实现sip的聊天客户端，它为架设voip提供参考和学习-Achieve sip chat client, it is set up voip reference and learning

SIP Communicator, the OpenSource Java VoIP and Instant Messaging client but has been significantly changed for Andriod.

基于 sip 协议 进行 voip 分机客户端开发，分步为 注册 ，构建会话，结束会话等功能(Based on the SIP protocol, the VoIP extension client is developed step by step to register, build session, end the session and other functions)