I have 2 CallManager clusters that I am trying to combine into 1. The first is on CUCM 7.5 with Unity 5, and the other is on CUCM 8.6 with CUPS, & UCXN. I am in the middle of a project to move all the users out of the cluster on 7.5 and migrate them over to CUCM 8.6 with UCXN 8.6. They also want CUPS and that is my problem. CPG CUCM V7.5 CUCM is connected to CPG.LOCAL domain for LDAP Sync and LDAP Authentication. Unity is connected to Exchange 2010 on server called CPG EMAIL. GW CUCM 8.6 CUCM is connected to GW.CDS.LOCAL for LDAP Sync and Authentication. UCXN is connected to Exch 2010 on Server called GW Email. CUPS is connected to CUCM 8.6 and to GW Email through Presence Gateway via EWS. CPG and GW domain are trusted domains, but not parent/child domains. Here is where I am at on my migration. On CUCM 8.6: I added CPG.LOCAL to LDAP Sync All users in the CPG domain are now users in CUCM8.6 PROBLEM – I need to know how to Authenticate users to 2 different domains. It appears that I can only autenticate to 1 domain I built a new UCXN Server and connected it to CPG Email. This is working fine. CUPS = PROBLEM!!!! I am not sure how to proceed with building the CUPS design. Do I configure 1 CUPS Server and point it to two different Exchange servers on two different domains? How do I tell CUPS which server to pull calendaring from for which users? OR Do I build a separate CUPS server pointed to CPG email? If I build a separate server, how do I tell CUCM which CUPS server the user is on? Thanks for any guidance you can provide. ... View more