El Viernes, 16 de Octubre de 2009, Sharanabasavaraj Mathapati escribió: > Hi All, > > I had some queries on SIP
> 1) Why ACK is separate transaction? Just ACK for 2XX is a new transaction. And it's been explained several times. One reason is: If the ACK for 2XX would be part of the same INVITE transaction then it would be hop-by-hop rather than send-to-end. This is, the ACK sent by UAC would be different than the ACK received by UAS (in fact the ACK received by UAS could occur first as a proxy must not wait for a ACK to sends its own ACK). This would make imposible the ACK to contain information, and remeber that SDP information can be carried in "200-ACK" rather than "INVITE-200". There are more reasons but I invite you to search then in the maillist archive :) > 2) why can't we send CANCEL in case of BYE to terminate the call? Hummmm, the way to terminate an *established* call is BYE, not CANCEL. Just it. -- Iñaki Baz Castillo <i...@aliax.net> _______________________________________________ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
