In There a Role for TDM and ATM in IP Networks?

摘要

Today, most carrier services, including IP, are delivered over a Time Division Multiplexing- (TDM) and Asynchronous Transfer Mode- (ATM) based WAN infrastructure running on top of a SONET -based fiber core. This multi-layered approach evolved for good reasons, but inherent inefficiencies that were once tolerable arenow becoming a barrier to scalability. While technology advances like Dense Wave Division Multiplexing (DWDM) are accelerating the bandwidth potential of the core optical infrastructure, Digital Subscriber (DSL) and cable modems are generating order-of-magnitude increases in subscriber demand for bandwidth. At the same time, technologies like Gigabit Ethernet are gaining momentum as part of the inevitable migration toward IP convergence. The traditional, multi-service overlay systems that were optimized for voice requirements have not kept pace and are becoming a critical bottleneck.