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 mailto:audet@NortelNetworks.com Nortel Networks Fax:+1 408 565 2375 http://www.nortelnetworks.com/ http://www.NortelNetworks.com