【作者】 胡昱林；

【导师】 孙莉；

【作者基本信息】 东华大学 ， 计算机软件与理论， 2008， 硕士

【摘要】 随着VoIP技术的发展和成熟,基于internet的网络电话等产品逐渐兴起,并依靠其简单方便、价格低廉等优点迅速占领传统的电信领域。H.323协议是较早推出的VOIP协议,它功能强大,适应电信运营商的需求,并占有大量的市场份额。SIP协议是近几年迅速发展起来的VoIP协议,它的机制简单、扩展性强,在其推出后迅速发展,目前已经被公认为互联网上最好的全面集成通信的方式。本论文所设计的软交换系统是上海伟功网络通信有限公司基于市场需求开发的适用于中小型运营商运营需要的软交换系统。系统采用软件处理的方式,实现H.323消息和SIP消息之间的地址映射和信令交互,使H.323终端和SIP终端间可以建立通话,实现两种协议之间的信令互通,满足市场上H.323产品和SIP产品的兼容性问题,提高两种产品的应用范围。本论文首先提出了适用于中小型电信运营商的软交换系统的设计方案,设计以用户管理为核心、以软交换技术为基础的系统架构,然后在保证稳定性和高效率的基础上,根据设计的系统架构对系统加以实现。此外,在技术手段上,本系统引入XML机制描述媒体流信息,为媒体流描述提供更大的灵活性。论文首先讨论了课题提出的背景和意义,分析了国内外的研究和应用现状。其次,论文研究了系统中使用到的H.323协议和SIP协议等相关协议以及协议间的地址映射和消息映射情况。然后,论文根据对当今电信市场的调研和分析,按照模块化的方式设计系统架构。同时,根据功能需要设计相关的消息处理方案、呼叫流程处理方案和数据库结构设计方案。最后,论文讨论了系统各模块的实现方法,消息处理机制和呼叫过程中采用的状态机模型。同时,根据实际业务的需求,本系统在实现目前市场上通用的SDP消息格式描述媒体流机制的同时,引入XML机制描述媒体流信息,增强了系统的性能,并取得了良好的效果。更多还原

【Abstract】 With the development of VoIP, such products based on internet as ip phones are booming and occupying the traditional telecommunication market very soon due to its convenience and low prices. H.323 which was proposed several years ago, satisfies the needs of telecommunication operators and occupies remarkable market quota with its powerful functionalities. SIP which has been developing and burgeoning in the past few years with its simple mechanism and strong extensibility, was ackowledged as the best and comprehensive integrated telecommunication approach of internet.The software switch system is a system for small and medium scale operators. It is developed by Shanghai Weigong Networking and Telecommunication Co. on the account of market needs. It applies a software processing mechanism to implement address mapping and message interaction between H.323 and SIP and establishes communication between two end points to achieve command interaction and to satisfy compatability of these two protocols, and also to extend its application ranges. We first put forward a software switch system architecture for small and medium scale operators according to research and analysis of current telecommunication markets. Then based on the desgin architecture, we implement a stable and efficient system. Furthermore, besides SDP mechanism, we also import XML mechanism to describe media stream information, and thus provides flexibility to media stream description.In the paper, we first look into the background and value of the topic and its research and application situations inside and outside the country. Section 2 and Section 3 describes H.323 and SIP and other relevant protocols in the system where they are used and their address mapping and message interaction. Then, on the grounds of the analysis of system needs and their respective functions, the system is devided into session management module, messagage receiving/sending module, calculating cost module and blog module. Meanwhile, corresponding mechanisms such as message processing and call flowing processing, as well as the design of data base strcutre are explained in Section 4. At last, Section 5 represents how these modules are implmeneted, and the state machine employed in message processing and call flowing mechanism. In addition, the combination of XML mechanism for media stream information description promoted by the practical needs also strengthens the system’s functionality and produces an ideal result.更多还原