Ethernet Cfm Overview - Cisco ASR 920 Series Configuration Manual Ethernet Router

Configuring Ethernet Local Management Interface at a Provider Edge

Ethernet CFM Overview

Ethernet Connectivity Fault Management (CFM) is an end-to-end per-service-instance (per VLAN) Ethernet
layer Operation, Administration, and Management (OAM) protocol that includes proactive connectivity
monitoring, fault verification, and fault isolation. End-to-end CFM can be from provider edge (PE) device to
PE device or from customer edge (CE) device to CE device. For more information about Ethernet CFM, see
"Configuring Ethernet Connectivity Fault Management in a Service Provider Network"
Configuration Guide.
OAM Manager Overview
The OAM manager is an infrastructure element that streamlines interaction between Operation, Administration,
and Management (OAM) protocols. The OAM manager requires two interworking OAM protocols, Ethernet
Connectivity Fault Management (CFM) and Ethernet Local Management Interface (LMI). No interactions
are required between Ethernet LMI and the OAM manager on the customer edge (CE) side. On the User
Provider-Edge (UPE) side, the OAM manager defines an abstraction layer that relays data collected from
Ethernet CFM to the Ethernet LMI device.
Ethernet LMI and the OAM manager interaction is unidirectional, from the OAM manager to Ethernet LMI
on the UPE side of the device. An information exchange results from an Ethernet LMI request or is triggered
by the OAM manager when it receives notification from the OAM protocol that the number of UNIs has
changed. A change in the number of UNIs may cause a change in Ethernet virtual circuit (EVC) status.
The OAM manager calculates EVC status given the number of active user network interfaces (UNIs) and the
total number of associated UNIs. You must configure CFM to notify the OAM manager of all changes to the
number of active UNIs or to the remote UNI ID for a given service provider VLAN (S-VLAN) domain.
The information exchanged is as follows:
• EVC name and availability status (active, inactive, partially active, or not defined)
• Remote UNI name and status (up, disconnected, administratively down, excessive frame check sequence
• Remote UNI counts (the total number of expected UNIs and the number of active UNIs)
Benefits of Ethernet LMI at a Provider Edge
• Communication of end-to-end status of the Ethernet virtual circuit (EVC) to the customer edge (CE)
• Communication of EVC and user network interface (UNI) attributes to a CE device
• Competitive advantage for service providers
[FCS] failures, or not reachable)
device
Carrier Ethernet Configuration Guide (Cisco ASR 920 Series)
Ethernet CFM Overview
in the Carrier Ethernet
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