In CUCM, Locations are used for call admission control (CAC) to manage bandwidth between sites. If the Location is configured with a finite bandwidth (like 0 kbps remaining), it will allow the call signaling but block the media streams, resulting in one-way or no audio. This is a classic symptom when internal calls (within the same location/bandwidth pool) work but external calls fail.

For a user to have functional voicemail in a Webex Calling with Cisco Unified Communications Manager (CUCM) deployment, two core elements are needed: 1) A voicemail pilot number must be assigned to the directory number so the system knows where to route missed calls. 2) A mailbox must be provisioned in Cisco Unity Connection and linked to that directory number to store and retrieve messages. The other options relate to device registration or features not directly tied to basic voicemail functionality.

A phased, pilot-group approach is a critical best practice. It allows administrators to validate configurations, test call flows (internal, PSTN, voicemail), train support staff, and gather user feedback on a small, controlled scale. This minimizes risk and allows for adjustments before committing the entire organization to the new platform.

To meet the requirements: ‘Circular’ distributes calls in a round-robin order. ‘No Answer Ring Duration’ set to 20 defines how long the hunt list members ring before the ‘No Answer’ condition is triggered. ‘Forward No Answer’ set to the voicemail pilot number directs the call to voicemail after that duration. The ‘Busy Trigger’ is for a different condition (when lines are busy), and ‘Broadcast’ rings all agents simultaneously, which was not specified.

The CTL file is a security feature used in CAPF (Certificate Authority Proxy Function) enabled environments. It contains the public certificates of trusted entities (like the CUCM servers and CAPF itself). The phone uses this list to verify that the server it is connecting to (for TLS-encrypted signaling) is legitimate and not an imposter, establishing a chain of trust.

Emergency calls must be routed with high priority and locality. The correct method is to create a distinct, highly specific route pattern (e.g., 112) that is not part of a catch-all international pattern. This pattern is then associated with a route list/gateway that provides physical local egress, ensuring the call is handled by the nearest Public Safety Answering Point (PSAP).

The Webex Cloud Connected UC (CCUC) service, specifically the directory synchronization process, is responsible for synchronizing user information (including extension-to-URI mapping) from the on-premises CUCM into the Webex Cloud. When a Webex Calling user dials an internal extension, the cloud uses this synchronized directory to resolve the extension to the target user’s cloud URI for routing.

After confirming the MAC address, the next logical step is to verify the phone’s broader configuration. The ‘Registration Rejected’ message often means the phone is attempting to register but is being refused. A common cause is that the phone is configured with a Device Pool that points to a Call Manager Group containing an incorrect or unreachable CUCM server IP address. The phone cannot find a valid server to register with.

Call Park places an active call on hold in a system-wide ‘parking lot’ (with a park number) so it can be retrieved from any phone by dialing that number. Call Pickup allows a user to answer a call that is ringing on another phone, typically within their designated pickup group (like a team of agents), without needing a specific park number.

In CUCM, Locations are used for call admission control (CAC) to manage bandwidth between sites. If the Location is configured with a finite bandwidth (like 0 kbps remaining), it will allow the call signaling but block the media streams, resulting in one-way or no audio. This is a classic symptom when internal calls (within the same location/bandwidth pool) work but external calls fail.0