draft-ietf-avt-rtp-howto-03.txt   draft-ietf-avt-rtp-howto-04.txt 
Audio Video Transport Working M. Westerlund Audio Video Transport Working M. Westerlund
Group Ericsson Group Ericsson
Intended status: Informational Intended status: Informational
Expires: August 28, 2008 Expires: January 12, 2009
How to Write an RTP Payload Format How to Write an RTP Payload Format
draft-ietf-avt-rtp-howto-03 draft-ietf-avt-rtp-howto-04
Status of this Memo Status of this Memo
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This Internet-Draft will expire on August 28, 2008. This Internet-Draft will expire on January 12, 2009.
Copyright Notice
Copyright (C) The IETF Trust (2008).
Abstract Abstract
This document contains information on how to best write an RTP This document contains information on how to best write an RTP
payload format. Reading tips, design practices, and practical tips payload format. Reading tips, design practices, and practical tips
on how to quickly and with good results produce an RTP payload format on how to quickly and with good results produce an RTP payload format
specification. A template is also included with instructions that specification. A template is also included with instructions that
can be used when writing an RTP payload format. can be used when writing an RTP payload format.
Table of Contents Table of Contents
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2.2. Acronyms . . . . . . . . . . . . . . . . . . . . . . . . . 6 2.2. Acronyms . . . . . . . . . . . . . . . . . . . . . . . . . 6
3. Preparations . . . . . . . . . . . . . . . . . . . . . . . . . 8 3. Preparations . . . . . . . . . . . . . . . . . . . . . . . . . 8
3.1. Recommend Reading . . . . . . . . . . . . . . . . . . . . 8 3.1. Recommend Reading . . . . . . . . . . . . . . . . . . . . 8
3.1.1. IETF Process and Publication . . . . . . . . . . . . . 8 3.1.1. IETF Process and Publication . . . . . . . . . . . . . 8
3.1.2. RTP . . . . . . . . . . . . . . . . . . . . . . . . . 9 3.1.2. RTP . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.2. Important RTP details . . . . . . . . . . . . . . . . . . 13 3.2. Important RTP details . . . . . . . . . . . . . . . . . . 13
3.2.1. The RTP Session . . . . . . . . . . . . . . . . . . . 13 3.2.1. The RTP Session . . . . . . . . . . . . . . . . . . . 13
3.2.2. RTP Header . . . . . . . . . . . . . . . . . . . . . . 14 3.2.2. RTP Header . . . . . . . . . . . . . . . . . . . . . . 14
3.2.3. RTP Multiplexing . . . . . . . . . . . . . . . . . . . 15 3.2.3. RTP Multiplexing . . . . . . . . . . . . . . . . . . . 15
3.2.4. RTP Synchronization . . . . . . . . . . . . . . . . . 16 3.2.4. RTP Synchronization . . . . . . . . . . . . . . . . . 15
3.3. Signalling Aspects . . . . . . . . . . . . . . . . . . . . 17 3.3. Signalling Aspects . . . . . . . . . . . . . . . . . . . . 17
3.3.1. Media Types . . . . . . . . . . . . . . . . . . . . . 17 3.3.1. Media Types . . . . . . . . . . . . . . . . . . . . . 17
3.3.2. Mapping to SDP . . . . . . . . . . . . . . . . . . . . 18 3.3.2. Mapping to SDP . . . . . . . . . . . . . . . . . . . . 18
3.4. Transport Characteristics . . . . . . . . . . . . . . . . 21 3.4. Transport Characteristics . . . . . . . . . . . . . . . . 21
3.4.1. Path MTU . . . . . . . . . . . . . . . . . . . . . . . 21 3.4.1. Path MTU . . . . . . . . . . . . . . . . . . . . . . . 21
4. Specification Process . . . . . . . . . . . . . . . . . . . . 22 4. Specification Process . . . . . . . . . . . . . . . . . . . . 22
4.1. IETF . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 4.1. IETF . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
4.1.1. Steps from Idea to Publication . . . . . . . . . . . . 22 4.1.1. Steps from Idea to Publication . . . . . . . . . . . . 22
4.1.2. WG meetings . . . . . . . . . . . . . . . . . . . . . 24 4.1.2. WG meetings . . . . . . . . . . . . . . . . . . . . . 24
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that either updates or replaces the old one. Therefore it is that either updates or replaces the old one. Therefore it is
important to both consider the Category field in the header and check important to both consider the Category field in the header and check
if the RFC one is reading or going to reference is the latest and if the RFC one is reading or going to reference is the latest and
valid. One way of checking the current status of an RFC is to use valid. One way of checking the current status of an RFC is to use
the RFC-editor's RFC search engine, which displays the current status the RFC-editor's RFC search engine, which displays the current status
and which if any RFCs that updates or obsolete it. and which if any RFCs that updates or obsolete it.
Before starting to write an draft one should also read the Internet Before starting to write an draft one should also read the Internet
Draft writing guidelines Draft writing guidelines
(http://www.ietf.org/ietf/1id-guidelines.txt), the ID checklist (http://www.ietf.org/ietf/1id-guidelines.txt), the ID checklist
(http://www.ietf.org/ID-Checklist.html) and "Instructions to Request (http://www.ietf.org/ID-Checklist.html) and the RFC editoral
for Comments (RFC) Authors" [I-D.rfc-editor-rfc2223bis]. Another guidelines and procedures [RFC-ED]. Another document that can be
document that can be useful is the "Guide for Internet Standards useful is the "Guide for Internet Standards Writers" [RFC2360].
Writers" [RFC2360].
There are also a number of documents to consider in process of There are also a number of documents to consider in process of
writing of drafts intended to become RFCs. These are important when writing of drafts intended to become RFCs. These are important when
writing certain type of text. writing certain type of text.
RFC 2606: When writing examples using DNS names in Internet drafts, RFC 2606: When writing examples using DNS names in Internet drafts,
those name shall be using the example.com, example.net, and those name shall be using the example.com, example.net, and
example.org domains. example.org domains.
RFC 3849: Defines the range of IPv6 unicast addresses (2001: RFC 3849: Defines the range of IPv6 unicast addresses (2001:
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media type name must be registered and this is done by requesting media type name must be registered and this is done by requesting
that IANA register that media name. When that registration request that IANA register that media name. When that registration request
is written it shall also be requested that the media type is included is written it shall also be requested that the media type is included
under the "RTP Payload Format MIME types" list part of the RTP under the "RTP Payload Format MIME types" list part of the RTP
registry. registry.
In addition to the above request for media type registration some In addition to the above request for media type registration some
payload formats may have parameters where in the future new parameter payload formats may have parameters where in the future new parameter
values needs to be added. In these cases a registry for that values needs to be added. In these cases a registry for that
parameter must be created. This is done by defining the registry in parameter must be created. This is done by defining the registry in
the IANA consideration section. BCP 26 (RFC 2434) [RFC2434] provides the IANA consideration section. BCP 26 (RFC 5226) [RFC5226] provides
guidelines to writing such registries. Care should be taken when guidelines to writing such registries. Care should be taken when
defining the policy for new registrations. defining the policy for new registrations.
Before writing a new registry it is worth checking the existing ones Before writing a new registry it is worth checking the existing ones
in the IANA "MIME Media Type Sub-Parameter Registries". For example in the IANA "MIME Media Type Sub-Parameter Registries". For example
video formats needing a media parameter expressing color sub-sampling video formats needing a media parameter expressing color sub-sampling
may be able to reuse those defined for video/raw [RFC4175]. may be able to reuse those defined for video/raw [RFC4175].
8. Authoring Tools 8. Authoring Tools
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consideration sections and what should be particular considered when consideration sections and what should be particular considered when
specifying RTP payload formats. specifying RTP payload formats.
12. RFC Editor Consideration 12. RFC Editor Consideration
Note to RFC Editor: This section may be removed after carrying out Note to RFC Editor: This section may be removed after carrying out
all the instructions of this section. all the instructions of this section.
13. Acknowledgements 13. Acknowledgements
The author would like to thank the invididuals that has provied input
to this document. These individuals include: John Lazzaro.
14. Informative References 14. Informative References
[CSP-RTP] Colin , "RTP: Audio and Video for the Internet", [CSP-RTP] Colin , "RTP: Audio and Video for the Internet",
June 2003. June 2003.
[I-D.rfc-editor-rfc2223bis]
Reynolds, J. and R. Braden, "Instructions to Request for
Comments (RFC) Authors", draft-rfc-editor-rfc2223bis-08
(work in progress), July 2004.
[MACOSFILETYPES] [MACOSFILETYPES]
Apple Knowledge Base Article Apple Knowledge Base Article
55381<http://www.info.apple.com/kbnum/n55381>, "Mac OS: 55381<http://www.info.apple.com/kbnum/n55381>, "Mac OS:
File Type and Creator Codes, and File Formats", 1993. File Type and Creator Codes, and File Formats", 1993.
[RFC-ED] http://www.rfc-editor.org/policy.html, "RFC Editorial
Guidelines and Procedures", July 2008.
[RFC1305] Mills, D., "Network Time Protocol (Version 3) [RFC1305] Mills, D., "Network Time Protocol (Version 3)
Specification, Implementation", RFC 1305, March 1992. Specification, Implementation", RFC 1305, March 1992.
[RFC2026] Bradner, S., "The Internet Standards Process -- Revision [RFC2026] Bradner, S., "The Internet Standards Process -- Revision
3", BCP 9, RFC 2026, October 1996. 3", BCP 9, RFC 2026, October 1996.
[RFC2198] Perkins, C., Kouvelas, I., Hodson, O., Hardman, V., [RFC2198] Perkins, C., Kouvelas, I., Hodson, O., Hardman, V.,
Handley, M., Bolot, J., Vega-Garcia, A., and S. Fosse- Handley, M., Bolot, J., Vega-Garcia, A., and S. Fosse-
Parisis, "RTP Payload for Redundant Audio Data", RFC 2198, Parisis, "RTP Payload for Redundant Audio Data", RFC 2198,
September 1997. September 1997.
[RFC2326] Schulzrinne, H., Rao, A., and R. Lanphier, "Real Time [RFC2326] Schulzrinne, H., Rao, A., and R. Lanphier, "Real Time
Streaming Protocol (RTSP)", RFC 2326, April 1998. Streaming Protocol (RTSP)", RFC 2326, April 1998.
[RFC2360] Scott, G., "Guide for Internet Standards Writers", BCP 22, [RFC2360] Scott, G., "Guide for Internet Standards Writers", BCP 22,
RFC 2360, June 1998. RFC 2360, June 1998.
[RFC2418] Bradner, S., "IETF Working Group Guidelines and [RFC2418] Bradner, S., "IETF Working Group Guidelines and
Procedures", BCP 25, RFC 2418, September 1998. Procedures", BCP 25, RFC 2418, September 1998.
[RFC2434] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 2434,
October 1998.
[RFC2508] Casner, S. and V. Jacobson, "Compressing IP/UDP/RTP [RFC2508] Casner, S. and V. Jacobson, "Compressing IP/UDP/RTP
Headers for Low-Speed Serial Links", RFC 2508, Headers for Low-Speed Serial Links", RFC 2508,
February 1999. February 1999.
[RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H., [RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H.,
Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext
Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999. Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999.
[RFC2736] Handley, M. and C. Perkins, "Guidelines for Writers of RTP [RFC2736] Handley, M. and C. Perkins, "Guidelines for Writers of RTP
Payload Format Specifications", BCP 36, RFC 2736, Payload Format Specifications", BCP 36, RFC 2736,
skipping to change at page 46, line 5 skipping to change at page 45, line 6
[RFC4975] Campbell, B., Mahy, R., and C. Jennings, "The Message [RFC4975] Campbell, B., Mahy, R., and C. Jennings, "The Message
Session Relay Protocol (MSRP)", RFC 4975, September 2007. Session Relay Protocol (MSRP)", RFC 4975, September 2007.
[RFC5109] Li, A., "RTP Payload Format for Generic Forward Error [RFC5109] Li, A., "RTP Payload Format for Generic Forward Error
Correction", RFC 5109, December 2007. Correction", RFC 5109, December 2007.
[RFC5124] Ott, J. and E. Carrara, "Extended Secure RTP Profile for [RFC5124] Ott, J. and E. Carrara, "Extended Secure RTP Profile for
Real-time Transport Control Protocol (RTCP)-Based Feedback Real-time Transport Control Protocol (RTCP)-Based Feedback
(RTP/SAVPF)", RFC 5124, February 2008. (RTP/SAVPF)", RFC 5124, February 2008.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226,
May 2008.
Appendix A. RTP Payload Format Template Appendix A. RTP Payload Format Template
This section contains a template for writing an RTP payload format in This section contains a template for writing an RTP payload format in
form as a Internet draft. Text within [...] are instructions and form as a Internet draft. Text within [...] are instructions and
must be removed. Some text proposals that are included are must be removed. Some text proposals that are included are
conditional. "..." is used to indicate where further text should be conditional. "..." is used to indicate where further text should be
written. written.
A.1. Title A.1. Title
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attempt made to obtain a general license or permission for the use of attempt made to obtain a general license or permission for the use of
such proprietary rights by implementers or users of this such proprietary rights by implementers or users of this
specification can be obtained from the IETF on-line IPR repository at specification can be obtained from the IETF on-line IPR repository at
http://www.ietf.org/ipr. http://www.ietf.org/ipr.
The IETF invites any interested party to bring to its attention any The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary copyrights, patents or patent applications, or other proprietary
rights that may cover technology that may be required to implement rights that may cover technology that may be required to implement
this standard. Please address the information to the IETF at this standard. Please address the information to the IETF at
ietf-ipr@ietf.org. ietf-ipr@ietf.org.
Acknowledgment
Funding for the RFC Editor function is provided by the IETF
Administrative Support Activity (IASA).
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