摘要
NGN是下一代网络（Next Generation Network）的简称，ITU-T对NGN的定义如下：NGN是基于分组的网络，能够提供电信业务；利用多种宽带能力和QoS保证的传送技术；其业务相关功能与其传送技术柏独立。NGN使用户可以自由接人到不同的业务提供商；NGN支持通用移动性。从这个定义可以看出，
NGN is the abbreviation for Next Generation Network,definition for NGN by ITU-T is as follows： NGN is packet- based network, capable of providing telecom services; transmitting technology using multiple broadband abilities and QoS guarantee; its service- related functions are independent of its transmitting technology. NGN enables users to freely access different service providers; NGN supports common mobility. It could be seen from this definition that NGN has the following characteristics： NGN belongs to telecom networks, adopts packet network as bearing networks, control and bearing are separated,
