The multicast forwarding information base (MFIB) ping OAM tool allows to easily verify inside a VPLS which SAPs would normally egress a specific multicast stream. The multicast stream is identified by a source unicast and destination multicast IP address, which are mandatory when issuing an MFIB ping command.
An MFIB ping packet is sent through the data plane and goes out with the data plane format containing a configurable VC label TTL. This packet traverses each hop using forwarding plane information for next hop, VC label, and so on. The VC label is swapped at each service-aware hop, and the VC TTL is decremented. If the VC TTL is decremented to 0, the packet is passed up to the management plane for processing. If the packet reaches an egress node, and would be forwarded out a customer facing port (SAP), it is identified by the OAM label below the VC label and passed to the management plane.