Cisco Systems UBR904 manual Feature Summary, Benefits

Troubleshooting Tips for the Cisco uBR904 Cable Modem

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Feature Summary on page 1

Prerequisites on page 3

Supported MIBs and RFCs on page 3

CMTS to Cable Modem Network Topology on page 4

Troubleshooting Tips on page 5

Command Reference on page 16

Debug Commands on page 42

What to do Next on page 54

Feature Summary

This document provides MSOs (multiple service operators) with a set of software tools for troubleshooting a cable modem for data-over-cable connections. These tools are Cisco IOS troubleshooting commands used for verifying communication between the cable modem and other peripheral devices installed in the HFC network, such as the headend Cisco uBR7246, a DHCP server, and TFTP server.

Benefits

•A MAC layer system log file exists inside the cable modem, which provides you with a snapshot of detailed reasons why an interface might reset and all the negotiations that occurred between the cable modem and the CMTS (a Cisco uBR7246 positioned at the headend). Over 220 possible description fields exist in this log. The log is displayed using the show controller cable-modem 0 mac log EXEC command.

•Debug does not need to be turned on to troubleshoot a cable modem.

•Cable technicians can understand the progression of normal data-over-cable communication events, from which they can resolve faulty system connections.

•A cable technician can remotely telnet into a Cisco uBR904 cable modem, which could be installed in a customer’s home, and perform simple diagnostic tasks.

Troubleshooting Tips for the Cisco uBR904 Cable Modem 1