Cisco Systems UBR900 User Manual

 Configuring the Cisco uBR900 Series Cable Access Routers 91

This output indicates that the Cisco uBR900 series 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 uBR900 series 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 Table 10; 
however, the reset messages in Table 10 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