Configuring Headend Broadband Access Router Features

Troubleshooting Using Cable Flap Lists

Command

Purpose

 

 

CMTS01(config)# cable flap-list power-adjust threshold dbmv

Specifies the minimum power adjustment that will

 

constitute a flap list event.

 

 

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:

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.

 

 

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

Cisco IOS Multiservice Applications Configuration Guide

MC-605

Page 87
Image 87
Cisco Systems uBR7200 Setting Cable Flap List Miss Threshold, Verifying Cable Flap List Power Adjustment Threshold, MC-605