ZyXEL Communications MSC1000G Series, User Manual

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Management Switch Card User’s Guide
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C
H A P T E R
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diagnostic Commands
This chapter describes the
diagnostic
commands.
23.1 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 352
CFM Terms and Definitions
TERM DESCRIPTION
CFM CFM (Connectivity Fault Management) is used to detect, analyze connectivity faults in
bridged LANs.
MD An MD (Maintenance Domain) is a group identified by a level number. You can create more
than one MA group in one MD.
MA An MA (Maintenance Association) is a group identified by a VLAN ID. One MA should belong
to one and only one MD group.
CFM Domain 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.
CFM Loop Back
Test 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.
CFM Link Trace
Test 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.
MEP 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.
MIP 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).