You are deploying a combination of Cisco Unified Wireless IP Phones 7921G and 7925G at your branch offices in a centralized call processing environment that requires high availability at branch…

SRST (Survivable Remote Site Telephony) licenses must be confirmed at each branch gateway so phones can register locally and continue processing calls when the WAN link to the centralized CUCM is unavailable, directly satisfying the high-availability requirement.

Local voice mail support is an optional feature enhancement and not a prerequisite component that must be verified before the phones can be deployed and registered.

Music on Hold (MoH) support on branch gateways is a supplementary call feature and is not a required verification item for the initial wireless IP phone deployment.

Proper QoS configuration over IP WAN links must be verified to ensure voice traffic receives the low latency, bounded jitter, and minimal packet loss necessary for acceptable call quality between branch wireless phones and the centralized CUCM.

Single Number Reach is a Cisco Unified Mobility feature for extending calls to mobile devices and is not a required component for deploying wireless IP phones in a branch environment.

E.164 dialing format is a dial plan design consideration and not a hardware, licensing, or infrastructure prerequisite that must be verified prior to physical phone deployment.

Sufficient IP phone licenses (Device License Units or User Connect Licenses) in the CUCM cluster must exist before deployment; phones cannot register without a valid license assignment in the cluster.