Network Working Group J. Rosenberg
Request for Comments: 3840 dynamicsoft
Category: Standards Track H. Schulzrinne
Columbia University
P. Kyzivat
Cisco Systems
August 2004
Indicating User Agent Capabilities in
the Session Initiation Protocol (SIP)
Status of this Memo
This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
Copyright Notice
Copyright (C) The Internet Society (2004).
Abstract
This specification defines mechanisms by which a Session Initiation
Protocol (SIP) user agent can convey its capabilities and
characteristics to other user agents and to the registrar for its
domain. This information is conveyed as parameters of the Contact
header field.
Rosenberg, et al. Standards Track [Page 1]
RFC 3840 SIP Capabilities August 2004
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Usage of the Content Negotiation Framework . . . . . . . . . . 6
5. Computing Capabilities . . . . . . . . . . . . . . . . . . . . 7
6. Expressing Capabilities in a Registration . . . . . . . . . . 10
7. Indicating Feature Sets in Remote Target URIs . . . . . . . . 12
8. OPTIONS Processing . . . . . . . . . . . . . . . . . . . . . . 13
9. Contact Header Field . . . . . . . . . . . . . . . . . . . . . 13
10. Media Feature Tag Definitions . . . . . . . . . . . . . . . . 14
10.1. Audio . . . . . . . . . . . . . . . . . . . . . . . . . 15
10.2. Application . . . . . . . . . . . . . . . . . . . . . . 16
10.3. Data. . . . . . . . . . . . . . . . . . . . . . . . . . 16
10.4. Control . . . . . . . . . . . . . . . . . . . . . . . . 17
10.5. Video . . . . . . . . . . . . . . . . . . . . . . . . . 17
10.6. Text. . . . . . . . . . . . . . . . . . . . . . . . . . 18
10.7. Automata. . . . . . . . . . . . . . . . . . . . . . . . 18
10.8. Class . . . . . . . . . . . . . . . . . . . . . . . . . 19
10.9. Duplex. . . . . . . . . . . . . . . . . . . . . . . . . 20
10.10. Mobility. . . . . . . . . . . . . . . . . . . . . . . . 20
10.11. Description . . . . . . . . . . . . . . . . . . . . . . 21
10.12. Event Packages. . . . . . . . . . . . . . . . . . . . . 22
10.13. Priority. . . . . . . . . . . . . . . . . . . . . . . . 22
10.14. Methods . . . . . . . . . . . . . . . . . . . . . . . . 23
10.15. Extensions. . . . . . . . . . . . . . . . . . . . . . . 24
10.16. Schemes . . . . . . . . . . . . . . . . . . . . . . . . 24
10.17. Actor . . . . . . . . . . . . . . . . . . . . . . . . . 25
10.18. Is Focus. . . . . . . . . . . . . . . . . . . . . . . . 26
11. Security Considerations . . . . . . . . . . . . . . . . . . . 26
11.1. Considerations for Media Feature Tags . . . . . . . . . 26
11.2. Considerations for Registrations. . . . . . . . . . . . 27
11.3. Considerations for OPTIONS Responses. . . . . . . . . . 28
11.4. Considerations for Dialog Initiating Messages . . . . . 28
12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 28
12.1. SIP Media Feature Tag Registration Tree . . . . . . . . 28
12.2. Media Feature Tags. . . . . . . . . . . . . . . . . . . 29
12.3. SIP Option Tag. . . . . . . . . . . . . . . . . . . . . 30
13. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 30
14. References . . . . . . . . . . . . . . . . . . . . . . . . . . 31
14.1. Normative References. . . . . . . . . . . . . . . . . . 31
14.2. Informative References. . . . . . . . . . . . . . . . . 31
Appendix. Overview of RFC 2533. . . . . . . . . . . . . . . . . . 33
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 35
Full Copyright Statement . . . . . . . . . . . . . . . . . . . . . 36
Rosenberg, et al. Standards Track [Page 2]
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