More recent developments in such wireless technologies as short message service and session initiation protocol have provided for innovative solutions that leverage the capabilities of web services 近来在无线技术，例如短信服务( short message service ， sms )和会话发起协议( session initiation protocol ， sip ) ，领域中的更多进展已经提供了创新解决方案，这些方案利用了web服务的功能。
Windows messenger allows real - time communication with other contacts who are using instant messaging services including those provided by the session initiation protocol as offered by microsoft office live communications server Windows messenger允许用户与使用即时消息( im )服务的其他联系人进行实时通信，这些即时消息服务包括由microsoft office live communications server推出的会话初始化协议( sip )所提供的服务。
The innovations of the thesis lie in combining the dns query , authentication and session initiation into a transaction to finish , which originally need several transactions to finish . it improve the efficiency effectively , simplify the session flow 本文的创新点在于把按照协议规范原本需要多个会话事务才能完成的域名解析,鉴权和会话发起的呼叫过程封装到单一会话事务中,很好地提高了协议的运行效率,简化了会话流程。
Session initiation protocol which was first proposed by the ietf at 1999 is a widely used voip protocol nowadays , mainly for the realization of instruction control over ip , including the creation , management and termination of the multi - user participatory voice conversation process 1999年由ietf提出的sip协议是目前广泛使用的一种voip协议,主要用于实现ip网上的信令控制,包括建立、管理和终止由多方参与的语音会话进程。
Under the background , ietf ’ s sip ( session initiation protocol ) can provide an excellent support to the multimedia communication session management as a soft switch application layer ’ s protocol . we can build a low cost , multi - service , high adding value multimedia communication network with it and other protocols from ietf . the system can also support terminal user ’ s mobility very well 在此背景下,由ietf提出的sip ( sessioninitiationprotocol ,会话初始化协议)作为ngn ( nextgenerationnetwork ,下一代网络)的软交换应用层控制信令协议能对包括音频,视频,数据在内的多媒体通信会话管理提供良好支持。
Now , h . 323 has widely applied in the ip phone in china . at the same time the merits about session initiation protocol should be seen in the simpliness , the distributing controlling and so on . and session initiation protocol can quickly develop with the technology of soft switch , the performance of internet 目前，在中国的ip电话领域中h . 323已被广泛应用，同时也应看到sip简单灵活、分布式控制和易于扩展等优点，并且随着软交换等技术的发展， sip的应用正迅速地向前发展，并且随着internet传输质量的提高， ip电话的语音质量会得到很好的改善。
Finally the software of all the modules was give . experiment in pc demonstrates this designed software can accomplish the basic function of ip phone such as creating the connection by session initiation protocol , negotiating the media by session description protocol , transporting the stream of data by rtp / udp / ip 最后在pc上进行了实验，结果显示本课题所设计的软件可以完成ip电话的功能，使用sip信令建立连接、使用sdp信息进行媒体流协商和使用rtp / udp / ip传输音频数据流。
Main research is as the following : first , this article discusses the correlative protocol such as session initiation protocol , session description protocol and real - time transport protocol , analyses the format of the message , the field for the message and the meanings of all the fields , demonstrates the hardware 主要工作如下：首先，探讨了sip协议栈的相关协议，包括sip 、 sdp和rtp ，详细地分析了各个协议所需要的字段以及各字段的具体意义和具体的消息格式；同时还论证了实现ip电话终端的硬件平台。
