Audio/Video Transport (avt) Charter
NOTE: This charter is accurate as of the 31st IETF Meeting in San Jose. It
may now be out-of-date. (Consider this a "snapshot" of the working
group from that meeting.) Up-to-date charters for all active working
groups can be found elsewhere in this Web server.
Chair(s)
- Stephen Casner <casner@isi.edu>
Transport Area Director(s):
- Allison Mankin <mankin@isi.edu>
Mailing List Information
- General Discussion:rem-conf@es.net
- To Subscribe: rem-conf-request@es.net
- Archive: nic.es.net:pub/mailing-lists/mail-archive/rem-conf
Description of Working Group
The Audio/Video Transport Working Group was formed to specify
experimental protocols for real-time transmission of audio and
video over UDP and IP multicast. The focus of this group is
near-term and its purpose is to integrate and coordinate the
current AVT efforts of existing research activities. No
standards-track protocols are expected to be produced because
UDP transmission of audio and video is only sufficient for
small-scale experiments over fast portions of the Internet.
However, the transport protocols produced by this working group
should be useful on a larger scale in the future in conjunction
with additional protocols to access network-level resource
management mechanisms. Those mechanisms, research efforts now,
will provide low-delay service and guard against unfair consumption
of bandwidth by audio/video traffic.
Similarly, initial experiments can work without any connection
establishment procedure so long as a priori agreements on port
numbers and coding types have been made. To go beyond that, we
will need to address simple control protocols as well. Since IP
multicast traffic may be received by anyone, the control
protocols must handle authentication and key exchange so that the
audio/video data can be encrypted. More sophisticated connection
management is also the subject of current research. It is
expected that standards-track protocols integrating transport,
resource management, and connection management will be the result
of later working group efforts.
The AVT Working Group may design independent protocols specific to each
medium, or a common, lightweight, real-time transport protocol
may be extracted. Sequencing of packets and synchronization
among streams are important functions, so one issue is the form
of timestamps and/or sequence numbers to be used. The working group will
not focus on compression or coding algorithms which are domain of
higher layers.
Goals and Milestones
- Done
- Define the scope of the working group, and who might contribute. The first step will be to solicit contributions of potential protocols from projects that have already developed packet audio and video. From these contributions the group will distill the appropriate protocol features.
- Done
- Conduct a teleconference working group meeting using a combination of packet audio and telephone. The topic will be a discussion of issues to be resolved in the process of synthesizing a new protocol.
- Done
- Review contributions of existing protocols, and discuss which features should be included and tradeoffs of different methods. Make writing assignments for first-draft documents.
- Done
- Post an Internet-Draft of the lightweight audio/video transport protocol.
- Done
- Post a revision of the AVT protocol addressing new work and security options as an Internet-Draft.
- Jun 93
- Submit the AVT protocol to the IESG for consideration as an Experimental Protocol.
Current Internet-Drafts
No Request for Comments