CONNECTION ISSUE BETWEEN VTC ENDPOINT TO VOIP

[Chet Cronin]

We are running CM 8.6.1 and VCS x8.5.1 with a SIP trunk between them.  We can call both ways to/from a VOIP phone to our Codian Bridge.

We are unable to call from a VOIP phone to a VTC Endpoint either direction.  Call will ring and when answered, will go immediately to fast busy???

It's like the three way handshake isn't completing.  There is no firewall involved and both the Codian and VTC endpoints are registered to the same VCS. Only one VCS Control on the network, no cluster involved.

Any ideas???   Also what is the difference in call set up between a Codian and VTC endpoint???  They both should perform the same way using the same process when setting up a call??   The bridge works but the VTC endpoint does not. 

This is a head scratcher. 

[Jonathan Schulenberg]

What does the call result show on VCS for the failed call? Any differences compared to the working one?

What do the SDI/SDL traces from CUCM show? Since pre-9.x you would need to turn on SIP stack detailed traces to see the actual SIP headers.

Likely an SDP problem since that version of CUCM would want to do Delayed Offer and not finish the SDL exchange until the 200 Ok/ACK.

[Chet Cronin]

Here is an update of what we have going on.

We can make good calls from the Codian Bridge to a VOIP phone and a VOIP phone to a Codian bridge. 

We call a VTC Endpoint from a VOIP phone or call VOIP to VTC Endpoint it still isn't working.

Call rings and immediately goes to fast busy.  The phone indicates the call is connected and the counter increments and the VTC device indicates call disconnected.  That is after the call is answered??