Which three items are required to provision core telephony service on the Cisco Unified Communications Manager Express router? (Choose three.)

A MAC address is used when defining an individual ephone to bind a specific physical phone to the configuration, but it is not a prerequisite for bringing up the core telephony service itself.

The 'ip source-address' command specifies the router interface IP address and TCP port (default 2000) that SCCP phones use to register with CME. Without this command, IP phones have no defined endpoint to contact and cannot establish a registration session with the router.

Dial peers are used for VoIP call routing to destinations such as the PSTN or remote sites, but they are not required to provision the telephony-service block that enables IP phone registration.

The 'ephone' command creates a configuration context for an individual IP phone after the core service is already provisioned; it is not a core provisioning requirement.

The 'max-dn' command, entered under telephony-service, sets the maximum number of directory numbers the system will support and pre-allocates the corresponding resource slots. It must be configured before any ephone-dn definitions can be created.

The 'max-ephone' command sets the upper limit on how many IP phones may register simultaneously with the CME router. CME uses this value to pre-allocate memory and processing resources required to handle phone registration and call signaling.