Video calls between Polycom and UCM phones work through a SIP trunk?
My expertise in Video is 0, however looking at the documentation, I think h323 fast start is not supported. Or I am not sure, you we are running into internetworking limitation in IP-IP Gateway itself.
So I think you are running into a design limitation. As sip eo-h323 ss is also not supported. You can check witht he Video telephony forum.
If Polycom end device supports sccp, configure line side to be sccp(telephony-service ) if not and if it is allowed then change the trunk side to sip and check.
I have worked around this issue by configuring in such a way that different outbound dial-peers will be selected for calls from IP 7000 and for other calls between CME and CUCM. The outbound dial-peer related to IP 7000 calls will have "call start fast" and the outbound dial-peer related to other IP phone calls will have "call start fast". So, this fixes our issue.
Thanks a lot for your help here. This issue is now fixed.
Murali, I have actually asked a question related to CME LPCOR in another thread and I did not get any reply. Could you please check https://supportforums.cisco.com/message/3629705#3629705 once and let me know if you know how to achieve this?