Troubleshooting guide
7-9
Cisco Broadband Local Integrated Services Solution Troubleshooting Guide
OL-5169-01
Chapter 7 Troubleshooting the CMTS
Troubleshooting the Cisco uBR7246VXR
2d18h: 239198.524 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND 95/217760800/39770
2d18h: 239198.528 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND 94/121756000/16970
2d18h: 239198.528 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND 93/175758700/21170
2d18h: 239198.528 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND 92/79753900/857540
2d18h: 239198.532 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND 91/55752700/677530
2d18h: 239198.532 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND 90/177000000/21300
2d18h: 239198.532 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND 89/219000000/22500
2d18h: 239198.536 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND 88/141000000/17100
2d18h: 239198.536 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND 87/135012500/13500
2d18h: 239198.540 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND 86/123012500/12900
2d18h: 239198.540 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND 85/405000000/44700
2d18h: 239198.540 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND 84/339012500/39900
2d18h: 239198.544 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND 83/333025000/33300
2d18h: 239198.544 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND 82/231012500/32700
2d18h: 239198.544 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND 81/111025000/11700
2d18h: 239198.548 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND 80/93000000/105000
2d18h: 239198.548 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND 79/453000000/85500
NOTE—unable to lock on:
2d18h: 239198.552 CMAC_LOG_WILL_SEARCH_SAVED_DS_FREQUENCY 453000000
2d18h: 239199.672 CMAC_LOG_DS_NO_QAM_FEC_LOCK 453000000
2d18h: 239200.788 CMAC_LOG_DS_NO_QAM_FEC_LOCK 453000000
2d18h: 239201.904 CMAC_LOG_DS_NO_QAM_FEC_LOCK 453000000
2d18h: 239203.020 CMAC_LOG_DS_NO_QAM_FEC_LOCK 459000000
Another reason for the MTA not achieving QAM lock is incorrect downstream center frequency being
configured on the upconverter. For example, on the NTSC frequency map for standard 6-MHz channel
bands in North America, channel 100-100 uses 648.0-654.0 with a center frequency of 651 MHz.
However, if you are using an upconverter that is designed to work of the video carrier frequency (for
example, GI C6U which is 1.75MHz below the center frequency), then you need to set a frequency of
649.25 MHz for Channel 100-100.
Another common mistake is to specify an incorrect frequency value in the Downstream Frequency field
under the Radio Frequency Info in the DOCSIS CPE Configurator. Usually there is no need to specify a
frequency value under this option, however, if there is a need (such as when certain modems need to lock
on a different frequency), then proper frequency values should be selected, as explained previously. The
following debug output illustrates this: an MTA locks on initially at 453MHz and then at 535.25MHz
(which was specified in the DOCSIS configuration file), thus causing the cable modem to reset and cycle
through this process indefinitely:
4d00h: 345773.916 CMAC_LOG_WILL_SEARCH_SAVED_DS_FREQUENCY 453000000
4d00h: 345774.956 CMAC_LOG_UCD_MSG_RCVD 1
4d00h: 345775.788 CMAC_LOG_DS_64QAM_LOCK_ACQUIRED 453000000
4d00h: 345775.792 CMAC_LOG_DS_CHANNEL_SCAN_COMPLETED
4d00h: 345775.794 CMAC_LOG_STATE_CHANGE wait_ucd_state
4d00h: 345776.946 CMAC_LOG_UCD_MSG_RCVD 1
4d00h: 345778.960 CMAC_LOG_UCD_MSG_RCVD 1
4d00h: 345778.962 CMAC_LOG_ALL_UCDS_FOUND
4d00h: 345778.966 CMAC_LOG_STATE_CHANGE wait_map_state
4d00h: 345778.968 CMAC_LOG_FOUND_US_CHANNEL 1
4d00h: 345780.996 CMAC_LOG_UCD_MSG_RCVD 1
4d00h: 345781.000 CMAC_LOG_UCD_NEW_US_FREQUENCY 27984000
4d00h: 345781.004 CMAC_LOG_SLOT_SIZE_CHANGED 8
4d00h: 345781.084 CMAC_LOG_UCD_UPDATED
4d00h: 345781.210 CMAC_LOG_MAP_MSG_RCVD
4d00h: 345781.212 CMAC_LOG_INITIAL_RANGING_MINISLOTS 40
4d00h: 345781.216 CMAC_LOG_STATE_CHANGE ranging_1_state
4d00h: 345781.220 CMAC_LOG_RANGING_OFFSET_SET_TO 9610
4d00h: 345781.222 CMAC_LOG_POWER_LEVEL_IS 22.0 dBmV (comma)
4d00h: 345781.226 CMAC_LOG_STARTING_RANGING
4d00h: 345781.228 CMAC_LOG_RANGING_BACKOFF_SET 0
4d00h: 345781.232 CMAC_LOG_RNG_REQ_QUEUED 0
4d00h: 345781.272 CMAC_LOG_RNG_REQ_TRANSMITTED