Optical networks in the real world

Current optical transmission systems (currently based on the SONET or SDH standards in particular) provide many features that aid an operator in determining system performance, system status, and help to isolate faults. As the need for data transmission is growing rapidly in the network, the desire to transport Internet Protocol (IP) frames over optical systems arises, in addition to traditional time division multiplexed (TDM) telephony voice and data signals.