So I don't know if this is design issue or my own lack of knowledge and configuration expertise.
I am trying to connect two seperate (i.e. not clustered) CUP Servers to 1 CUCM cluster. I need to do this because I need to enable calendar integration to different Exchange domains for different users.
We have had one CUPS up and running, with calendar integration, for one group for about 6 months. This was originally setup with a SIP PUBLISH Trunk. (It was also setup by a contractor, so I am not intimately familiar with everything that was doen to get that one working.) I understand that a CUCM cluster will only support 1 SIP PUBLISH Trunk. Therefore, when it came time to bring up the second CUPS, I set the SIP PUBLISH Enterprise Parameter within CUCM to <NONE> and I unchecked the 'Use SIP PUBLISH Trunk' on the CUPS Settings page. Not only did this not break our existing CUPC users, it cleared up some problems we were having with users' status either not updating or changing without cause.
However, with the new server up, I cannot log into Presence from the CUPC. Everything else comes up fine, but it just cycles between "Connecting..." and "Disconnected" for the Presence status under Show Server Health... Client logs don't show me anything useful. When I sniff the traffic on the new CUPS, I see the CUPS send a SIP OPTIONS method to the CUCM, and CUCM reply with a 200 OK message that includes the list of acceptable SIP Methods (which does not include PUBLISH), but that is the only SIP traffic I see. I see no SIP PUBLISH going to/from the CUPC, no SIP SUBSCRIBE going to the CUCM. I can see both of these on the traffic on the first CUPS.
So I don't know if I am just missing something in the Presence configuration or if I'm trying to do something that the software just will not allow me to do. I have engaged my Cisco Sales Team and they are supposedly getting the technical people together to work this out, but I haven't heard anything for a couple days and I'm starting to worry about this deployment.
CUPC presence (more accurately, should be referred as "status") has nothing to do with SIP trunk. It's totally between CUPC and CUPS.
If CUPC not able to connect to 'presence' (from 'show server health), there could be couple reasons:
1) Digest Credential configuration on CUCM end user. (can be bypassed by ACL)
2) Presence address (hostname of CUPS + SIP domain) has to be resolvable from client side.
3) Firewall/network issue.