SIP

Summary

This chapter examined the role of gateways in the CallManager architecture. Gateways bridge the gap between the packet-switched network and the circuit-switched network. This chapter described the circuit-switch technologies Cisco gateways support and the VoIP protocols H.323, MGCP, and SIP, which CallManager uses to talk to gateways and to other CallManagers. In addition, this chapter detailed the role of the gatekeeper and RAS, the H.323 gatekeeper communication protocol.