Reference Guide

802.1ag | 87

Figure 5-1. OAM Domains

Maintenance Points

Domains are comprised of logical entities called Maintenance Points. A maintenance point is an interface

demarcation that confines CFM frames to a domain. There are two types of maintenance points:

• Maintenance End Points (MEPs): a logical entity that marks the end-point of a domain

• Maintenance Intermediate Points (MIPs): a logical entity configured at a port of a switch that is an

intermediate point of a Maintenance Entity (ME). An ME is a point-to-point relationship between two

MEPs within a single domain. MIPs are internal to a domain, not at the boundary, and respond to CFM

only when triggered by linktrace and loopback messages. MIPs can be configured to snoop Continuity

Check Messages (CCMs) to build a MIP CCM database.

These roles define the relationships between all devices so that each device can monitor the layers under its

responsibility. Maintenance points drop all lower-level frames and forward all higher-level frames.

Figure 5-2. Maintenance Points

Ethernet Access

MPLS Core MPLS Access

Customer Network

Customer Domain (7)

Provider Domain (6)

Operator Dom

ain (5

)

Operator Domain (5)

MPLS D

omain (4)

Service Provider Network