Cisco Unified Communications Manager nodes, adding users with the
"Jabber for Everyone" offer should not impact the scalability for the core voice and video users.
For IM and Presence, mixing full UC mode users and users added with the "Jabber for Everyone" offer is supported on the same node, or cluster. The following formula shows how to determine how many users you can add to your deployment with the "Jabber for Everyone" offer:
Number of "Jabber for Everyone" users = (Number of full UC users/Maximum number of full UC users) x Maximum number of "Jabber for Everyone" users
For example, if you have 10,000 full UC users on a server that supports a maximum of 15,000 users, then you are operating at 2/3 of the scale for UC, which means that 1/3 is available for "Jabber for Everyone" users. The IM and Presence Service supports 25,000 users for IM-only mode, therefore, you can add 8,333 users (25,000 x 1/3) through "Jabber for Everyone". This amounts to a total of 18,333 users.