Troubleshooting guide

BSR Troubleshooting Guide
4-50
• Save the flap list statistics to a database server at least once a day to keep a
record of flap list statistics which includes upstream performance and quality
control data. These statistics can be used again at a later time to evaluate
trends and solve intermittant problems on the HFC networks. Once the flap list
statistics are backed up daily on the database server, the flap list statistics can
be cleared.
Resolving HFC Network Performance Problems
If Cable Modem (CM) subscribers can use their data connection, but experience
slow network performance during activities such as Web surfing and exchanging
files. The problem may be the following:
• Downstream Signal Reflected on Upstream Path
• Slow Performance Detected on Upstream Port
• Too Many CPE Hosts on Subscriber CM
The following sections describe how to handle these problems.
Downstream Signal Reflected on Upstream Path
Follow these steps to correct common path distortion that occurs when the
downstream signal is reflected on the upstream path:
1. Check for corrosion or loose connections on common point contacts such as
F-connectors, G-connectors, screw-down seizures, or terminators.
2. Inspect connections for poor craftsmanship on common point contacts.
3. If one or more poor or damaged contacts have been detected, these contacts
may develop an electronic potential that functions like a tiny diode. This
situation causes the forward (downstream) signals to mix with the return
(upstream) signal causing unwanted beat signals on the spectrum.
4. To determine if common path distortion is occuring, use a spectrum analyser
to check for unwanted beat signals on the upstream path. This impairment
happens on the spectrum at points where both the upstream and downstream
signals are present.