Figure17.1使用SONET设备的简单网络 ADM:Add/drop multiplexer R:Regenerator STS MUX:Synchronous transport signal multiplexer T:Terminal STS DEMUX:Synchronous transport signal demultiplexer STS ADM STS MUX DEMUX Add YDrop Section Section Section Section Section Line Line Path 17.5 17.5 Figure 17.1 使用SONET设备的简单网络