城域网必须具备大容量、高带宽、多业务、高可靠性等能力，从而实现骨干层层面的宽带IP化业务支持能力。
MAN must possess large capacity, high-bandwidth, multi-service and high reliability to achieve broadband IP service suppont capabilites on backbone layer.
通信网已实现由小容量向大容量、模拟技术数字技术、单一业务向多样化业务的跨越。
Communication network has been expanded from small to large capacity, from analog to digital technology, from single service to diversified services.
应用推荐