Troubleshooting guide

BSR Troubleshooting Guide
4-46
A CM has roughly the same number of
hits and misses and contain a lot of
insertions.
There is a problematic downstream path.
For example, the downstream power level
to the CM may have a power level that is too
low.
A high flap list insertion (Ins) time
number.
Intermittent downstream synchronization
loss.
DHCP or CM registration problems.
Low miss/hit ratio, low insertion, low
P-adj, low flap counter and old
timestamp.
Indicates an optimal network situation.
High ratio of misses over hits (> 10%) Hit/miss analysis should be done after the
"Ins" count stops incrementing. In general, if
the hit and miss counts are about the same
order of magnitude, then the upstream may
be experiencing noise. If the miss count is
greater, then the CM is probably dropping
out frequently and not completing
registration. The upstream or downstream is
perhaps not stable enough for reliable link
establishment. Very low hits and miss
counters and high insertion counters
indicate provisioning problems.
High power adjustment counter. Indicates the power adjustment threshold is
probably set at default value of 2 dB
adjustment. The CM transmitter step size is
1.5 dB, whereas the headend may
command 0.25 dB step sizes. Tuning the
power threshold to 6 dB is recommended to
decrease irrelevant entries in the flap list.
The power adjustment threshold may be set
using <cable flap power threshold <0-10
dB> from Global Configuration mode. A
properly operating HFC network with short
amplifier cascades can use a 2-3 dB
threshold.
Table 4-2 Troubleshooting CM Problems
Cause or Symptom Problem