On Thursday 21 April 2005 02:04 am, Richard Dobson wrote: > > Voice and audio is not like that. You will need to transfer it reliably. > > > > TCP is what SIP/SDP has selected (there's another protocol at that layer > > too that's been drafted for use). Their model of getting around NATs and > > firewalls is also a lot like proxy65 in that a third party server is > > used. > > Are you sure? I thought they used RTP, and I was under the impression RTP > uses UDP not TCP, as TCP is not appropriate for real time data (audio) due > to various reasons that are outlined in the information about RTP.
You are correct. "TCP is what SIP/SDP has selected" is a misleading statement. Even though SIP may be able to use TCP, the voice data doesn't actually go over SIP itself. It goes over a separate RTP channel, and more often than not this is UDP. -Justin _______________________________________________ jdev mailing list [email protected] http://mail.jabber.org/mailman/listinfo/jdev
