【作者】 车彦；

【导师】 陈辉煌； 石江宏；

【作者基本信息】 厦门大学 ， 通信与信息系统， 2007， 硕士

【摘要】 随着网络技术的发展,多种通信方式应运而生,然而每一种单一的通信方式并不能提供满足用户所有需求,多种通信方式的同时使用又给用户带来极大的不便,影响效率。为解决上述问题,本课题致力于研发一种将音频、视频、数据传输等所有通信能力集于一身,并具备有线和无线两种传输方式的终端设备。此终端设备的核心技术是基于SIP协议的IP可视电话,本文着重介绍这一核心技术的软件设计和实现。本文首先概要介绍了IP电话的发展现状和技术基础,着重研究了基于SIP的信令技术、媒体协商技术和实时传输技术。然后从整体上提出了本终端基于通用性考虑的系统架构,包括硬件架构和软件总体设计。接着详细论述了基于SIP协议的IP可视电话软件中的两个重要模块SIP信令模块和媒体会话模块的设计思路和实现方案。本文在设计方面主要提出两个重要思路。在信令控制部分,重点研究并定义了一种基于事务状态机模型的用户代理结构,通过对用户状态的迁移过程的抽象分析,定义了一系列对应的处理接口,从而解决了信令控制复杂的问题。在音视频通信部分,出于程序结构性、可移植性,以及增加扩展功能的易行性方面的考虑,提出一种Pipeline的设计思想,即封装处理器、抽象处理链路,将媒体会话模块的三个子模块定义为几个处理器来分别实现,在主流程中将这些处理器连成一条链路,协同工作。最后,本文将实现了的终端设备与多个基于SIP协议的IP电话进行了音视频交互的测试,分析发现本终端SIP信令控制正确,音视频通信质量良好,且具有良好的互通性。更多还原

【Abstract】 With the development of network technology, a variety of means of communication has emerged. However every single means of communication can not meet all requirements of users, so users will often use a variety of means of communication. But use a variety of means of communication at the same time can bring a great deal of inconvenience and inefficiencies to customers. In order to solve the above problem, the subject efforts to design a terminal equipment that can provide audio, video and data communications and have both wire line and wireless transmission systems.The core technology of this terminal communications equipment is IP Video Phone based on SIP protocol. This paper describes the software design and implementation of IP Video Phone base on SIP.Firstly, this paper outlines the development trend and some key technologies about IP telephony, and the research emphasis is on the SIP signaling technology, media negotiation technology and real-time transmission technology. Then the framework design of terminal considering the common system architecture is proposed, including hardware and software part. Subsequently, this paper discusses the design and realization of the SIP signaling module and the media session module which are two important modules of IP video phone software modules in detail. This paper presents two important ideas in the part of software design. In the signaling control part, a kind of user-agent structure based on the transaction state machine is designed to solve the complexity problem on the signaling control. That is achieved by analyzing the user state migration process and defining a series of process interface. In the part of audio and video communication, taking procedural structure, portability and functional expansion into account, Pipeline design idea is proposed. Pipeline can realize the audio and video communication by defining and packaging the processors of three sub modules of the media session module, then forming and running the handling link including all the processors.Finally, this paper tests the communication of this terminal equipment with other IP Telephony based on SIP, the test results show that terminal can provide right control for SIP Signal, satisfying quality for audio and video communication and good compatibility.更多还原