RTP Header Extension for the RTP Control Protocol (RTCP) Source Description Items
RFC 7941
Internet Engineering Task Force (IETF) M. Westerlund
Request for Comments: 7941 B. Burman
Category: Standards Track Ericsson
ISSN: 2070-1721 R. Even
Huawei Technologies
M. Zanaty
Cisco Systems
August 2016
RTP Header Extension for
the RTP Control Protocol (RTCP) Source Description Items
Abstract
Source Description (SDES) items are normally transported in the RTP
Control Protocol (RTCP). In some cases, it can be beneficial to
speed up the delivery of these items. The main case is when a new
synchronization source (SSRC) joins an RTP session and the receivers
need this source's identity, relation to other sources, or its
synchronization context, all of which may be fully or partially
identified using SDES items. To enable this optimization, this
document specifies a new RTP header extension that can carry SDES
items.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 7841.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc7941.
Westerlund, et al. Standards Track [Page 1]
RFC 7941 RTP HE for RTCP SDES August 2016
Copyright Notice
Copyright (c) 2016 IETF Trust and the persons identified as the
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
2.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4
3. Motivation . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Specification . . . . . . . . . . . . . . . . . . . . . . . . 5
4.1. SDES Item Header Extension . . . . . . . . . . . . . . . 5
4.1.1. One-Byte Format . . . . . . . . . . . . . . . . . . . 6
4.1.2. Two-Byte Format . . . . . . . . . . . . . . . . . . . 6
4.2. Usage of the SDES Item Header Extension . . . . . . . . . 6
4.2.1. One-Byte or Two-Byte Headers . . . . . . . . . . . . 6
4.2.2. MTU and Packet Expansion . . . . . . . . . . . . . . 7
4.2.3. Transmission Considerations . . . . . . . . . . . . . 8
4.2.4. Different Usages . . . . . . . . . . . . . . . . . . 9
4.2.5. SDES Items in RTCP . . . . . . . . . . . . . . . . . 10
4.2.6. Update Flaps . . . . . . . . . . . . . . . . . . . . 10
4.2.7. RTP Header Compression . . . . . . . . . . . . . . . 11
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11
5.1. Registration of an SDES Base URN . . . . . . . . . . . . 11
5.2. Creation of the "RTP SDES Compact Header Extensions"
Sub-Registry . . . . . . . . . . . . . . . . . . . . . . 12
5.3. Registration of SDES Item . . . . . . . . . . . . . . . . 12
6. Security Considerations . . . . . . . . . . . . . . . . . . . 13
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 14
7.1. Normative References . . . . . . . . . . . . . . . . . . 14
7.2. Informative References . . . . . . . . . . . . . . . . . 14
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 17
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 17
Westerlund, et al. Standards Track [Page 2]
RFC 7941 RTP HE for RTCP SDES August 2016
1. Introduction
This specification defines an RTP header extension [RFC3550][RFC5285]
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