I cannot say I have it fully functional as of yet, but I am in the process of trying to integrate a SIP trunk between VCX 7.1.16c and CUCM 8.6 systems. Able to get calls to pass between the system every time now but there is an issue with calls going Cisco > VCX, where once the rings timeout, something disconnects the call instead of forwarding to the VM. This is the last issue I have before I can call it complete. Currently working with HP support to try and figure out which side the issue is on. It seems like it could be a media offer related issue, where an MTP is being required for communications to the VCX's IPM from CUCM.
Some key points and things I have used to configure the SIP Trunk for VCX on Cisco..that I can remember at the moment:
> Create SIP Trunk Security Profile with "Outgoing transport type: UDP" (only VCX v9+ supports TCP for SIP) (Also can just copy the default one generated by CUCM then modify that item)
> Create a SIP trunk used to route the specified patterns via Route Groups, use only single Call Processor IP for destination.
>> If you have branch VCX systems, also add separate SIP Trunk and route pattern for each system unless you can figure out the Proxy Authentication issue I had run in to when trying to route calls through the region primary...
> Create an extra SIP trunk with no attached route groups, simply add in all the other IPs on the VCX interfaces there to allow CUCM to receive SIP traffic. (Basically just making a dummy SIP trunk to list IPs you want to receive traffic from)
> Ensure your CSSs for incoming calls are set in the SIP Trunk.
> On ALL VCX systems you intend to communicate with, use VCX TA (Troubleshooting Assistant) or CLI to add trusted IPs (IPs of Cisco CUCM servers)
> Standard route pattern creation for VCX, point to Cisco CUCM.
If you cannot establish calls in a specific direction, verify which IP the VCX wants to send/receive calls on and make sure the extra dummy SIP trunk on the CUCM has the other interface IP(s) to allow receiving calls from VCX.
There are probably some more parts for the setup but for now this is what has stuck in my head without logging in to the system and reviewing every config option. If you try it out and still not working with at least basic calls between sites, I can provide screenshots for details of what I currently have.