基于H.323协议的网守的设计与实现

【作者】 欧力；

【导师】 曾家智；

【作者基本信息】 电子科技大学 ， 计算机应用， 2003， 硕士

【摘要】 随着互联网的飞速发展，IP协议成为事实上的网络协议标准。而基于IP分组交换的VoIP技术正在成为当前网络应用的热点。作为VoIP的最重要协议体系之一的H．323，得到了几乎所有VoIP厂商的强力支持，被广泛应用于电信级商用IP电话网。与其它相关VoIP协议相比较，H．323以其成熟，市场占有率高，可靠的优势，显示出强大的生命力。大多数人认为，H．323将在相当长的一段时期内继续作为事实上的VoIP工业标准。 本文仔细的分析了H．323的协议，H．323系统组成的各部分功能以及典型的基于H．323的网络电话的呼叫过程。作为H．323的商业应用，对用户的认证和计费是运营商所关心的问题。而在此方面作为业界标准的Radius协议提供了可靠的AAA(Authentication，Authorization，Accounting)解决方案。因此将基于H．323协议的网络电话系统与Radius协议结合起来具有现实的意义。本文详细的介绍和分析了Radius协议并给出了一个实现方案。 本文重点描述了一个基于H．323的网守的实现。该网守被设计为面向中小电信运营商或行业用户。它符合H．323国际标准第四版和相关国内标准，能够和其它H．323设备互通，具有地址解析、呼叫接入、区域管理、呼叫管理和带宽控制等协议中所规定的功能，还支持Web管理，运行参数动态修改，以及支持NAT运行环境和能够通过Radius协议进行认证和计费等其它来自客户的应用功能需求。首先，根据这些需求定义给出了网守的模块划分，介绍了网守总体设计方案，并对各个模块的功能、接口作了仔细说明。接着，对于网守的部分模块，如网守核心协议模块(GKCore)、认证模块和Radius客户端模块作了详细描述，并给出了部分实现细节和重要工作流程。最后，论述了网守的测试运行环境，给出了与Cisco网关、Microsoft Netmeeting、Dialogic网关，PALM的IP电话终端以及Radius服务器的测试结果，并提出了下一步工作的改进建议。该网守完全遵循面向对象的设计思想，具有良好的可扩充性和代码可重用性。更多还原

【Abstract】 With the fast development of Internet, IP has become the standard protocols of networks. VoIP technology, based on IP, is being becoming the focus of applications of Internet. Meanwhile, VoIP protocols and standards, the currently researching hotspots, are continuously renovated. H.323, one of the most important VoIP protocols, has been nearly supported by all of VoIP manufacturers, and has a mass of loyal users. The most advantage of H.323 is its maturity, and highest market share. With the development of VoIP technology, H.323 is becoming more mature and sturdy, and showing a strong vitality. Many people believe that H.323 will continue to be the de facto VoIP standard.In this thesis, we discuss the structure of the H.323 stack, functions of main modules of H.323 system, and a typical calling process. Because of the practical values of Authentication and Accounting, it is important to bind the H.323 system and the Radius protocal, which is the actual standart of AAA(Authentication, Authorization, Accounting). We also discuss the structure of the Radius protcoal and give an implementation.In this thesis, we describe the implementation of a gatekeeper based H.323. This gatekeeper is designed for small telecom operators or business customs. It is conformed to the H.323v4 and relevant national standards and ensures interoperability. Besides the functions specified in H.323, such as Address Translation, Admissions Control, Zone Management, Call Management and Bandwidth Control, it can satisfied with the requirements defined by users, such as Web management, dynamic modification of running parameters, NAT environment and AAA(Authentication, Authorization, Accounting) which is based on Radius protocal.Firstly, according to the requirements mentioned above, we provide the module partitions of the gatekeeper, introduce its total design scheme, and explain the functions and interfaces of each module in detail. Secondly, we particularly describe some modules such as gatekeeper kernel module (GKCore), authorization module, and Radius module, and provide some parts of implementing details and important workflows. Lastly, we describe the testing environment for the gatekeeper, provide the testing result cooperating with Cisco gateway, Microsoft Netmeeting, Dialogic gateway, Palm IP phone and Radius Servers, and give suggestions for the future research. Because the gatekeeper is fully conformed to the object oriented designtechnology, it has good scalability and code reusability.更多还原