ATM OAM
OAM has the following expansions:
Operation and Maintenance in the ITU-T I.610 recommendation (02/99).
Operation Administration and Maintenance in LUCENT APC User Manual (03/99).
Whichever expansion is used, OAM provides a way of detecting faults, isolating faults, and monitoring network performance without interrupting ongoing services. By inserting OAM cells, which are constructed in the standard ATM cell format, in cell streams, you can obtain specific information about the network.
ATM OAM provides the following functions:
OAM Alarm Indication Signal/Remote Defect Indication—The PVC goes down when specific number of successive AIS/RDI alarm cells are received. The PVC comes up when no AIS/RDI alarm cells are received within the specified time.
OAM Continuity Check—OAM CC requires that one end of the PVC must be configured as the CC cell source and the other end as the CC cell sink. If the detecting end fails to receive CC cells within 3 seconds, the state of the PVC changes to down. The PVC comes up only after CC cells are received again.
OAM F5 Loopback—Sends OAM F5 Loopback cells at the specified interval after you enable OAM F5 Loopback transmission and retransmission detection and specify related parameters. If the sender fails to receive a response cell within the specified interval, it sends an OAM F5 Loopback cell again. The state of the PVC is updated during the Loopback detection. The PVC comes up when the specified number of successive OAM F5 Loopback cells are received. The PVC goes down when the specified number of successive OAM F5 Loopback cells are not received.
OAM F5 end-to-end—Sends OAM F5 end-to-end cells through the specified PVC on the specified ATM interface. If no response is received within the specified period, the link might be disconnected or congested.