Troubleshooting guide

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Cisco Broadband Local Integrated Services Solution Troubleshooting Guide
OL-5169-01
Chapter 7 Troubleshooting the CMTS
Troubleshooting the Cisco uBR7246VXR
Setting Cable Flap List Insertion Time
You can set the cable flap list insertion time. When a cable modem makes an insertion request more
frequently than the amount of insertion time defined by this command, the cable modem is placed in the
flap list. The valid range is from 60 to 86400 seconds. A cable modem will not “flap” more than once in
each insertion time interval.
To set the cable flap list insertion time interval, use the cable flap-list insertion-time command in global
configuration mode. To disable insertion time, use the no form of this command.
Command:
[no] cable flap-list insertion-time seconds
Syntax Description:
seconds
Insertion time interval in seconds. Valid values are from 60 to 86,400 seconds.
No default behavior or values.
The following example shows how to set the insertion time interval to 62 seconds:
router(config)# cable flap-list insertion-time 62
Verifying Cable Flap List Insertion Time
To verify cable flap list insertion time, enter the following command, and note the Time column:
show cable flap list
Mac Addr CableIF Ins Hit Miss CRC P-Adj Flap Time
0010.7b6b.5d1d C3/0 U0 0 688 169 0 0 3 Nov 5 12:28:50
0010.7b6b.5e15 C3/0 U0 1 707 185 0 0 5 Nov 5 12:29:52
0010.7b6b.5e27 C3/0 U0 1 707 198 0 0 5 Nov 5 12:29:55
0010.7b6b.5d29 C3/0 U0 1 709 205 0 0 5 Nov 5 12:29:52
0010.7b6b.5e2b C3/0 U0 1 710 204 0 0 7 Nov 5 12:30:16
Setting Cable Flap List Power Adjustment Threshold
You can specify the minimum power adjustment threshold that will cause a flap-list event to be recorded.
When the power adjustment of a cable modem meets or exceeds the threshold, the cable modem is placed
in the flap list. The valid range is from 1 to 10 dBmV.
Note A power adjustment threshold of less than 2 dB might cause excessive flap list event recording. Cisco
recommends setting this threshold value to 3 dB or higher.
To specify the power-adjust threshold for recording a flap list event, use the cable flap-list power-adjust
threshold command in global configuration mode. To disable power-adjust thresholds, use the no form
of this command.
Command:
[no] cable flap-list power-adjust threshold dB
Syntax Description:
dB—Specifies the minimum power adjustment, in decibels, that results in a flap-list event. Valid values
are from 1 to 10 dB. The default value is 2 dB.