ZyXEL Communications MSC1000G Series, User Manual

Page: 703 / 1168

Chapter 23 diagnostic Commands
Management Switch Card User’s Guide
703
where
23.4.4 diagnostic ldm show Command
Syntax:
diagnostic ldm show < slot-port > result|hlin|hlog|qln|snr
where
Use this command to display the most recent loop diagnostic mode test results for an ADSL or
VDSL port. Use the loop diagnostics results to analyze problems with the physical ADSL or VDSL
line.
Note: Wait at least one minute after using the
diagnostic ldm test
command before
using the
diagnostic ldm show
command.
The following example performs loop diagnostics on DSL port 4 of the line card in slot 5.
md-name
= The maintenance domain name (length<32).
ma-name
= The maintenance association name (length<16)
ep-id
= The endpoint identifier (1~8191).
remote-ep-id
= The remote endpoint identifier used to resolve the remote MAC address in the
CCM database.
mac
=
An arbitrary unicast MAC address.
ttl
=
This is Time-To-Live value (1~63 seconds). Sets this to stop a test once it
exceeds the time duration without receiving any response.
result
=
Displays the basic loop diagnostic mode test results.
hlin
=
Displays the channel characteristics function represented in linear format by a scale
factor and a complex number. These are the maximum upstream and downstream scale
factors used in producing the channel characteristics function.
hlog
= Displays channel characteristics. The format provides magnitude values in a logarithmic
scale. This can be used in analyzing the physical condition of the ADSL or VDSL line.
qln
=
Displays the Quiet Line Noise for a DMT tone is the rms (root mean square) level of the
noise present on the line, when no ADSL or VDSL signals are present. It is measured in
dBm/Hz. The QLN can be used in analyzing crosstalk.
snr
= Displays the upstream and downstream Signal to Noise Ratio (in dB). A DMT tone’s SNR
is the ratio between the received signal power and the received noise power. The SNR
can be used in analyzing time dependent changes in crosstalk levels and line
attenuation (such as those caused by temperature variations and moisture).