Enterprise-class Voip Call Management

For about one hundred years, the telephone operation and circuit switch are always been the mainstream of telecom. During the quick development of computer and broad band network, the multimedia information network has become the focus around the world. The network based on TCP/IP has begun entering the telecom. The successful apply of IP network telephone (VoIP) indicated new generation information network. Recently, VoIP has made further progresses and improvement; there are two major protocols for VoIP: H.323 protocol stacks put forward by ITU-T and SIP-based telephone tech by IETF. H.323 standards have been the international standards for VoIP.The object of this article is the manage functions of gatekeeper in VoIP system for corporations. Gatekeeper manages the H.323 terminals and calls. It is a very important part in H.323 system. This article discusses the realization of gatekeeper's functions. For this purpose, we used two protocols: H.323 and RADIUS. H.323 protocol defines what functions should gatekeeper has. RADIUS means Remote Authentication Dial-In User Service; it can be used in some of the gatekeeper's functions. This article includes four parts: (1) Foreword. Introduced the background and apply of IP telephone. (2)System Design. This part discusses the design for VoIP system. (3) Theory and Realization. This part includes chapter 3 and 4. Chapter 3 discusses the theory of gatekeeper's manage functions, especially about using RADIUS for the functions. Chapter 4 discusses the software realization of those functions. (4)Test and Conclusion. This part discusses the test environment and test result and makes some suggestions for future research.