说明：  采用X-Lite记录下来的SIP的会话过程,其中分为建立连接和取消连接两个部分,包含了最基本的会话协议内容和参数.可以作为一个入门级的会话例子参考.
(X-Lite record of the conversation SIP process. It is divided into establishing connections and the abolition of connecting two parts includes basic conversational content and parameters of the agreement. as an entry-level session examples reference.)