Pdh vs sdh describes difference between pdh and sdh

DWDM Technology Application

The DWDM layer is protocol and bit rate independent, which means that it can carry ATM (Asynchronous Transfer Mode), SONET, and/or IP packets simultaneously. WDM technology may also be used in Passive Optical Networks (PONs) which are access networks in which the entire transport, switching and routing happens in optical mode. With the inclusion of recent 3R (reshape, retime, retransmit) devices, internal towards the DWDM system, circuits utilizing only DWDM equipment can now be built that may span the country. New performance monitoring capabilities happen to be built into these devices so that maintenance and repair of the link can be done. With DWDM as the transmission method, the bandwidth of the existing fiber plant is maximized.