ZyXEL Communications Corporation EMG3415-B10A Manual De Usuario

EMG3415-B10A User’s Guide

The Diagnostic screens display information to help you identify problems with the EMG.

The route between a CO VDSL switch and one of its CPE may go through switches owned by 
independent organizations. A connectivity fault point generally takes time to discover and impacts 
subscriber’s network access. In order to eliminate the management and maintenance efforts, IEEE 
802.1ag is a Connectivity Fault Management (CFM) specification which allows network administrators to 
identify and manage connection faults. Through discovery and verification of the path, CFM can 
detect, analyze and isolate connectivity faults in bridged LANs.

• The Ping & TraceRoute & NsLookup screen lets you ping an IP address or trace the route packets take 

to a host (

).

The following terms and concepts may help as you read through this chapter.

A Maintenance Association (MA) defines a VLAN and associated Maintenance End Point (MEP) ports 
on the device under a Maintenance Domain (MD) level. An MEP port has the ability to send 
Connectivity Check Messages (CCMs) and get other MEP ports information from neighbor devices’ 
CCMs within an MA. 

CFM provides two tests to discover connectivity faults. 

• Loopback test - checks if the MEP port receives its Loop Back Response (LBR) from its target after it 

sends the Loop Back Message (LBM). If no response is received, there might be a connectivity fault 

between them. 

• Link trace test - provides additional connectivity fault analysis to get more information on where the 

fault is. If an MEP port does not respond to the source MEP, this may indicate a fault. Administrators 

can take further action to check and resume services from the fault according to the line 
connectivity status report.