show controllers cable-modem mac
Troubleshooting Tips for the Cisco uBR924 Cable Access Router 41
Example 2
MAC error log information is displayed in the following example, which is also reported via SNMP:
uBR924# show controllers cable-modem 0 mac errors
74373.574 R02.0 No Ranging Response received. T3 time-out.
74374.660 R02.0 No Ranging Response received. T3 time-out.
74375.508 R02.0 No Ranging Response received. T3 time-out.
74375.748 R02.0 No Ranging Response received. T3 time-out.
74375.748 R03.0 Ranging Request Retries exhausted.
74376.112 R02.0 No Ranging Response received. T3 time-out.
74376.354 R02.0 No Ranging Response received. T3 time-out.
74376.778 R02.0 No Ranging Response received. T3 time-out.
74377.442 R02.0 No Ranging Response received. T3 time-out.
This output indicates that the Cisco uBR924 acquired a downstream lock, successfully read a UCD,
and successfully read a MAP. However, it was unable to communicate with the CMTS after ranging
through all upstream transmit power levels. The Cisco uBR924 tried to communicate with the CMTS
16 times without success, after which it reset the cable interface to try to find a better downstream
frequency.
If the DHCP server could not be reached, the error would look like this in the MAC error display:
uBR924# show controllers cable-modem 0 mac errors
497989.804 D01.0 Discover sent no Offer received. No available DHCP Server.
498024.046 D01.0 Discover sent no Offer received. No available DHCP Server.
498058.284 D01.0 Discover sent no Offer received. No available DHCP Server.
Example 3
The show controllers cable-modem 0 mac resets command shows only the entries in the MAC log
that begin with the field CMAC_LOG_RESET. Collectively presenting these fields provides you with a
summary of the most recent reasons why the cable interface was reset.
Reset messages and brief explanations are included in the following examples and in Table6;
however, the reset messages in Table6 do not commonly occur.
In the following example, the configuration file downloaded from the TFTP server could not be read.
The file might not exist, or the file might have incorrect permissions.
uBR924# show controllers cable-modem 0 mac resets
62526.114 CMAC_LOG_RESET_CONFIG_FILE_READ_FAILED
62564.368 CMAC_LOG_RESET_T4_EXPIRED
62677.178 CMAC_LOG_RESET_CONFIG_FILE_READ_FAILED
62717.462 CMAC_LOG_RESET_CONFIG_FILE_READ_FAILED
62757.746 CMAC_LOG_RESET_CONFIG_FILE_READ_FAILED
62796.000 CMAC_LOG_RESET_T4_EXPIRED
62908.808 CMAC_LOG_RESET_CONFIG_FILE_READ_FAILED
62949.092 CMAC_LOG_RESET_CONFIG_FILE_READ_FAILED
62989.380 CMAC_LOG_RESET_CONFIG_FILE_READ_FAILED
63029.662 CMAC_LOG_RESET_CONFIG_FILE_READ_FAILED
63069.944 CMAC_LOG_RESET_CONFIG_FILE_READ_FAILED
63110.228 CMAC_LOG_RESET_CONFIG_FILE_READ_FAILED
63148.484 CMAC_LOG_RESET_T4_EXPIRED
63261.296 CMAC_LOG_RESET_CONFIG_FILE_READ_FAILED
The following example shows that the DHCP server could not be reached, or that it took too long to
respond.
uBR924# show controllers cable-modem 0 mac resets
497989.804 CMAC_LOG_RESET_DHCP_WATCHDOG_EXPIRED
498024.046 CMAC_LOG_RESET_DHCP_WATCHDOG_EXPIRED
498058.284 CMAC_LOG_RESET_DHCP_WATCHDOG_EXPIRED