Cable Modem Power Level Graphing

As I hinted last week, I graph a fair amount of data, since I find it pretty handy at times, not to mention just interesting to see in a pretty graph form. I’ve been doing this for years and it’s served me well.

One thing I really wanted to get going was monitoring the cable modem’s power levels. This is now implemented:

Cable Modem Power Levels

How pretty is that? I also moved my ping/latency graphs away from MRTG to RRDTool based graphs. Next up is interface traffic (when I get around to figuring out why it didn’t work when I just tried it).

Poor Broadband Performance

For the past several weeks, the cable modem has been getting more and more unstable. Having dealt with this before I knew the signal quality was pretty poor from looking at the stats. By using a different line that goes more direct, it made a real difference as the data below shows (sidenote: I need to start tracking this using RRDtool).

Before

Forward Path:
Signal Acquired at 723.000 MHz
SNR: 27.1 dB
Received Signal Strength: -19.4 dBmV
Bit Error Rate: 0.459 %
Modulation: 256 QAM

Return Path:
Connection: Acquired
Frequency: 31.6 MHz
Power Level: 61.0 dBmV
Channel ID: 4
Modulation: 16 QAM

After

Forward Path:
Signal Acquired at 723.000 MHz 
SNR: 37.1 dB 
Received Signal Strength: -6.9 dBmV 
Bit Error Rate: 0.000 % 
Modulation: 256 QAM 

Return Path:
Connection: Acquired 
Frequency: 31.6 MHz 
Power Level: 49.8 dBmV 
Channel ID: 4 
Modulation: 16 QAM 

The performance before was getting pretty bad (never more than 10Mbps, often below 4Mbps). Just ran another test and got this:

Comcast Speed

You can see the packet loss was at 100% for several hours yesterday, and was even when up the connection was pretty poor. Around 3:00 it was disconnected while they fixed the coax hookup. You can see the clean connection afterward, with only one small hiccup while I made a little adjustment to the networking cabling that resulted in a few minutes down.
Packet Loss

Pings to this server are still a little high after the tornado incident due to some weird routing on Comcast’s part. Not sure when will get resolved.