Cisco Systems UBR924 manual Debug cable-modem mac, Usage Guidelines

debug cable-modem mac

debug cable-modem mac

To troubleshoot the Cisco uBR924 MAC layer, use the debug cable-modem mac command in privileged EXEC mode. To turn the debugging messages off, use the no form of this command.

[no] debug cable-modem mac {log [verbose] messages}

Syntax Description

log	Realtime MAC log display.
verbose	(Optional) Displays periodic MAC layer events, such as ranging.
messages	MAC layer management messages.

Defaults

No default behavior or values.

Command Modes

Privileged EXEC

Command History

ReleaseModification

11.3 NA This command was first introduced.

Usage Guidelines

Of all the available debug cable modem commands, the most useful is debug cable-modem mac log.

MAC log messages are written to a circular log file even when debugging is not turned on. These messages include timestamps, events, and information pertinent to these events. Enter the debug cable-modem mac log command to view MAC log messages. If you want to view this information without entering debug mode, enter the show controllers cable-modemnumber mac log command. The same information is displayed by both commands.

If the Cisco uBR924 interface fails to come up or resets periodically, the MAC log will show what happened. For example, if an address is not obtained from the DHCP server, an error is logged, initialization starts over, and the Cisco uBR924 scans for a downstream frequency. The debug cable-modem mac log command displays the log from the oldest to the newest entry.

After initial ranging is successful (dhcp_state has been reached), further RNG-REQ/RNG-RSPmessages and watchdog timer entries are suppressed from output unless the verbose keyword is used. Note that CMAC_LOG_WATCHDOG_TIMER entries while in the maintenance_state are normal when using the verbose keyword.

Troubleshooting Tips for the Cisco uBR924 Cable Access Router 67