32-3
Cisco ME 3800X and 3600X Switch Software Configuration Guide
OL-23400-01
Chapter 32 Configuring Ethernet OAM, CFM, and E-LMI
Understanding Ethernet CFM
Figure 32-1
CFM Maintenance Domains
Figure 32-2
Allowed Domain Relationships
Maintenance Associations and Maintenance Points
A maintenance association (MA) identifies a service that can be uniquely identified within the
maintenance domain. The CFM protocol runs within a maintenance association. A maintenance point is
a demarcation point on an interface that participates in CFM within a maintenance domain. Maintenance
points drop all lower-level frames and forward all higher-level frames. There are two types of
maintenance points:
•
Maintenance end points (MEPs) are points at the edge of the domain that define the boundaries and
confine CFM messages within these boundaries. Outward facing or Down MEPs communicate
through the wire side (connected to the port). Inward facing or Up MEPs communicate through the
relay function side, not the wire side.
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Operator Domains
Service Provider Domain Level 6
Operator 1
PE 1
CE 1
CE 2
PE 2
PE 3
PE 4
Operator 2
MEP
Level 6
Level 6
Level 4
Level 3
MEP
MEP
MIP
MIP
MIP
MEP
MEP
MIP
MIP
MIP
MEP
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Scenario A:
Touching Domains OK
Scenario B:
Nested Domains OK
Scenario C:
Intersecting Domains
Not Allowed
