Maintenance End-Point (MEP)

The Maintenance End-Point (MEP) serves as the logical boundary between devices that belong to different maintenance domains. A MEP resides at the edge of an MD. A MEP is associated with a single MA that monitors a primary VLAN service and any services associated with the primary service configured in an enabled VLAN table. The MEP must belong to the primary service associated with the MA or a service associated with the primary service. A MEP has a direction of either Up or Down. A Down-MEP sends CFM PDUs towards and receives CFM PDUs from the link. In our overview example, The MEPs associated with the customer equipment monitored service configure their MEPs as Down-MEPs. An Up-MEP sends PDUs towards the bridge relay and receives PDUs from the bridge relay. Up-MEPs communicate through the bridge relay with all other ports attached to the protective service within that bridge. All non-customer equipment MEPs are configured as Up-MEPs for a customer equipment monitored service.

Maintenance End-Point Overview displays MEP location and direction for our overview example. Customer equipment devices CE Device 1 and CE Device 2 belong to MA maCE1 and each are configured with a Down-MEP facing the service provider MD configured as MA maSP1. The customer equipment administrator wants to monitor the service between CE Device 1 and CE Device 2. The customer equipment Down-MEPs send CFM PDUs towards the link and therefore towards the remote Down-MEP belonging to maCE1 at the other end of the service. All Up-MEPs, belonging to other domains configured between the initiating and remote customer equipment down-MEPs, will transparently forward the CFM PDUs to the remote customer equipment MEP.

If a MEP fails to receive CFM PDUs in a timely fashion, CFM reports the failure.