Re: [AVT] One more change to draft-ietf-avt-rfc2833bisdata

[Colin Perkins <csp at csperkins.org>]

On 3 Mar 2005, at 15:10, Tom Taylor wrote:
> While digging requirements out of 
> draft-ietf-avt-rfc2833bisdata-01.txt, I discovered a couple of typos 
> in the section on V.18 terminals.  This led to reflect that after the 
> general introduction to V.18 the section is really an extended 
> example, and not one that's particularly needed.  I will propose on 
> Monday that the detailed description of the V.18 probing be deleted, 
> leaving only the general description.

Also in this draft, I notice (in section 2.6.1):

   It is assumed in all cases that the event reports described here are
   being transmitted in addition to other media content, typically G.711
   voice-band data.  A natural method to do this is to combine the
   voice-band data with event reports in an RFC 2198 [2] redundancy
   payload.

This should be clarified, since RFC 2198 only allows multiple 
representations of the same data to be conveyed, and this draft could 
be interpreted to allow multiplexing of text with some other audio data 
(which should be handled by a different RTP stream sent on the audio 
port, using a different SSRC).

The same issue appears in section 3.2.2: following RFC 2198 the example 
would playout ONLY the G.711 audio in the usual case, playing the data 
sent using the telephone events format only if a packet was lost (an 
offset of zero is not meaningful in RFC 2198). If the intent is to play 
the voice band data and the tones simultaneously, they should be sent 
as separate RTP streams - each with their own SSRC - to the same IP 
address and UDP port.

Colin


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