Subject: [AVT] Data-related event codes from RFC 2833bis

From: Tom Taylor <[email-masked]>
Date: Fri, 14 Jan 2005 08:20:20 -0500

I have just submitted draft-ietf-avt-rfc2833bisdata-00.txt, capturing all of the 
data-related event codes formerly provided in section 3.2 of 
draft-ietf-avt-rfc2833bis-05.txt.  The section has had some rework, both 
substantive and editorial.  I've added an extensive example based on the V.8 
negotiation that occurs at the start-up of a V.34 modem session.

I mentioned the other day a couple of the lessons gained from working the example. 
  A lot of the substantive changes are repetition of the same theme: you can start 
out with a longer packetization interval for the first event report, but to avoid 
gaps in playout you generally have to keep your packetization interval constant 
after that.

I also redefined the V.8 CI event to say that it ends with the completion of the 
20-bit synchronization pattern for that signal.  In the previous version it 
covered the entire CI signal including the call function octet, with the result 
that the bits of the latter would be reported as concurrent events to the CI 
event.  This is a bit awkward, basically requiring separate packets to report CI 
completion and the bit events of the call function octet.  It's much simpler to 
make these consecutive events so they will fit into the same packet.  (BTW I think 
the CI event is an almost useless optimization and could easily be eliminated if 
nobody cares about it.)

After submitting the draft, I had a sudden insight into that rather wooly section 
on V.18.  Most of that section is about events for various varieties of text 
telephony.  In fact, there is little normative text on the reporting of V.18 
signalling itself.  In the next revision of the draft I will separate the two 
topics.  This should make matters clearer.

-- 
Tom Taylor
Carrier VoIP Standards Development
Nortel
Phone +1 613 763 1496  (ESN 393-1496)
E-mail: [email-masked]

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