Audio/Video Transport (avt)
---------------------------
 
 Charter 
 
 Current status: active working group
 
 Chair(s):
     Stephen Casner  <casner@isi.edu>
 
 Transport Area Director(s) 
     Allison Mankin  <mankin@cmf.nrl.navy.mil>
 
 Mailing lists: 
     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.                                                            

   May 93 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.                                               


 Internet-Drafts:

Posted Revised       I-D Title  <Filename>
------ ------- ------------------------------------------
 Dec 92 Oct 93  <draft-ietf-avt-rtp-04.txt, .ps> 
                RTP: A Transport Protocol for Real-Time Applications           
 
 Mar 93 Dec 93  <draft-ietf-avt-video-packet-02.txt> 
                Packetization of H.261 video streams                           

 Request For Comments:

  None to date.