ZyXEL Communications ZyXEL Dimension ES-2024PWR - Manual (Page 49)

Ethernet Switch CLI Reference Guide
49
C
H A P T E R
9
CFM Commands
Use these commands to configure the Connectivity Fault Management (CFM) on the Switch.
9.1 CFM Overview
The route between two users may go through aggregated switches, routers and/or DSLAMs
owned by independent organizations. A connectivity fault point generally takes time to
discover and impacts subscribers’ network access. IEEE 802.1ag is a Connectivity Fault
Management (CFM) specification which allows network administrators to identify and
manage connection faults in order to ease management and maintenance. Through discovery
and verification of the path, CFM can detect and analyze connectivity faults in bridged LANs.
The figure shown below is an example of a connection fault between switches in the service
provider’s network. CFM can be used to identify and management this kind of connection
problem.
Figure 1 Connectivity Fault Example
9.1.1 How CFM Works
CFM sends pro-active Connectivity Check (CC) packets between two CFM-aware devices in
the same MD (Maintenance Domain) network. An MA (Maintenance Association) defines a
VLAN and associated ports on the device under an MD level. In this MA, a port can be an
MEP (Maintenance End Point) port or an MIP (Maintenance Intermediate Point) port.
CPE
Service Provider Network
CPE