Not recommend to use soft switching plus media gateway to replace the existing local and long distance switching systems . for the newly added and need to be changed local telephone switching systems , it will up to the cost of media gateway ?不建议使用软交换加媒体网关的方式替换目前的本地和长途交换机，对于新增和需要更换的本地电话交换机要视媒体网关成本情况而定，不对pstn进行大规模根本性改造；
Provides various narrow and broadband access . it consists of broadband lan access equipment , adsl equipment , narrow band access equipment , broadband atm multipal service access wuipment , media gateway equipment , fibre , type five and wisted cable , etc 提供各种宽、窄带业务的接入，由宽带lan接入设备、 adsl设备、窄带接入网设备、宽带atm多业务接入设备、媒体网关设备、光纤、五类线、双绞线等组成。
Firstly the next generation network is introduced in this thesis , including its development , features , network framework and relevant protocols . then we introduce the h . 248 protocol subsequently . based on those researches , we emphasize to describe the designing and implementation of a media gateway system , which is based on the h . 248 protocol 本文首先介绍了下一代网络( ngn ) ,包括它的发展,网络特征,网络体系结构以及相关协议,接着介绍了h . 248协议,在此基础上,本文着重描述了一个企业级的基于h . 248协议的模块化的媒体网关的设计和实现,该媒体网关符合h . 248v2版本以及国内相关标准,与标准媒体网关控制器配合,完成呼叫接续和媒体处理等功能。
Along with the development of ngn technology , traditional ip voice gateway is divided into two parts according to its function . one is media gateway controller ( mgc ) which is responsible for call control , and the other one is media gateway ( mg ) which is responsible for resource management and media process 随着ngn技术的发展,传统的ip电话网关按功能分为负责呼叫控制的媒体网关控制器和负责资源管理以及媒体处理的媒体网关两个部分,这个体系结构实现了呼叫控制与媒体承载相分离。
Media gatewaytdmatm integrated access equipment is the main way of narrow band and data private line access . users may access fixed telephone network and dial - up access braodband man through twisted cable ; users may access broadband data network through adsl or ddn , or fr , etc ; mobile comminication users may access 2g or 3g mobile communication network through base station equipment and wireless gateway 媒体网关tdmatm综合接入设备主要是窄带和数据专线接入方式，用户通过双绞线可以接入固定电话网以及拨号接入宽带ip城域网；用户通过adsl或ddn 、 fr等可接入宽带基础数据网；移动通信用户通过基站设备和无线网关可接入第二代或第三代移动通信网。
Along with the technology mature in the soft switching and media gateway , the narrow band access equipment will be integrated the function of media gateway . users may access directly to the broadband ip man through twisted cabling or wireless base station . dial - up server will also be replaced by the media gateway , narrow band dial - up users will be diverted to broadband ip man at the access network 随着软交换和媒体网关技术的成熟，在窄带接入层设备上将综合媒体网关的功能，用户通过双绞线或无线基站接入后，可以通过媒体网关直接接入宽带ip城域网，拨号服务器也将大量被媒体网关取代，窄带用户拨号上网将在接入网被分流至宽带ip城域网。
It is accounted to the important signal technology in the ngn . sip is an application - layer control ( signaling ) protocol proposed by ietf for creating , modify and terminating session . the structure of the voip system and the relative technologies including audio coding / decoding and signal control technologies are discussed in this article 现有的ip电话信令控制协议h . 323协议由于自身的限制无法很好的满足这种新要求,而sip协议以其所具有的结构简洁、易于扩展和适于internet接入等良好的特性使它可以有效的控制媒体网关,控制pc呼叫,从而使其在ngn的控制协议中具有重要的地位。
H . 248 protocol is just located in the separated framework , and provides communication between mgc equipment and mg equipment . h . 248 inherits all the advantages of the media gateway control protocols before , so it achieves mighty description function , provides more supports to the application layer and is easier to manage and implement . in addition , h . 248 has better control to media bearer , including media resources and bearer resources H . 248协议正是处在这个分离体系结构之间,提供媒体网关控制设备与媒体处理设备间的通信的协议, h . 248协议在继承了以往的媒体控制协议的所有优点的基础上,实现了强大的描述功能,对应用层提供了更多的支持,管理和实现更为简单,对媒体承载(包括媒体资源和承载资源)有着良好的控制。
