节点文献
基于SIP的移动VoIP的研究与实现
【作者】 汤晶；
【导师】 秦志光；
【作者基本信息】 电子科技大学 ， 信息与通信工程， 2010， 硕士
【摘要】 随着无线网络技术的快速发展,移动设备功能的不断强大,传统的多媒体业务已不能满足人们的需求。如何在现有的异构网络环境之上发展更多的移动多媒体增值业务,成了当前研究的热门。其中典型的应用为VoIP技术。实现VoIP的一个关键的技术就是信令技术,目前广泛应用的有两种信令体系：H.323和SIP。H.323功能强大但却非常复杂,它规定了完整多媒体应用架构,要求较高,实现起来比较困难。SIP协议是一个简单的、易扩展和实现的,基于文本的信令控制协议。更重要的是,它是一个底层接入无关的应用层信令协议。基于以上原因,研究SIP对移动VoIP的支持与应用,对发展接入无关的移动多媒体应用有着重要的意义和价值。本文设计实现了基于SIP的网络服务组件,通过该系统基于SIP的移动VoIP用户可以很简单的进行定位和建立多媒体会话,进而完成语音交互过程。本系统遵循RFC3261规范,并基于MJSIP协议栈,对SIP协议栈进行了重新设计和改进,实现了包括：传输层、事务层和事务用户层。然后基于此协议栈设计实现了包括代理服务器、注册服务器和重定向服务器等SIP网元,构建了一个基于SIP的网络融合平台。同时,本文又对新兴的开源手机操作系统Android进行了研究,将SIP协议栈成功应用于Android平台上,实现了模拟终端到服务器的通信。在完成以上功能的同时,本文重点研究了SIP对移动性的支持,提出了一种动态分层注册模型,用于实现移动设备域内移动时切换延迟问题。由于SIP协议本身缺少安全机制保护,故在SIP应用中,安全性问题也是考虑的重点,本文也对SIP的安全性进行了相关研究,并实现了Http摘要认证方案。本系统在模拟网络环境上进行了多次测试,验证了SIP服务器的正确性和稳定性。本文通过构建的SIP网络,验证了SIP移动多媒体应用的可行性和方便性,下一阶段,本项目将重点研究基于SIP网络的多媒体应用系统,譬如：多方会议系统等。
【Abstract】 With the rapid development of wireless network technology and the continually strong mobile device features, the traditional media businesses have been unable to meet people’s needs. How to develop the mobile media with more value-added services in the existing heterogeneous network environment has become the most popular of current research. One of the most typical applications is VoIP technology. A key realization achieving VoIP technology is the signaling technology. There are two wildly used signaling systems:H.323 and SIP. H.323 is powerful but complex. It provides a complete framework with higher requirement and is achieved more difficultly. SIP protocol is a signaling control protocol which is simply expensing and achieving, based on text. More important is that it is unrelated to the low-level access. Above the reasons, the research based on the support and application of SIP for mobile VoIP has more important significance and value for developing access unrelated mobile multimedia applications.This thesis design enables network service components of SIP. Through this system, mobile VoIP users based on SIP are easily able to locate and establish multi-media session, then complete the voice interaction. Follows RFC3261 specification, this system redesigns the SIP protocol stack based on the MJSIP protocol stack and achieves transport layer, transaction layer and transaction user layer. It achieves SIP element location, including proxy servers, registration servers and redirect servers and builds a SIP-based platform for network convergence. Meanwhile, this paper has researched on emerging open-source Android mobile operating system which uses the SIP protocol stack on the Android platform to achieve a simulated end-to-server communication.While completing the above functions, this thesis focuses on the support of SIP for mobility and raises a dynamic hierarchical registration model, used to implement the switching delays within the domain for mobile device.Because the SIP protocol is lack of security mechanisms, in the SIP applications, security issues are valued to concern. This thesis also carried out the safety of SIP-related research and realized Http summary of certification program.This system carries out a number of tests to verify the correctness and stability of the SIP server in a simulated network environment. This article only provides the basic functions of SIP network and verifies feasibility and conveniences of SIP mobile multimedia. Next stage, we will focus on web development SIP-based multimedia applications, such as:multi-party conferencing systems.