ABSTRACT
This chapter deals with network switching concepts that are used in emerging synchronous optical network (SONET)/asynchronous transfer mode (ATM) broadband transport networks. The primary purpose of the network switching function is to maximize the transmission system efficiency by sharing the capacity of the transmission system among communications circuits. To help understand how the broadband SONET/ATM network is used to support high-speed data and video services. The chapter focuses on reviewing switching concepts used in the SONET layer and the ATM layer. It reviews signal switching formats and their bandwidth relationship in a multilayer SONET/ATM network environment and explains the operations of STM and ATM switching concepts. The ATM layer is divided into two sublayers: virtual path and virtual channel. The chapter discusses the switching operation for ATM cells. The physical path concept used in the SONET STM system has a hierarchical structure with a fixed capacity for each physical path.
