Troubleshooting guide

BSR Troubleshooting Guide
4-56
1. Check for bad optical amplifiers in the HFC network.
2. Check for defective equipment in the HFC network.
3. Determine if there is a cable that is physically cracked or damaged in such a
way to cause external ingress from a variety of sources is entering into the
network.
4. Look for loose connections.
5. Study the HFC network topology and look for flaws that may be causing
additional ingress noise.
6. If there is too much ingress noise detected, increase the interleave depth.To set
the downstream port interleave depth, use the cable downstream
interleave-depth command in Interface Configuration mode, as shown below.
RDN(config-if)#cable downstream 0 interleave-depth {8 | 12 | 16 | 32
| 64 | 128}
where:
0 is the number of the downstream port.
7. If the cable plant is clean and the interleave depth is set too high, there may be
too much latency on the downstream path causing CMs to experience slow
performance. To decrease the interleave depth, use the cable downstream
interleave-depth command in Interface Configuration mode.
8. Determine if there are too many nodes that are combined on an upstream port.
Too much segmentation can affect the signal-to-noise ratio.
9. Check the individual nodes that are combined on an upstream port that is
experiencing ingress problems. For example, there may be three nodes that
have an acceptable signal-to-noise ratio, but the fourth node has a bad
signal-to-noise ratio that is cascading into the other three nodes and causing
poor performance on the upstream port.
10. Determine if impulse and electrical ingress noise is entering the network from
electrical sources within a home, such as hair dryers, light switches, and
thermostats; or from high-voltage lines that run near cabling in the network.