Ethernet Connectivity Fault Management (ETH-CFM) is defined in the IEEE 802.1ag and ITU Y.1731 standards. ETH-CFM specifies protocols, procedures, and managed objects to support fault management (including discovery and verification of the path), detection, and isolation of a connectivity fault in an Ethernet network.
IEEE 802.1ag and Y.1731 can detect:
loss of connectivity
unidirectional loss
loops
merging of services
The implementation of Y.1731 on the 7705 SAR also provides the following enhancements:
Ethernet Alarm Indication Signal (ETH-AIS)
Ethernet Test function (ETH-Test)
ETH-CFM uses Ethernet frames and can be distinguished by its Ethertype value (8902). With ETH-CFM, interoperability can be achieved between different vendor equipment in the service provider network, up to and including customer premises bridges.
ETH-CFM is configured at the global level and at the Ethernet service level (Epipes and VPLS) or network interface level. The following entities and their configuration levels are listed below:
global level
MA and MEG
MD
MD level and MEG level
Ethernet service level
MEP
Ethernet network interface level
facility MEP
For information about configuring ETH-CFM to set up an Ethernet OAM architecture, see the 7705 SAR Services Guide, "ETH-CFM (802.1ag and Y.1731)". Most of the configuration information applies to Ethernet network interfaces as well; for information about ETH-CFM support specific to network interfaces,see the 7705 SAR Router Configuration Guide, "ETH-CFM Support".