Which services are required for CUCM cluster communication?

Which services are required for CUCM cluster communication?

• A. Only DNS/NTP.
• B. Only core CUCM services.
• C. Database replication plus core CUCM services and DNS/NTP.
• D. Only endpoints licensing.

Answer: (C)

For CUCM cluster communication to work, you need three things: the essential CUCM services running on each node, database replication to keep configuration data synchronized across the cluster, and reliable DNS and time sources (NTP). The core services on every node are what allow that node to participate in the cluster, handle call processing, directory information, and overall cluster operations. Without these services active, a node cannot join or communicate within the cluster. Database replication is what propagates changes made on the publisher to all subscriber nodes. If replication isn’t functioning, different nodes hold different data, leading to inconsistencies in device configurations, user settings, and call routing. DNS and NTP provide the naming and timing foundation the cluster relies on. DNS ensures nodes can resolve each other’s hostnames consistently, which is important for stable inter-node communication. NTP keeps clocks synchronized across all nodes, which is crucial for certificate validity, scheduling, and the timing of replication processes. Without accurate time and proper name resolution, cluster messaging and trust relationships can fail. Endpoints licensing by itself does not enable cluster communication; it doesn’t address data synchronization or the services that keep the cluster functioning.

For CUCM cluster communication to work, you need three things: the essential CUCM services running on each node, database replication to keep configuration data synchronized across the cluster, and reliable DNS and time sources (NTP).

The core services on every node are what allow that node to participate in the cluster, handle call processing, directory information, and overall cluster operations. Without these services active, a node cannot join or communicate within the cluster.

Database replication is what propagates changes made on the publisher to all subscriber nodes. If replication isn’t functioning, different nodes hold different data, leading to inconsistencies in device configurations, user settings, and call routing.

DNS and NTP provide the naming and timing foundation the cluster relies on. DNS ensures nodes can resolve each other’s hostnames consistently, which is important for stable inter-node communication. NTP keeps clocks synchronized across all nodes, which is crucial for certificate validity, scheduling, and the timing of replication processes. Without accurate time and proper name resolution, cluster messaging and trust relationships can fail.

Endpoints licensing by itself does not enable cluster communication; it doesn’t address data synchronization or the services that keep the cluster functioning.