I'm currently testing with CUCM 7, exchange 2007, and the fax features. My trunk already has the T.38 exchange interoperability box checked in it's sip profile, and my exchange server is detecting the CNG tones inband and issuing the re-invite, with the new image sdp. My CUCM does (eventually) respond to the re-invite with a 200 OK, with an image SDP, but it does so exactly 50 seconds later, and after the test fax machine has given up on the fax. Does anyone know why the response with the image SDP answer is delayed? Does anyone know how to fix/change that?
With a different source fax machine, the delay is exactly 55 seconds. but on further inspection, (removed a filter), it appears that my cucm may be immediatly issuing a BYE after receiving an ACK for the 200 OK that it sends late. Any Ideas?
Trillium Staffing Solutions
This doesn't really add up.
What's on the other side of CUCM?
Most likely whatever is on the other side of CUCM is causing the delays. It's possible that it is CUCM, but not nearly as likely that it is just passing through what it is receiving.