论文总字数：19149字

摘 要

下一代网络是一个将语音电话、数据传输和视频对话等业务融合的网络，基于IP的语音传输技术就是NGN的产物。软交换在下一代网络中处于核心地位，而媒体网关又是软交换的关键。以IP网络作为基础，把现有的语音，数据，图像等电信业务结合起来是将来下一代网络发展的必然主流。提升媒体网关性能，推广软交换技术，可以降低成本和不同媒体间过过渡的开支。实现不同网络的流畅交换，通信通道在异构网络之中被高效的建立，提升通信的网络安全和速度，增加通讯的可靠性，这些都离不开媒体网关技术的研究。

本文首先简要分析了下一代网络以及VOIP技术的优势、基础原理，以及其中所需要用到的各种协议。然后介绍了媒体网关的结构以及协议体系，在本文中着重介绍了定义即什么是媒体网关以及其主要核心功能，以及用到的H.248/MEGACO 协议。然后从现网大型网关入手，从产品的功能和工作原理等方面分析媒体网关的架构体系以及软件和硬件的组成，分别介绍了现行大型媒体网关的硬件框架，中心控制单元、BCTC背框的功能以及原理，还有各个软件结构子系统的原理分析。然后基于现网大型网关，从热备份、媒体流处理流程、信令流处理流程等方面来设计一个单框中继媒体网关。将三框的现网大型网关集成为单框，需要把现网大型网关的设计中多余的业务功能单板缩减，减少与其他单框的接口，考虑需要进行热备份的核心部件以及处理单板，分别从硬件和软件两方面设计。最终将三框的大型综合媒体网关集成为一个单框的中继媒体网关，并对各个单板的原理和功能以及设计思想和各类数据处理流程进行了介绍。

最后，给出技术的发展趋势和方向，对现有的NGN网络架构进行介绍，分析其优点和不足。然后对本次的设计做出的工作进行总结和反思，提出设计中可能存在的问题和缺陷。最后对未来的NGN进行展望，并对本设计的下一步工作进行规划。

关键词：下一代网络；软交换；媒体网关

Design of Media Gateway in Softswitch Network System

Abstract

The next generation network is a network that integrates services such as voice telephony, data transmission, and video conversation. The voice transmission technology based on IP is the product of NGN. Softswitch is at the core of next-generation networks, and media gateway is the key to softswitch. Based on the IP network, combining the existing voice, data, image and other telecommunications services is the inevitable mainstream of the future development of next-generation networks. Improving the performance of media gateways and promoting soft-switching technology can reduce costs and the cost of transition between different media. The smooth exchange of different networks, the efficient establishment of communication channels in heterogeneous networks, the improvement of network security and speed of communication, and the increase of communication reliability are all inseparable from the research of media gateway technology.

This article first briefly analyzes the advantages and basic principles of the next-generation network and VOIP technology, as well as the various protocols needed in it. Then it introduces the structure and protocol system of the media gateway. In this article, it focuses on the definition of what is the media gateway and its main core functions, as well as the H.248 / MEGACO protocol used. Then, starting with the large-scale gateway on the current network, the architecture and software and hardware components of the media gateway are analyzed in terms of product functions and working principles. The hardware framework of the current large-scale media gateway, the functions of the central control unit and the BCTC back frame are introduced And the principle, as well as the principle analysis of each software structure subsystem. Then, based on the existing large-scale gateways, a single-frame relay media gateway is designed from the aspects of hot backup, media flow processing flow, and signaling flow processing flow. Integrating the three-frame large-scale existing network gateway into a single frame, it is necessary to reduce the redundant service function boards in the design of the large-scale network gateway, reducing the interface with other single frames, considering the core components that need to be hot-backed and processing the single board , Designed from two aspects of hardware and software. Finally, the three-frame large integrated media gateway is integrated into a single-frame relay media gateway, and the principles and functions, design ideas, and various data processing processes of each board are introduced.

Finally, the development trend and direction of the technology are given, the existing NGN network architecture is introduced, and its advantages and disadvantages are analyzed. Then summarize and reflect on the work made in this design, and propose possible problems and defects in the design. Finally, the future NGN is prospected, and the next step of this design is planned.

Keywords: Next Generation Network, Softswitch,Media Gateway

目 录

摘 要 I

Abstract II

第一章 绪 论 1

1.1引 言 1

1.2技术优势及前景 1

1.3技术发展现状 1

1.4本文工作 2

1.5论文结构安排 2

第二章 VOIP综述 3

2.1 引 言 3

2.2 基于IP的语音传输基本原理 3

2.3 系统结构 4

2.4协议体系 5

2.5 本章总结 5

第三章 媒体网关综述 7

3.1引 言 7

3.2媒体网关定义 7

3.3媒体网关的功能 7

3.4 H.248/MEGACO 协议 7

3.5 本章总结 8

第四章 现网大型网关的设计分析 9

4.1 现网大型网关产品介绍 9

4.2 现网大型网关功能介绍 9

4.3 现网大型网关系统硬件 10

4.3.1总体架构 10

4.3.2单元介绍 10

4.4软件结构 12

4.5 BCTC框配置介绍 13

4.6工作原理 14

4.7本章总结 14

第五章 单框中继媒体网关设计 15

5.1硬件设计 15

5.2单板介绍 15

5.3软件设计 18

5.4处理流程 18

5.5本章小结 19

第六章 总结与展望 20

致 谢 21

参考文献 22

附 录 23

第一章 绪 论

1.1引 言

从上世纪八十年代我国逐渐步入信息时代以来，通信、多媒体、计算机等新兴科技飞速发展，人民生活的质量因此被提升到了新的高度。由新兴科技发展所带来的话音业务，数据业务，视频与音频相结合的多媒体业务，这三类通信业务分别依靠电话网，数据网和多媒体网承载实现。但是因此带来了三网之间不能流畅互通的新问题，下一代网络（NGN）应运而生。分组网络的架构模式被NGN利用，可以满足多种类型的通信业务服务的市场需求。NGN的关键技术是软交换，它可以组合服务，将PSTN的接入部分和控制部分分开，同时提供用于应用和开发的接口，模块之间通过协议进行交互，从而可以开发各种灵活的服务以满足电信市场用户的需求。

1.2技术优势及前景

最近的五年里，VoIP（Voice over Internet Protocol）的服务需求呈现了爆炸式的增涨。并且随着技术的发展，VoIP的优势也越来越在行业中被认可。

VoIP主要的优势有：

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