This chapter covers the following topics:
This chapter covers the deployment of Cisco CallManager Express (CME) for branch offices in conjunction with a Cisco CallManager deployed at a central or head office site. In this situation, the central Cisco CallManager site can act as a hub linking the remote Cisco CME sites. Cisco CME and Cisco CallManager can communicate across IP WAN links using H.323 (or using Session Initiation Protocol [SIP] with Cisco CallManager 4.1 or later versions).
In H.323 networks, Cisco CME provides supplementary service interworking (H.450) using voice over IP (VoIP) hairpin call routing when needed for intersite call transfer and forwarding. The basics of this operation are covered in Chapter 5, "Cisco CME Call Processing Features." Chapter 7, "Connecting Multiple Cisco CMEs with VoIP," covers inter-Cisco CME H.323 network operation. This chapter discusses these services in a network that has both Cisco CME systems and one or more Cisco CallManagers.
Goals of Interoperability