Hi -
I am seeing problems with call hold (specifically the ExpressTalk softphone being put on hold) regarding the SDP session version number in the response to the INVITE for the hold operation (the 2nd offer) being incremented by 2 from the response to the original INVITE instead of by 1 as specified in RFC 3264 section 8.
In fact it looks like the version number is always incremented by 2 anytime the SDP data changes, when the specification says it should be incremented by 1.
This seems to cause problems with some SIP back-to-back user agents.
Other phones (Grandstream BT-100 and snom 320) follow the specification.
Anyone know if this is a bug in ExpressTalk, or if there is a setting that affects it?
- Thanks