Implementing VoIP Support in an Enterprise Network (Cisco VoIP Implementations)

This section is intended to give you an overview of telephony deployment models and their necessary elements and components in an enterprise network. It briefly introduces Cisco Unified CallManager, and it discusses a few different implementation options for CallManager clusters. The last part of this section includes a simple configuration for a Cisco voice gateway and concludes with a brief discussion of CAC.

Enterprise Voice Implementations

The main telephony elements of an enterprise Cisco VoIP implementation are gateway, gatekeeper, Cisco Unified CallManager, and Cisco IP phones. Cisco IP phones need CallManager, because it acts as an IP PBX for the Cisco IP phones. The gateways provide connectivity between analog, digital, and IP-based telephony devices and circuits. Gatekeeper is an H.323 device that provides call routing or CAC services.

Enterprise voice implementations can vary based on many factors. One of those factors is the number of sites, and the preferred method of data and voice connectivity (primary and backup) between the sites. Some sites might not have VoIP implemented; other sites might have VoIP connectivity but no IP phones or other IP Telephony services. The sites with IP phones and services might have the control components, such as Cisco Unified CallManager cluster, locally present, or they might have to communicate with the control devices that reside at another branch or site. Figure 1-15 displays an enterprise with three branches: Branch A, Branch B, and Branch C.

Figure 1-15 VoIP Implementation Within an Enterprise