Organization and maintenance loopback cell processing in ATM networks

A communication system comprising a plurality of sources, a plurality of destinations, and a plurality of switches forming an asynchronous transfer mode (ATM) network connecting the sources to the destinations. Each switch in the plurality of switches includes a plurality of line cards. The ATM network comprises a plurality of connections where, for each respective connection, one of the plurality of sources is linked to one of the plurality of destinations through the network by linking one or more switches, in the plurality of switches, that is associated with the respective connection. The ATM network further comprises operation administration and maintenance (OAM) cell processing circuitry for detecting a failure in a connection in the network. The failure is localized to the exact line card in a switch associated with the connection that is causing the connection to fail. The OAM cell processing circuitry detects the failure of the connection without use of the line card control blocks in the various line cards in the data path of the failed connection.