Re: [AVT] 2833bis - V.21

[Flemming Andreasen <fandreas@cisco.com>]

Henning Schulzrinne wrote:

> > - V.21 data bits:  It would be nice if we had a more efficient way of
> > sending
> > V.21 data bits which also doesn't require us to use RFC 2198
> > redundancy. We
> > could for example define two new events (one for each V.21 channel)
> > that simply
> > use the (otherwise unused) volume field to encode the actual bit
> > values. That
> > would enable us to send 20 ms of V.21 data bits in a single event.
> > Alternatively, we could consider encoding it in the duration field as well
> > (e.g. have volume indicate number of bits and duration the actual
> > bits), but
> > that seems more inconsistent (it would on the other hand allow us to
> > encode up
> > to the recommended 50 ms).
>
> I'd rather not mess with the duration field, since that seems to
> possibly break things and requires more special-casing. I added the
> first option. Also, you need the duration to indicate which bits are
> actually valid. Otherwise, how would you express 0101, say?
>

You could special-case everything but I agree that the first option is
preferable.

Nit:    Both entries in Table 3 for V.21 compressed say "channel 1". One of them
should say "channel 2".

-- Flemming


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