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8
Release 11.3(4)NA
Display the Cable Modem’s MAC Log File
A MAC layer circular log file is inside the cable modem. This file contains a history of log messages,
such as state event activities and timestamps, which are used for troubleshooting purposes. This log
file contains the most valuable information for a cable technician or engineer to debug the cable
interface.
The MAC log file is displayed by entering the show controller cable-modem 0 mac log EXEC
command.
The most useful display fields in this log file are the reported state changes. These fields are preceded
by the message
CMAC_LOG_STATE_CHANGE. These fields show how the cable modem progresses
through the various processes involved in establishing communication with the CMTS and
registration. The
maintenance_state is the normal operational state, and the
wait_for_link_up_state is the normal state when the interface is shutdown.
Here is the normal progression of states as displayed by the MAC log:
wait_for_link_up_state
ds_channel_scanning_state
wait_ucd_state
wait_map_state
ranging_1_state
ranging_2_state
dhcp_state
establish_tod_state
security_association_state
configuration_file_state
registration_state
establish_privacy_state
maintenance_state
Note To translate this output into more meaningful information, see the “Interpret the MAC Log
File and Take Action” section on page 10.
Here is what an example MAC log file looks like when the cable modem interface successfully
comes up and registers with the cable network. The output you see is directly related to the messages
that are exchanged between the cable modem and the CMTS (the Cisco uBR7246).
uBR904# show controller cable-modem 0 mac log
508144.340 CMAC_LOG_DRIVER_INIT_IDB_RESET 0x08098FEA
508144.342 CMAC_LOG_LINK_DOWN
508144.344 CMAC_LOG_LINK_UP
508144.348 CMAC_LOG_STATE_CHANGE ds_channel_scanning_state
508144.350 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND 88/453000000/855000000/6000000
508144.354 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND 89/93000000/105000000/6000000
508144.356 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND 90/111250000/117250000/6000000
508144.360 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND 91/231012500/327012500/6000000
508144.362 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND 92/333015000/333015000/6000000
508144.366 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND 93/339012500/399012500/6000000
508144.370 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND 94/405000000/447000000/6000000
508144.372 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND 95/123015000/129015000/6000000
508144.376 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND 96/135012500/135012500/6000000
508144.380 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND 97/141000000/171000000/6000000
508144.382 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND 98/219000000/225000000/6000000
508144.386 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND 99/177000000/213000000/6000000
508144.390 CMAC_LOG_WILL_SEARCH_SAVED_DS_FREQUENCY 699000000
508145.540 CMAC_LOG_UCD_MSG_RCVD 3
508146.120 CMAC_LOG_DS_64QAM_LOCK_ACQUIRED 699000000