Hi all,
I spotted a number of issues
concerning third party initiated pause and rerouting, H.323 Annex F, the new
"share with voice" capability in H.323v4, and of course, everybody's favorite:
fast start.
- How do we do third party
inititated pause and re-routing for a call initiated with fast start for a
non-Annex F endpoint?
- Reading H.323v4 suggest that
the way to do this is sending the null Terminal Capability Set in a tunnelled
H.245 message, or alternatively in a newly-created H.245 channel. This implies
the master-slave determination, the terminal capability set exchange, and the
actual opening of the media channels.
- However, is it allowed to use
the Annex F procedures of sending a nullChannel in a fastStart in any H.225.0
call control message in a non-Annex F endpoint? Are these procedures of
resending fastStart allowed in H.323v4 without Annex
F?
- Interestingly enough, the
"share with voice" capability of section 9.10 use the Annex F method of
sending fastStart in a FACILITY message. I can't see how we could allow this
for switching between voice and fax, but not for generic "third party pause
and re-routing".
- Why is section 9.10 where it
is? Shouldn't it be integrated in H.323 Annex D for Fax? If not, there should
at least be a reference to 9.10 in Annex D for fax. A side note is that I am
not shure what we gain by having two methods of doing switchover from voice to
fax (one with 2 always opened channels for voice and fax as per Annex D, and
the other involving the replacing of the channel as per
9.10).
- Lastly, this "share with
voice" procedure allows the receiving side to modify the content of the
proposed OpenLogicalChannel in fastStart (i.e., it allows for reponding
shareWithVoice=FALSE in return to an incoming fastStart with
shareWithVoice=TRUE). Technically, this is not allowed in H.323 which mandates
that the receiving side choose as is from the list of
OpenLogicalChannel in the fastStart. This point was mentioned earlier on the
list when discussing problems with payload size negotiation with fast
start.
-----
François Audet Tel:+1 408 565 5675
mailto:audet@NortelNetworks.com
Nortel Networks Fax:+1 408 565 2375 http://www.NortelNetworks.com