What is call admission control in CUCM?

• A. A mechanism limiting voice/video sessions to protect quality.
• B. It monitors call logs for troubleshooting.
• C. It defines codecs to use for calls.
• D. It routes calls to backup gateways.

Answer: (A)

Call Admission Control is a mechanism that protects voice and video quality by not admitting new calls when there isn’t enough available bandwidth on the network path to support them. In CUCM, it checks the bandwidth required for a new call (based on the chosen codec and any overhead) against the remaining bandwidth on the trunk or WAN link. If admitting the call would exceed the available capacity, the call is blocked or denied, preventing congestion and preserving QoS for existing calls. It’s not about monitoring logs, selecting codecs, or routing to backup gateways.