Port 8002

Cisco Unified Communications Manager (CUCM) is a highly scalable, IP-based communications system that provides voice, video, messaging, and mobility capabilities. Port 8002 specifically serves as an intercluster signaling port, allowing distinct CUCM clusters to communicate in multi-cluster deployments. This enables features like call routing, directory lookups, user presence sharing, and intercluster trunk connections, which are essential for large enterprises with distributed call control domains.

Intercluster communication facilitates call setup, teardown, and supplementary services such as call transfer and conferencing between clusters. Signaling on port 8002 typically uses Cisco’s proprietary protocols encapsulated over TCP, ensuring reliable session establishment and management. Proper functioning of this port is critical for maintaining uninterrupted collaboration across geographically dispersed sites.

Network administrators must ensure that port 8002 remains reachable across firewall boundaries where intercluster features are needed. While this port is primarily unofficial, it’s widely recognized in Cisco VoIP deployments. Non-standard ports and proprietary protocols should be documented and monitored to ensure interoperability and support.