【作者】 叶恒；

【导师】 王秋光；

【作者基本信息】 哈尔滨理工大学 ， 信号与信息处理， 2008， 硕士

【摘要】 VoIP(Voice over IP)是下一代网络NGN(Next Generation Net)的一个研究热点,具有广阔的应用市场。它以分组的形式传输语音数据,能提供创新的综合业务和功能,其发展的关键技术之一就是信令技术。SIP(Session Initiation Protocol)协议是专门针对IP电话提出的一种信令协议,增加了QoS(Quality of Service)要求。SIP协议借鉴了许多互联网标准和协议的设计思想,在风格上遵循兼容、可扩展等原则;支持传统公共电话网的各种业务。由于SIP系统往往工作在开放、复杂的网络环境之中,使得SIP网络元素和SIP消息可能面对各种各样的安全威胁和攻击。本文重点是将oSIP(Open Session Initiation Protocol)协议栈引入嵌入式环境中,使VoIP网关与其他网络设备间的互操作性增强。成功实现了网关新的业务功能,通过加密处理和网关注册服务器时采用摘要认证的手段,保证了网关在网络中的通信安全。本文首先介绍了VoIP原理及技术,分析了VoIP网关在网络中的作用;接着说明了SIP各网络元素作用和SIP消息组成及功能,通过研究oSIP协议栈来分析SIP消息解析和生成方法;随后给出了VoIP网关的硬件组成,在充分考虑硬件资源的情况下制定了开发应用层各软件模块的方案及相互之间的作用机制。最后实现了网关的呼叫转移、SIP消息的加密、注册时摘要认证等功能,通过测试验证了设计方案和开发流程的合理性。VoIP网关呼叫转移的功能实现不仅满足了市场的需求,而且提高了本产品在同类产品中竞争力,加密的实现既保证了网络通信的安全,又能使网关更好地为客户服务。更多还原

【Abstract】 VoIP(Voice over IP) is a one of research hotsopts of NGN(Next Generation Net) with very wide application space. It transmits the vocal data in grouping, and can provide innovative comprehensive operations and functions. One of the key techniques of its development is the signal technique. SIP(Session Initiation Protocol) protocol is one signal protocol advanced aiming at IP telephone, and it adds the Qos(Quality of Service) requirement. It adopts many a design ideology of the internet criteria and agreement, and follows the principle of compatibility and extensiveness. It can support the various operation of the traditional public telephone net. Since SIP system always works in an open and complicated network, SIP net elements and SIP information may be confronted with various safety threats and attacks.The oSIP(Opensource Session Initiation Protocol) protocol stack is introduced into the embedded situation in the dissertation, enabling the gateway the mutual operation between the gateway and other network equipment can also get improved. The employment of oSIP protocol stack successfully realizes the new operation function of the gateway. By means of the encryption techniques and digest authentication in registering server, the communication safety of the gateway in the network can be ensured.First, the dissertation introduces the principle and technique of VoIP, analyzes VoIP gateway functions in the network. Second, analyzes the functions of each SIP network element, the structure and functions of SIP message, and how SIP message come into being and it is parsed by studying the oSIP stack. Later, introduces the structure of gateway hardware, establish each software module in application layer and reciprocity mechanism under considering hardware resources. Finally, realize the gateway functions, such as calling transfer, encryption, digest -authentication. the rationality of design blue print and exploitation procedure are validated by testingThe calling transfer function of the gateway not only satisfy the demand of market, but also boost competition capability. Realizing the encryption not only ensure the security of the network communications, but also enable the gateway to serve customers well.更多还原