Specifications

17-2
System Management Software Configuration Guide for Cisco IE 2000U and Connected Grid Switches
Chapter 17 Configuring Ethernet OAM, CFM, and E-LMI
Information About Ethernet CFM
• Information About E-LMI, page 17-51
• Configuring E-LMI, page 17-52
• Displaying E-LMI and OAM Manager Information, page 17-59
• Ethernet CFM and Ethernet OAM Interaction, page 17-59
• Related Documents, page 17-63
• Feature History, page 17-64
Information About Ethernet CFM
Ethernet CFM is an end-to-end per-service-instance (per VLAN) Ethernet layer OAM protocol that
includes proactive connectivity monitoring, fault verification, and fault isolation. End-to-end can be
provider-edge-to-provider-edge (PE-to-PE) device or customer-edge-to-customer-edge (CE-to-CE)
device. Ethernet CFM, as specified by 802.1ag, is the standard for Layer 2 ping, Layer 2 traceroute, and
end-to-end connectivity check of the Ethernet network.
These sections contain conceptual information about Ethernet CFM:
• CFM Domain, page 17-2
• Maintenance Associations and Maintenance Points, page 17-3
• CFM Messages, page 17-5
• Crosscheck Function and Static Remote MEPs, page 17-5
• SNMP Traps and Fault Alarms, page 17-5
• Configuration Error List, page 17-5
• CFM Version Interoperability, page 17-6
• IP SLAs Support for CFM, page 17-6
CFM Domain
A CFM maintenance domain is a management space on a network that is owned and operated by a single
entity and defined by a set of ports internal to it, but at its boundary. You assign a unique maintenance
level (from 0 to 7) to define the hierarchical relationship between domains. The larger the domain, the
higher the level. For example, as shown in Figure 17-1, a service-provider domain would be larger than
an operator domain and might have a maintenance level of 6, while the operator domain maintenance
level is 3 or 4.
As shown in Figure 17-2, domains cannot intersect or overlap because that would require management
by more than one entity, which is not allowed. Domains can touch or nest (if the outer domain has a
higher maintenance level than the nested domain). Nesting domains is useful when a service provider
contracts with one or more operators to provide Ethernet service. Each operator has its own maintenance
domain and the service provider domain is a superset of the operator domains. Maintenance levels of
nesting domains should be communicated among the administrating organizations. CFM exchanges
messages and performs operations on a per-domain basis.