A10E/A28E/A28F Configuration Guide
8.2.1 Introduction
Connectivity Fault Management (CFM) is end to end service level Ethernet OAM technology,
implementing end-to-end connectivity fault detection, fault notification, judgement and
location functions. This function is used to actively diagnose fault for Ethernet Virtual
Connection (EVC) and provide cost-effective network maintenance solution via fault
management function and improve network maintenance.
The Device provides CFM function that compatible ITU-Y.1731 and IEEE802.1ag
recommendations.
CFM Component
CFM is made from below components:
MD
Maintenance Domain (MD, also called MEG, Maintenance Entity Group) is a network that
runs CFM function. It defines network range for OAM management. MD has level property
with 8 different levels (level 0 to level 7), the greater the number is, the higher the level is,
and the larger the range is. Protocol packets of a lower level MD will be discarded when
entering a higher level MD; while the higher level MD packets can transmit through the lower
level MD. In one VLAN range, different MDs can be adjacent, embedded, crossed over.
As shown in Figure 8-3, MD2 is contained in MD1. MD1 packets need to transmit through
MD2. Configure MD1 level as 6, and MD2 level as 3. Then MD1 packets can traverse
through MD2 and implement connectivity fault management of whole MD1, but MD2
packets will not diffuse into MD1. MD2 is server layer and MD1 is client layer.
Figure 8-3 Different MD Levels
Service instance
Service Instance also called Maintenance Association (MA) is part of MD. One MD can be
divided into one or multiple service instances. One service instance corresponds to one
service, mapping to one VLAN group, VLAN of different service instances cannot crossover.
Though service instance can mapping to multiple VLAN, one instance can use one VLAN for
transmitting or receiving OAM packets. The VLAN is master VLAN of the instance.
MEP
As shown in Figure 8-4, Maintenance associations End Point (MEP) is edge node of service
instance. MEP can transmit and deal with CFM packets, instance that MEP located and MD
decide MEP transmit and receive packets VLAN and level.
To Next Page
Loading...