I have a case where a single Expressway will integrate with multiple CUCM clusters which are part of same domain. They are separate clusters due to capacity planning. My understanding is that with _cisco-uds SRV records, Expressway can detect all clusters in the environment and connect a user to his corresponding home cluster.
Question: When a user A connects via expressway to cluster 1 which is his home cluster, will the user be able to search contacts on Cluster 2? Even though these users are LDAP sync'd, the LDAP filters only sync in limited set of users so each cluster will not have entire user list from LDAP.
Unless you're running CUCM/IM&P 11.5 and x8.8+, MRA devices will use UDS for directory resolution. That means only users who are in UDS, will be available.
If you're running the latest releases, you can configure UDS to work as a proxy for LDAP directory resolution over MRA.
Is there a timeout parameters that need to be considered for a deployment with a single Expressway but multiple CUCM clusters? the _Cisco-UDS entries will help identify various CUCM clusters, but I have not found any documentation on how expressway searches through all clusters. If the searches are sequential and the user is located on 5th cluster, will it timeout? or even if there is a limit on how many clusters can expressway search through.
This is why you configure ILS between the clusters, EXP will not do any search for this, it will reach out to one CUCM cluster, and then CUCM will re-direct the request as needed, with the info it learned via ILS.
With UDS LDAP proxy, you can only configure 3 different LDAP user search bases (newer tried, if not correct). Not enough for more than 3 clusters. What about external contacts outside LDAP? What about filtering out mobile numbers for one group of users in the same CCM cluster? What about identity management on per-user basis?
In my opinion, Cisco does not put enough effort on this. Same problem for identity management exists since CCM 3x. For example, Cisco IP Phone does not show contact names not even from its personal directory.
To overcome this problem, not using CCMs UDS service for off-premises Jabber clients, same way as MRA Telepresence endpoints to use alternate UDS type directory, a simple REST application, that returns requested XML in the same way CCM UDS does, can be an option.
I have same question regarding UDS discovery in multiple CUCM clusters. I have ILS configuration between two clusters using SME. I also have centralized TFTP configured. Do we only need to configured UC neighbor zone for one CUCM cluster or both? What's priority/Weight recommendation for UDS SRV record in DNS?
All the clusters that will have MRA registered endpoints need to be configured in EXP-C.
There is no recommendation regarding _cisco-uds SRVs, if you want to use SME to find the services for your deployment, you can point to it, ILS will be used to search for the home cluster of the user, and then that info will be provided to EXP-C so it can establish the registration to that cluster.
If you want to have redundancy for your SRVs, you can configure it as you wish. The process will be exactly the same, if you land on a cluster who is not the home cluster for the user, ILS will be used to find it.