光纤通信网异步转移方式的发展

The Development of ATM Technology in Optical Fiber Telecommunication Network

近年来,人们预测宽带图象和高速数据业务的需求量将迅猛增长,研究力量集中于宽带综合业务数字网(B-ISDN)。传输媒介主要利用长波长单模光纤已得到公认。同步光纤网(SONET)和光纤局域网的标准也已得到赞同。为了适应各种不同业务和不同码速,需要适当灵活的复接和交换技术,把原有的分组交换加以改进,这就是异步转移方式(ATM)的由来。本文介绍ATM技术的概貌。先简述ATM的发展过程,再对ATM单元(Cell),及其系统模型、服务性能、流量控制分别加以讨论,最后对ATM与同步STM作比较,并说明它们在市内宽带网的混合使用。

In recent years,the demands of broadband video and high bit-rate data services are rapidly increasing, more research efforts are in favor of B-ISDN. It has been widely accepted that the transmission media would be single mode fiber operating at long wavelength, and standards of SONET and FDDI have been drafted. In order to meet with the requirments of broadband video and high bit-rate data services, appropriately flexible multiplexing and switching technology must be devised,and conventional packet switching technique must be modified-these give rise of the Asynchronous Transfer Mode(ATM).This paper briefly explains the course of its development, then describes the ATM cell structure, system modelling, service performance, flow control, and the comparison between ATM and STM, as well as their hybrid operation in broadband local subscriber network.