| Summary: | 碩士 === 國立交通大學 === 資訊工程系 === 89 === In recent years, “Internet telephony” is becoming more popular and is an important trend to the next generation voice communications. It could provide long-distance call services at the cost of local calls. In order to unify the protocols of Internet telephony and improve the scalability of Internet telephony gateways, IETF proposed an Internet telephony structure that separates signaling from data streams by extracting call control functions out from gateways to Call Agents. After several evolutions, IETF proposed the Media Gateway Control Protocol (MGCP).
The current specification of MGCP does not support terminal mobility. In this thesis, we focus on the design and implementation of terminal mobility for MGCP. We enhance the functionality of Call Agent and Media Gateway in MGCP by proposing a new location management mechanism to keep tracking of the terminal devices. We provide a systematic numbering plan for all phone numbers, and introduce the concept of Home Call Agents, Foreign Call Agents, and Directory Servers. We also design the communication protocols, Registration, Roaming, Handoff, and Deregistration, required to support terminal mobility. The presented location tracking mechanism is simple and efficient, and is backward compatible with the original static MGCP terminals and media gateways.
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