Cable modem woes

General off-topic, anything goes discussions.
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StefanR5R
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Cable modem woes

Post by StefanR5R »

Ever since I moved to my current place three years ago, I had days during which internet connectivity through the cable modem would go down, without the modem reconnecting by itself. Only a software reset of the modem (via its web GUI) or alternatively a power toggle would make it reconnect. Sometimes this happens several times a day, and then there can be many weeks without such incident.

It's a Compal CH7485E modem/ router. The fact that it needed the reset made me wonder if the router firmware just wasn't robust enough to handle traffic from my little array of Distributed Computing hosts.

However, via your suggestions in the mchat, I found that after logging in into the simplistic web GUI through https://192.168.100.1/index.asp, I can access the pages https://192.168.100.1/RgConnect.asp to view current connection quality stats, and https://192.168.100.1/RgEventLog.asp for the SNMP event log, by entering these URLs directly. (They are not linked from the web GUI.)

Today is another day on which the modem disconnected a few times. Today is also a Sunday, in the middle of the extended Easter weekend which goes from Friday to Monday, and also part of school holidays. So, lots of people could sit at home and crowd the cables in the city district. On the other hand, weather is fine, so they should rather be out and about. (And some are, as I noted myself earlier today.)

Anyway: During a failure shortly ago, the RgConnect.asp page was showing 0 correctable/ 0 uncorrectable errors on all 16 downstream channels. I forgot to look at the power levels when the failure occurred, but right now they are fine, going by speedguide.net's "What cable modem signal levels are considered good?".

RgEventLog.asp showed this at the time of failure:
"Critical (3) — Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=[redacted;CMTS-MAC=[redacted;CM-QOS=1.1;CM-VER=3.0;"
"Critical (3) — No Ranging Response received - T3 time-out"

Similar or same critical messages were also logged during last night (when the connection must have survived or at least was re-established automatically, because I found it working in the morning), and during earlier today (when the connection eventually died during my absence and the modem wanted to be reset when I returned).

My conclusion so far:
  • It's not an issue with possibly weak IPv4 router firmware/ hardware, which I could work around by adding an own IPv4 router.
  • It doesn't seem to be an issue on the cable — between the modem and the next amplifier (which for all I know could sit very close, as this is a multi-unit building).
That's all a bit off-topic here... and not making for a particularly good campfire story. ;-)
I should bring this up with the service provider, but this is likely to become a tedious procedure.
Skillz
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Re: Cable modem woes

Post by Skillz »

Not sure what those error codes mean so I looked them up. Here is one article I found.

https://robotpoweredhome.com/comcast-xf ... -time-out/
crashtech
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Re: Cable modem woes

Post by crashtech »

Perhaps simply asking for a simple exchange of modems wouldn't be so tedious, and might help.
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biodoc
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Re: Cable modem woes

Post by biodoc »

I would have your provider replace or upgrade the cable modem/router.
Icecold
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Re: Cable modem woes

Post by Icecold »

Dealing with an ISP is tedious but maybe less so than dealing with unreliable internet. I think I would also ask the provider to replace the modem, or even just buy my own to avoid that hassle, if they allow you to.
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