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EN2251 sudden high high ping, packet loss- phone support says modem fine...

purduephotogpurduephotog Posts: 3 Spectator
in Connectivity Nov 20, 2021

I need to get to the bottom of serious lag induced issues that disrupt and bring down my remote work capability. It is sporadic which has made the 'plug it into another PC' option impossible.

I have the EN2251 plugged directly into a known genuine Intel dual NIC. That NIC is on hardware, 16gb ram PC running pfSense (overkill, I know).

Randomly with no predictability the network connectivity will drop- and the gateway monitor (pfpinger) will show increasing packet loss and eventual disconnect.

According to the technician I spoke with on the phone, all of the disconnects were on my side of the connection- and then self restores after anywhere from 10 sec to 4 minutes. He also stated company policy prohibits sharing 'admin' information showing power levels and t3/t4 error, etc- that's another gripe for another day.

These issues occurred in the past, too, and Spectrum support stated it was because my 3.0 modem 'couldn't handle the bandwidth' (8down/4up) and had nothing to do with the service work going on down the road- and that I'd have to deploy a new modem (the EN2551 was all they had). Coincidentally the problems went away when the work stopped, and things have been fairly stable until recently.

There is no evidence or report of 'flapping' in the log files on the pfsense and no indication of quality connection issues on any other interface (as if the hardware itself was becoming unresponsive).

I don't care to really drop nearly 200$ on another modem to get around this issue but:

How do I diagnose this and resolve it?

You're aware the Puma7 chipset in these modems are notoriously bad...

I actually do have a complete setup of identical hardware for the pfsense box and was going to deploy it in order to demonstrate there isn't a problem - but then, how do you prove a negative?

Suggestions, please, as these disruptions have already come during conference calls- had I not installed an LTE cellular modem as an alternative gateway I would have completely missed paid work (and no, there's never been any issues with that connection going 'down' even though it uses the same hardware)

Thanks in advance.


  • Renee_TRenee_T Posts: 114 Moderator
    Nov 20, 2021


    I'm sorry to hear about all the issues and the confusion in trying to get them resolved. I just want to make sure that I'm understanding the set up correctly. You are wired direct to the modem with no router connected at all?

    We have started phasing out the older DOCSIS 3.0 modems as the 3.1s can support much higher speeds and are less prone to noise issues due to the larger spread of channels available. We can typically let you know if we see timeouts or signal levels that are outside of the range, though some of that information is only available if you are the account holder or an authorized user on the account. We wouldn't be able to forward that information along to you if the request was along those lines at all.

    Have you done any troubleshooting at all recently beyond the diagnostics from pfSense?

  • purduephotogpurduephotog Posts: 3 Spectator
    Nov 27, 2021

    Thank you Renee_T. The Coax comes in, attaches to the modem (EN2251), then goes to a computer. There is nothing between the two; there is a Spectrum supplied connector with a properly tested ground, and the coax from the junction to the modem has an intact ground as well (and was supplied by Spectrum on last tech run)

    Issues arose during 'service' down the street. The noise on my line, according to the admin page on my previous modem, was minimal once the cable to the house was replaced (it had been nicked). Service was stable up until mid-july when things came to a head, which was when I was informed there was a service change and had to upgrade to the Docsis 3.1 modems. Problems continued for the next few days after this 'upgraded' modem and then suddenly went away with no other hardware changes.

    Attaching it directly to a computer would completely disrupt everything in the household- on the off-chance it would capture an event occurring. I'm more than willing to put a dedicated cisco switch in front of the pfsense box (which is, I know you're aware, really a PC). Since the quality monitoring software monitors all links and connections simultaneously and the only link that is problematic is the link to the EN2251 modem... that in and of itself should be telling.

    All cables have been replaced with blackbox cables that had previously been tested. I can and will replace the cable again with a new, sealed one.

    For example, here is a typical event that was fairly short. Add in about 1 minute on each side for the alarm to trigger.

    Nov 27 10:40:29 dpinger72189 WAN_CABLE_DHCP XXXXX: Clear latency 13506us stddev 7598us loss 14%

    Nov 27 10:39:48 dpinger72189 WAN_CABLE_DHCP XXXXX: Alarm latency 15159us stddev 10084us loss 21%

    In other cases there are no routes to host/response from the modem while attempting to ping out, and they do not match up with DHCP request renewals or any other event I can determine. Without those 'proprietary' logs that tell me things about the signal quality coming to my machine- there really isn't anything I can do from my end except hope that it doesn't happen.

    I had no issues from July 7th after a hardware replacement (again) until August 23rd, and now the rate of problems are increasing. Much of October and November are the same- sudden increases in ping, massive upsurge in packet loss, then back to normal. They appear to be occurring in 2 day windows.

  • Paul_BPaul_B Posts: 419 Moderator
    Nov 27, 2021

    Thank you for the detailed explanation of your setup. One thing we can try is to refresh / reprogram your modem to see if that changes anything. I was able to locate your account with the information you used to register on the community and I took a look at your modem. The refresh / reprogram is the first thing I would recommend doing to try to get to the bottom of this. Please let us know if you would like us to go ahead and do this for you and we can certainly do that for you.

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