draft-ietf-avtext-sdes-hdr-ext-04.txt   draft-ietf-avtext-sdes-hdr-ext-05.txt 
Network Working Group M. Westerlund Network Working Group M. Westerlund
Internet-Draft B. Burman Internet-Draft B. Burman
Intended status: Standards Track Ericsson Intended status: Standards Track Ericsson
Expires: August 25, 2016 R. Even Expires: September 3, 2016 R. Even
Huawei Technologies Huawei Technologies
M. Zanaty M. Zanaty
Cisco Systems Cisco Systems
February 22, 2016 March 2, 2016
RTP Header Extension for RTCP Source Description Items RTP Header Extension for RTCP Source Description Items
draft-ietf-avtext-sdes-hdr-ext-04 draft-ietf-avtext-sdes-hdr-ext-05
Abstract Abstract
Source Description (SDES) items are normally transported in RTP Source Description (SDES) items are normally transported in RTP
control protocol (RTCP). In some cases it can be beneficial to speed control protocol (RTCP). In some cases it can be beneficial to speed
up the delivery of these items. Mainly when a new source (SSRC) up the delivery of these items. Mainly when a new source (SSRC)
joins an RTP session and the receivers needs this source's identity, joins an RTP session and the receivers needs this source's identity,
relation to other sources, or its synchronization context, all of relation to other sources, or its synchronization context, all of
which may be fully or partially identified using SDES items. To which may be fully or partially identified using SDES items. To
enable this optimization, this document specifies a new RTP header enable this optimization, this document specifies a new RTP header
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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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This Internet-Draft will expire on August 25, 2016. This Internet-Draft will expire on September 3, 2016.
Copyright Notice Copyright Notice
Copyright (c) 2016 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.
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
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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 . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1. Requirements Language . . . . . . . . . . . . . . . . . . 3 2.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
2.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3 2.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
3. Motivation . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Motivation . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Specification . . . . . . . . . . . . . . . . . . . . . . . . 5 4. Specification . . . . . . . . . . . . . . . . . . . . . . . . 5
4.1. SDES Item Header Extension . . . . . . . . . . . . . . . 5 4.1. SDES Item Header Extension . . . . . . . . . . . . . . . 5
4.1.1. One-Byte Format . . . . . . . . . . . . . . . . . . . 5 4.1.1. One-Byte Format . . . . . . . . . . . . . . . . . . . 5
4.1.2. Two-Byte Format . . . . . . . . . . . . . . . . . . . 5 4.1.2. Two-Byte Format . . . . . . . . . . . . . . . . . . . 6
4.2. Usage of the SDES Item Header Extension . . . . . . . . . 6 4.2. Usage of the SDES Item Header Extension . . . . . . . . . 6
4.2.1. One or Two Byte Headers . . . . . . . . . . . . . . . 6 4.2.1. One or Two Byte Headers . . . . . . . . . . . . . . . 6
4.2.2. MTU and Packet Expansion . . . . . . . . . . . . . . 7 4.2.2. MTU and Packet Expansion . . . . . . . . . . . . . . 7
4.2.3. Transmission Considerations . . . . . . . . . . . . . 7 4.2.3. Transmission Considerations . . . . . . . . . . . . . 7
4.2.4. Different Usages . . . . . . . . . . . . . . . . . . 9 4.2.4. Different Usages . . . . . . . . . . . . . . . . . . 9
4.2.5. SDES Items in RTCP . . . . . . . . . . . . . . . . . 9 4.2.5. SDES Items in RTCP . . . . . . . . . . . . . . . . . 9
4.2.6. Update Flaps . . . . . . . . . . . . . . . . . . . . 10 4.2.6. Update Flaps . . . . . . . . . . . . . . . . . . . . 10
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
5.1. Reservation of the SDES URN sub-space . . . . . . . . . . 11 5.1. Registration of an SDES Base URN . . . . . . . . . . . . 11
5.2. Registration of SDES Items . . . . . . . . . . . . . . . 12 5.2. Creation of an SDES Sub-Registry . . . . . . . . . . . . 11
5.3. Registration of SDES Items . . . . . . . . . . . . . . . 12
6. Security Considerations . . . . . . . . . . . . . . . . . . . 12 6. Security Considerations . . . . . . . . . . . . . . . . . . . 12
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 13 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 13
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 13 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 13
8.1. Normative References . . . . . . . . . . . . . . . . . . 13 8.1. Normative References . . . . . . . . . . . . . . . . . . 13
8.2. Informative References . . . . . . . . . . . . . . . . . 13 8.2. Informative References . . . . . . . . . . . . . . . . . 13
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 15
1. Introduction 1. Introduction
This specification defines an RTP header extension [RFC3550][RFC5285] This specification defines an RTP header extension [RFC3550][RFC5285]
that can carry RTCP source description (SDES) items. By including that can carry RTCP source description (SDES) items. By including
selected SDES items in a header extension the determination of selected SDES items in a header extension the determination of
relationship and synchronization context for new RTP streams (SSRCs) relationship and synchronization context for new RTP streams (SSRCs)
in an RTP session can be optimized. Which relationship and what in an RTP session can be optimized. Which relationship and what
information depends on the SDES items carried. This becomes a information depends on the SDES items carried. This becomes a
complement to using only RTCP for SDES Item delivery. complement to using only RTCP for SDES Item delivery.
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This section makes the following requests to IANA: This section makes the following requests to IANA:
o Create a new sub-registry reserved for RTCP SDES items with the o Create a new sub-registry reserved for RTCP SDES items with the
URN sub-space "urn:ietf:params:rtp-hdrext:sdes:" in the RTP URN sub-space "urn:ietf:params:rtp-hdrext:sdes:" in the RTP
Compact Header Extensions registry. Compact Header Extensions registry.
o Register the SDES items appropriate for use with the RTP header o Register the SDES items appropriate for use with the RTP header
extension defined in this document. extension defined in this document.
5.1. Reservation of the SDES URN sub-space RFC-editor note: Please replace all occurrences of RFCXXXX with the
RFC number this specification receives when published.
The reason to require registering a URN within an SDES sub-space is
that the name represents an RTCP Source Description item, where a
specification is strongly recommended [RFC3550]. The formal policy
MUST be maintained from the main space, as specified by [RFC5285],
i.e. Expert Review. However, the following additional items need to
be considered when applying for a registration within this sub-space
of the RTP Compact Header Extensions registry:
o Any registration using an Extension URI that starts with
"urn:ietf:params:rtp-hdrext:sdes:" MUST also have a registered
Source Description item in the "RTP SDES item types" registry.
o Secondly, a security and privacy consideration for the SDES item
MUST be provided with the registration.
o Thirdly, information MUST be provided on why this SDES item 5.1. Registration of an SDES Base URN
requires timely delivery, motivating it to be transported in a
header extension rather than as RTCP only.
IANA is requested to register the below in the RTP Compact Header IANA is requested to register the below entry in the RTP Compact
Extensions, and to create the corresponding sub-registry: Header Extensions registry:
Name: RTP SDES Compact Header Extensions
Extension URI: urn:ietf:params:rtp-hdrext:sdes Extension URI: urn:ietf:params:rtp-hdrext:sdes
Description: Reserved as base URN for RTP SDES items that are also Description: Reserved as base URN for RTCP SDES items that are also
defined as RTP Compact header extensions. defined as RTP Compact header extensions.
Contact: Authors of [RFCXXXX] Contact: Authors of [RFCXXXX]
Reference: [RFCXXXX] Reference: [RFCXXXX]
RFC-editor note: Please replace all occurrences of RFCXXXX with the The reason to register a base URN for an SDES sub-space is that the
RFC number this specification receives when published. name represents an RTCP Source Description item, where a
specification is strongly recommended [RFC3550].
The formal reference for registrations in the RTP SDES Compact Header 5.2. Creation of an SDES Sub-Registry
Extensions registry is the RFC number of the RFC documenting the
extension.
5.2. Registration of SDES Items IANA is requested to create a sub-registry to the RTP Compact Header
Extensions registry, with the same basic requirements, structure and
layout as the RTP Compact Header Extensions registry.
o Registry name: RTP SDES Compact Header Extensions
o Specification: RFCXXXX and RFCs updating RFCXXXX
o Information required: Same as for RTP Header Extensions [RFC5285]
registry
o Review process: Same as for RTP Header Extensions [RFC5285]
registry, with the following requirements added to the expert
review:
1. Any registration using an Extension URI that starts with
"urn:ietf:params:rtp-hdrext:sdes:" (Section 5.1) MUST also
have a registered Source Description item in the "RTP SDES
item types" registry.
2. A security and privacy consideration for the SDES item MUST be
provided with the registration.
3. Information MUST be provided on why this SDES item requires
timely delivery, motivating it to be transported in a header
extension rather than as RTCP only.
o Size and format of entries: Same as for RTP Header Extensions
[RFC5285] registry.
o Initial assignments: See Section 5.3 below.
5.3. Registration of SDES Items
It is requested that the following SDES item is registered in the It is requested that the following SDES item is registered in the
newly formed RTP SDES Compact Header Extensions registry: newly formed RTP SDES Compact Header Extensions registry:
Extension URI: urn:ietf:params:rtp-hdrext:sdes:cname Extension URI: urn:ietf:params:rtp-hdrext:sdes:cname
Description: Source Description: Canonical End-Point Identifier Description: Source Description: Canonical End-Point Identifier
(SDES CNAME) (SDES CNAME)
Contact: Authors of [RFCXXXX] Contact: Authors of [RFCXXXX]
Reference: [RFCXXXX] Reference: [RFCXXXX]
RFC-editor note: Please move the MID SDES item already registered in
the main registry by [I-D.ietf-mmusic-sdp-bundle-negotiation] to the
newly formed RTP SDES Compact Header Extensions.
6. Security Considerations 6. Security Considerations
Source Description items may contain data that are sensitive from a Source Description items may contain data that are sensitive from a
security perspective. There are SDES items that are or may be security perspective. There are SDES items that are or may be
sensitive from a user privacy perspective, like CNAME, NAME, EMAIL, sensitive from a user privacy perspective, like CNAME, NAME, EMAIL,
PHONE, LOC and H323-CADDR. Some may contain sensitive information, PHONE, LOC and H323-CADDR. Some may contain sensitive information,
like NOTE and PRIV, while others may be sensitive from profiling like NOTE and PRIV, while others may be sensitive from profiling
implementations for vulnerability or other reasons, like TOOL. The implementations for vulnerability or other reasons, like TOOL. The
CNAME sensitivity can vary depending on how it is generated and what CNAME sensitivity can vary depending on how it is generated and what
persistence it has. A short term CNAME identifier generated using a persistence it has. A short term CNAME identifier generated using a
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As the SDES items are used by the RTP based application to establish As the SDES items are used by the RTP based application to establish
relationships between RTP streams or between an RTP stream and relationships between RTP streams or between an RTP stream and
information about the originating participant, there SHOULD be strong information about the originating participant, there SHOULD be strong
integrity protection and source authentication of the header integrity protection and source authentication of the header
extensions. If not, an attacker can modify the SDES item value to extensions. If not, an attacker can modify the SDES item value to
create erroneous relationship bindings in the receiving application. create erroneous relationship bindings in the receiving application.
7. Acknowledgements 7. Acknowledgements
The authors likes to thank the following individuals for feedback and The authors likes to thank the following individuals for feedback and
suggestions; Colin Perkins. suggestions; Colin Perkins, Ben Campbell.
8. References 8. References
8.1. Normative References 8.1. 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, 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>.
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Real-time Transport Protocol (SRTP)", RFC 6904, Real-time Transport Protocol (SRTP)", RFC 6904,
DOI 10.17487/RFC6904, April 2013, DOI 10.17487/RFC6904, April 2013,
<http://www.rfc-editor.org/info/rfc6904>. <http://www.rfc-editor.org/info/rfc6904>.
8.2. Informative References 8.2. Informative References
[I-D.ietf-mmusic-sdp-bundle-negotiation] [I-D.ietf-mmusic-sdp-bundle-negotiation]
Holmberg, C., Alvestrand, H., and C. Jennings, Holmberg, C., Alvestrand, H., and C. Jennings,
"Negotiating Media Multiplexing Using the Session "Negotiating Media Multiplexing Using the Session
Description Protocol (SDP)", draft-ietf-mmusic-sdp-bundle- Description Protocol (SDP)", draft-ietf-mmusic-sdp-bundle-
negotiation-26 (work in progress), February 2016. negotiation-27 (work in progress), February 2016.
[RFC3611] Friedman, T., Ed., Caceres, R., Ed., and A. Clark, Ed., [RFC3611] Friedman, T., Ed., Caceres, R., Ed., and A. Clark, Ed.,
"RTP Control Protocol Extended Reports (RTCP XR)", "RTP Control Protocol Extended Reports (RTCP XR)",
RFC 3611, DOI 10.17487/RFC3611, November 2003, RFC 3611, DOI 10.17487/RFC3611, November 2003,
<http://www.rfc-editor.org/info/rfc3611>. <http://www.rfc-editor.org/info/rfc3611>.
[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>.
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