unique address to each "m=" line within the offer, o Assign a unique address to each "m=" line within the offer,
following the procedures in [RFC3264]; following the procedures in [RFC3264];
o Assign an SDP 'group:BUNDLE' attribute to the offer; o Assign an SDP 'group:BUNDLE' attribute to the offer;
o Place the SDP 'mid' attribute value [RFC5888] of each bundled "m=" o Place the SDP 'mid' attribute value [RFC5888] of each bundled "m="
line to the SDP 'group:BUNDLE' attribute mid value list; and line to the SDP 'group:BUNDLE' attribute mid value list; and
o Indicate which unique address the offerer wants the answerer to o Indicate which unique address the offerer wants the answerer to
select as the offerer BUNDLE address [Section 8.2.2]. select as the offerer BUNDLE address [Section 8.2.2].
If the offerer wants to request that the answerer accepts a given If the offerer wants to request that the answerer accepts a given
"m=" line only if the the answerer keeps the "m=" line within the "m=" line only if the answerer keeps the "m=" line within the BUNDLE
BUNDLE group, the offerer MUST: group, the offerer MUST:
o Associate an SDP 'bundle-only' attribute [Section 8.2.2] with the o Associate an SDP 'bundle-only' attribute [Section 8.2.2] with the
"m=" line; and "m=" line; and
o Assign a zero port value to the "m=" line. o Assign a zero port value to the "m=" line.
NOTE: If the offerer assigns a zero port value to an "m=" line, but NOTE: If the offerer assigns a zero port value to an "m=" line, but
does not also associate an SDP 'bundle-only' attribute with the "m=" does not also associate an SDP 'bundle-only' attribute with the "m="
line, it is an indication that the offerer wants to disable the "m=" line, it is an indication that the offerer wants to disable the "m="
line [Section 8.5.5]. line [Section 8.5.5].
[Section 15.1] shows an example of an initial offer. [Section 16.1] shows an example of an initial offer.
8.2.2. Request offerer BUNDLE address selection 8.2.2. Request offerer BUNDLE address selection
In the offer, the address assigned to the "m=" line associated with In the offer, the address assigned to the "m=" line associated with
the offerer suggested BUNDLE mid indicates the address that the the offerer suggested BUNDLE mid indicates the address that the
offerer wants the answer to select as the offerer BUNDLE address offerer wants the answer to select as the offerer BUNDLE address
[Section 8.3.2]. [Section 8.3.2].
8.3. Generating the SDP Answer 8.3. Generating the SDP Answer
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When an answerer generates an answer, which contains a BUNDLE group, When an answerer generates an answer, which contains a BUNDLE group,
the following general SDP grouping framework restrictions, defined in the following general SDP grouping framework restrictions, defined in
[RFC5888], also apply to the BUNDLE group: [RFC5888], also apply to the BUNDLE group:
o The answerer MUST NOT include a BUNDLE group in the answer, unless o The answerer MUST NOT include a BUNDLE group in the answer, unless
the offerer requested the BUNDLE group to be created in the the offerer requested the BUNDLE group to be created in the
associated offer; and associated offer; and
o The answerer MUST NOT include an "m=" line within a BUNDLE group, o The answerer MUST NOT include an "m=" line within a BUNDLE group,
unless the offerer requested to "m=" line to be within a BUNDLE unless the offerer requested the "m=" line to be within that
group in the associated offer. BUNDLE group in the associated offer.
If the answer contains a BUNDLE group, the answerer MUST: If the answer contains a BUNDLE group, the answerer MUST:
o Select an Offerer BUNDLE Address [Section 8.3.2]; and o Select an Offerer BUNDLE Address [Section 8.3.2]; and
o Select an Answerer BUNDLE Address [Section 8.3.3]; o Select an Answerer BUNDLE Address [Section 8.3.3];
The answerer is allowed to select a new Answerer BUNDLE address each The answerer is allowed to select a new Answerer BUNDLE address each
time it generates an answer to an offer. time it generates an answer to an offer.
If the answerer does not want to keep an "m=" line within a BUNDLE If the answerer does not want to keep an "m=" line within a BUNDLE
group, it MUST: group, it MUST:
o Move the "m=" line out of the BUNDLE group [Section 8.3.4]; or o Move the "m=" line out of the BUNDLE group [Section 8.3.4]; or
o Reject the "m=" line [Section 8.3.5]; o Reject the "m=" line [Section 8.3.5];
If a bundled "m=" line in an offer has an associated SDP 'bundle- If the answerer keeps a bundle-only "m=" line within the BUNDLE
only' attribute, and if the answerer keeps the "m=" line within the group, it follows the procedures (assigns the answerer BUNDLE address
BUNDLE group, the answerer MUST process the "m=" line as any other to the "m=" line etc) for any other "m=" line kept within the BUNDLE
bundled "m=" line in the offer. The answerer MUST NOT include a group.
'bundle-only' attribute in an answer.
If the answerer does not want to keep a bundle-only "m=" line within
the BUNDLE group, it MUST reject the "m=" line [Section 8.3.5].
The answerer MUST NOT include a 'bundle-only' attribute in an
answer."
NOTE: If a bundled "m=" line in an offer contains a port zero value, NOTE: If a bundled "m=" line in an offer contains a port zero value,
but the "m=" line does not contain an SDP 'bundle-only' attribute, it but the "m=" line does not contain an SDP 'bundle-only' attribute, it
is an indication that the offerer wants to disable the "m=" line is an indication that the offerer wants to disable the "m=" line
[Section 8.5.5]. [Section 8.5.5].
8.3.2. Answerer Selection of Offerer Bundle Address 8.3.2. Answerer Selection of Offerer Bundle Address
In an offer, the address (unique or shared) assigned to the bundled In an offer, the address (unique or shared) assigned to the bundled
"m=" line associated with the offerer suggested BUNDLE mid indicates "m=" line associated with the offerer suggested BUNDLE mid indicates
the address that the offerer wants the answer to select as the the address that the offerer wants the answer to select as the
offerer BUNDLE address [Section 8.2.2]. The answerer MUST check offerer BUNDLE address [Section 8.2.2]. The answerer MUST check
whether the "m=" line fulfills the following criteria: whether the "m=" line fulfils the following criteria:
o The answerer will not move the "m=" line out of the BUNDLE group o The answerer will not move the "m=" line out of the BUNDLE group
[Section 8.3.4]; [Section 8.3.4];
o The answerer will not reject the "m=" line [Section 8.3.5]; and o The answerer will not reject the "m=" line [Section 8.3.5]; and
o The "m=" line does not contain a zero port value. o The "m=" line does not contain a zero port value.
If all of the criteria above is fulfilled, the answerer MUST select If all of the criteria above is fulfilled, the answerer MUST select
the address associated with the "m=" line as the offerer BUNDLE the address associated with the "m=" line as the offerer BUNDLE
address. In the answer, the answerer selected BUNDLE mid represents address. In the answer, the answerer selected BUNDLE mid represents
the "m=" line, and the address associated with the "m=" line in the the "m=" line, and the address associated with the "m=" line in the
offer becomes the offerer BUNDLE address. offer becomes the offerer BUNDLE address.
If all of the criteria is not fulfilled, the answerer MUST select the If all of the criteria is not fulfilled, the answerer MUST select the
next mid value in the mid list, and perform the same criteria check next mid value in the mid list, and perform the same criteria check
for the "m=" line associated with that mid value. If there are no for the "m=" line associated with that mid value. If there are no
more mid values in the mid list, the answerer MUST NOT create the more mid values in the mid list, the answerer MUST NOT create the
BUNDLE group. BUNDLE group.
[Section 15.1] shows an example of an offerer BUNDLE address [Section 16.1] shows an example of an offerer BUNDLE address
selection. selection.
8.3.3. Answerer Selection of Answerer BUNDLE Address 8.3.3. Answerer Selection of Answerer BUNDLE Address
When the answerer selects a BUNDLE address for itself, referred to as When the answerer selects a BUNDLE address for itself, referred to as
the answerer BUNDLE address, it MUST assign the address to each the answerer BUNDLE address, it MUST assign the address to each
bundled "m=" line within the created BUNDLE group in the answer. bundled "m=" line within the created BUNDLE group in the answer.
The answerer MUST NOT assign the answerer BUNDLE address to an "m=" The answerer MUST NOT assign the answerer BUNDLE address to an "m="
line that is not within the BUNDLE group, or to an "m=" line that is line that is not within the BUNDLE group, or to an "m=" line that is
within another BUNDLE group. within another BUNDLE group.
[Section 15.1] shows an example of an answerer BUNDLE address [Section 16.1] shows an example of an answerer BUNDLE address
selection. selection.
8.3.4. Moving A Media Description Out Of A BUNDLE Group 8.3.4. Moving A Media Description Out Of A BUNDLE Group
When an answerer moves a "m=" line out of a BUNDLE group, it assigns When an answerer moves a "m=" line out of a BUNDLE group, it assigns
an address to the "m=" line in the answer based on the following an address to the "m=" line in the answer based on the following
rules: rules:
o In the associated offer, if the "m=" line contains a shared o In the associated offer, if the "m=" line contains a shared
address (e.g. a previously selected offerer BUNDLE address), the address (e.g. a previously selected offerer BUNDLE address), the
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8.4. Offerer Processing of the SDP Answer 8.4. Offerer Processing of the SDP Answer
8.4.1. General 8.4.1. General
When an offerer receives an answer, if the answer contains a BUNDLE When an offerer receives an answer, if the answer contains a BUNDLE
group, the offerer MUST check that any bundled "m=" line in the group, the offerer MUST check that any bundled "m=" line in the
answer was indicated as bundled in the associated offer. If there is answer was indicated as bundled in the associated offer. If there is
no mismatch, the offerer MUST apply the offerer BUNDLE address, no mismatch, the offerer MUST apply the offerer BUNDLE address,
selected by the answerer [Section 8.3.2], to each bundled "m=" line. selected by the answerer [Section 8.3.2], to each bundled "m=" line.
The offerer MUST assign the address to each bundled "m=" line
(excluding a bundled "m=" line added to a BUNDLE group, to which the
offerer MAY assign a unique address [Section 8.5.3]) in any
subsequent offer.
NOTE: As the answerer might reject one or more bundled "m=" lines, or NOTE: As the answerer might reject one or more bundled "m=" lines, or
move a bundled "m=" line out of a BUNDLE group, each bundled "m=" move a bundled "m=" line out of a BUNDLE group, each bundled "m="
line in the offer might not be indicated as bundled in the answer. line in the offer might not be indicated as bundled in the answer.
If the answer does not contain a BUNDLE group, the offerer MUST If the answer does not contain a BUNDLE group, the offerer MUST
process the answer as a normal answer. process the answer as a normal answer.
8.4.2. Bundle Address Synchronization (BAS) 8.4.2. Bundle Address Synchronization (BAS)
When an offerer receives an answer, if the answer contains a BUNDLE When an offerer receives an answer, if the answer contains a BUNDLE
group, the offerer MUST check whether the offerer BUNDLE address, group, the offerer MUST check whether the offerer BUNDLE address,
selected by the answerer [Section 8.3.2], matches was assigned to selected by the answerer [Section 8.3.2], matches what was assigned
each bundled "m=" line (excluding any bundled "m=" line that was to each bundled "m=" line (excluding any bundled "m=" line that was
rejected, or moved out of the BUNDLE group, by the answer) in the rejected, or moved out of the BUNDLE group, by the answer) in the
associated offer. If there is a mismatch, the offerer SHOULD as soon associated offer. If there is a mismatch, the offerer SHOULD as soon
as possible generate a subsequent offer, in which it assigns the as possible generate a subsequent offer, in which it assigns the
offerer BUNDLE address to each bundled "m=" line. Such offer is offerer BUNDLE address to each bundled "m=" line. Such offer is
referred to as a Bundle Address Synchronization (BAS) offer. referred to as a Bundle Address Synchronization (BAS) offer.
A BAS offer is typically sent in the following scenarios: A BAS offer is typically sent in the following scenarios:
o The offerer receives an answer to an initial offer, as the bundled o The offerer receives an answer to an initial offer, as the bundled
"m=" lines in the initial offer always contain unique addresses "m=" lines in the initial offer always contain unique addresses
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necessity to modify SDP parameters in the BAS offer, in such a way necessity to modify SDP parameters in the BAS offer, in such a way
that could trigger the answerer to reject the BAS offer. Disabling that could trigger the answerer to reject the BAS offer. Disabling
"m=" lines, or reducing the number of codecs, in a BAS offer is "m=" lines, or reducing the number of codecs, in a BAS offer is
considered to have a low risk of being rejected. considered to have a low risk of being rejected.
NOTE: The main purpose of the BAS offer is to ensure that NOTE: The main purpose of the BAS offer is to ensure that
intermediaries, that might not support the BUNDLE extension, have intermediaries, that might not support the BUNDLE extension, have
correct information regarding the address is going to be used to correct information regarding the address is going to be used to
transport the bundled media. transport the bundled media.
[Section 15.1] shows an example of a BAS offer. [Section 16.1] shows an example of a BAS offer.
8.5. Modifying the Session 8.5. Modifying the Session
8.5.1. General 8.5.1. General
When an offerer generates a subsequent offer, it MUST assign the When an offerer generates a subsequent offer, it MUST assign the
previously selected offerer BUNDLE address [Section 8.3.2], to each previously selected offerer BUNDLE address [Section 8.3.2], to each
bundled "m=" line (including any bundle-only "m=" line), with the bundled "m=" line (including any bundle-only "m=" line), with the
following exceptions: following exceptions:
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associate a 'bundle-only' attribute with the same "m=" line in a associate a 'bundle-only' attribute with the same "m=" line in a
previous offer. previous offer.
8.5.2. Request a new offerer BUNDLE address 8.5.2. Request a new offerer BUNDLE address
When an offerer generates an offer, in which it wants the answerer to When an offerer generates an offer, in which it wants the answerer to
select a new offerer BUNDLE address [Section 8.2.2], the offerer select a new offerer BUNDLE address [Section 8.2.2], the offerer
MUST: MUST:
o Assign a unique address, which the offerer wants the answerer to o Assign a unique address, which the offerer wants the answerer to
select as the offerer BUNDLE address, to a bundled "m=" line select as the offerer BUNDLE address, to a bundled "m=" line; and
(added to the BUNDLE group in a previous offer/answer transaction,
or requested to be added to the BUNDLE group in the current
offer); and
o Indicate that the offerer wants the answerer to select the unique o Indicate that the offerer wants the answerer to select the unique
address as the offerer BUNDLE address [Section 8.2.2] address as the offerer BUNDLE address [Section 8.2.2]
NOTE: The offerer can assign a unique address to each bundled "m=" NOTE: The offerer can assign a unique address to each bundled "m="
line in the offer, or it can assign the previously negotiated offerer line in the offer, or it can assign the previously negotiated offerer
BUNDLE address to each "m=" line (except the "m=" line to which it BUNDLE address to each "m=" line (except the "m=" line to which it
assigns the unique address that it wants the answerer to select as assigns the unique address that it wants the answerer to select as
the new offerer BUNDLE address). the new offerer BUNDLE address).
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If the offerer wants the answerer to select the address associated If the offerer wants the answerer to select the address associated
with the added "m=" line as the new offerer BUNDLE address, the with the added "m=" line as the new offerer BUNDLE address, the
offerer suggested BUNDLE mid MUST represent the added "m=" line offerer suggested BUNDLE mid MUST represent the added "m=" line
[Section 8.2.2]. [Section 8.2.2].
If the offerer associates an SDP 'bundle-only' attribute with the If the offerer associates an SDP 'bundle-only' attribute with the
added "m=" line, the offerer MUST assign the offerer BUNDLE address added "m=" line, the offerer MUST assign the offerer BUNDLE address
(selected by the answerer in a previous offer/answer transaction) to (selected by the answerer in a previous offer/answer transaction) to
the "m=" line. the "m=" line.
[Section 15.3] shows an example where an offerer sends an offer in [Section 16.3] shows an example where an offerer sends an offer in
order to add a bundled "m=" line to a BUNDLE group. order to add a bundled "m=" line to a BUNDLE group.
8.5.4. Moving A Media Description Out Of A BUNDLE Group 8.5.4. Moving A Media Description Out Of A BUNDLE Group
When an offerer generates an offer, in which it wants to move a When an offerer generates an offer, in which it wants to move a
bundled "m=" line (added to the BUNDLE group in a previous offer/ bundled "m=" line out of a BUNDLE group it was added to in a previous
answer transaction), the offerer: offer/answer transaction, the offerer:
o MUST assign a unique address to the "m=" line; o MUST assign a unique address to the "m=" line;
o MUST NOT place a mid value associated with the "m=" line in the o MUST NOT place a mid value associated with the "m=" line in the
SDP 'group:BUNDLE' attribute mid list associated with the BUNDLE SDP 'group:BUNDLE' attribute mid list associated with that BUNDLE
group; and group; and
o MUST NOT associate an SDP 'bundle-only' attribute with the "m=" o MUST NOT associate an SDP 'bundle-only' attribute with the "m="
line. line.
[Section 15.4] shows an example of an offer for moving an "m=" line NOTE: If an "m=" line, when being moved out of a BUNDLE group, is
added to another BUNDLE group, the offerer applies the procedures in
[Section 8.5.3] to the "m=" line.
[Section 16.4] shows an example of an offer for moving an "m=" line
out of a BUNDLE group. out of a BUNDLE group.
8.5.5. Disabling A Media Description In A BUNDLE Group 8.5.5. Disabling A Media Description In A BUNDLE Group
When an offerer generates an offer, in which it wants to disable a When an offerer generates an offer, in which it wants to disable a
bundled "m=" line (added to the BUNDLE group in a previous offer/ bundled "m=" line (added to the BUNDLE group in a previous offer/
answer transaction), the offerer: answer transaction), the offerer:
o MUST assign an address with a zero port value to the "m=" line, o MUST assign an address with a zero port value to the "m=" line,
following the procedures in [RFC4566]; following the procedures in [RFC4566];
o MUST NOT place a mid value associated with the "m=" line in the o MUST NOT place a mid value associated with the "m=" line in the
SDP 'group:BUNDLE' attribute mid list associated with the BUNDLE SDP 'group:BUNDLE' attribute mid list associated with the BUNDLE
group; and group; and
o MUST NOT associate an SDP 'bundle-only' attribute with the "m=" o MUST NOT associate an SDP 'bundle-only' attribute with the "m="
line. line.
[Section 15.5] shows an example of an offer for disabling an "m=" [Section 16.5] shows an example of an offer for disabling an "m="
line within a BUNDLE group. line within a BUNDLE group.
9. Protocol Identification 9. Protocol Identification
9.1. General 9.1. General
If bundled "m=" lines represent different transport protocols, there If bundled "m=" lines represent different transport protocols, there
MUST exist a publically available specification which describes a MUST exist a publically available specification which describes a
mechanism, for this specific transport protocol combination, how to mechanism, for this specific transport protocol combination, how to
associate a received packet with the correct transport protocol. associate a received packet with the correct transport protocol.
In addition, if a received packet can be associated with more than In addition, if a received packet can be associated with more than
one bundled "m=" line, there MUST exist a publically available one bundled "m=" line, there MUST exist a publically available
specification which describes a mechanism how to associated the specification which describes a mechanism how to associate the
received packet with the correct "m=" line. received packet with the correct "m=" line.
9.2. STUN, DTLS, SRTP 9.2. STUN, DTLS, SRTP
Section 5.1.2 of [RFC5764] describes a mechanism how to identify the Section 5.1.2 of [RFC5764] describes a mechanism how to identify the
protocol among the STUN, DTLS and SRTP protocols (in any protocol among the STUN, DTLS and SRTP protocols (in any
combination). If an offer or answerer in offers or answers include combination). If an offer or answerer in offers or answers include
bundled "m=" lines that represent these protocols, the offerer or bundled "m=" lines that represent these protocols, the offerer or
answerer MUST support the mechanism described in [RFC5764], and no answerer MUST support the mechanism described in [RFC5764], and no
explicit negotiation is required in order to indicate support and explicit negotiation is required in order to indicate support and
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The following rules and restrictions apply for a single RTP session: The following rules and restrictions apply for a single RTP session:
o A specific payload type value can be used in multiple bundled "m=" o A specific payload type value can be used in multiple bundled "m="
lines if each codec associated with the payload type number shares lines if each codec associated with the payload type number shares
an identical codec configuration [Section 10.1.2]. an identical codec configuration [Section 10.1.2].
o The "proto" value in each bundled "m=" line MUST be identical o The "proto" value in each bundled "m=" line MUST be identical
(e.g. RTP/AVPF). (e.g. RTP/AVPF).
o A given SSRC SHOULD NOT transmit RTP packets using payload types o A given SSRC SHOULD NOT transmit RTP packets using payload types
that originates from different bundled "m=" lines. that originate from different bundled "m=" lines.
NOTE: The last bullet above is to avoid sending multiple media types NOTE: The last bullet above is to avoid sending multiple media types
from the same SSRC. If transmission of multiple media types are done from the same SSRC. If transmission of multiple media types are done
with time overlap RTP and RTCP fails to function. Even if done in with time overlap, RTP and RTCP fail to function. Even if done in
proper sequence this causes RTP Timestamp rate switching issues [ref proper sequence this causes RTP Timestamp rate switching issues [ref
to draft-ietf-avtext-multiple-clock-rates]. to draft-ietf-avtext-multiple-clock-rates].
10.1.2. Payload Type (PT) Value Re-usage 10.1.2. Payload Type (PT) Value Re-usage
Multiple bundled "m=" lines might represent RTP based media. As all Multiple bundled "m=" lines might represent RTP based media. As all
RTP based media associated with a BUNDLE group belong to the same RTP RTP based media associated with a BUNDLE group belong to the same RTP
session, in order for a given payload type value to used inside more session, in order for a given payload type value to used inside more
than one bundled "m=" line, all codecs associated with the payload than one bundled "m=" line, all codecs associated with the payload
type numbers MUST share an identical codec configuration. This means type numbers MUST share an identical codec configuration. This means
that the codecs MUST share the same media type, encoding name, clock that the codecs MUST share the same media type, encoding name, clock
rate and any parameter that can affect the codec configuration and rate and any parameter that can affect the codec configuration and
packetization. [I-D.mmusic-sdp-mux-attributes] lists SDP attributes, packetization. [I-D.mmusic-sdp-mux-attributes] lists SDP attributes,
which attribute values must be identical for all codecs that use the whose attribute values must be identical for all codecs that use the
same payload type value. same payload type value.
10.2. Associating RTP/RTCP Packets With Correct SDP Media Description 10.2. Associating RTP/RTCP Packets With Correct SDP Media Description
In general, there are multiple mechanisms that can be used by an In general, there are multiple mechanisms that can be used by an
endpoint in order to associate received RTP/RTCP packets with the endpoint in order to associate received RTP/RTCP packets with the
bundled "m=" line representing the RTP packets. Such mechanisms bundled "m=" line representing the RTP packets. Such mechanisms
include using the local address:port combination on which the RTP include using the local address:port combination on which the RTP
packets are received, the payload type value carried inside the RTP packets are received, the payload type value carried inside the RTP
packets, the SSRC values carried inside the RTP packets, and other packets, the SSRC values carried inside the RTP packets, and other
skipping to change at page 18, line 51 skipping to change at page 19, line 26
received using the same 5-tuple, the local address:port combination received using the same 5-tuple, the local address:port combination
cannot be used to associate received RTP packets with the correct cannot be used to associate received RTP packets with the correct
"m=" line. "m=" line.
As described in [Section 10.1.2], the same payload type value might As described in [Section 10.1.2], the same payload type value might
be used inside RTP packets described by multiple "m=" lines. In such be used inside RTP packets described by multiple "m=" lines. In such
cases, the payload type value cannot be used to associate received cases, the payload type value cannot be used to associate received
RTP packets with the correct "m=" line. RTP packets with the correct "m=" line.
An offerer and answerer can in an offer and answer inform each other An offerer and answerer can in an offer and answer inform each other
which SSRC values they will use inside sent RTP/RTCP packets by, by which SSRC values they will use inside sent RTP/RTCP packets, by
assigning an SDP 'ssrc' attribute [RFC5576] to each bundled "m=" line assigning an SDP 'ssrc' attribute [RFC5576] to each bundled "m=" line
which contains a payload type value that is also used inside another which contains a payload type value that is also used inside another
bundled "m=" line. As the SSRC values will be carried inside the bundled "m=" line. As the SSRC values will be carried inside the
RTP/RTCP packets, the offerer and answerer can then use that RTP/RTCP packets, the offerer and answerer can then use that
information to associate received RTP packets with the correct "m=" information to associate received RTP packets with the correct "m="
line. However, an offerer will not know which SSRC values the line. However, an offerer will not know which SSRC values the
answerer will use until it has received the answer providing that answerer will use until it has received the answer providing that
information. Due to this, before the offerer has received the information. Due to this, before the offerer has received the
answer, the offerer will not be able to associate received RTP/RTCP answer, the offerer will not be able to associate received RTP/RTCP
packets with the correct "m=" line using the SSRC values. packets with the correct "m=" line using the SSRC values.
skipping to change at page 19, line 39 skipping to change at page 20, line 14
If RTP/RTCP multiplexing is not enabled, separate 5-tuples will be If RTP/RTCP multiplexing is not enabled, separate 5-tuples will be
used for sending and receiving the RTP packets and the RTCP packets. used for sending and receiving the RTP packets and the RTCP packets.
10.3.2. SDP Offer/Answer Procedures 10.3.2. SDP Offer/Answer Procedures
10.3.2.1. General 10.3.2.1. General
This section describes how an offerer and answerer can use the SDP This section describes how an offerer and answerer can use the SDP
'rtcp-mux' attribute [RFC5761] and the SDP 'rtcp' attribute [RFC3605] 'rtcp-mux' attribute [RFC5761] and the SDP 'rtcp' attribute [RFC3605]
to negotiate usage of RTP/RTCP multiplexing for RTP based associated to negotiate usage of RTP/RTCP multiplexing for RTP based media
with a BUNDLE group. associated with a BUNDLE group.
10.3.2.2. Generating the Initial SDP Offer 10.3.2.2. Generating the Initial SDP Offer
When an offerer generates an initial offer, if the offerer wants to When an offerer generates an initial offer, if the offerer wants to
negotiate usage of RTP/RTCP multiplexing within a BUNDLE group, the negotiate usage of RTP/RTCP multiplexing within a BUNDLE group, the
offerer MUST assign an SDP 'rtcp-mux' attribute [RFC5761] to each offerer MUST assign an SDP 'rtcp-mux' attribute [RFC5761] to each
bundled "m=" line (including any bundle-only "m=" line) in the offer. bundled "m=" line (including any bundle-only "m=" line) in the offer.
In addition, the offerer MUST assign an SDP 'rtcp' attribute In addition, the offerer MUST assign an SDP 'rtcp' attribute
[RFC3605] to each bundled "m=" line (including any bundle-only "m=" [RFC3605] to each bundled "m=" line (including any bundle-only "m="
line), with an attribute value that is identical to the port value line), with an attribute value that is identical to the port value
skipping to change at page 20, line 38 skipping to change at page 21, line 13
the answerer MUST assign an SDP 'rtcp-mux' attribute to each bundled the answerer MUST assign an SDP 'rtcp-mux' attribute to each bundled
"m=" line in the answer. I.e. the answerer MUST NOT disable the "m=" line in the answer. I.e. the answerer MUST NOT disable the
usage of RTP/RTCP multiplexing. usage of RTP/RTCP multiplexing.
10.3.2.4. Offerer Processing of the SDP Answer 10.3.2.4. Offerer Processing of the SDP Answer
When the offerer receives an answer, if the answerer accepts the When the offerer receives an answer, if the answerer accepts the
usage of RTP/RTCP multiplexing, by including an SDP 'rtcp-mux' usage of RTP/RTCP multiplexing, by including an SDP 'rtcp-mux'
attribute to each bundled "m=" line in the answer [Section 10.3.2.3], attribute to each bundled "m=" line in the answer [Section 10.3.2.3],
the answerer follows the procedures for RTP/RTCP multiplexing defined the answerer follows the procedures for RTP/RTCP multiplexing defined
in [RFC5245]. in [RFC5761].
If the answerer does not accept the usage of RTP/RTCP multiplexing If the answerer does not accept the usage of RTP/RTCP multiplexing
[Section 10.3.2.3], the offerer MUST use separate 5-tuples for RTP [Section 10.3.2.3], the offerer MUST use separate 5-tuples for RTP
and RTCP. and RTCP.
10.3.2.5. Modifying the Session 10.3.2.5. Modifying the Session
When an offerer generates a subsequent offer, if it wants to When an offerer generates a subsequent offer, if it wants to
negotiate usage of RTP/RTCP multiplexing within a BUNDLE group, or if negotiate usage of RTP/RTCP multiplexing within a BUNDLE group, or if
it wants to continue usage of RTP/RTCP multiplexing (negotiated in a it wants to continue usage of RTP/RTCP multiplexing (negotiated in a
skipping to change at page 23, line 42 skipping to change at page 24, line 21
A stream that is offered with a port of zero MUST be marked with port A stream that is offered with a port of zero MUST be marked with port
zero in the answer. Like the offer, the answer MAY omit all zero in the answer. Like the offer, the answer MAY omit all
attributes present previously, and MAY list just a single media attributes present previously, and MAY list just a single media
format from amongst those in the offer. format from amongst those in the offer.
12.5. New text replacing section 8.2 (2nd paragraph) of RFC 3264 12.5. New text replacing section 8.2 (2nd paragraph) of RFC 3264
A stream that is offered with a port of zero MUST by default be A stream that is offered with a port of zero MUST by default be
marked with port zero in the answer, unless an extension mechanism, marked with port zero in the answer, unless an extension mechanism,
which specifies semantics for the usage of a non-zero port value, is which specifies semantics for the usage of a non-zero port value, is
used. used. If the stream is marked with port zero in the answer, the
answer MAY omit (like the offer) all attributes present previously,
and MAY list just a single media format from amongst those in the
offer."
12.6. Original text of section 8.4 (6th paragraph) of RFC 3264 12.6. Original text of section 8.4 (6th paragraph) of RFC 3264
RFC 2543 [10] specified that placing a user on hold was accomplished RFC 2543 [10] specified that placing a user on hold was accomplished
by setting the connection address to 0.0.0.0. Its usage for putting by setting the connection address to 0.0.0.0. Its usage for putting
a call on hold is no longer recommended, since it doesn't allow for a call on hold is no longer recommended, since it doesn't allow for
RTCP to be used with held streams, doesn't work with IPv6, and breaks RTCP to be used with held streams, doesn't work with IPv6, and breaks
with connection oriented media. However, it can be useful in an with connection oriented media. However, it can be useful in an
initial offer when the offerer knows it wants to use a particular set initial offer when the offerer knows it wants to use a particular set
of media streams and formats, but doesn't know the addresses and of media streams and formats, but doesn't know the addresses and
skipping to change at page 24, line 31 skipping to change at page 25, line 13
number MUST NOT be zero, if it would specify that the stream has been number MUST NOT be zero, if it would specify that the stream has been
disabled. However, an extension mechanism might specify different disabled. However, an extension mechanism might specify different
semantics of the zero port number usage. An agent MUST be capable of semantics of the zero port number usage. An agent MUST be capable of
receiving SDP with a connection address of 0.0.0.0, in which case it receiving SDP with a connection address of 0.0.0.0, in which case it
means that neither RTP nor RTCP should be sent to the peer. means that neither RTP nor RTCP should be sent to the peer.
13. RTP/RTCP extensions for mid value transport 13. RTP/RTCP extensions for mid value transport
13.1. General 13.1. General
SDP Offerers and Answerers [RFC3264] can assign values, mid values, SDP Offerers and Answerers [RFC3264] can assign mid values to SDP
to SDP Media Descriptions (m= lines) within SDP Offers and Answers, Media Descriptions (m= lines) within SDP Offers and Answers, using
using the procedures in [RFC5888]. Each mid value uniquely the procedures in [RFC5888]. Each mid value uniquely identifies an
references an m= line. m= line.
This section defines a new RTP SDES item [RFC3550], 'MID', which is This section defines a new RTP SDES item [RFC3550], 'MID', which is
used to carry mid values within RTCP SDES packets. This section also used to carry mid values within RTCP SDES packets. This section also
defines a new RTP header extension [RFC5285], which can be used to defines a new RTP header extension [RFC5285], which can be used to
carry the mid value in RTP packets. carry the mid value in RTP packets.
The SDES item and RTP header extension makes is possible for a The SDES item and RTP header extension makes is possible for a
receiver to associate received RTCP- and RTP packets with a specific receiver to associate received RTCP- and RTP packets with a specific
m= line, to which the receiver has assigned a mid value, even if m= line, to which the receiver has assigned a mid value, even if
those m= lines are part of the same RTP session. The endpoint those m= lines are part of the same RTP session. The endpoint
informs the remote endpoint about the mid values using the procedures informs the remote endpoint about the mid values using the procedures
in [RFC5888], and the remote endpoint then inserts the mid values in in [RFC5888], and the remote endpoint then inserts the mid values in
RTCP- and RTP packets sent towards the other endpoint. RTCP- and RTP packets sent towards the other endpoint.
NOTE: This text above defines how the mid value is carried in SDP NOTE: This text above defines how the mid value is carried in SDP
Offers and Answers. The usage of other signalling protocols for Offers and Answers. The usage of other signalling protocols for
carrying the mid value is not prevented, but the usage of such carrying the mid value is not prevented, but the usage of such
protocols is outside the scope of this document. protocols is outside the scope of this document.
The RTP MID SDES item SHOULD be sent in the first few RTCP packets [RFC3550] defines general procedures regarding the RTCP transmission
sent on joining the session, and SHOULD be sent regularly thereafter. interval. The RTP MID SDES item SHOULD be sent in the first few RTCP
The exact number of RTCP packets in which this SDES item is sent is packets sent on joining the session, and SHOULD be sent regularly
intentionally not specified here, as it will depend on the expected thereafter. The exact number of RTCP packets in which this SDES item
packet loss rate, the RTCP reporting interval, and the allowable is sent is intentionally not specified here, as it will depend on the
overhead. expected packet loss rate, the RTCP reporting interval, and the
allowable overhead.
The RTP MID header extension SHOULD be included in some RTP packets The RTP MID header extension SHOULD be included in some RTP packets
at the start of the session and whenever the SSRC changes. It might at the start of the session and whenever the SSRC changes. It might
also be useful to include the header extension in RTP packets that also be useful to include the header extension in RTP packets that
comprise random access points in the media (e.g., with video comprise random access points in the media (e.g., with video
I-frames). The exact number of RTP packets in which this header I-frames). The exact number of RTP packets in which this header
extension is sent is intentionally not specified here, as it will extension is sent is intentionally not specified here, as it will
depend on expected packet loss rate and loss patterns, the overhead depend on expected packet loss rate and loss patterns, the overhead
the application can tolerate, and the importance of immediate receipt the application can tolerate, and the importance of immediate receipt
of the mid value. of the mid value.
skipping to change at page 25, line 38 skipping to change at page 26, line 21
13.2. RTP MID SDES Item 13.2. RTP MID SDES Item
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MID=TBD | length | mid value ... | MID=TBD | length | mid value ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The mid value payload is UTF-8 encoded, as in SDP. The mid value payload is UTF-8 encoded, as in SDP.
[RFC EDITOR NOTE: Please replace TBD with the assigned SDES
identifier value.]
13.3. RTP MID Header Extension 13.3. RTP MID Header Extension
The payload, containing the mid value, of the RTP MID header The payload, containing the mid value, of the RTP MID header
extension element can be encoded using either the one-byte or two- extension element can be encoded using either the one-byte or two-
byte header [RFC5285]. The mid value payload is UTF-8 encoded, as in byte header [RFC5285]. The mid value payload is UTF-8 encoded, as in
SDP. SDP.
13.4. IANA Considerations 14. IANA Considerations
14.1. New SDES item
[RFC EDITOR NOTE: Please replace RFCXXXX with the RFC number of this [RFC EDITOR NOTE: Please replace RFCXXXX with the RFC number of this
document.] document.]
[RFC EDITOR NOTE: Please replace TBD with the assigned SDES [RFC EDITOR NOTE: Please replace TBD with the assigned SDES
identifier value.] identifier value.]
This document adds the MID SDES item to the IANA "RTP SDES item This document adds the MID SDES item to the IANA "RTP SDES item
types" registry as follows: types" registry as follows:
Value: TBD Value: TBD
Abbrev.: MID Abbrev.: MID
Name: Media Identification Name: Media Identification
Reference: RFCXXXX Reference: RFCXXXX
14.2. New RTP Header Extension URI
This document defines a new extension URI in the RTP Compact Header This document defines a new extension URI in the RTP Compact Header
Extensions subregistry of the Real-Time Transport Protocol (RTP) Extensions subregistry of the Real-Time Transport Protocol (RTP)
Parameters registry, according to the following data: Parameters registry, according to the following data:
Extension URI: urn:ietf:params:rtp-hdrext:sdes:mid Extension URI: urn:ietf:params:rtp-hdrext:sdes:mid
Description: Media identification Description: Media identification
Contact: christer.holmberg@ericsson.com Contact: christer.holmberg@ericsson.com
Reference: RFCXXXX Reference: RFCXXXX
14. Security Considerations 14.3. New SDP Attribute
This document defines a new SDP media-level attribute, according to
the following data:
Attribute name: bundle-only
Type of attribute: Media-level
Subject to charset: No
Purpose: Request a media description to be accepted
in the answer only if kept within a BUNDLE group
by the answerer
Appropriate values: N/A
Contact name: Christer Holmberg
Contact e-mail: christer.holmberg@ericsson.com
15. Security Considerations
The security considerations defined in [RFC3264] and [RFC5888] apply The security considerations defined in [RFC3264] and [RFC5888] apply
to the BUNDLE extension. to the BUNDLE extension.
When the BUNDLE extension is used the a single set of security When the BUNDLE extension is used a single set of security
credentials might be used for all media streams associated with a credentials might be used for all media streams associated with a
BUNDLE group. If the security credentials are compromised, an BUNDLE group. If the security credentials are compromised, an
attacker will have access to all media content. attacker will have access to all media content.
15. Examples 16. Examples
15.1. Example: Bundle Address Selection 16.1. Example: Bundle Address Selection
The example below shows: The example below shows:
o 1. An offer, in which the offerer assigns a unique address to o 1. An offer, in which the offerer assigns a unique address to
each bundled "m=" line within the BUNDLE group. each bundled "m=" line within the BUNDLE group.
o 2. An answer, in which the answerer selects the offerer BUNDLE o 2. An answer, in which the answerer selects the offerer BUNDLE
address, and in which selects its own BUNDLE address (the answerer address, and in which selects its own BUNDLE address (the answerer
BUNDLE address) and assigns it each bundled "m=" line within the BUNDLE address) and assigns it each bundled "m=" line within the
BUNDLE group. BUNDLE group.
skipping to change at page 28, line 19 skipping to change at page 29, line 25
b=AS:200 b=AS:200
a=rtpmap:0 PCMU/8000 a=rtpmap:0 PCMU/8000
a=rtpmap:8 PCMA/8000 a=rtpmap:8 PCMA/8000
a=rtpmap:97 iLBC/8000 a=rtpmap:97 iLBC/8000
m=video 10000 RTP/AVP 31 32 m=video 10000 RTP/AVP 31 32
a=mid:bar a=mid:bar
b=AS:1000 b=AS:1000
a=rtpmap:31 H261/90000 a=rtpmap:31 H261/90000
a=rtpmap:32 MPV/90000 a=rtpmap:32 MPV/90000
15.2. Example: BUNDLE Extension Rejected 16.2. Example: BUNDLE Extension Rejected
The example below shows: The example below shows:
o 1. An offer, in which the offerer assigns a unique address to o 1. An offer, in which the offerer assigns a unique address to
each bundled "m=" line within the BUNDLE group. each bundled "m=" line within the BUNDLE group.
o 2. An answer, in which the answerer rejects the offered BUNDLE o 2. An answer, in which the answerer rejects the offered BUNDLE
group, and assigns a unique addresses to each "m=" line (following group, and assigns a unique addresses to each "m=" line (following
normal RFC 3264 procedures). normal RFC 3264 procedures).
skipping to change at page 29, line 39 skipping to change at page 30, line 39
s= s=
c=IN IP4 biloxi.example.com c=IN IP4 biloxi.example.com
t=0 0 t=0 0
m=audio 20000 RTP/AVP 0 m=audio 20000 RTP/AVP 0
b=AS:200 b=AS:200
a=rtpmap:0 PCMU/8000 a=rtpmap:0 PCMU/8000
m=video 30000 RTP/AVP 32 m=video 30000 RTP/AVP 32
b=AS:1000 b=AS:1000
a=rtpmap:32 MPV/90000 a=rtpmap:32 MPV/90000
15.3. Example: Offerer Adds A Media Description To A BUNDLE Group 16.3. Example: Offerer Adds A Media Description To A BUNDLE Group
The example below shows: The example below shows:
o 1. An offer, in which the offerer adds a new "m=" line, o 1. An offer, in which the offerer adds a new "m=" line,
represented by the "zen" mid value, to a previously negotiated represented by the "zen" mid value, to a previously negotiated
BUNDLE group, assigns a unique address to the added "m=" line, and BUNDLE group, assigns a unique address to the added "m=" line, and
assigns the previously selected offerer BUNDLE address to each of assigns the previously selected offerer BUNDLE address to each of
the other bundled "m=" lines within the BUNDLE group. the other bundled "m=" lines within the BUNDLE group.
o 2. An answer, in which the answerer assigns the answerer BUNDLE o 2. An answer, in which the answerer assigns the answerer BUNDLE
skipping to change at page 31, line 34 skipping to change at page 32, line 34
m=video 10000 RTP/AVP 31 32 m=video 10000 RTP/AVP 31 32
a=mid:bar a=mid:bar
b=AS:1000 b=AS:1000
a=rtpmap:31 H261/90000 a=rtpmap:31 H261/90000
a=rtpmap:32 MPV/90000 a=rtpmap:32 MPV/90000
m=video 10000 RTP/AVP 66 m=video 10000 RTP/AVP 66
a=mid:zen a=mid:zen
b=AS:1000 b=AS:1000
a=rtpmap:66 H261/90000 a=rtpmap:66 H261/90000
15.4. Example: Offerer Moves A Media Description Out Of A BUNDLE Group 16.4. Example: Offerer Moves A Media Description Out Of A BUNDLE Group
The example below shows: The example below shows:
o 1. An offer, in which the offerer moves a bundled "m=" line out o 1. An offer, in which the offerer moves a bundled "m=" line out
of a BUNDLE group, assigns a unique address to the moved "m=" of a BUNDLE group, assigns a unique address to the moved "m="
line, and assigns the offerer BUNDLE address to each other bundled line, and assigns the offerer BUNDLE address to each other bundled
"m=" line within the BUNDLE group. "m=" line within the BUNDLE group.
o 2. An answer, in which the answerer moves the "m=" line out of o 2. An answer, in which the answerer moves the "m=" line out of
the BUNDLE group, assigns unique address to the moved "m=" line, the BUNDLE group, assigns unique address to the moved "m=" line,
skipping to change at page 33, line 5 skipping to change at page 34, line 5
b=AS:200 b=AS:200
a=rtpmap:0 PCMU/8000 a=rtpmap:0 PCMU/8000
m=video 20000 RTP/AVP 32 m=video 20000 RTP/AVP 32
a=mid:bar a=mid:bar
b=AS:1000 b=AS:1000
a=rtpmap:32 MPV/90000 a=rtpmap:32 MPV/90000
m=video 60000 RTP/AVP 66 m=video 60000 RTP/AVP 66
b=AS:1000 b=AS:1000
a=rtpmap:66 H261/90000 a=rtpmap:66 H261/90000
15.5. Example: Offerer Disables A Media Description Within A BUNDLE 16.5. Example: Offerer Disables A Media Description Within A BUNDLE
Group Group
The example below shows: The example below shows:
o 1. An offer, in which the offerer disables a bundled "m=" line o 1. An offer, in which the offerer disables a bundled "m=" line
within BUNDLE group, assigns a zero port number the disabled "m=" within BUNDLE group, assigns a zero port number the disabled "m="
line, and assigns the offerer BUNDLE address to each of the other line, and assigns the offerer BUNDLE address to each of the other
bundled "m=" lines within the BUNDLE group. bundled "m=" lines within the BUNDLE group.
o 2. An answer, in which the answerer moves the disabled "m=" line o 2. An answer, in which the answerer moves the disabled "m=" line
skipping to change at page 35, line 5 skipping to change at page 36, line 5
a=mid:foo a=mid:foo
b=AS:200 b=AS:200
a=rtpmap:0 PCMU/8000 a=rtpmap:0 PCMU/8000
m=video 20000 RTP/AVP 32 m=video 20000 RTP/AVP 32
a=mid:bar a=mid:bar
b=AS:1000 b=AS:1000
a=rtpmap:32 MPV/90000 a=rtpmap:32 MPV/90000
m=video 0 RTP/AVP 66 m=video 0 RTP/AVP 66
a=rtpmap:66 H261/90000 a=rtpmap:66 H261/90000
16. IANA Considerations 17. IANA Considerations
This document requests IANA to register the new SDP Grouping semantic This document requests IANA to register the new SDP Grouping semantic
extension called BUNDLE. extension called BUNDLE.
17. Acknowledgements 18. Acknowledgements
The usage of the SDP grouping extension for negotiating bundled media The usage of the SDP grouping extension for negotiating bundled media
is based on a similar alternatives proposed by Harald Alvestrand and is based on a similar alternatives proposed by Harald Alvestrand and
Cullen Jennings. The BUNDLE extension described in this document is Cullen Jennings. The BUNDLE extension described in this document is
based on the different alternative proposals, and text (e.g. SDP based on the different alternative proposals, and text (e.g. SDP
examples) have been borrowed (and, in some cases, modified) from examples) have been borrowed (and, in some cases, modified) from
those alternative proposals. those alternative proposals.
The SDP examples are also modified versions from the ones in the The SDP examples are also modified versions from the ones in the
Alvestrand proposal. Alvestrand proposal.
Thanks to Paul Kyzivat, Martin Thompson and Flemming Andreasen for Thanks to Paul Kyzivat, Martin Thomson and Flemming Andreasen for
taking the time to read the text along the way, and providing useful taking the time to read the text along the way, and providing useful
feedback. feedback.
18. 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-bundle-negotiation-10
o SDP bundle-only attribute added to IANA Considerations.
o SDES item and RTP header extension added to Abstract and
Introduction.
o Modification to text updating section 8.2 of RFC 3264.
o Reference corrections.
o Editorial corrections.
Changes from draft-ietf-mmusic-sdp-bundle-negotiation-09 Changes from draft-ietf-mmusic-sdp-bundle-negotiation-09
o Terminology change: "bundle-only attribute assigned to m= line" to o Terminology change: "bundle-only attribute assigned to m= line" to
"bundle-only attribute associated with m= line". "bundle-only attribute associated with m= line".
o Editorial corrections. o Editorial corrections.
Changes from draft-ietf-mmusic-sdp-bundle-negotiation-08 Changes from draft-ietf-mmusic-sdp-bundle-negotiation-08
o Editorial corrections. o Editorial corrections.
skipping to change at page 38, line 14 skipping to change at page 39, line 25
o Draft name changed. o Draft name changed.
o Harald Alvestrand added as co-author. o Harald Alvestrand added as co-author.
o "Multiplex" terminology changed to "bundle". o "Multiplex" terminology changed to "bundle".
o Added text about single versus multiple RTP Sessions. o Added text about single versus multiple RTP Sessions.
o Added reference to RFC 3550. o Added reference to RFC 3550.
19. References 20. References
19.1. 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.
[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, June with Session Description Protocol (SDP)", RFC 3264, June
2002. 2002.
[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.
skipping to change at page 38, line 45 skipping to change at page 40, line 10
Control Packets on a Single Port", RFC 5761, April 2010. Control Packets on a Single Port", RFC 5761, April 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.
[I-D.mmusic-sdp-mux-attributes] [I-D.mmusic-sdp-mux-attributes]
Nandakumar, S., "A Framework for SDP Attributes when Nandakumar, S., "A Framework for SDP Attributes when
Multiplexing", draft-ietf-mmusic-sdp-mux-attributes-02 Multiplexing", draft-ietf-mmusic-sdp-mux-attributes-02
(work in progress), July 2014. (work in progress), July 2014.
19.2. Informative References 20.2. Informative References
[RFC3550] Schulzrinne, H., Casner, S., Frederick, R., and V. [RFC3550] Schulzrinne, H., Casner, S., Frederick, R., and V.
Jacobson, "RTP: A Transport Protocol for Real-Time Jacobson, "RTP: A Transport Protocol for Real-Time
Applications", STD 64, RFC 3550, July 2003. Applications", STD 64, RFC 3550, 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, October in Session Description Protocol (SDP)", RFC 3605, October
2003. 2003.
[RFC5245] Rosenberg, J., "Interactive Connectivity Establishment [RFC5245] Rosenberg, J., "Interactive Connectivity Establishment
 End of changes. 69 change blocks. 
132 lines changed or deleted 186 lines changed or added

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