NGN 下一代网络
The market for information and communications technology is currently undergoing a structural change. The classic telecommunication networks were planned and implemented for the transfer of specific data such as telephone calls or pure data packages. The recent growth in competition, new requirements for the market and technological developments have fundamentally changed the traditional attitudes of the telecommunications industry. The present industry is characterized by the rapid growth of broadband connections, the convergence processes of various network technologies and the emergence of a uniform IP standard for individual and mass communications.
信息和通信技术市场目前正在经历结构化变革。传统的电信网络是为电话呼叫或纯数据包这类特定数据的传输规划和实施的。近来随着竞争的加剧，对市场和技术发展的新需求已经彻底改变了电信业原有的态度。目前电信业对个人通信和大众通信的特点是：宽带连接的快速增长、各种网络技术的汇聚进程和统一IP通信标准的出现。 Traditional
telecommunication
operators
find
themselves
confronted with a host of new challenges. In particular, their previously successful fixed-network business is coming increasingly under pressure. New communication possibilities, such as telephoning via the Internet, and also growing market shares in mobile telephony are causing a great
deal of concern. To counteract these losses, the net work operators are investing more strongly in broadband, the growth driver. The traditionally familiar market boundaries between fixed networks, mobile telephony and data networks are disappearing more and more quickly. This gives the customer the advantage that he can call on an extremely wide range of services, regardless of his access technology. This development requires a meta infrastructure beyond the exiting, subordinated networks-a core network for all the access networks. This new network is called the Next Generation Network. The Internet Protocol is the most significant integration factor because it is available globally and, at least in principle, it can use almost all the services and applications in all the networks. 传统电信运营商发现自己正面临许多新的挑战。尤其是他们以前成功的固定电话业务正承受着越来越大的压力。像通过Internet打电话这类新的通信方式，以及移动电话增长的市场份额正在引起极大的关注。为了抵消由此带来的损失，网络运营商对宽带业务进行了更大的投资，宽带业务是运营商利润增长的驱动力。人们过去熟悉的固定网络、移动电话和数据网络间的界限正在越来越快地消失。这为客户带来了好处，客户可以得到非常广泛的服务而不管他采用的是哪种接入技术。这一发展需要一个超越现有的、被动网络的全新网络结构---为所有接入网络服务的核心网络。这一新网络称为下一代网络。Internet IP协议是这一网络的最重要的构成因素，因为IP是全球通用的，至少在原理上，它可以在所有的网络中使用几乎所有的业务和应
用。
In fact, Next Generation Network (NGN) is a broad term to describe some key architectural evolutions in telecommunication core and access networks that will be deployed over next 5~10 years. The general idea behind NGN is that one network transports all information and services (voice, data, and all sorts of media such as video) by encapsulating these into packets. Like it is on the Internet, NGN are commonly built around the Internet protocol, and therefore the term \is also sometimes used to describe the transformation towards NGN.
事实上，下一代网络（NGN）是一个宽泛的术语，用来描述电信核心网和接入网中一些关键的结构演进，在今后5?10年将部署这些网络。NGN的一般思路在于通过将信息和业务打包成分组，一个网络可以传输所有的信息和业务（语音、数据和各种媒体，如视频等）。就像在Internet上一样，下一代网络通常是围绕着IP来构建，因此“全IP”这一术语有时也用来描述向NGN转型。
According to ITU-T, the definition of NGN is: A Next Generation Network(NGN) is a packet-based network able to provide services including Telecommunication Services and able to make use of multiple broadband, QoS-enabled transport technologies and in which service-related
functions
are
independent
from
underlying
transport-related technologies. It offers unrestricted access by users to
different service providers. It supports generalized mobility which will allow consistent and ubiquitous provision of services to users.
根据ITU - T的说明，NGN的定义为：NGN是基于分组的网络，能够提供电信业务，并能够利用多种宽带并保证QoS的传送技术；其业务相关功能与其传送技术相独立。NGN使用户可以自由接入到不同的业务提供商；它支持通用移动性，这使其可以连续不断、无处不在地向用户提供服务。
The basic premise for NGN is the architecture on several independent levels. These include the access area, the core network area, the control level and the service management level. The connection of subscribers and terminals to the NGN can be achieved with various access technologies. The information and transmission formats of the various networks must be converted into information that is comprehensible for the NGN. This calls for Gateways for the connection of business and private customers. The core network of the NGN is an IP network. This is a standardized transport platform consisting of various IP routers and switches. The connection control of the individual components is carried out by the control level. Standard and value-added services can then be provided via the service management level.
NGN的基本前提是在若干独立层面上的体系结构。这些独立层面包括接入范围、控制层面和业务管理层面。用户和终端与NGN的连接可以通过各种接入技术进行。各网络的信息和传输格式必须转换
成NGN能够理解的信息格式。这需要网关进行商务和个人客户连接。NGN网络的核心网络是IP网络。这是一个由各种IP路由器和交换机构成的标准化的传送平台。各种部件的连接控制是由控制层面来完成的。标准业务和附加服务可以通过业务管理层面来提供。
The prerequisite for the efficient use of the NGN is a network access with high bandwidth for the subscriber. It is to be expected that access networks in the future will be able to provide bandwidths of up to 100 Mbit/s for private subscribers. For business customs, transmission rates in the gigabyte range are conceivable. The possible options for access to the IP backbone would include copper, cable, fiber-optic and wireless connections.
有效使用NGN的先决条件是为用户提供高带宽的网络接入。人们期望在未来能够提供高达带宽为100 Mbit / s的带宽。对于商业用户，提供吉字节的传输速率是可以想象的。接入IP骨干网的可能选择包括铜先、有线电缆、光纤和无线连接。
For voice application one of the most important devices in NGN is a softswitch—a programmable device that controls Voice over IP calls. It enables correct integration of different protocols within NGN. The most important function of the softswitch is creating the interface to the existing telephone network, PSTN, through sifnaling Gateways (SG) and Media Gateway(MG). However, the softswitch as a term may be defined differently by the different equipment manufacturers and have somewhat