Introduction

Cisco s CallManager software provides the necessary functions of call-processing, signaling, and connection services for an AVVID IP telephony solution. Call processing involves the set-up and tear-down of calls, supplementary services, and other required functions for the entire telephony system. In a legacy telephony system, this function is normally provided by a PBX. CallManager provides this function via a software application on one or more PC-based hardware platforms running the Windows NT or Windows 2000 operating system.

The CallManager software communicates with devices such as IP telephones, voice gateways, legacy telephony devices, and multimedia applications such as conferencing and voice messaging in a distributed network environment. Communications with these devices is enabled with support for such protocols as the Skinny Station Protocol, H.323, MGCP, and SMDI.

CallManager also serves as a platform for extending the functionality of the telephony system. Additional voice applications are available separately from Cisco that can add voice messaging, soft-phone, voice conferencing, manual attendant console, and other functions. Other data, voice, and video services can also be added to a CallManager-based system by integrating with third-party software applications from a growing list of application developers. This extensibility is enabled via the Telephony Application Programming Interface (TAPI) and Java Telephony Application Programming Interface (JTAPI) standards supported on the CallManager platform. Examples of such applications include interactive voice response (IVR) systems, automated attendant, unified messaging, and multimedia conferencing.