Maintenance Points - Cisco ME 3400 Software Configuration Manual

Chapter 41 Configuring Ethernet OAM, CFM, and E-LMI
Figure 41-1
CE 1
Figure 41-2

Maintenance Points

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:
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OL-9639-07
CFM Maintenance Domains
Operator 1
PE 1
MEP
Level 4
MEP MIP MIP
Level 2
Allowed Domain Relationships
Scenario A:
Touching Domains OK
Maintenance end points (MEPs) are inward-facing points at the edge of the domain that define the
boundary and confine CFM messages within these boundaries. Inward facing means that they
communicate through the relay function side, not the wire side (connected to the port). A MEP sends
and receives CFM frames through the relay function. It drops all CFM frames of its level or lower
that come from the wire side. For CFM frames from the relay side, it processes the frames at its level
and drops frames at a lower level. The MEP transparently forwards all CFM frames at a higher level,
regardless of whether they are received from the relay or wire side. CFM runs at the provider
maintenance level (UPE-to-UPE), specifically with inward-facing MEPs at the user network
interface (UNI).
Service Provider Domain Level 6
Operator Domains
PE 2
MIP
MEP
Scenario B:
Nested Domains OK
Cisco ME 3400 Ethernet Access Switch Software Configuration Guide
Understanding Ethernet CFM
Operator 2
PE 3 PE 4
MIP MEP
MEP MIP MIP MEP
Scenario C:
Intersecting Domains Not
Allowed
CE 2
Level 4
Level 3
41-3