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.