Cisco Cisco IOS Software Release 12.4(9)T

An EVC as defined by the Metro Ethernet Forum could be a port level point-to-point or 
multipoint-to-multipoint Layer 2 circuit. EVC status can be used by the CE device to find an alternative 
path in to the service provider network or in some cases, fall back to a backup path over Ethernet or 
another alternative service such as Frame Relay or ATM.

Ethernet LMI is an Ethernet layer OAM protocol between a CE device and the PE in large Ethernet 
MANs and WANs. It provides information that enables service providers to autoconfigure CE devices 
with service parameters and parameter changes from a user provider edge (UPE) device.

 shows where in a network Etheret LMI functions.

LMI also provides the status of Ethernet EVCs in large Ethernet MANs and WANs to the CE. 
Specifically, Ethernet LMI notifies a CE device of the operating state of an EVC and the time when an 
EVC is added or deleted. Ethernet LMI also communicates EVC and UNI attributes to a CE device.

The Ethernet LMI protocol includes the following procedures, as defined by the MEF 16 Technical 
Specification: 

Notifying the CE when an EVC is added

Notifying the CE when an EVC is deleted

Notifying the CE of the availability state of a configured EVC (Active, Not Active, or Partially 
Active)

Communicating UNI and EVC attributes to the CE 

Ethernet LMI provides the following benefits:

Communication of end-to-end status of the EVC to the CE device

Communication of EVC and UNI attributes to a CE device

Competitive advantage for service providers

Metro Ethernet Network 

(MEN)

CE

CE

User Network Interface

(UNI)

User Network Interface

(UNI)

E-LMI

E-LMI

PE

PE

E-LMI: Ethernet Provisioning and Management entity across UNI (CE-PE)