城域传送网是一种面向企事业用户的、最大可覆盖城市及郊区范围的、可提供丰富业务和支持多种通信协议的公用网。城域传送网的主要特点是:业务类型多,需要各种类型的接口;业务流量有一定的不确定性,受用户和应用驱动大,灵活性十分重要;有可扩展性,以适合于网络的新业务类型和升级扩容;技术多样性,且没有一个主流技术,每种技术都有其应用空间。 Metro transport network is a kind of public network for enterprises and users, which can cover most of the cities and suburbs and can provide rich services and support multiple communication protocols. The main features of the metro transport network are: many types of services, all kinds of interfaces are required; business traffic has some uncertainty, driven by user and application large, flexibility is very important; scalable to fit the network New business types and upgrades to expand; technology diversity, and not a mainstream technology, each technology has its application space.