Troubleshooting guide

11-4
Cisco Broadband Local Integrated Services Solution Troubleshooting Guide
OL-5169-01
Chapter 11 Element Management and MIBs
Cisco uBR7246vxr MIBs
ccsFlapMisses The number of times the CMTS misses the Ranging request
from the MTA.
The CMTS issues a Station Maintenance packet every 10
seconds and waits for a Ranging request from the MTA. If the
CMTS misses a Ranging request within 25 msec then the
Misses count are increased.
If ccsFlapTotal is high, Hits and Misses are high but
ccsFlapPowerAdjustments and ccsFlapInsertionFails are low
then the flapping is probably caused by the modem going up
and down.
Miss counts can indicate:
• Intermittent upstream,
• Laser clipping, or
• Noise bursts.
Laser clipping can happen if the signal power is too high when
the upstream electrical signal is converted to an optical signal.
When it happens the more input produces less output, until
finally there is no more increase in output. This phenomena is
called laser clipping.
Discontinuities in the value of this counter can occur if this
entry is removed from the table and then re-added, and are
indicated by a change in the value of ccsFlapCreateTime.
ccsFlapCrcErrors The number of times the CMTS upstream receiver flagged a
packet with a CRC error.
If ccsFlapCrcErrors is high, it indicates the cable upstream may
have high noise level. The modem may not be flapping yet but
it may be a potential problem.
This count can indicate:
• Intermittent upstream,
• Laser clipping, or
• Noise bursts.
Laser clipping can happen if the signal power is too high when
the upstream electrical signal is converted to an optical signal.
When it happens the more input produces less output, until
finally there is no more increase in output. This phenomena is
called laser clipping.
Discontinuities in the value of this counter can occur if this
entry is removed from the table and then re-added, and are
indicated by a change in the value of ccsFlapCreateTime.
Table 11-1 CISCO-CABLE-SPECTRUM-MIB.my Objects (continued)
Object Description