[AVT] Use of RFC 2793(bis) between gateways

[Tom Taylor <taylor at nortel.com>]

I'm currently updating draft-ietf-avt-rfc2833bisdata along the lines I've 
indicated earlier, and in particular rewriting the V.18 section.  I have added 
words encouraging the use of RFC 2793(bis) between gateways when possible.  Having 
said that, however, I can see the need for another RFC providing advice on how to 
do it.  I have two particular issues:

1) How does such a session start up?  Does either gateway act as a proxy for the 
far-end terminal?  Do both of them?  Do they each try to appear to the terminal at 
their end as if they were a similar terminal?  As a result, do they modify any 
V.8- or similarly-signalled capabilities they receive from the remote end?

This question would have to be worked through using various terminal types and 
startup sequences.

2) I see the possibility that a gateway knows how to convert V.21 signals, for 
example, into RFC 2793(bis) payload, but doesn't understand V.23.  How does it 
signal which modems it understands?

On a peripherally related topic, I'm adding a generic voice-band data indicator 
event to draft-ietf-avt-rfc2833bisdata to allow for the case where the sending 
gateway recognizes that it is receiving modem-like tone sequences but doesn't 
recognize the particular modem involved.

Tom Taylor

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