Abstract: SIP is playing a more and more important role in VoIP as the application-layer control protocols. This paper proposes the implementation of an IP phone server system using the functional plug-ins technology based on the SIP protocol. It introduces the SIP protocol and SIP server components, presents the structure and the thought of implementation of IP phone server which is implemented with the plug-ins technology mentioned above. At last it explains some details of implementing the function of plug-ins.

Key words: VoIP, Session initiation protocol(SIP), SIP server, Plug-in

摘要： SIP协议作为VoIP的应用层控制协议已经变得十分重要。该文提出了一种以功能插件形式实现基于SIP协议的IP电话服务器方法，介绍了SIP协议及SIP服务器组件，设计并实现了IP电话服务器的系统结构，说明了实现插件功能的细节。

关键词: VoIP, SIP, SIP服务器, 插件