Oam Feature Overview; Oam Discovery Feature - Juniper JUNOSE SOFTWARE FOR E SERIES 11.3.X - LINK LAYER CONFIGURATION GUIDE 2010-10-13 Configuration Manual

JunosE 11.3.x Link Layer Configuration Guide

OAM Feature Overview

Related
Documentation

OAM Discovery Feature

230
An important behavior of a carrier-class network element is the implementation of OAM
capabilities. These capabilities relate to operational fields, such as link monitoring, fault
signaling, and remote loopback across multi-vendor equipment, administrative boundaries,
and diversified physical locations. OAM capabilities currently exist in ATM and SONET
infrastructures. With the continued upgrade to Ethernet-based infrastructures, comparable
OAM functions at the MAC (802.3) level are essential. The IEEE 802.3 CSMA/CD Working
Group, using its Ethernet in First Mile (802.3ah) task force, defined a set of OAM
enhancements for Ethernet links in the 802.3ah standard. These enhancements gracefully
ensure backward compatibility with existing Ethernet implementations, while also
providing advanced monitoring functionality required in public networks.
JunosE Software supports the following OAM features:
OAM Discovery Feature on page 230
OAM Link Monitoring Feature on page 232
OAM Remote Fault Detection Feature on page 234
OAM Remote and Local Loopback Feature on page 235
Ethernet OAM Link-Fault Management Overview on page 224
Configuring 802.3ah OAM Link-Fault Management on page 238
Guidelines for Configuring 802.3ah OAM Link-Fault Management on page 237
Discovery is the first phase of Ethernet OAM and it is used to detect the devices in the
network and their OAM capabilities. The discovery process is triggered automatically
when OAM is enabled on the interface. The discovery phase uses Information OAM PDUs.
The discovery process permits Ethernet interfaces to discover and monitor the peer on
the link if it also supports the IEEE 802.3ah standard. You can specify the discovery mode
used for IEEE 802.3ah OAM support as active or passive.
In active mode, the interface discovers and monitors the peer on the link if the peer
also supports IEEE 802.3ah OAM functionality. In active mode, the peer initiates the
discovery process. After the discovery process has been initiated, both sides participate
in discovery.
In passive mode, an OAM entity does not initiate the discovery process. Therefore, the
OAM exchange cannot be performed if you configure both the endpoints, the local and
the peer entities, for passive mode operation.
The discovery mode that you set up for an OAM entity also determines certain other
attributes that can be initiated by an OAM entity. For example, a passive mode OAM
entity cannot initiate a variable request or a loopback procedure. In a carrier environment,
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