Troubleshooting Tips
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
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
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 |
| |
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 |
8Release 11.3(4)NA
