From: "Agrawal, Vishal" <[EMAIL PROTECTED]> Why does SIP not recommend a single way to put the UAS on hold? Has there ever been any discussion to provide the hold indication in a separate SIP header in the re-INVITE?
No, there hasn't. So far I've not seen two SIP endpoints (different vendors) which offer or accept the hold and MOH the same way (some expect c=0.0.0.0 (old way), some respond back with (a=recvonly in response to re-INVITE with a=sendonly), some respond back with (a=sendrecv), some respond back with (a=inactive), There is a third method also, which is to do a re-INVITE which changes the value of the "+sip.rendering" parameter on the Contact header. (If I remember correctly.) That is reasonably close to the separate header you inquired about. Also, the hold is not bidirectional right? That is correct, hold is not bidirectional. The act of "A puts the call on hold" is orthogonal to the act of "B puts the call on hold". So for any call, there are actually 4 hold states, and any hold mechanism must distinguish them. (Even though audio does not pass between the users in 3 of the states.) Dale _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
