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C
H A P T E R
This chapter describes the
26.1 Terms and Definitions
This section lists the terms and definitions appearing in several commands in this section.
Refer to your User's Guide for more detailed information.
Table 314 CFM Terms and Definitions
TERM
CFM
MD
MA
CFM Domain
CFM Loop Back
Test
CFM Link Trace
Test
MEP
MIP
MSC1000G/1024G/1224G Series User's Guide
diagnostic Commands
commands.
diagnostic
DESCRIPTION
CFM (Connectivity Fault Management) is used to detect, analyze connectivity
faults in bridged LANs.
An MD (Maintenance Domain) is a group identified by a level number. You can
create more than one MA group in one MD.
An MA (Maintenance Association) is a group identified by a VLAN ID. One MA
should belong to one and only one MD group.
A CFM domain is a group identified by an MD and an MA. For example, ports in
MD level 1 and MA VLAN 2 are in the same CFM domain while ports in MD level 7
and MA VLAN 2 are in another CFM domain.
Loop Back Test (LBT) checks if the MEP port receives its LBR (Loop Back
Response) from its target after it sends the LBM (Loop Back Message). If no
response is received, there might be a connectivity fault between them.
Link Trace Test (LTT) provides additional connectivity fault analysis to get more
information on where the fault is. In the link trace test, MIP ports also send LTR
(Link Trace Response) to response the source MEP port's LTM (Link Trace
Message). If an MIP or 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.
An MEP port has the ability to send and reply the CCMs, LBMs and LTMs. It also
gets other MEP port information from neighbor switches' CCMs in an MA.
An MIP port forwards the CCMs, LBMs, and LTMs and replies the LBMs and LTMs
by sending Loop Back Responses (LBRs) and Link Trace Responses (LTRs).
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Troubleshooting
