draft-ietf-mmusic-sdp-bundle-negotiation-23.txt   draft-ietf-mmusic-sdp-bundle-negotiation-24.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: January 21, 2016 C. Jennings Expires: July 14, 2016 C. Jennings
Cisco Cisco
July 20, 2015 January 11, 2016
Negotiating Media Multiplexing Using the Session Description Protocol Negotiating Media Multiplexing Using the Session Description Protocol
(SDP) (SDP)
draft-ietf-mmusic-sdp-bundle-negotiation-23.txt draft-ietf-mmusic-sdp-bundle-negotiation-24.txt
Abstract Abstract
This specification defines a new Session Description Protocol (SDP) This specification defines a new Session Description Protocol (SDP)
Grouping Framework extension, 'BUNDLE'. The extension can be used Grouping Framework extension, 'BUNDLE'. The extension can be used
with the SDP Offer/Answer mechanism to negotiate the usage of a with the SDP Offer/Answer mechanism to negotiate the usage of a
single address:port combination (BUNDLE address) for receiving media, single address:port combination (BUNDLE address) for 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). descriptions ("m=" lines).
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
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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 January 21, 2016. This Internet-Draft will expire on July 14, 2016.
Copyright Notice Copyright Notice
Copyright (c) 2015 IETF Trust and the persons identified as the Copyright (c) 2016 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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7.3. Bandwidth (b=) . . . . . . . . . . . . . . . . . . . . . 9 7.3. Bandwidth (b=) . . . . . . . . . . . . . . . . . . . . . 9
7.4. Attributes (a=) . . . . . . . . . . . . . . . . . . . . . 9 7.4. Attributes (a=) . . . . . . . . . . . . . . . . . . . . . 9
8. SDP Offer/Answer Procedures . . . . . . . . . . . . . . . . . 9 8. SDP Offer/Answer Procedures . . . . . . . . . . . . . . . . . 9
8.1. General . . . . . . . . . . . . . . . . . . . . . . . . . 9 8.1. General . . . . . . . . . . . . . . . . . . . . . . . . . 9
8.2. Generating the Initial SDP Offer . . . . . . . . . . . . 10 8.2. Generating the Initial SDP Offer . . . . . . . . . . . . 10
8.2.1. General . . . . . . . . . . . . . . . . . . . . . . . 10 8.2.1. General . . . . . . . . . . . . . . . . . . . . . . . 10
8.2.2. Suggesting the offerer BUNDLE address . . . . . . . . 11 8.2.2. Suggesting the offerer BUNDLE address . . . . . . . . 11
8.3. Generating the SDP Answer . . . . . . . . . . . . . . . . 11 8.3. Generating the SDP Answer . . . . . . . . . . . . . . . . 11
8.3.1. General . . . . . . . . . . . . . . . . . . . . . . . 11 8.3.1. General . . . . . . . . . . . . . . . . . . . . . . . 11
8.3.2. Answerer Selection of Offerer Bundle Address . . . . 12 8.3.2. Answerer Selection of Offerer Bundle Address . . . . 12
8.3.3. Answerer Selection of Answerer BUNDLE Address . . . . 12 8.3.3. Answerer Selection of Answerer BUNDLE Address . . . . 13
8.3.4. Moving A Media Description Out Of A BUNDLE Group . . 13 8.3.4. Moving A Media Description Out Of A BUNDLE Group . . 13
8.3.5. Rejecting A Media Description In A BUNDLE Group . . . 13 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 . . . . . . . . . . 14
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. Suggesting a new offerer BUNDLE address . . . . . . . 14 8.5.2. Suggesting a new offerer BUNDLE address . . . . . . . 14
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 . . 15 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 . . . . . . . . . . . . . . . . . . . 16
9.1. General . . . . . . . . . . . . . . . . . . . . . . . . . 16 9.1. General . . . . . . . . . . . . . . . . . . . . . . . . . 16
9.2. STUN, DTLS, SRTP . . . . . . . . . . . . . . . . . . . . 17 9.2. STUN, DTLS, SRTP . . . . . . . . . . . . . . . . . . . . 17
10. RTP Considerations . . . . . . . . . . . . . . . . . . . . . 17 10. RTP Considerations . . . . . . . . . . . . . . . . . . . . . 17
10.1. Single RTP Session . . . . . . . . . . . . . . . . . . . 17 10.1. Single RTP Session . . . . . . . . . . . . . . . . . . . 17
10.1.1. General . . . . . . . . . . . . . . . . . . . . . . 17 10.1.1. General . . . . . . . . . . . . . . . . . . . . . . 18
10.1.2. Payload Type (PT) Value Reuse . . . . . . . . . . . 18 10.1.2. Payload Type (PT) Value Reuse . . . . . . . . . . . 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 . . . . . . . . . . . . 20 10.3.2. SDP Offer/Answer Procedures . . . . . . . . . . . . 20
11. ICE Considerations . . . . . . . . . . . . . . . . . . . . . 22 11. ICE Considerations . . . . . . . . . . . . . . . . . . . . . 21
11.1. General . . . . . . . . . . . . . . . . . . . . . . . . 22 11.1. General . . . . . . . . . . . . . . . . . . . . . . . . 21
11.2. SDP Offer/Answer Procedures . . . . . . . . . . . . . . 23 11.2. SDP Offer/Answer Procedures . . . . . . . . . . . . . . 22
11.2.1. General . . . . . . . . . . . . . . . . . . . . . . 23 11.2.1. General . . . . . . . . . . . . . . . . . . . . . . 22
11.2.2. Generating the Initial SDP Offer . . . . . . . . . . 23 11.2.2. Generating the Initial SDP Offer . . . . . . . . . . 22
11.2.3. Generating the SDP Answer . . . . . . . . . . . . . 23 11.2.3. Generating the SDP Answer . . . . . . . . . . . . . 22
11.2.4. Offerer Processing of the SDP Answer . . . . . . . . 24 11.2.4. Offerer Processing of the SDP Answer . . . . . . . . 22
11.2.5. Modifying the Session . . . . . . . . . . . . . . . 24 11.2.5. Modifying the Session . . . . . . . . . . . . . . . 22
12. DTLS Considerations . . . . . . . . . . . . . . . . . . . . . 24 12. DTLS Considerations . . . . . . . . . . . . . . . . . . . . . 23
13. Update to RFC 3264 . . . . . . . . . . . . . . . . . . . . . 24 13. Update to RFC 3264 . . . . . . . . . . . . . . . . . . . . . 23
13.1. General . . . . . . . . . . . . . . . . . . . . . . . . 24 13.1. General . . . . . . . . . . . . . . . . . . . . . . . . 23
13.2. Original text of section 5.1 (2nd paragraph) of RFC 3264 25 13.2. Original text of section 5.1 (2nd paragraph) of RFC 3264 24
13.3. New text replacing section 5.1 (2nd paragraph) of RFC 13.3. New text replacing section 5.1 (2nd paragraph) of RFC
3264 . . . . . . . . . . . . . . . . . . . . . . . . . . 25 3264 . . . . . . . . . . . . . . . . . . . . . . . . . . 24
13.4. Original text of section 8.2 (2nd paragraph) of RFC 3264 25 13.4. Original text of section 8.2 (2nd paragraph) of RFC 3264 24
13.5. New text replacing section 8.2 (2nd paragraph) of RFC 13.5. New text replacing section 8.2 (2nd paragraph) of RFC
3264 . . . . . . . . . . . . . . . . . . . . . . . . . . 26 3264 . . . . . . . . . . . . . . . . . . . . . . . . . . 24
13.6. Original text of section 8.4 (6th paragraph) of RFC 3264 26 13.6. Original text of section 8.4 (6th paragraph) of RFC 3264 25
13.7. New text replacing section 8.4 (6th paragraph) of RFC 13.7. New text replacing section 8.4 (6th paragraph) of RFC
3264 . . . . . . . . . . . . . . . . . . . . . . . . . . 26 3264 . . . . . . . . . . . . . . . . . . . . . . . . . . 25
14. RTP/RTCP extensions for identification-tag transport . . . . 26 14. RTP/RTCP extensions for identification-tag transport . . . . 25
14.1. General . . . . . . . . . . . . . . . . . . . . . . . . 26 14.1. General . . . . . . . . . . . . . . . . . . . . . . . . 25
14.2. RTCP MID SDES Item . . . . . . . . . . . . . . . . . . . 27 14.2. RTCP MID SDES Item . . . . . . . . . . . . . . . . . . . 26
14.3. RTP MID Header Extension . . . . . . . . . . . . . . . . 28 14.3. RTP MID Header Extension . . . . . . . . . . . . . . . . 27
15. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 28 15. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 27
15.1. New SDES item . . . . . . . . . . . . . . . . . . . . . 28 15.1. New SDES item . . . . . . . . . . . . . . . . . . . . . 27
15.2. New RTP Header Extension URI . . . . . . . . . . . . . . 29 15.2. New RTP Header Extension URI . . . . . . . . . . . . . . 28
15.3. New SDP Attribute . . . . . . . . . . . . . . . . . . . 29 15.3. New SDP Attribute . . . . . . . . . . . . . . . . . . . 28
15.4. New SDP Group Semantics . . . . . . . . . . . . . . . . 30 15.4. New SDP Group Semantics . . . . . . . . . . . . . . . . 28
16. Security Considerations . . . . . . . . . . . . . . . . . . . 30 16. Security Considerations . . . . . . . . . . . . . . . . . . . 29
17. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 31 17. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 29
17.1. Example: Bundle Address Selection . . . . . . . . . . . 31 17.1. Example: Bundle Address Selection . . . . . . . . . . . 29
17.2. Example: BUNDLE Extension Rejected . . . . . . . . . . . 33 17.2. Example: BUNDLE Extension Rejected . . . . . . . . . . . 31
17.3. Example: Offerer Adds A Media Description To A BUNDLE 17.3. Example: Offerer Adds A Media Description To A BUNDLE
Group . . . . . . . . . . . . . . . . . . . . . . . . . 34 Group . . . . . . . . . . . . . . . . . . . . . . . . . 32
17.4. Example: Offerer Moves A Media Description Out Of A 17.4. Example: Offerer Moves A Media Description Out Of A
BUNDLE Group . . . . . . . . . . . . . . . . . . . . . . 36 BUNDLE Group . . . . . . . . . . . . . . . . . . . . . . 34
17.5. Example: Offerer Disables A Media Description Within A 17.5. Example: Offerer Disables A Media Description Within A
BUNDLE Group . . . . . . . . . . . . . . . . . . . . . . 37 BUNDLE Group . . . . . . . . . . . . . . . . . . . . . . 35
18. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 39 18. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 37
19. Change Log . . . . . . . . . . . . . . . . . . . . . . . . . 39 19. Change Log . . . . . . . . . . . . . . . . . . . . . . . . . 37
20. References . . . . . . . . . . . . . . . . . . . . . . . . . 45 20. References . . . . . . . . . . . . . . . . . . . . . . . . . 43
20.1. Normative References . . . . . . . . . . . . . . . . . . 45 20.1. Normative References . . . . . . . . . . . . . . . . . . 43
20.2. Informative References . . . . . . . . . . . . . . . . . 46 20.2. Informative References . . . . . . . . . . . . . . . . . 45
Appendix A. Design Considerations . . . . . . . . . . . . . . . 47 Appendix A. Design Considerations . . . . . . . . . . . . . . . 45
A.1. General . . . . . . . . . . . . . . . . . . . . . . . . . 47 A.1. General . . . . . . . . . . . . . . . . . . . . . . . . . 45
A.2. UA Interoperability . . . . . . . . . . . . . . . . . . . 48 A.2. UA Interoperability . . . . . . . . . . . . . . . . . . . 46
A.3. Usage of port number value zero . . . . . . . . . . . . . 49 A.3. Usage of port number value zero . . . . . . . . . . . . . 47
A.4. B2BUA And Proxy Interoperability . . . . . . . . . . . . 49 A.4. B2BUA And Proxy Interoperability . . . . . . . . . . . . 48
A.4.1. Traffic Policing . . . . . . . . . . . . . . . . . . 50 A.4.1. Traffic Policing . . . . . . . . . . . . . . . . . . 48
A.4.2. Bandwidth Allocation . . . . . . . . . . . . . . . . 50 A.4.2. Bandwidth Allocation . . . . . . . . . . . . . . . . 48
A.5. Candidate Gathering . . . . . . . . . . . . . . . . . . . 50 A.5. Candidate Gathering . . . . . . . . . . . . . . . . . . . 49
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 51 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 49
1. Introduction 1. Introduction
This specification defines a way to use a single address:port This specification defines a way to use a single address:port
combination (BUNDLE address) for receiving media associated with combination (BUNDLE address) for receiving media associated with
multiple SDP media descriptions ("m=" lines). multiple SDP media descriptions ("m=" lines).
This specification defines a new SDP Grouping Framework [RFC5888] This specification defines a new SDP Grouping Framework [RFC5888]
extension called 'BUNDLE'. The extension can be used with the extension called 'BUNDLE'. The extension can be used with the
Session Description Protocol (SDP) Offer/Answer mechanism [RFC3264] Session Description Protocol (SDP) Offer/Answer mechanism [RFC3264]
to negotiate the usage of a BUNDLE group. Within the BUNDLE group, a to negotiate the usage of a BUNDLE group. Within the BUNDLE group, a
BUNDLE address is used for receiving media associated with multiple BUNDLE address is used for receiving media associated with multiple
"m=" lines. This is referred to as bundled media. "m=" lines. This is referred to as bundled media.
The offerer and answerer [RFC3264] use the BUNDLE extension to The offerer and answerer [RFC3264] use the BUNDLE extension to
negotiate the BUNDLE addresses, one for the offerer (offerer BUNDLE negotiate the BUNDLE addresses, one for the offerer (offerer BUNDLE
address) and one for the answerer (answerer BUNDLE address), to be address) and one for the answerer (answerer BUNDLE address), to be
used for receiving the bundled media associated with a BUNDLE group. used for receiving the bundled media associated with a BUNDLE group.
Once the offerer and the answerer have negotiated a BUNDLE group, Once the offerer and the answerer have negotiated a BUNDLE group,
they assign their respective BUNDLE address to each "m=" line in the they associate their respective BUNDLE address with each "m=" line in
BUNDLE group. The BUNDLE addresses are used to receive all media the BUNDLE group. The BUNDLE addresses are used to receive all media
associated with the BUNDLE group. associated with the BUNDLE group.
The use of a BUNDLE group and a BUNDLE address also allows the usage The use of a BUNDLE group and a BUNDLE address also allows the usage
of a single set of Interactive Connectivity Establishment (ICE) of a single set of Interactive Connectivity Establishment (ICE)
[RFC5245] candidates for multiple "m=" lines. [RFC5245] candidates for multiple "m=" lines.
This specification also defines a new SDP attribute, 'bundle-only', This specification also defines a new SDP attribute, 'bundle-only',
which can be used to request that specific media is only used if kept which can be used to request that specific media is only used if kept
within a BUNDLE group. within a BUNDLE group.
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correlate a RTP packet with the correct media. correlate a RTP packet with the correct media.
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. The address MUST only be associated with a single BUNDLE group. The
procedures in this specification apply independently to a given procedures in this specification apply independently to a given
BUNDLE group. All RTP based media flows associated with a single BUNDLE group. All RTP based media flows associated with a single
BUNDLE group belong to a single RTP session [RFC3550]. BUNDLE group belong to a single RTP session [RFC3550].
The BUNDLE extension is backward compatible. Endpoints that do not The BUNDLE extension is backward compatible. Endpoints that do not
support the extension are expected to generate offers and answers support the extension are expected to generate offers and answers
without an SDP 'group:BUNDLE' attribute, and are expected to assign a without an SDP 'group:BUNDLE' attribute, and are expected to
unique address to each "m=" line within an offer and answer, associate a unique address with each "m=" line within an offer and
according to the procedures in [RFC4566] and [RFC3264] answer, according to the procedures in [RFC4566] and [RFC3264]
2. Terminology 2. Terminology
"m=" line: SDP bodies contain one or more media descriptions. Each "m=" line: SDP bodies contain one or more media descriptions. Each
media description is identified by an SDP "m=" line. media description is identified by an SDP "m=" line.
5-tuple: A collection of the following values: source address, source 5-tuple: A collection of the following values: source address, source
port, destination address, destination port, and transport-layer port, destination address, destination port, and transport-layer
protocol. protocol.
Unique address: An IP address and port combination that is assigned Unique address: An IP address and port combination that is associated
to only one "m=" line in an offer or answer. with only one "m=" line in an offer or answer.
Shared address: An IP address and port combination that is assigned Shared address: An IP address and port combination that is associated
to multiple "m=" lines within an offer or answer. with multiple "m=" lines within an offer or answer.
Offerer BUNDLE-tag: The first identification-tag in a given SDP Offerer BUNDLE-tag: The first identification-tag in a given SDP
'group:BUNDLE' attribute identification-tag list in an offer. 'group:BUNDLE' attribute identification-tag list in an offer.
Answerer BUNDLE-tag: The first identification-tag in a given SDP Answerer BUNDLE-tag: The first identification-tag in a given SDP
'group:BUNDLE' attribute identification-tag list in an answer. 'group:BUNDLE' attribute identification-tag list in an answer.
Offerer BUNDLE address: Within a given BUNDLE group, an IP address Offerer BUNDLE address: Within a given BUNDLE group, an IP address
and port combination used by an offerer to receive all media and 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.
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MAY be the same as the BUNDLE address, used to receive bundled media, MAY be the same as the BUNDLE address, used to receive bundled media,
depending on whether symmetric RTP [RFC4961] is used. depending on whether symmetric RTP [RFC4961] is used.
All media associated with a BUNDLE group share a single 5-tuple, i.e. All media associated with a BUNDLE group share a single 5-tuple, i.e.
in addition to using a single address:port combination all bundled in addition to using a single address:port combination all bundled
media MUST be transported using the same transport-layer protocol media MUST be transported using the same transport-layer protocol
(e.g. UDP or TCP). (e.g. UDP or TCP).
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 identification-tag is a "BUNDLE" semantics value [RFC5888]. An identification-tag is
assigned to each bundled "m=" line, and each identification-tag is associated with each bundled "m=" line, and each identification-tag
listed in the SDP 'group:BUNDLE' attribute identification-tag list. is listed in the SDP 'group:BUNDLE' attribute identification-tag
Each "m=" line whose identification-tag is listed in the list. Each "m=" line whose identification-tag is listed in the
identification-tag list is associated with a given BUNDLE group. identification-tag list is associated 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
This section defines a new SDP media-level attribute [RFC4566], This section defines a new SDP media-level attribute [RFC4566],
'bundle-only'. 'bundle-only'. 'bundle-only' is a property attribute [RFC4566], and
hence has no value.
Name: bundle-only Name: bundle-only
Value: Value: N/A
Usage Level: media Usage Level: media
Charset Dependent: no Charset Dependent: no
Example: Example:
a=bundle-only a=bundle-only
In order to ensure that an answerer that does not support the BUNDLE In order to ensure that an answerer that does not support the BUNDLE
extension always rejects a bundled "m=" line, the offerer can assign extension always rejects a bundled "m=" line, the offerer can assign
a zero port value to the "m=" line. According to [RFC4566] an a zero port value to the "m=" line. According to [RFC4566] an
answerer will reject such "m=" line. By associating an SDP 'bundle- answerer will reject such "m=" line. By associating an SDP 'bundle-
only' attribute with such "m=" line, the offerer can request that the only' attribute with such "m=" line, the offerer can request that the
answerer accepts the "m=" line if the answerer supports the Bundle answerer accepts the "m=" line if the answerer supports the Bundle
extension, and if the answerer keeps the "m=" line within the extension, and if the answerer keeps the "m=" line within the
associated BUNDLE group. associated BUNDLE group.
NOTE: Once the offerer BUNDLE address has been selected, the offerer NOTE: Once the offerer BUNDLE address has been selected, the offerer
does not need to include the 'bundle-only' attribute in subsequent does not need to include the 'bundle-only' attribute in subsequent
offers. By assigning the offerer BUNDLE address to an "m=" line of a offers. By associating the offerer BUNDLE address with an "m=" line
subsequent offer, the offerer will ensure that the answerer will of a subsequent offer, the offerer will ensure that the answerer will
either keep the "m=" line within the BUNDLE group, or the answerer either keep the "m=" line within the BUNDLE group, or the answerer
will have to reject the "m=" line. will have to reject the "m=" line.
The usage of the 'bundle-only' attribute is only defined for a The usage of the 'bundle-only' attribute is only defined for a
bundled "m=" line with a zero port value, within an offer. Other bundled "m=" line with a zero port value, within an offer. Other
usage is unspecified. usage is unspecified.
Section 8 defines the detailed SDP Offer/Answer procedures for the Section 8 defines the detailed SDP Offer/Answer procedures for the
'bundle-only' attribute. 'bundle-only' attribute.
skipping to change at page 9, line 36 skipping to change at page 9, line 36
An offerer and answerer MUST use the rules and restrictions defined An offerer and answerer MUST use the rules and restrictions defined
in [I-D.mmusic-sdp-mux-attributes] for when associating SDP in [I-D.mmusic-sdp-mux-attributes] for when associating SDP
attributes with bundled "m=" lines. attributes with bundled "m=" lines.
8. SDP Offer/Answer Procedures 8. SDP Offer/Answer Procedures
8.1. General 8.1. General
This section describes the SDP Offer/Answer [RFC3264] procedures for: This section describes the SDP Offer/Answer [RFC3264] procedures for:
o Negotiating and creating of a BUNDLE group; o Negotiating and creating of a BUNDLE group; and
o Selecting the BUNDLE addresses (offerer BUNDLE address and o Selecting the BUNDLE addresses (offerer BUNDLE address and
answerer BUNDLE address); answerer BUNDLE address); and
o Adding an "m=" line to a BUNDLE group; o Adding an "m=" line to a BUNDLE group; and
o Moving an "m=" line out of a BUNDLE group; and o Moving an "m=" line out of a BUNDLE group; and
o Disabling an "m=" line within a BUNDLE group. o Disabling an "m=" line within a BUNDLE group.
The generic rules and procedures defined in [RFC3264] and [RFC5888] The generic rules and procedures defined in [RFC3264] and [RFC5888]
also apply to the BUNDLE extension. For example, if an offer is also apply to the BUNDLE extension. For example, if an offer is
rejected by the answerer, the previously negotiated SDP parameters rejected by the answerer, the previously negotiated SDP parameters
and characteristics (including those associated with a BUNDLE group) and characteristics (including those associated with a BUNDLE group)
apply. Hence, if an offerer generates an offer in which the offerer apply. Hence, if an offerer generates an offer in which the offerer
skipping to change at page 10, line 28 skipping to change at page 10, line 28
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], unless the media line is a following the procedures in [RFC3264], unless the media line is a
'bundle-only' "m=" line (see below); 'bundle-only' "m=" line (see below); and
o Add an SDP 'group:BUNDLE' attribute to the offer; o Add an SDP 'group:BUNDLE' attribute to the offer; and
o Place the identification-tag of each bundled "m=" line in the SDP o Place the identification-tag of each bundled "m=" line in the SDP
'group:BUNDLE' attribute identification-tag list; and 'group:BUNDLE' attribute identification-tag list; and
o Indicate which unique address the offerer suggests as the offerer o Indicate which unique address the offerer suggests as the offerer
BUNDLE address [Section 8.2.2]. 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
bundled "m=" line only if the answerer keeps the "m=" line within the bundled "m=" line only if the answerer keeps the "m=" line within the
BUNDLE group, the offerer MUST: BUNDLE group, the offerer MUST:
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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 17.1] shows an example of an initial offer. [Section 17.1] shows an example of an initial offer.
8.2.2. Suggesting the offerer BUNDLE address 8.2.2. Suggesting the offerer BUNDLE address
In the offer, the address assigned to the "m=" line associated with In the offer, the address associated with the "m=" line associated
the offerer BUNDLE-tag indicates the address that the offerer with the offerer BUNDLE-tag indicates the address that the offerer
suggests as the offerer BUNDLE address. suggests as the offerer BUNDLE address.
The "m=" line associated with the offerer BUNDLE-tag MUST NOT contain
a zero port value or an SDP 'bundle-only' attribute.
8.3. Generating the SDP Answer 8.3. Generating the SDP Answer
8.3.1. General 8.3.1. General
When an answerer generates an answer that contains a BUNDLE group, When an answerer generates an answer that 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
skipping to change at page 11, line 46 skipping to change at page 11, line 49
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 the answerer keeps a bundle-only "m=" line within the BUNDLE If the answerer keeps a bundle-only "m=" line within the BUNDLE
group, it follows the procedures (assigns the answerer BUNDLE address group, it follows the procedures (associates the answerer BUNDLE
to the "m=" line etc) for any other "m=" line kept within the BUNDLE address with the "m=" line etc) for any other "m=" line kept within
group. the BUNDLE group.
If the answerer does not want to keep a bundle-only "m=" line within 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 BUNDLE group, it MUST reject the "m=" line [Section 8.3.5].
The answerer MUST NOT associate an SDP 'bundle-only' attribute with The answerer MUST NOT associate an SDP 'bundle-only' attribute with
any "m=" line in an answer. any "m=" line in an answer.
NOTE: If a bundled "m=" line in an offer contains a zero port value, NOTE: If a bundled "m=" line in an offer contains a zero port 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) associated with the
"m=" line associated with the offerer BUNDLE-tag indicates the bundled "m=" line associated with the offerer BUNDLE-tag indicates
address that the offerer suggests as the offerer BUNDLE address the address that the offerer suggests as the offerer BUNDLE address
[Section 8.2.2]. The answerer MUST check whether that "m=" line [Section 8.2.2]. The answerer MUST check whether that "m=" line
fulfils the following criteria: 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]; and
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 are fulfilled, the answerer MUST select If all of the criteria above are 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 BUNDLE-tag represents the "m=" address. In the answer, the answerer BUNDLE-tag represents the "m="
line, and the address associated with the "m=" line in the offer line, and the address associated with the "m=" line in the offer
becomes the offerer BUNDLE address. becomes the offerer BUNDLE address.
skipping to change at page 12, line 50 skipping to change at page 13, line 8
answerer MUST apply the answerer procedures for moving an "m=" line answerer MUST apply the answerer procedures for moving an "m=" line
out of a BUNDLE group [Section 8.3.4] to each bundled "m=" line in out of a BUNDLE group [Section 8.3.4] to each bundled "m=" line in
the offer when creating the answer. the offer when creating the answer.
[Section 17.1] shows an example of an offerer BUNDLE address [Section 17.1] 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 that address to each the answerer BUNDLE address, it MUST associate that address with 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 associate the answerer BUNDLE address with an
line that is not within the BUNDLE group, or to an "m=" line that is "m=" line that is not within the BUNDLE group, or to an "m=" line
within another BUNDLE group. that is within another BUNDLE group.
[Section 17.1] shows an example of an answerer BUNDLE address [Section 17.1] 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 wants to move an "m=" line out of a BUNDLE group, it When an answerer wants to move an "m=" line out of a BUNDLE group, it
MUST first check the following criteria: MUST first check the following criteria:
o In the associated offer, the "m=" line contains a shared address o In the associated offer, the "m=" line is associated with a shared
(e.g. a previously selected offerer BUNDLE address); or address (e.g. a previously selected offerer BUNDLE address); or
o In the associated offer, if an SDP 'bundle-only' attribute is o In the associated offer, if an SDP 'bundle-only' attribute is
associated with the "m=" line, and if the "m=" line contains a associated with the "m=" line, and if the "m=" line contains a
zero port value. zero port value.
If either criteria above is fulfilled, the answerer MUST reject the If either criteria above is fulfilled, the answerer MUST reject the
"m=" line [Section 8.3.5]. "m=" line [Section 8.3.5].
Otherwise, if in the associated offer the "m=" line contains a unique Otherwise, if in the associated offer the "m=" line is associated
address, the answerer MUST assign a unique address to the "m=" line with a unique address, the answerer MUST associate a unique address
in the answer (the answerer does not reject the "m=" line). with the "m=" line in the answer (the answerer does not reject the
"m=" line).
In addition, in either case above, the answerer MUST NOT place the In addition, in either case above, the answerer MUST NOT place the
identification-tag, associated with the moved "m=" line, in the SDP identification-tag, associated with the moved "m=" line, in the SDP
'group' attribute identification-tag list associated with the BUNDLE 'group' attribute identification-tag list associated with the BUNDLE
group. group.
8.3.5. Rejecting A Media Description In A BUNDLE Group 8.3.5. Rejecting A Media Description In A BUNDLE Group
When an answerer rejects an "m=" line, it MUST assign an address with When an answerer rejects an "m=" line, it MUST associate an address
a zero port value to the "m=" line in the answer, according to the with a zero port value with the "m=" line in the answer, according to
procedures in [RFC4566]. the procedures in [RFC4566].
In addition, the answerer MUST NOT place the identification-tag, In addition, the answerer MUST NOT place the identification-tag,
associated with the rejected "m=" line, in the SDP 'group' attribute associated with the rejected "m=" line, in the SDP 'group' attribute
identification-tag list associated with the BUNDLE group. identification-tag list associated with the BUNDLE group.
8.4. Offerer Processing of the SDP Answer 8.4. Offerer Processing of the SDP Answer
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
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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.
8.5. 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 associate the
previously selected offerer BUNDLE address [Section 8.3.2], to each previously selected offerer BUNDLE address [Section 8.3.2] with each
bundled "m=" line (including any bundle-only "m=" line), except if: bundled "m=" line (including any bundle-only "m=" line), except if:
o The offerer suggests a new offerer BUNDLE address [Section 8.5.2]; o The offerer suggests a new offerer BUNDLE address [Section 8.5.2];
or
o The offerer wants to add a bundled "m=" line to the BUNDLE group o The offerer wants to add a bundled "m=" line to the BUNDLE group
[Section 8.5.3]; [Section 8.5.3]; or
o The offerer wants to move a bundled "m=" line out of the BUNDLE o The offerer wants to move a bundled "m=" line out of the BUNDLE
group [Section 8.5.4]; or group [Section 8.5.4]; or
o The offerer wants to disable the bundled "m=" line o The offerer wants to disable the bundled "m=" line
[Section 8.5.5]. [Section 8.5.5].
In addition, the offerer MUST select an offerer BUNDLE-tag In addition, the offerer MUST select an offerer BUNDLE-tag
[Section 8.2.2] associated with the previously selected offerer [Section 8.2.2] associated with the previously selected offerer
BUNDLE address, unless the offerer suggests a new offerer BUNDLE BUNDLE address, unless the offerer suggests a new offerer BUNDLE
skipping to change at page 15, line 5 skipping to change at page 15, line 10
offerer BUNDLE address [Section 8.2.2], the offerer MUST: offerer BUNDLE address [Section 8.2.2], the offerer MUST:
o Assign the address (shared address) to each "m=" line within the o Assign the address (shared address) to each "m=" line within the
BUNDLE group; or BUNDLE group; or
o Assign the address (unique address) to one bundled "m=" line. o Assign the address (unique address) to one bundled "m=" line.
In addition, the offerer MUST indicate that the address is the new In addition, the offerer MUST indicate that the address is the new
suggested offerer BUNDLE address [Section 8.2.2]. suggested offerer BUNDLE address [Section 8.2.2].
NOTE: Unless the offerer assigns the new suggested offerer BUNDLE NOTE: Unless the offerer associates the new suggested offerer BUNDLE
address to each bundled "m=" line, it can assign unique addresses to address with each bundled "m=" line, it can associate unique
any number of bundled "m=" lines (and the previously selected offerer addresses with any number of bundled "m=" lines (and the previously
BUNDLE address to any remaining bundled "m=" line) if it wants to selected offerer BUNDLE address to any remaining bundled "m=" line)
suggest multiple alternatives for the new offerer BUNDLE address. if it wants to suggest multiple alternatives for the new offerer
BUNDLE address.
8.5.3. Adding a media description to a BUNDLE group 8.5.3. Adding a media description to a BUNDLE group
When an offerer generates an offer, in which it wants to add a When an offerer generates an offer, in which it wants to add a
bundled "m=" line to a BUNDLE group, the offerer MUST: bundled "m=" line to a BUNDLE group, the offerer MUST:
o Assign a unique address to the "m=" line; o Assign a unique address to the added "m=" line; or
o Assign the previously selected offerer BUNDLE address to the "m=" o Assign the previously selected offerer BUNDLE address to the added
line; or "m=" line; or
o If the offerer assigns a new (shared address) suggested offerer o If the offerer associates a new (shared address) suggested offerer
BUNDLE address to each bundled "m=" line [Section 8.5.2], also BUNDLE address with each bundled "m=" line [Section 8.5.2], also
assign that address to the added "m=" line. associate that address with the added "m=" line.
In addition, the offerer MUST extend the SDP 'group:BUNDLE' attribute In addition, the offerer MUST extend the SDP 'group:BUNDLE' attribute
identification-tag list with the BUNDLE group [Section 8.2.2] by identification-tag list with the BUNDLE group [Section 8.2.2] by
adding the identification-tag associated with the added "m=" line to adding the identification-tag associated with the added "m=" line to
the list. the list.
NOTE: Assigning a unique address to the "m=" line allows the answerer NOTE: Assigning a unique address to the "m=" line allows the answerer
to move the "m=" line out of the BUNDLE group [Section 8.3.4], to move the "m=" line out of the BUNDLE group [Section 8.3.4],
without having to reject the "m=" line. without having to reject the "m=" line.
If the offerer assigns a unique address to the added "m=" line, and If the offerer associates a unique address with the added "m=" line,
if the offerer suggests that address as the new offerer BUNDLE and if the offerer suggests that address as the new offerer BUNDLE
address [Section 8.5.2], the offerer BUNDLE-tag MUST represent the address [Section 8.5.2], the offerer BUNDLE-tag MUST represent the
added "m=" line [Section 8.2.2]. added "m=" line [Section 8.2.2].
If the offerer assigns a new suggested offerer BUNDLE address to each If the offerer associates a new suggested offerer BUNDLE address with
bundled "m=" line [Section 8.5.2], including the added "m=" line, the each bundled "m=" line [Section 8.5.2], including the added "m="
offerer BUNDLE-tag MAY represent the added "m=" line [Section 8.2.2]. line, the offerer BUNDLE-tag MAY represent the added "m=" line
[Section 8.2.2].
[Section 17.3] shows an example where an offerer sends an offer in [Section 17.3] 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 out of a BUNDLE group it was added to in a previous bundled "m=" line out of a BUNDLE group it was added to in a previous
offer/answer transaction, the offerer: offer/answer transaction, the offerer:
o MUST assign a unique address to the "m=" line; and o MUST associate a unique address with the "m=" line; and
o MUST NOT place the identification-tag associated with the "m=" o MUST NOT place the identification-tag associated with the "m="
line in the SDP 'group:BUNDLE' attribute identification-tag list line in the SDP 'group:BUNDLE' attribute identification-tag list
associated with the BUNDLE group. associated with the BUNDLE group.
NOTE: If the removed "m=" line is associated with the previously NOTE: If the removed "m=" line is associated with the previously
selected BUNDLE-tag, the offerer needs to suggest a new BUNDLE-tag selected BUNDLE-tag, the offerer needs to suggest a new BUNDLE-tag
[Section 8.2.2]. [Section 8.2.2].
NOTE: If an "m=" line, when being moved out of a BUNDLE group, is 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 added to another BUNDLE group, the offerer applies the procedures in
skipping to change at page 16, line 25 skipping to change at page 16, line 34
[Section 17.4] shows an example of an offer for moving an "m=" line [Section 17.4] 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 associate an address with a zero port value with the "m="
following the procedures in [RFC4566]; and line, following the procedures in [RFC4566]; and
o MUST NOT place the identification-tag associated with the "m=" o MUST NOT place the identification-tag associated with the "m="
line in the SDP 'group:BUNDLE' attribute identification-tag list line in the SDP 'group:BUNDLE' attribute identification-tag list
associated with the BUNDLE group. associated with the BUNDLE group.
[Section 17.5] shows an example of an offer for disabling an "m=" [Section 17.5] 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
skipping to change at page 18, line 26 skipping to change at page 18, line 37
o A given SSRC MUST NOT transmit RTP packets using payload types o A given SSRC MUST NOT transmit RTP packets using payload types
that originate 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 fail 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 proper sequence this causes RTP Timestamp rate switching issues
[RFC7160]. However, once an SSRC has left the RTP session (by [RFC7160]. However, once an SSRC has left the RTP session (by
sending an RTCP BYE packet), that SSRC value can later be reused by sending an RTCP BYE packet), that SSRC value can later be reused by
another source(possible associated with a different bundled "m=" another source(possibly associated with a different bundled "m="
line. line.
10.1.2. Payload Type (PT) Value Reuse 10.1.2. Payload Type (PT) Value Reuse
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 be used inside session, in order for a given payload type value to be used inside
more than one bundled "m=" line, all codecs associated with the more than one bundled "m=" line, all codecs associated with the
payload type number MUST share an identical codec configuration. payload type number MUST share an identical codec configuration.
This means that the codecs MUST share the same media type, encoding This means that the codecs MUST share the same media type, encoding
skipping to change at page 19, line 37 skipping to change at page 19, line 49
received RTP and RTCP packets with the correct "m=" line, an offerer received RTP and RTCP packets with the correct "m=" line, an offerer
and answerer using the BUNDLE extension MUST support the mechanism and answerer using the BUNDLE extension MUST support the mechanism
defined in Section 14, where the remote endpoint inserts the defined in Section 14, where the remote endpoint inserts the
identification-tag associated with an "m=" line in RTP and RTCP identification-tag associated with an "m=" line in RTP and RTCP
packets associated with that "m=" line. packets associated with that "m=" line.
10.3. RTP/RTCP Multiplexing 10.3. RTP/RTCP Multiplexing
10.3.1. General 10.3.1. General
When a BUNDLE group, which contains RTP based media, is created, the Within a BUNDLE group, the offerer and answerer MUST enable RTP/RTCP
offerer and answerer MUST negotiate whether to enable RTP/RTCP multiplexing [RFC5761] for the RTP-based media associated with the
multiplexing for the RTP based media associated with the BUNDLE group BUNDLE group.
[RFC5761].
If RTP/RTCP multiplexing is enabled, the same address:port When RTP/RTCP multiplexing is enabled, the same address:port
combination will be used for sending all RTP packets and the RTCP combination will be used for sending all RTP packets and the RTCP
packets associated with the BUNDLE group. Each endpoint will send packets associated with the BUNDLE group. Each endpoint will send
the packets towards the BUNDLE address of the other endpoint. The the packets towards the BUNDLE address of the other endpoint. The
same address:port combination MAY be used for receiving RTP packets same address:port combination MAY be used for receiving RTP packets
and RTCP packets. and RTCP packets.
If RTP/RTCP multiplexing is not enabled, separate address:port
combinations will be used for sending the RTP packets and the RTCP
packets. The same address:port combinations MAY be used for
receiving RTP packets and RTCP packets. If the remote endpoint has
associated an SDP 'rtcp' attribute with the "m=" line associated with
the BUNDLE-tag, the attribute value will be used for sending all RTCP
packets associated with the BUNDLE group towards that endpoint.
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 use the SDP 'rtcp-
'rtcp-mux' attribute [RFC5761] and the SDP 'rtcp' attribute [RFC3605] mux' attribute [RFC5761] to negotiate usage of RTP/RTCP multiplexing
to negotiate usage of RTP/RTCP multiplexing for RTP based media for RTP-based media associated with a BUNDLE group.
associated with a BUNDLE group.
10.3.2.2. Generating the Initial SDP Offer The procedures in this section only apply to RTP-based "m=" lines.
When an offerer generates an initial offer, if the offerer wants to 10.3.2.2. Generating the Initial SDP Offer
negotiate usage of RTP/RTCP multiplexing within a BUNDLE group, the
offerer MUST associate an SDP 'rtcp-mux' attribute [RFC5761] with
each bundled RTP-based "m=" line (including any bundle-only "m="
line) in the offer.
If the offerer does not want to negotiate usage of RTP/RTCP When an offerer generates an initial offer, the offerer MUST
multiplexing, it MUST NOT associate an SDP 'rtcp-mux' attribute with associate an SDP 'rtcp-mux' attribute [RFC5761] with each bundled
any bundled "m=" line in the offer. RTP-based "m=" line (including any bundle-only "m=" line) in the
offer.
In addition, the offerer can associate an SDP 'rtcp' attribute NOTE: The offerer might also associate an SDP 'rtcp' attribute
[RFC3605] with one or more bundled RTP-based "m=" lines (including [RFC3605] with a bundled "m=" line, excluding a bundle-only "m="
any bundle-only "m=" line) in the offer, in order to provide a port line, in order to provide a fallback port for RTCP. However, the
for receiving RTCP packets (if the answerer does not accept usage of fallback port will only be used in case the answerer does not include
RTP/RTCP multiplexing, or if the offerer does not want to negotiate the "m=" line in the BUNDLE group in the associated answer.
usage of RTP/RTCP multiplexing).
In the initial offer, the IP address and port combination for RTCP In the initial offer, the IP address and port combination for RTCP
MUST be unique in each bundled RTP-based "m=" line, similar to RTP. MUST be unique in each bundled RTP-based "m=" line (excluding a
'bundle-only' "m=" line), similar to RTP.
NOTE: In case the offer wants to receive RTCP packets on the next
higher port value, the SDP 'rtcp' attribute is not needed.
10.3.2.3. Generating the SDP Answer 10.3.2.3. Generating the SDP Answer
When an answerer generates an answer, if the offerer indicated When an answerer generates an answer, if the offerer indicated
support of RTP/RTCP multiplexing [RFC5761] within a BUNDLE group in support of RTP/RTCP multiplexing [RFC5761] within a BUNDLE group in
the associated offer, the answerer MUST either accept or reject the the associated offer, the answerer MUST accept usage of RTP/RTCP
usage of RTP/RTCP multiplexing for the whole BUNDLE group in the multiplexing within the BUNDLE group. If an SDP "rtcp-mux" attribute
answer. was not associated with a bundled "m=" line in the associated offer,
the answerer MUST NOT included that "m=" line in the BUNDLE group.
If the answerer accepts the usage of RTP/RTCP multiplexing within the
BUNDLE group, it MUST associate an SDP 'rtcp-mux' attribute with each
bundled RTP-based "m=" line in the answer. The answerer MUST NOT
associate an SDP 'rtcp' attribute with any bundled "m=" line in the
answer. The answerer will use the port value of the selected offerer
BUNDLE address for sending RTP and RTCP packets associated with each
RTP-based bundled "m=" line towards the offerer.
If the answerer does not accept the usage of RTP/RTCP multiplexing When the answerer accepts the usage of RTP/RTCP multiplexing within
within the BUNDLE group, it MUST NOT associate an SDP 'rtcp-mux' the BUNDLE group, it MUST associate an SDP 'rtcp-mux' attribute with
attribute with any bundled "m=" line in the answer. The answerer each bundled RTP-based "m=" line in the answer. The answerer MUST
will use the RTP and RTCP port values associated with the selected NOT associate an SDP 'rtcp' attribute with any bundled "m=" line in
the answer. The answerer will use the port value of the selected
offerer BUNDLE address for sending RTP and RTCP packets associated offerer BUNDLE address for sending RTP and RTCP packets associated
with each RTP-based bundled "m=" line towards the offerer. with each RTP-based bundled "m=" line towards the offerer.
In addition, if the answerer rejects the usage of RTP/RTCP
multiplexing within the BUNDLE group, it MAY associate an SDP 'rtcp'
attribute, with identical attribute values, with each RTP-based
bundled "m=" line in the answer, in order to provide a port value for
receiving RTCP packets from the offerer.
NOTE: In case the answerer wants to receive RTCP packets on the next
higher port value, the SDP 'rtcp' attribute is not needed.
If the usage of RTP/RTCP multiplexing within a BUNDLE group has been If the usage of RTP/RTCP multiplexing within a BUNDLE group has been
negotiated in a previous offer/answer transaction, and if the offerer negotiated in a previous offer/answer transaction, the answerer MUST
indicates that it wants to continue using RTP/RTCP multiplexing in a associate an SDP 'rtcp-mux' attribute with each bundled RTP-based
subsequent offer, the answerer MUST associate an SDP 'rtcp-mux' "m=" line in the answer.
attribute with each bundled "m=" line in the answer. I.e. the
answerer MUST NOT disable the usage of RTP/RTCP multiplexing.
If the usage of RTP/RTCP multiplexing within a BUNDLE group has not
been negotiated in a previous offer/answer transaction, and if the
offerer indicates that it wants to use RTP/RTCP multiplexing in a
subsequent offer, the answerer either accepts or rejects the usage,
using the procedures above.
10.3.2.4. Offerer Processing of the SDP Answer 10.3.2.4. Offerer Processing of the SDP Answer
When an offerer receives an answer, if the answerer has accepted the When an offerer receives an answer, if the answerer has accepted the
usage of RTP/RTCP multiplexing (see Section 10.3.2.3), the answerer usage of RTP/RTCP multiplexing (see Section 10.3.2.3), the answerer
follows the procedures for RTP/RTCP multiplexing defined in follows the procedures for RTP/RTCP multiplexing defined in
[RFC5761]. The offerer will use the port value associated with the [RFC5761]. The offerer will use the port value associated with the
answerer BUNDLE address for sending RTP and RTCP packets associated answerer BUNDLE address for sending RTP and RTCP packets associated
with each RTP-based bundled "m=" line towards the answerer. with each RTP-based bundled "m=" line towards the answerer.
If the answerer did not accept the usage of RTP/RTCP multiplexing NOTE: If is considered a protocol error if the answerer has not
(see Section 10.3.2.3), the offerer will use separate address:port accpeted the usage of RTP/RTCP multiplexing for RTP-based "m=" lines
combinations for sending RTP and RTCP packets towards the answerer. that the answerer included in the BUNDLE group.
If the answerer associated an SDP 'rtcp' attribute with the "m=" line
representing the answerer BUNDLE address, the offerer will use the
attribute port value for sending RTCP packets associated with each
bundled RTP-based "m=" line towards the answerer. Otherwise the
offerer will use the next higher port value associated with the
answerer BUNDLE address for sending RTCP packets towards the
answerer.
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 generatees a subsequent offer, it MUST associate an
negotiate the usage of RTP/RTCP multiplexing within a BUNDLE group, SDP 'rtcp-mux' attribute with each RTP-based bundled "m=" line
or if it wants to continue the use of previously negotiated RTP/RTCP (including any bundled "m=" line that the offerer wants to add to the
multiplexing, it MUST associate an SDP 'rtcp-mux' attribute with each BUNDLE group), unless the offerer wants to disable or remove the "m="
RTP-based bundled "m=" line (including any bundled "m=" line that the line from the BUNDLE group.
offerer wants to add to the BUNDLE group), unless the offerer wants
to disable or remove the "m=" line from the BUNDLE group.
If the offerer does not want to negotiate the usage of RTP/RTCP
multiplexing within the BUNDLE group, or if it wants to disable
previously negotiated usage of RTP/RTCP multiplexing, it MUST NOT
associate an SDP 'rtcp-mux' and attribute with any bundled "m=" line
in the subsequent offer.
In addition, if the offerer does not indicate support of RTP/RTCP
multiplexing within the subsequent offer, it MAY associate an SDP
'rtcp' attribute, with identical attribute values, with each RTP-
based bundled "m=" line (including any bundled "m=" line that the
offerer wants to add to the BUNDLE group), in order to provide a port
for receiving RTCP packets.
NOTE: It is RECOMMENDED that, once the usage of RTP/RTCP multiplexing
has been negotiated within a BUNDLE group, that the usage is not
disabled. Disabling RTP/RTCP multiplexing means that the offerer and
answerer need to reserve new ports, to be used for sending and
receiving RTCP packets. Similar, if the usage of a specific RTCP
port has been negotiated within a BUNDLE group, it is RECOMMENDED
that the port value is not modified.
11. ICE Considerations 11. ICE Considerations
11.1. General 11.1. General
This section describes how to use the BUNDLE grouping extension This section describes how to use the BUNDLE grouping extension
together with the Interactive Connectivity Establishment (ICE) together with the Interactive Connectivity Establishment (ICE)
mechanism [RFC5245]. mechanism [RFC5245].
The procedures defined in [RFC5245] also apply to usage of ICE with The procedures defined in [RFC5245] also apply to usage of ICE with
skipping to change at page 23, line 20 skipping to change at page 22, line 9
to be performed for the whole BUNDLE group, instead of per bundled to be performed for the whole BUNDLE group, instead of per bundled
"m=" line. "m=" line.
Support and usage of ICE mechanism together with the BUNDLE extension Support and usage of ICE mechanism together with the BUNDLE extension
is OPTIONAL. is OPTIONAL.
11.2. SDP Offer/Answer Procedures 11.2. SDP Offer/Answer Procedures
11.2.1. General 11.2.1. General
When an offerer assigns a unique address to a bundled "m=" line When an offerer associates a unique address with a bundled "m=" line
(excluding any bundle-only "m=" line), it MUST also associate unique (excluding any bundle-only "m=" line), it MUST also associate unique
ICE candidates [RFC5245] to the "m=" line. ICE candidates [RFC5245] to the "m=" line.
An offerer MUST NOT assign ICE candidates to a bundle-only "m=" line An offerer MUST NOT associate ICE candidates with a bundle-only "m="
with a zero port value. line with a zero port value.
NOTE: The bundle-only "m=" line, if accepted by the answerer, will NOTE: The bundle-only "m=" line, if accepted by the answerer, will
inherit the candidates associated with the selected offerer BUNDLE inherit the candidates associated with the selected offerer BUNDLE
address. An answerer that does not support BUNDLE would not accept a address. An answerer that does not support BUNDLE would not accept a
bundle-only "m=" line. bundle-only "m=" line.
When an offerer or answerer assigns a shared address (i.e. a When an offerer or answerer associates a shared address (i.e. a
previously selected BUNDLE address) to one or more bundled "m=" previously selected BUNDLE address) with one or more bundled "m="
lines, it MUST associate identical ICE candidates (referred to as lines, it MUST associate identical ICE candidates (referred to as
shared ICE candidates) to each of those "m=" lines. shared ICE candidates) with each of those "m=" lines.
11.2.2. Generating the Initial SDP Offer 11.2.2. Generating the Initial SDP Offer
When an offerer generates an initial offer, it assigns unique or When an offerer generates an initial offer, it associates unique ICE
shared ICE candidates to the bundled "m=" lines, according to candidates with the bundled "m=" lines, according to Section 11.2.1.
Section 11.1.
11.2.3. Generating the SDP Answer 11.2.3. Generating the SDP Answer
When an answerer generates an answer that contains a BUNDLE group, When an answerer generates an answer that contains a BUNDLE group,
the answerer MUST assign shared ICE candidates to each bundled "m=" the answerer MUST associate shared ICE candidates with each bundled
line (including "m=" lines that were indicated as bundle-only in the "m=" line (including "m=" lines that were indicated as bundle-only in
associated offer) in the answer. the associated offer) in the answer.
11.2.4. Offerer Processing of the SDP Answer 11.2.4. Offerer Processing of the SDP Answer
When an offerer receives an answer, if the answerer supports and uses When an offerer receives an answer, if the answerer supports and uses
the ICE mechanism and the BUNDLE extension, the offerer MUST assign the ICE mechanism and the BUNDLE extension, the offerer MUST
the same ICE candidates, associated with the "m=" line representing associate the same ICE candidates, associated with the "m=" line
the offerer BUNDLE address (selected by the answerer), to each representing the offerer BUNDLE address (selected by the answerer),
bundled "m=" line. with each bundled "m=" line.
11.2.5. Modifying the Session 11.2.5. Modifying the Session
When an offerer generates a subsequent offer, it assigns unique or When an offerer generates a subsequent offer, it associates unique or
shared ICE candidates to the bundled "m=" lines, according to shared ICE candidates with the bundled "m=" lines, according to
(Section 11.1). (Section 11.2.1).
12. DTLS Considerations 12. DTLS Considerations
One or more media streams within a BUNDLE group might use the One or more media streams within a BUNDLE group might use the
Datagram Transport Layer Security (DTLS) protocol [RFC6347] in order Datagram Transport Layer Security (DTLS) protocol [RFC6347] in order
to encrypt the data, or to negotiate encryption keys if another to encrypt the data, or to negotiate encryption keys if another
encryption mechanism is used to encrypt media. encryption mechanism is used to encrypt media.
When DTLS is used within a BUNDLE group, the following rules apply: When DTLS is used within a BUNDLE group, the following rules apply:
o There can only be one DTLS association [RFC6347] associated with o There can only be one DTLS association [RFC6347] associated with
the BUNDLE group; the BUNDLE group; and
o Each usage of the DTLS association within the BUNDLE group MUST o Each usage of the DTLS association within the BUNDLE group MUST
use the same mechanism for determining which endpoints (the use the same mechanism for determining which endpoints (the
offerer or answerer) becomes DTLS client and DTLS server; and offerer or answerer) becomes DTLS client and DTLS server; and
o Each usage of the DTLS association within the Bundle group MUST
use the same mechanism for determining whether an offer or answer
will trigger the establishment of a new DTLS association, or
whether an existing DTLS association will be used; and
o If the DTLS client supports DTLS-SRTP [RFC5764] it MUST include o If the DTLS client supports DTLS-SRTP [RFC5764] it MUST include
the 'use_srtp' extension [RFC5764] in the DTLS ClientHello message the 'use_srtp' extension [RFC5764] in the DTLS ClientHello message
[RFC5764], The client MUST include the extension even if the usage [RFC5764], The client MUST include the extension even if the usage
of DTLS-SRTP is not negotiated as part of the multimedia session of DTLS-SRTP is not negotiated as part of the multimedia session
(e.g. SIP session [RFC3261]. (e.g. SIP session [RFC3261].
NOTE: The inclusion of the 'use_srtp' extension during the initial NOTE: The inclusion of the 'use_srtp' extension during the initial
DTLS handshake ensures that a DTLS renegotiation will not be required DTLS handshake ensures that a DTLS renegotiation will not be required
in order to include the extension, in case DTLS-SRTP encrypted media in order to include the extension, in case DTLS-SRTP encrypted media
is added to the BUNDLE group later during the multimedia session. is added to the BUNDLE group later during the multimedia session.
skipping to change at page 27, line 12 skipping to change at page 26, line 7
procedures in [RFC5888]. Each identification-tag uniquely represents procedures in [RFC5888]. Each identification-tag uniquely represents
an "m=" line. an "m=" line.
This section defines a new RTCP SDES item [RFC3550], 'MID', which is This section defines a new RTCP SDES item [RFC3550], 'MID', which is
used to carry identification-tags within RTCP SDES packets. This used to carry identification-tags within RTCP SDES packets. This
section also defines a new RTP header extension [RFC5285], which is section also defines a new RTP header extension [RFC5285], which is
used to carry identification-tags in RTP packets. used to carry identification-tags in RTP packets.
The SDES item and RTP header extension make it possible for a The SDES item and RTP header extension make it 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 an identification-tag, "m=" line, with which the receiver has associated an identification-
even if those "m=" lines are part of the same RTP session. A media tag, even if those "m=" lines are part of the same RTP session. A
recipient informs the media sender about the identification-tag media recipient informs the media sender about the identification-tag
associated with an "m=" line through the use of an 'mid' attribute associated with an "m=" line through the use of an 'mid' attribute
[RFC5888]. The media sender then inserts the identification-tag in [RFC5888]. The media sender then inserts the identification-tag in
RTCP and RTP packets sent to the media recipient. RTCP and RTP packets sent to the media recipient.
NOTE: This text above defines how identification-tags are carried in NOTE: This text above defines how identification-tags are carried in
SDP Offers and Answers. The usage of other signalling protocols for SDP Offers and Answers. The usage of other signalling protocols for
carrying identification-tags is not prevented, but the usage of such carrying identification-tags is not prevented, but the usage of such
protocols is outside the scope of this document. protocols is outside the scope of this document.
[RFC3550] defines general procedures regarding the RTCP transmission [RFC3550] defines general procedures regarding the RTCP transmission
skipping to change at page 28, line 32 skipping to change at page 27, line 25
encoded, as in SDP. encoded, as in SDP.
The identification-tag is not zero terminated. Note, that set of The identification-tag is not zero terminated. Note, that set of
header extensions included in the packet needs to be padded to the header extensions included in the packet needs to be padded to the
next 32-bit boundary using zero bytes [RFC5285]. next 32-bit boundary using zero bytes [RFC5285].
As the identification-tag is included in either an RTCP SDES item or As the identification-tag is included in either an RTCP SDES item or
an RTP header extension, or both, there should be some consideration an RTP header extension, or both, there should be some consideration
about the packet expansion caused by the identification-tag. To about the packet expansion caused by the identification-tag. To
avoid Maximum Transmission Unit (MTU) issues for the RTP packets, the avoid Maximum Transmission Unit (MTU) issues for the RTP packets, the
header extension's size needs to be taken into account when the header extension's size needs to be taken into account when encoding
encoding media. the media.
It is recommended that the identification-tag is kept short. Due to It is recommended that the identification-tag is kept short. Due to
the properties of the RTP header extension mechanism, when using the the properties of the RTP header extension mechanism, when using the
one-byte header, a tag that is 1-3 bytes will result in that a one-byte header, a tag that is 1-3 bytes will result in that a
minimal number of 32-bit words are used for the RTP header extension, minimal number of 32-bit words are used for the RTP header extension,
in case no other header extensions are included at the same time. in case no other header extensions are included at the same time.
Note, do take into account that some single characters when UTF-8 Note, do take into account that some single characters when UTF-8
encoded will result in multiple octets. encoded will result in multiple octets.
15. IANA Considerations 15. IANA Considerations
skipping to change at page 30, line 33 skipping to change at page 29, line 16
"Session Description Protocol (SDP) Parameters" registry: "Session Description Protocol (SDP) Parameters" registry:
Semantics Token Reference Semantics Token Reference
------------------------------------- ------ --------- ------------------------------------- ------ ---------
Media bundling BUNDLE [RFCXXXX] Media bundling BUNDLE [RFCXXXX]
16. Security Considerations 16. Security Considerations
The security considerations defined in [RFC3264] and [RFC5888] apply The security considerations defined in [RFC3264] and [RFC5888] apply
to the BUNDLE extension. Bundle does not change which information to the BUNDLE extension. Bundle does not change which information
flows over the network but only changes which ports that information flows over the network but only changes which addresses and ports
is flowing on and thus has very little impact on the security of the that information is flowing on and thus has very little impact on the
RTP sessions. security of the RTP sessions.
When the BUNDLE extension is used, 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. BUNDLE group.
When the BUNDLE extension is used, the number of SSRC values within a When the BUNDLE extension is used, the number of SSRC values within a
single RTP session increases, which increases the risk of SSRC single RTP session increases, which increases the risk of SSRC
collision. [RFC4568] describes how SSRC collision may weaken SRTP collision. [RFC4568] describes how SSRC collision may weaken SRTP
and SRTCP encryption in certain situations. and SRTCP encryption in certain situations.
17. Examples 17. Examples
17.1. Example: Bundle Address Selection 17.1. 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 An offer, in which the offerer associates a unique address with
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 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 associates it with each bundled "m=" line
BUNDLE group. within the BUNDLE group.
SDP Offer (1) SDP Offer (1)
v=0 v=0
o=alice 2890844526 2890844526 IN IP4 atlanta.example.com o=alice 2890844526 2890844526 IN IP4 atlanta.example.com
s= s=
c=IN IP4 atlanta.example.com c=IN IP4 atlanta.example.com
t=0 0 t=0 0
a=group:BUNDLE foo bar a=group:BUNDLE foo bar
m=audio 10000 RTP/AVP 0 8 97 m=audio 10000 RTP/AVP 0 8 97
skipping to change at page 33, line 9 skipping to change at page 31, line 9
m=video 20000 RTP/AVP 32 m=video 20000 RTP/AVP 32
b=AS:1000 b=AS:1000
a=mid:bar a=mid:bar
a=rtpmap:32 MPV/90000 a=rtpmap:32 MPV/90000
a=extmap 1 urn:ietf:params:rtp-hdrext:sdes:mid a=extmap 1 urn:ietf:params:rtp-hdrext:sdes:mid
17.2. Example: BUNDLE Extension Rejected 17.2. 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 An offer, in which the offerer associates a unique address with
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 An answer, in which the answerer rejects the offered BUNDLE group,
group, and assigns a unique addresses to each "m=" line (following and associates a unique address with each "m=" line (following
normal RFC 3264 procedures). normal RFC 3264 procedures).
SDP Offer (1) SDP Offer (1)
v=0 v=0
o=alice 2890844526 2890844526 IN IP4 atlanta.example.com o=alice 2890844526 2890844526 IN IP4 atlanta.example.com
s= s=
c=IN IP4 atlanta.example.com c=IN IP4 atlanta.example.com
t=0 0 t=0 0
a=group:BUNDLE foo bar a=group:BUNDLE foo bar
skipping to change at page 34, line 45 skipping to change at page 32, line 45
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
17.3. Example: Offerer Adds A Media Description To A BUNDLE Group 17.3. Example: Offerer Adds A Media Description To A BUNDLE Group
The example below shows: The example below shows:
o 1. A subsequent offer (the BUNDLE group has been created as part o A subsequent offer (the BUNDLE group has been created as part of a
of a previous offer/answer transaction), in which the offerer adds previous offer/answer transaction), in which the offerer adds a
a new "m=" line, represented by the "zen" identification-tag, to a new "m=" line, represented by the "zen" identification-tag, to a
previously negotiated BUNDLE group, assigns a unique address to previously negotiated BUNDLE group, associates a unique address
the added "m=" line, and assigns the previously selected offerer with the added "m=" line, and associates the previously selected
BUNDLE address to each of the other bundled "m=" lines within the offerer BUNDLE address with each of the other bundled "m=" lines
BUNDLE group. within the BUNDLE group.
o 2. An answer, in which the answerer assigns the answerer BUNDLE o An answer, in which the answerer associates the answerer BUNDLE
address to each bundled "m=" line (including the newly added "m=" address with each bundled "m=" line (including the newly added
line) within the BUNDLE group. "m=" line) within the BUNDLE group.
SDP Offer (1) SDP Offer (1)
v=0 v=0
o=alice 2890844526 2890844526 IN IP4 atlanta.example.com o=alice 2890844526 2890844526 IN IP4 atlanta.example.com
s= s=
c=IN IP4 atlanta.example.com c=IN IP4 atlanta.example.com
t=0 0 t=0 0
a=group:BUNDLE foo bar zen a=group:BUNDLE foo bar zen
m=audio 10000 RTP/AVP 0 8 97 m=audio 10000 RTP/AVP 0 8 97
skipping to change at page 36, line 20 skipping to change at page 34, line 20
m=video 20000 RTP/AVP 66 m=video 20000 RTP/AVP 66
b=AS:1000 b=AS:1000
a=mid:zen a=mid:zen
a=rtpmap:66 H261/90000 a=rtpmap:66 H261/90000
a=extmap 1 urn:ietf:params:rtp-hdrext:sdes:mid a=extmap 1 urn:ietf:params:rtp-hdrext:sdes:mid
17.4. Example: Offerer Moves A Media Description Out Of A BUNDLE Group 17.4. Example: Offerer Moves A Media Description Out Of A BUNDLE Group
The example below shows: The example below shows:
o 1. A subsequent offer (the BUNDLE group has been created as part o A subsequent offer (the BUNDLE group has been created as part of a
of a previous offer/answer transaction), in which the offerer previous offer/answer transaction), in which the offerer moves a
moves a bundled "m=" line out of a BUNDLE group, assigns a unique bundled "m=" line out of a BUNDLE group, associates a unique
address to the moved "m=" line, and assigns the offerer BUNDLE address with the moved "m=" line, and associates the offerer
address to each other bundled "m=" line within the BUNDLE group. BUNDLE address with each other bundled "m=" line within the BUNDLE
group.
o 2. An answer, in which the answerer moves the "m=" line out of o An answer, in which the answerer moves the "m=" line out of the
the BUNDLE group, assigns unique address to the moved "m=" line, BUNDLE group, associates unique address with the moved "m=" line,
and assigns the answerer BUNDLE address to each of the remaining and associates the answerer BUNDLE address with each of the
bundled "m=" line within the BUNDLE group. remaining bundled "m=" line within the BUNDLE group.
SDP Offer (1) SDP Offer (1)
v=0 v=0
o=alice 2890844526 2890844526 IN IP4 atlanta.example.com o=alice 2890844526 2890844526 IN IP4 atlanta.example.com
s= s=
c=IN IP4 atlanta.example.com c=IN IP4 atlanta.example.com
t=0 0 t=0 0
a=group:BUNDLE foo bar a=group:BUNDLE foo bar
m=audio 10000 RTP/AVP 0 8 97 m=audio 10000 RTP/AVP 0 8 97
skipping to change at page 37, line 40 skipping to change at page 35, line 41
m=video 60000 RTP/AVP 66 m=video 60000 RTP/AVP 66
b=AS:1000 b=AS:1000
a=mid:zen a=mid:zen
a=rtpmap:66 H261/90000 a=rtpmap:66 H261/90000
17.5. Example: Offerer Disables A Media Description Within A BUNDLE 17.5. Example: Offerer Disables A Media Description Within A BUNDLE
Group Group
The example below shows: The example below shows:
o 1. A subsequent offer (the BUNDLE group has been created as part o A subsequent offer (the BUNDLE group has been created as part of a
of a previous offer/answer transaction), in which the offerer previous offer/answer transaction), in which the offerer disables
disables a bundled "m=" line within BUNDLE group, assigns a zero a bundled "m=" line within BUNDLE group, assigns a zero port
port number to the disabled "m=" line, and assigns the offerer number to the disabled "m=" line, and associates the offerer
BUNDLE address to each of the other bundled "m=" lines within the BUNDLE address with each of the other bundled "m=" lines within
BUNDLE group. the BUNDLE group.
o 2. An answer, in which the answerer moves the disabled "m=" line o An answer, in which the answerer moves the disabled "m=" line out
out of the BUNDLE group, assigns a zero port value to the disabled of the BUNDLE group, assigns a zero port value to the disabled
"m=" line, and assigns the answerer BUNDLE address to each of the "m=" line, and associates the answerer BUNDLE address with each of
remaining bundled "m=" line within the BUNDLE group. the remaining bundled "m=" line within the BUNDLE group.
SDP Offer (1) SDP Offer (1)
v=0 v=0
o=alice 2890844526 2890844526 IN IP4 atlanta.example.com o=alice 2890844526 2890844526 IN IP4 atlanta.example.com
s= s=
c=IN IP4 atlanta.example.com c=IN IP4 atlanta.example.com
t=0 0 t=0 0
a=group:BUNDLE foo bar a=group:BUNDLE foo bar
m=audio 10000 RTP/AVP 0 8 97 m=audio 10000 RTP/AVP 0 8 97
skipping to change at page 39, line 35 skipping to change at page 37, line 37
Thanks to Magnus Westerlund, Colin Perkins and Jonathan Lennox for Thanks to Magnus Westerlund, Colin Perkins and Jonathan Lennox for
providing help and text on the RTP/RTCP procedures. providing help and text on the RTP/RTCP procedures.
Thanks to Spotify for providing music for the countless hours of Thanks to Spotify for providing music for the countless hours of
document editing. document editing.
19. Change Log 19. Change Log
[RFC EDITOR NOTE: Please remove this section when publishing] [RFC EDITOR NOTE: Please remove this section when publishing]
Changes from draft-ietf-mmusic-sdp-bundle-negotiation-23
o - RTCP-MUX mandatory for bundled RTP m- lines
o - Editorial fixes based on comments from Flemming Andreasen
Changes from draft-ietf-mmusic-sdp-bundle-negotiation-22 Changes from draft-ietf-mmusic-sdp-bundle-negotiation-22
o - Correction of Ari's family name o - Correction of Ari's family name
o - Editorial fixes based on comments from Thomas Stach o - Editorial fixes based on comments from Thomas Stach
o - RTP/RTCP correction based on comment from Magnus Westerlund o - RTP/RTCP correction based on comment from Magnus Westerlund
o -- http://www.ietf.org/mail-archive/web/mmusic/current/ o -- http://www.ietf.org/mail-archive/web/mmusic/current/
msg14861.html msg14861.html
Changes from draft-ietf-mmusic-sdp-bundle-negotiation-21 Changes from draft-ietf-mmusic-sdp-bundle-negotiation-21
o - Correct based on comment from Paul Kyzivat o - Correct based on comment from Paul Kyzivat
o -- 'received packets' replaced with 'received data' o -- 'received packets' replaced with 'received data'
Changes from draft-ietf-mmusic-sdp-bundle-negotiation-20 Changes from draft-ietf-mmusic-sdp-bundle-negotiation-20
o - Clarification based on comment from James Guballa o - Clarification based on comment from James Guballa
o - Clarification based on comment from Flemming Andreasen o - Clarification based on comment from Flemming Andreasen
Changes from draft-ietf-mmusic-sdp-bundle-negotiation-19 Changes from draft-ietf-mmusic-sdp-bundle-negotiation-19
skipping to change at page 45, line 35 skipping to change at page 43, line 44
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>. <http://www.rfc-editor.org/info/rfc2119>.
[RFC3264] Rosenberg, J. and H. Schulzrinne, "An Offer/Answer Model [RFC3264] Rosenberg, J. and H. Schulzrinne, "An Offer/Answer Model
with Session Description Protocol (SDP)", RFC 3264, with Session Description Protocol (SDP)", RFC 3264,
DOI 10.17487/RFC3264, June 2002, DOI 10.17487/RFC3264, June 2002,
<http://www.rfc-editor.org/info/rfc3264>. <http://www.rfc-editor.org/info/rfc3264>.
[RFC3550] Schulzrinne, H., Casner, S., Frederick, R., and V.
Jacobson, "RTP: A Transport Protocol for Real-Time
Applications", STD 64, RFC 3550, DOI 10.17487/RFC3550,
July 2003, <http://www.rfc-editor.org/info/rfc3550>.
[RFC3605] Huitema, C., "Real Time Control Protocol (RTCP) attribute
in Session Description Protocol (SDP)", RFC 3605,
DOI 10.17487/RFC3605, October 2003,
<http://www.rfc-editor.org/info/rfc3605>.
[RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session [RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session
Description Protocol", RFC 4566, DOI 10.17487/RFC4566, Description Protocol", RFC 4566, DOI 10.17487/RFC4566,
July 2006, <http://www.rfc-editor.org/info/rfc4566>. July 2006, <http://www.rfc-editor.org/info/rfc4566>.
[RFC4961] Wing, D., "Symmetric RTP / RTP Control Protocol (RTCP)",
BCP 131, RFC 4961, DOI 10.17487/RFC4961, July 2007,
<http://www.rfc-editor.org/info/rfc4961>.
[RFC5245] Rosenberg, J., "Interactive Connectivity Establishment
(ICE): A Protocol for Network Address Translator (NAT)
Traversal for Offer/Answer Protocols", RFC 5245,
DOI 10.17487/RFC5245, April 2010,
<http://www.rfc-editor.org/info/rfc5245>.
[RFC5285] Singer, D. and H. Desineni, "A General Mechanism for RTP [RFC5285] Singer, D. and H. Desineni, "A General Mechanism for RTP
Header Extensions", RFC 5285, DOI 10.17487/RFC5285, July Header Extensions", RFC 5285, DOI 10.17487/RFC5285, July
2008, <http://www.rfc-editor.org/info/rfc5285>. 2008, <http://www.rfc-editor.org/info/rfc5285>.
[RFC5761] Perkins, C. and M. Westerlund, "Multiplexing RTP Data and [RFC5761] Perkins, C. and M. Westerlund, "Multiplexing RTP Data and
Control Packets on a Single Port", RFC 5761, Control Packets on a Single Port", RFC 5761,
DOI 10.17487/RFC5761, April 2010, DOI 10.17487/RFC5761, April 2010,
<http://www.rfc-editor.org/info/rfc5761>. <http://www.rfc-editor.org/info/rfc5761>.
[RFC5764] McGrew, D. and E. Rescorla, "Datagram Transport Layer
Security (DTLS) Extension to Establish Keys for the Secure
Real-time Transport Protocol (SRTP)", RFC 5764,
DOI 10.17487/RFC5764, May 2010,
<http://www.rfc-editor.org/info/rfc5764>.
[RFC5888] Camarillo, G. and H. Schulzrinne, "The Session Description [RFC5888] Camarillo, G. and H. Schulzrinne, "The Session Description
Protocol (SDP) Grouping Framework", RFC 5888, Protocol (SDP) Grouping Framework", RFC 5888,
DOI 10.17487/RFC5888, June 2010, DOI 10.17487/RFC5888, June 2010,
<http://www.rfc-editor.org/info/rfc5888>. <http://www.rfc-editor.org/info/rfc5888>.
[RFC6347] Rescorla, E. and N. Modadugu, "Datagram Transport Layer
Security Version 1.2", RFC 6347, DOI 10.17487/RFC6347,
January 2012, <http://www.rfc-editor.org/info/rfc6347>.
[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-08 Multiplexing", draft-ietf-mmusic-sdp-mux-attributes-08
(work in progress), January 2015. (work in progress), January 2015.
20.2. Informative References 20.2. Informative References
[RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, [RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston,
A., Peterson, J., Sparks, R., Handley, M., and E. A., Peterson, J., Sparks, R., Handley, M., and E.
Schooler, "SIP: Session Initiation Protocol", RFC 3261, Schooler, "SIP: Session Initiation Protocol", RFC 3261,
DOI 10.17487/RFC3261, June 2002, DOI 10.17487/RFC3261, June 2002,
<http://www.rfc-editor.org/info/rfc3261>. <http://www.rfc-editor.org/info/rfc3261>.
[RFC3550] Schulzrinne, H., Casner, S., Frederick, R., and V.
Jacobson, "RTP: A Transport Protocol for Real-Time
Applications", STD 64, RFC 3550, DOI 10.17487/RFC3550,
July 2003, <http://www.rfc-editor.org/info/rfc3550>.
[RFC3605] Huitema, C., "Real Time Control Protocol (RTCP) attribute
in Session Description Protocol (SDP)", RFC 3605,
DOI 10.17487/RFC3605, October 2003,
<http://www.rfc-editor.org/info/rfc3605>.
[RFC4568] Andreasen, F., Baugher, M., and D. Wing, "Session [RFC4568] Andreasen, F., Baugher, M., and D. Wing, "Session
Description Protocol (SDP) Security Descriptions for Media Description Protocol (SDP) Security Descriptions for Media
Streams", RFC 4568, DOI 10.17487/RFC4568, July 2006, Streams", RFC 4568, DOI 10.17487/RFC4568, July 2006,
<http://www.rfc-editor.org/info/rfc4568>. <http://www.rfc-editor.org/info/rfc4568>.
[RFC4961] Wing, D., "Symmetric RTP / RTP Control Protocol (RTCP)",
BCP 131, RFC 4961, DOI 10.17487/RFC4961, July 2007,
<http://www.rfc-editor.org/info/rfc4961>.
[RFC5245] Rosenberg, J., "Interactive Connectivity Establishment
(ICE): A Protocol for Network Address Translator (NAT)
Traversal for Offer/Answer Protocols", RFC 5245,
DOI 10.17487/RFC5245, April 2010,
<http://www.rfc-editor.org/info/rfc5245>.
[RFC5576] Lennox, J., Ott, J., and T. Schierl, "Source-Specific [RFC5576] Lennox, J., Ott, J., and T. Schierl, "Source-Specific
Media Attributes in the Session Description Protocol Media Attributes in the Session Description Protocol
(SDP)", RFC 5576, DOI 10.17487/RFC5576, June 2009, (SDP)", RFC 5576, DOI 10.17487/RFC5576, June 2009,
<http://www.rfc-editor.org/info/rfc5576>. <http://www.rfc-editor.org/info/rfc5576>.
[RFC5764] McGrew, D. and E. Rescorla, "Datagram Transport Layer
Security (DTLS) Extension to Establish Keys for the Secure
Real-time Transport Protocol (SRTP)", RFC 5764,
DOI 10.17487/RFC5764, May 2010,
<http://www.rfc-editor.org/info/rfc5764>.
[RFC6347] Rescorla, E. and N. Modadugu, "Datagram Transport Layer
Security Version 1.2", RFC 6347, DOI 10.17487/RFC6347,
January 2012, <http://www.rfc-editor.org/info/rfc6347>.
[RFC7160] Petit-Huguenin, M. and G. Zorn, Ed., "Support for Multiple [RFC7160] Petit-Huguenin, M. and G. Zorn, Ed., "Support for Multiple
Clock Rates in an RTP Session", RFC 7160, Clock Rates in an RTP Session", RFC 7160,
DOI 10.17487/RFC7160, April 2014, DOI 10.17487/RFC7160, April 2014,
<http://www.rfc-editor.org/info/rfc7160>. <http://www.rfc-editor.org/info/rfc7160>.
[I-D.ietf-mmusic-trickle-ice] [I-D.ietf-mmusic-trickle-ice]
Ivov, E., Rescorla, E., and J. Uberti, "Trickle ICE: Ivov, E., Rescorla, E., and J. Uberti, "Trickle ICE:
Incremental Provisioning of Candidates for the Interactive Incremental Provisioning of Candidates for the Interactive
Connectivity Establishment (ICE) Protocol", draft-ietf- Connectivity Establishment (ICE) Protocol", draft-ietf-
mmusic-trickle-ice-02 (work in progress), January 2015. mmusic-trickle-ice-02 (work in progress), January 2015.
 End of changes. 101 change blocks. 
326 lines changed or deleted 277 lines changed or added

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