[AVT] Re: I-D ACTION:draft-jones-avt-audio-t38-00.txt]

["Paul E. Jones" <paulej@packetizer.com>]

Tom,

The purpose is to register the MIME type "audio/t38".  The reason is that
work is underway within ITU-T Q14/16 to support the carriage of T.38's IFP
packets through RTP.  This will allow us to then signal a single "m=" like
that looks like this:

  m=audio 5600 RTP/AVP 18 98
  a=rtpmap:98 t38/8000

When two media gateways have negotiated this (or similar) SDP and a fax tone
is detected on the line side, a mode shift may occur by simply transmitting
packets with PT=98, rather than PT=18.  This reduces the need for either
consuming additional UDP ports per call for image/t38 or going through a
lengthy exchange of messages to open a fax channel.

Paul

----- Original Message ----- 
From: "Tom Taylor" <taylor@nortelnetworks.com>
To: <avt@ietf.org>
Cc: <paulej@packetizer.com>
Sent: Tuesday, August 12, 2003 11:10 AM
Subject: [Fwd: I-D ACTION:draft-jones-avt-audio-t38-00.txt]


> What's this all about?  First point is that image/t38 is already a
registered MIME
> type.  Second point is that T.38 does NOT use RTP transport, in
contradiction to the
> statement in the I-D that it does.
>
> -------- Original Message --------
> Subject: I-D ACTION:draft-jones-avt-audio-t38-00.txt
> Date: Mon, 11 Aug 2003 15:46:16 -0400
> From: Internet-Drafts@ietf.org
> Reply-To: Internet-Drafts@ietf.org
> To: IETF-Announce: ;
>
> A New Internet-Draft is available from the on-line Internet-Drafts
directories.
>
>
> Title : Real-Time Facsimile (T.38) - audio/t38 MIME Sub-type
>                            Registration
> Author(s) : P. Jones
> Filename : draft-jones-avt-audio-t38-00.txt
> Pages : 4
> Date : 2003-8-11
>
> This document defines the MIME sub-type audio/t38.  The packetization
> and usage of this MIME type, which is intended for use within SDP [2]
> and H.248 [3] systems, is specified within ITU-T Recommendation T.38
> [1].
>
> A URL for this Internet-Draft is:
> http://www.ietf.org/internet-drafts/draft-jones-avt-audio-t38-00.txt
>
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