Carrier Ethernet Configuration Guide (Cisco Asr 920 Series - Cisco ASR 920 Series Configuration Manual Ethernet Router

Configuring Ethernet Connectivity Fault Management in a Service Provider Network
Glossary
fault alarm—An out-of-band signal, typically an SNMP notification, that notifies a system administrator of
a connectivity failure.
inward-facing MEP—A MEP that resides in a bridge and transmits to and receives CFM messages from the
direction of the bridge relay entity.
maintenance domain—The network or part of the network belonging to a single administration for which
faults in connectivity are to be managed. The boundary of a maintenance domain is defined by a set of DSAPs,
each of which may become a point of connectivity to a service instance.
maintenance domain name—The unique identifier of a domain that CFM is to protect against accidental
concatenation of service instances.
MEP—maintenance endpoint. An actively managed CFM entity associated with a specific DSAP of a service
instance, which can generate and receive CFM frames and track any responses. It is an endpoint of a single
MA, and terminates a separate maintenance entity for each of the other MEPs in the same MA.
MEP CCDB—A database, maintained by every MEP, that maintains received information about other MEPs
in the maintenance domain.
MIP—maintenance intermediate point. A CFM entity, associated with a specific pair of ISS SAPs or EISS
Service Access Points, which reacts and responds to CFM frames. It is associated with a single maintenance
association and is an intermediate point within one or more maintenance entities.
MIP CCDB—A database of information about the MEPs in the maintenance domain. The MIP CCDB can
be maintained by a MIP.
MP—maintenance point. Either a MEP or a MIP.
MPID—maintenance endpoint identifier. A small integer, unique over a given MA, that identifies a specific
MEP.
OAM—operations, administration, and maintenance. A term used by several standards bodies to describe
protocols and procedures for operating, administrating, and maintaining networks. Examples are ATM OAM
and IEEE Std. 802.3ah OAM.
operator—Entity that provides a service provider a single network of provider bridges or a single Layer 2 or
Layer 3 backbone network. An operator may be identical to or a part of the same organization as the service
provider. For purposes of IEEE P802.1ag, Draft Standard for Local and Metropolitan Area Networks, the
operator and service provider are presumed to be separate organizations.
Terms such as "customer," "service provider," and "operator" reflect common business relationships among
organizations and individuals that use equipment implemented in accordance with IEEE P802.1ag.
UNI—user-network interface. A common term for the connection point between an operator's bridge and
customer equipment. A UNI often includes a C-VLAN-aware bridge component. The term UNI is used broadly
in the IEEE P802.1ag standard when the purpose for various features of CFM are explained. UNI has no
normative meaning.

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