Ethernet operation, administration, and maintenance (CE)
OAM techniques, Operation, Administration, and Maintenance, enable service providers in the lower layers of the network hierarchies to provide network services, monitor them, and detect and correct faults. OAM techniques are used in various network concepts such as ATM, time division multiplexing(TDM), synchronous digital hierarchy( SDH), and frame relay. Also in Carrier Ethernet( CE) as Ethernet OAM.
For Ethernet OAM, the Metro Ethernet Forum( MEF) has specified several techniques, including link OAM and service OAM. Link-OAM is typically used at the last mile between the subscriber network interfaces( UNI) of the network and the customer and is used for link monitoring, looping detection, and fault indication. Link-OAM can also operate other network segments.
Unlike link OAM, service OAM can be deployed throughout the network across all links in the link layer. Functionally, service OAM is carried by Connectivity Fault Management (CFM) specified in IEEE 802.1ag and by OAM Functions and Mechanisms for Ethernet Based Networks specified by the International Telecommunication Union( ITU-T).