An engineer wants to ensure that Cisco Jabber clients can communicate with instant messaging clients who are not registered to the same Jabber cluster. Which technology meets this requirement?

An intercluster trunk connects multiple Cisco Unified Communications Manager clusters for voice call routing, not for IM communication between Jabber users on different clusters.

Federation is the technology that allows Cisco IM and Presence to establish trusted XMPP or SIP-based connections with external IM domains, including other Jabber clusters or third-party IM platforms. It is configured at the IM and Presence Service level and enables cross-domain presence and messaging. Without federation, communication is restricted to users registered within the same cluster.

A SIP trunk is used to connect CUCM to external voice carriers or systems for call routing and does not address cross-cluster instant messaging.

A PRI (Primary Rate Interface) is a physical PSTN circuit used for voice connectivity and has no relevance to instant messaging interoperability.