Cisco UBR904 Troubleshooting Guide - Page 8

Troubleshooting Steps Step 3-Display the Cable Modem's MAC Log File A MAC-layer circular log file is stored inside the cable modem. This file contains the most valuable information for troubleshooting the cable interface: a history of the log messages such as state event activities and timestamps. The MAC log file is displayed by entering the show controllers cable-modem 0 mac log command from privileged EXEC mode. 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 and registration with the CMTS. The maintenance_state is the normal operational state, and the wait_for_link_up_state is the normal state when the interface is shut down. The following 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 "Step 4-Interpret the MAC Log File and Take Action" on page 10. Following is an example of what the MAC log file looks like when the cable modem interface successfully comes up and registers with the CMTS. The output you see is directly related to the messages that are exchanged between the cable modem and the headend Cisco uBR7246. uBR904# show controllers cable-modem 0 mac log 508144.340 CMAC_LOG_DRIVER_INIT_IDB_RESET 508144.342 CMAC_LOG_LINK_DOWN 508144.344 CMAC_LOG_LINK_UP 508144.348 CMAC_LOG_STATE_CHANGE 508144.350 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND 508144.354 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND 508144.356 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND 508144.360 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND 508144.362 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND 508144.366 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND 508144.370 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND 508144.372 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND 508144.376 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND 508144.380 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND 508144.382 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND 508144.386 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND 508144.390 CMAC_LOG_WILL_SEARCH_SAVED_DS_FREQUENCY 508145.540 CMAC_LOG_UCD_MSG_RCVD 508146.120 CMAC_LOG_DS_64QAM_LOCK_ACQUIRED 508146.122 CMAC_LOG_DS_CHANNEL_SCAN_COMPLETED 508146.124 CMAC_LOG_STATE_CHANGE 0x08098FEA ds_channel_scanning_state 88/453000000/855000000/6000000 89/93000000/105000000/6000000 90/111250000/117250000/6000000 91/231012500/327012500/6000000 92/333015000/333015000/6000000 93/339012500/399012500/6000000 94/405000000/447000000/6000000 95/123015000/129015000/6000000 96/135012500/135012500/6000000 97/141000000/171000000/6000000 98/219000000/225000000/6000000 99/177000000/213000000/6000000 699000000 3 699000000 wait_ucd_state 8 Cisco IOS Release 12.0(3)T