Information Technology Reference
In-Depth Information
Gathering Client-Side Performance Data
For trend analysis, it's very important to gather client-side performance data. Good information to get
includes this:
•
Client hardware model/firmware version (attainable with the command ATI3I7 on the client's
modem).
•
Client-reported disconnect reasons (use ATI6 or AT&V1).
•
Other information available on the client end, including the PC's modemlog.txt and ppplog.txt. The
PC won't generate these files unless configured to do so.
Analyze the Performance Data
When you have collected and understood the performance data for your modem system, it's time to look
at any remaining patterns/components that may have room for improvement.
Problems with Particular Server Modems
Use
show modem
or
show modem call-stats
, and look for any modems with abnormally high rates of
trainup failure or bad disconnect rates. If adjacent pairs of modems are having problems, the problem is
likely a hung or dead DSP. Use
copy flash modem
to the affected HMM to recover. Make sure that the
modems are running the latest version of portware.
Verify that all modems are correctly configured. To make sure that the modems are correctly configured,
use the configuration command
modem autoconfigure type <mica/microcom_server>
in the line
configuration. To make sure that the modems are being autoconfigured whenever a call is hung up, use
the exec command
debug confmodem
. In some cases, it may require a reverse Telnet to fix modems that
are badly misconfigured.
Problems with Particular DS0s
Bad DS0s are rare but possible. To find out if one is present, use the command
show controller t1
call-counters
. Look for any DS0s with abnormally high TotalCalls and abnormally low TotalDuration.
To target suspected DS0s, it is sometimes necessary to take out of service other DS0s with the
configuration command
isdn service dsl, ds0 busyout
under the serial interface for the T1. The output
from
show controller t1 call-counters
look like this:
TimeSlot Type TotalCalls TotalDuration
1 pri 873 1w6d
2 pri 753 2w2d
3 pri 4444 00:05:22
Obviously, time slot 3 is the suspect channel in this case.
A Few of the More Common Trends Seen by Cisco's TAC
The following are some of the more commonly seen problems. Each problem's telltale signs are listed.
1.
Bad Circuit Paths
