Ethernet CFM: Connection and path protection for Ethernet pseudowires

Ethernet connectivity fault management (CFM) can be used to monitor the pseudowire physical link between two devices. The following major features of CFM for Ethernet pseudowires only are supported: - Connection protection using the continuity check protocol for fault monitoring. The continuity check protocol is a neighbor discovery and health check protocol that discovers and maintains adjacencies at the VLAN or link level. - Path protection using the linktrace protocol for path discovery and fault verification. Similar to IP traceroute, the linktrace protocol maps the path taken to a destination MAC address through one or more bridged networks between the source and destination.