VM Business : Virgin Business connection consistantly going down around 2pm

[InsaneNutter]

Just wondering if anyone has ever had an issue like this before? around 2pm every day our Virgin Modem seems to lose connection.

This started happening with our Hitron CGNV4 which we'd had for a few years, so Virgin replaced it with a Hitron Chita, which seemed to solve the issue for a couple of weeks.

Now the modem seems to be consistently losing connection around 2pm every day once more.

10.08.26:



11.08.26:



The modem is in modem mode connected to a Netgate 6100 (pfSense).
We're not really pushing the connection or doing anything different around that time, its just general web and VoIP traffic. (The latency spike in the morning is a scheduled backup download).

Possibly something to do with the power levels looking at the logs perhaps?

Warning REG-RSP-MP Mismatch Between Calculated Value for P1.6hi Compared to CCAP Provided Value
Warning RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW
Warning RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW

Modem logs

We have an engineer coming out to have a look again later in the week. Just found it strange its generally around the same time each day this happens.

[gunner45]

Your modem is struggling to connect with the CMTS, so nothing to do with Netgate 6100 or pfSense. See if you can capture some log entries before and after 2pm.

[jem]

"Possibly something to do with the power levels looking at the logs perhaps?

Warning REG-RSP-MP Mismatch Between Calculated Value for P1.6hi Compared to CCAP Provided Value
Warning RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW
Warning RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW” *

I would say ‘sort of’ but these messages aren’ the issue but they are hinting at what the issue probably is. I’m going to hazard a guess that you have an upstream connectivity issue, the big clue is in the modem log you provided, specifically the ‘No ranging response received - T3 timeout’.

Cable modems ie the hub send out a ‘ranging request’ every 30 seconds or so, this is a sort of ‘I’m still on line, can you hear me’ to the device at the other end of the line, the CMTS in VM’s centres. The responses are sort of saying ‘yes but you are very faint, you need to increase power' and by more than the hub should do.

Eventually the hub loses connectivity completely (no ranging response received), and will reset itself, which appears as a complete disconnection.

So why around 2pm? Well this is just speculation but 2-3pm tends to be the hottest part of the day, heat makes the cables expand, which increases their impedance (resistance); if it is borderline, then this might just be enough to push it over the edge.

When the tech turns up, say that the logs clearly show an upstream power issue and can they check all of the connections and/or move you to a different tap on the street cabinet?


* just on the off chance that anyone is interested, ignore the first of the warning messages, it’s fine. The second and third are basically the same thing; translated into English, they are saying;

Warning (OK fair enough, this is just a warning message) RNG-RSP (that’s shorthand for ranging response, ie the reply from VM’s equipment) CCAP commanded power (CCAP is Converged Cable Access Platform - which is a fancy term for the equipment your hub is ultimately connected to) has instructed to hub to increase its power

However it has request the hub to increase power by more than the limit set buy the hub’s DRW - Dynamic Range Window, the upper and lower limits of what the hub should stick to, which hoppers to be 6dBm. The hub is complaining that it has been instructed to increase power by more than it is programmed to do in one go. I do think the message is not well worded though.

In general anything in the hub logs that are flagged as ‘Warning’, means just that, this is not quite right, but I can deal with it. Which is why I originally said that these menages are ‘hinting’ at what the issue is, but not really the issue itself.

[InsaneNutter]

Some solid advice, thank you.

I was thinking heat might possibly contributing to it in some way as it was over 30c here when the issue initially started a few weeks ago. The last couple of weeks have generally been cooler and without issue, however it really has got warmer again this week. So its certainly a common factor.

The engineer who replaced the modem last time did also fit an amplifier, similar to this: https://emea.technetix.com/product/p...ts-unity-gain/

[jem]

Originally Posted by InsaneNutter

Some solid advice, thank you.

I was thinking heat might possibly contributing to it in some way as it was over 30c here when the issue initially started a few weeks ago. The last couple of weeks have generally been cooler and without issue, however it really has got warmer again this week. So its certainly a common factor.

The engineer who replaced the modem last time did also fit an amplifier, similar to this: https://emea.technetix.com/product/p...ts-unity-gain/

An amplifier will do nothing, probably make it worse. OK, you have noticed some correlation between temperature and connectivity issues, which would tend to support (not prove, absolutely not prove) my supposition regardingn expansion of the cables.

Now I can't comment on the technical knowledge of the tech who show up, it’s variable, but if you were to mention ‘ramping upstream power levels’ and poor connections; you might get somewhere.

Good luck.