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Ethernet OAM Overview
Configuring Ethernet OAM
page 15-4
OmniSwitch AOS Release 6 Network Configuration Guide
September 2009
Ethernet OAM Overview
Ethernet OAM provides service assurance over a converged Ethernet network. It helps service providers to 
manage network operations efficiently and smoothly. Ethernet OAM provides effective monitoring capa-
bilities by increasing visibility in the network. It detects failure and degradation by raising warnings and 
alarms; also provides diagnostic and troubleshooting tools to resolve problems.
Ethernet OAM focuses on two main protocols that the service providers require the most and are rapidly 
evolving in the standards bodies: Service OAM and Link OAM. These OAM protocols are unique and 
complementary to each other. 
• Service OAM—for monitoring and troubleshooting end-to-end Ethernet service instances
• Link OAM—for monitoring and troubleshooting an individual Ethernet link
Ethernet OAM is not supported on mobile, mirrored, and aggregable ports (the physical port members of 
an aggregate). It is also not supported on dynamically learned VLANs. But, it can be implemented on any 
full-duplex point-to-point or emulated point-to-point Ethernet link. It need not be implemented system-
wide.
Management systems are important for configuring Ethernet OAM across the network. They also help to 
automate network monitoring and troubleshooting. Ethernet OAM can be configured in two phases, 
Network Configuration phase and Service Activation phase.
The Network Configuration phase enables Connectivity Fault Management (CFM) on the switches. CFM 
allows service providers to manage customer service instances individually. This phase also helps set up 
the Maintenance Intermediate Points (MIP) and Maintenance End Points (MEP). Any port of a bridge is 
referred to as a Maintenance Point (MP). An MP can be either a MEP or MIP. A MEP resides at the edge 
of a Maintenance Domain (MD), while a MIP is located within a Maintenance Domain. A Maintenance 
Domain is an administrative domain for managing and administering a network.
In the Service Activation phase, a new end point created on a VLAN needs to be configured as a MEP. 
This enables the configuration of continuity-check and cross-check functionalities.
Connectivity Fault Management
Connectivity Fault Management (CFM) permits service providers to manage customer service instances 
individually. A customer service instance or Ethernet Virtual Connection (EVC) is the service that is sold 
to a customer and is designated by a VLAN tag on the User-to-Network Interface (UNI). 
CFM consists of hierarchical Maintenance Domains (MD). Each MD comprises of MEPs and MIPs. The 
network administrator segregates these maintenance points. MDs provide different management scopes for 
different organizations. Different organizations are involved in a Metro Ethernet Service, such as Custom-
ers, Service Providers, and Operators. Customers avail Ethernet service from service providers. Service 
providers may use their own networks, or other operators’ networks to provide the Ethernet connectivity 
for the requested service. Each organization can have its own Maintenance Domain.