Hello all. A few days ago, I forked a github project called cabletools that provides monitoring for Motorola / Arris cable modems using PRTG. PRTG is free for up to 100 sensors and runs on Windows. The fork adds support for the Arris SB8200 and more advanced monitoring overall.
https://github.com/JJWatMyself/cabletools
So far the support is only for connections with 29 channels down and 4 channels up using one PRTG sensor and separate PRTG channel for the kinds of things you need to care about. This provides alerting via thresholds for when things are out of spec as well as historic. I also created a script for monitoring Uptime in a separate PRTG sensor, which has a warning threshold set for uptime less than 24 hours. I too am troubleshooting some issues at the moment and find this useful to monitor after I make changes, as well as not needing to memorize what is good and what is bad as it's not like I am a cable modem tech working with this every day.
Here is a screenshot of the 'Cable Modem Stats' PRTG sensor taken while I still had a quality amplifier (+8dBmV rated) in place. You can see I have a 10dBmV range for Downstream Power which would be fine if the max wasn't above 8 dBmV, OFDM SNR is borderline and Upstream Power is too high.
[att=1]
After taking the amplifier out downstream power came down by the exact amount of the amplifier rating, causing OFDM power, minimum downstream power and OFDM SNR to fall to values that are slightly too low. But after about 12 hours the Upstream Power came down and is now well within spec, which can also be seen. This is an indication that the amplifier isn't as transparent as you would hope for upstream. I plan to replace a questionable piece of coax next to see if that brings the min and max downstream power a little closer together as well as helping with the downstream SNR. If that doesn't help I will call Comcast for an in-site visit.
[att=2]
So, as you can see, the monitoring pretty much does the analysis for you, with respect to if levels are within spec or not and goes one step further to alert on channels that are not locked or if you start having uncorrectables.
Happy to answer any questions as well as provide versions for other up/down channel quantities. I would just need a copy paste of HTML output from the modem (Internet Explorer F12 Debugger tab) to test.
↧