user manual

Configuring Headend Broadband Access Router Features
Troubleshooting Using Cable Flap Lists
MC-605
Cisco IOS Multiservice Applications Configuration Guide
Verifying Cable Flap List Power Adjustment Threshold
To verify the cable flap list power adjustment threshold, enter the show cable flap list command:
CMTS01# 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 Miss Threshold
You can specify the miss threshold for recording a flap list event. A miss is the number of times a
cable modem does not acknowledge a MAC-layer keepalive message from a cable modem card. An
8 percent miss rate is normal for the Cisco cable modem cards. When the number of misses exceeds the
threshold, the cable modem is placed in the flap list.
Note A high miss rate can indicate intermittent upstream problems, fiber laser clipping, or
common-path distortion.
To set the miss threshold for recording a flap list event, use the following command in global
configuration mode:
Verifying Cable Flap List Miss Threshold
To verify the cable flap list miss threshold, enter the show cable flap list command:
CMTS01# 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
Command Purpose
CMTS01(config)# cable flap-list power-adjust threshold dbmv
Specifies the minimum power adjustment that will
constitute a flap list event.
Command Purpose
CMTS01(config)# cable flap-list miss-threshold misses
Specifies the number of MAC-layer keepalive
misses that will result in the cable modems being
place in the flap list.