Cisco 3845 Software Guide - Page 699

Chapter 32 Configuring Ethernet OAM, CFM, and E-LMI Understanding Ethernet CFM Figure 32-1 CFM Maintenance Domains Service Provider Domain Level 6 Operator Domains CE 1 Operator 1 PE 1 PE 2 Operator 2 PE 3 PE 4 CE 2 MEP MIP Level 6 MEP Level 3 MIP MIP MEP Figure 32-2 Allowed Domain Relationships MIP MEP Level 6 MEP MIP MIP MEP Level 4 157281 157282 Scenario A: Touching Domains OK Scenario B: Nested Domains OK Scenario C: Intersecting Domains Not Allowed 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. OL-23400-01 Cisco ME 3800X and 3600X Switch Software Configuration Guide 32-3