Chapter 4 Troubleshooting the System

Using Cable Interface Debug Commands

Verify the Ping

The ping docsis command returns a verification from a cable modem that is pinged:

Queueing 5 MAC-layer station maintenance intervals, timeout is 25 msec:

!!!!!

Success rate is 100 percent (5/5)

Tips If you are having trouble, make sure you are using a valid MAC or IP address for the cable modem you want to ping.

Using Cable Interface Debug Commands

To troubleshoot cable interfaces, use the following debug commands in enable (privileged EXEC) mode.

Table 4-32 Instructions to Use Debug Command

Command

 

Purpose

 

 

 

 

 

CMTS01# debug cable ?

 

View all debug cable commands that are available.

 

 

 

 

 

CMTS01# undebug all

 

Turn off all debugging information to the console

 

 

 

and choose a more selective debug command.

 

 

 

 

 

 

 

 

 

Note Refer to the debug commands

 

 

 

 

 

that follow.

 

 

 

 

 

 

 

 

 

 

 

 

 

Caution The following commands can generate large amounts of output as the number of

cable modems grows. On heavily loaded systems with thousands of cable modems, these commands can dramatically affect router performance.

Debug Cable ARP Requests

This command activates debugging of arp requests on the cable interfaces. When this command is activated, all cable arp request messages are displayed on the Cisco uBR7200 series console. The format for the command follows:

CMTS01# debug cable arp

To deactivate debugging of arp requests, use the following command:

CMTS01# no debug cable arp

Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide

 

78-5897-01

4-49

 

 

 

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Cisco Systems uBR7200 Series manual Using Cable Interface Debug Commands, Verify the Ping, Debug Cable ARP Requests