topic Re: Strange disconnects on adsl in Broadband

Strange disconnects on adsl

markangeltruema — Sat, 29 Mar 2025 21:19:30 GMT

Hi,

This one is confusing me; approximately once every one or two days, my internet will stop working and i'm not sure why. Line stays synced and account stays logged in with a valid ip address, but there is no data flowing. I am running a Netgear RAX70 and an (old) Openreach ADSL modem. When i see this issue, i can't get my internet connection back until I go into my router admin and disconnect and reconnect.. This isn't the sync failing as that stays up throughout, its a quick reconnect of the account that seems to resolve it.

It seems like an issue on the plusnet side; seems like they just stop me from receiving traffic until i reconnect.

Can someone help me dig into the issue more or check from the plusnet side to see if they see the disconnections?

Thanks

Mark

Re: Strange disconnects on adsl

outcast — Sun, 30 Mar 2025 00:37:58 GMT

@markangeltruema

What bufferbloat grade do you get with that RAX70 setup on ADSL ?

Run this speed test - https://www.waveform.com/tools/bufferbloat

When the test completes, find the "Share Your Results:" URL (found under the test results), click on the [Copy] button.

Then paste the results URL in to your forum reply.

Re: Strange disconnects on adsl

markangeltruema — Sun, 30 Mar 2025 07:17:29 GMT

https://www.waveform.com/tools/bufferbloat?test-id=beff757c-c8ce-4039-96b3-55ac807afefa

However, these disconnects don't happen under load, they appear to be more time based, more often happening in the evening between 9 and 10pm. Be interested to hear your thinking on why bufferbloat might cause disconnects.

Re: Strange disconnects on adsl

markangeltruema — Sun, 30 Mar 2025 08:51:18 GMT

Just to clarify something here that i didnt explain fully in the first post, this seems like a PPPoE hanging issue. Its the PPPoE connection that i have to manually disconnect and reconnect in the router pages to get things working again.

Re: Strange disconnects on adsl

outcast — Sun, 30 Mar 2025 11:12:31 GMT

@markangeltruema wrote:

... Be interested to hear your thinking on why bufferbloat might cause disconnects.

Specifically on ADSL lines, some routers can give symptoms that have the appearance of download traffic 'hang' due to unexpected upload path bufferbloat.

HOWEVER your test result shows that you are NOT on ADSL, so the bufferbloat theory is unlikely.

You are clearly on VDSL2 (typically known as FTTC or SOGEA)

I'm baffled that you have such an amazing router, and allow your connection to run with such high latency !

If you look at the User Manual for the RAX70

Go to page #96 and follow the instructions for "Enable Dynamic QoS"

then on page #97 ensure to "Enable the automatic QoS database update"

Now run the bufferbloat test again, your router you should be able to achieve an 'A' grade.

@markangeltruema wrote:

However, these disconnects don't happen under load, they appear to be more time based, more often happening in the evening between 9 and 10pm.

Now knowing that you are on VDSL2 and that the drop outs occur in the evening, then the most likely cause of that will be the modem's SNR margin varying throughout the day. The best times of day for good margins and low packet loss will be late morning, but worst times are typically in the evening - causing an increase in packet loss until the point when traffic appears to hang.

On your modem, are you able to see the line statistics, specifically the SNR margin ?

If you have a static WAN address, you could monitor your packet loss using ThinkBroadband BQM graphing.

If you are suffering SNR margin evening fade, I've overcome that by using a modem with SNR margin override to increase the daytime margin to a higher than default starting point, so that when the line does fade in the evening, that the lowest point doesn't go so low to be affecting traffic.

Other possibilities might be due to line interference possibly by some rogue electrical device in your home that gets used in the evening. Ensure that your modem is plugged directly in to the Openreach Master Socket faceplate with a short cable, and that you don't have ANY legacy internal telephone extension wiring attached to the back of the Master Socket faceplate.

Re: Strange disconnects on adsl

markangeltruema — Sun, 30 Mar 2025 12:23:46 GMT

Thanks for the detailed reply. I'll have a go at the QOS thing and get back to you on that.

As for the SNR stats, it doesnt seem to show them, probably due to the openreach modem not exposing them. Not sure if i can find out what they are from the modem in some way. That's a bit annoying. I do think they used to be available but maybe a firmware update on the router that i did ages ago stopped them showing.

I dont have a static WAN address, but i do have a dynamic dns set up in cloudflare so i'll take a look at the BQM monitoring and see if it can use a url instead of an ip.

What i don't understand about the interference/snr theory is that why, once the line drops off in the evening, does it not recover at all (even throughout the next day) until i do a full PPPoE re-connect and as soon as i do this, everything is fine for hours afterwards. Id expect that if there was an interference issue, this would still persist even after re-establishing a working connection (and i would have thought it would self-heal once the SNR is back to usable).

Connectivity wise, the modem is right next to the master socket running through a filtered faceplate on a pretty short cable. I'll put it directly into the master as one of my diagnosis steps.

I did find while searching for SNR stats, that the PPPoE setting for "Connection Mode" wasnt set to "always on" but was set to "dial on demand". I guess this might help with reconnections once the issue occurs but im guessing wont help with what is causing the disconnect in the first place..

Re: Strange disconnects on adsl

markangeltruema — Sun, 30 Mar 2025 12:35:58 GMT

@outcast wrote:

@markangeltruema wrote:

... Be interested to hear your thinking on why bufferbloat might cause disconnects.

Specifically on ADSL lines, some routers can give symptoms that have the appearance of download traffic 'hang' due to unexpected upload path bufferbloat.

HOWEVER your test result shows that you are NOT on ADSL, so the bufferbloat theory is unlikely.

You are clearly on VDSL2 (typically known as FTTC or SOGEA)

I'm baffled that you have such an amazing router, and allow your connection to run with such high latency !

If you look at the User Manual for the RAX70

Go to page #96 and follow the instructions for "Enable Dynamic QoS"

then on page #97 ensure to "Enable the automatic QoS database update"

Now run the bufferbloat test again, your router you should be able to achieve an 'A' grade.

I can get a B rating, which is better, so will leave QoS on.

https://www.waveform.com/tools/bufferbloat?test-id=a7b1d125-8fe7-4e78-8a45-33f23028786e

Re: Strange disconnects on adsl

jab1 — Sun, 30 Mar 2025 12:45:01 GMT

@markangeltruema wrote:

I did find while searching for SNR stats, that the PPPoE setting for "Connection Mode" wasnt set to "always on" but was set to "dial on demand". I guess this might help with reconnections once the issue occurs but im guessing wont help with what is causing the disconnect in the first place..

That is most likely 99.9% of your problem - 'dial on demand' is an ancient setting from the days of 28/56k modem connections, which died out when ADSL was introduced.

Re: Strange disconnects on adsl

markangeltruema — Wed, 02 Apr 2025 08:00:37 GMT

Even with the changes in place, i still had the same issue last night at about 8pm. (the 8am one was a forced disconnect as i was moving my modem)

Re: Strange disconnects on adsl

jab1 — Wed, 02 Apr 2025 09:00:57 GMT

@markangeltruema I assume your router has an error log. Can you share it - or at least the portion between (say) 19.55 and 20.05 last night?

Re: Strange disconnects on adsl

markangeltruema — Wed, 02 Apr 2025 09:19:54 GMT

There is a "log", but its about the worst log that I have ever seen (and my day job is basically working with log files). There is one entry at 19:36 which is a scan, and the next entry is me logging in and restarting the connection. It only seems to log security events, even with all options turned on. Can't even ssh into the router to find any more detailed logs. To be honest, its the most expensive garbage router in terms of functionality, even though the wifi speed is good.

[Internet connected] IP address: x.x.x.x, Tuesday, April 01, 2025 19:58:21
[Internet disconnected] Tuesday, April 01, 2025 19:58:03
[admin login] from source 192.168.1.242, Tuesday, April 01, 2025 19:57:35
[DoS Attack: RST Scan] from source: 17.253.29.210, port 443, Tuesday, April 01, 2025 19:36:48

I might try a factory reset of the router as im at my wits end with it. Raised a ticket with plusnet to see if they can see anything on their end. Maybe they can slow my speed down a bit to give me a more stable connection.

Re: Strange disconnects on adsl

jab1 — Wed, 02 Apr 2025 09:35:23 GMT

As you say, not very useful - at all. I think your only option is to see if PN can see anything, as something is amiss here, It is a long time since I was on ADSL, but I honestly don't remember having regular disconnects even when I was.

Out of interest, is ADSL your only option?

Re: Strange disconnects on adsl

markangeltruema — Wed, 02 Apr 2025 09:40:20 GMT

Yeah, unfortunately, I am out in the sticks and FTTC is all we have here. I'm pretty close to the cabinet, so i do get pretty good speeds in general, but I'd sacrifice a bit of that for slightly more stability, especially when i'm the only one tech savvy enough to restart things without a full plug pull on the router. Try to avoid that as i do have some devices that can be a bit problematic when trying to reconnect to wifi (home automation stuff)

Re: Strange disconnects on adsl

jab1 — Wed, 02 Apr 2025 09:52:40 GMT

Right - must learn to re-read a topic when I don't remember it. You are on FTTC, not ADSL and I'm now coming to the conclusion there is a fault somewhere, either in-home or on the OR network, but I have no idea what it could be.

My self-taught knowledge doesn't cover this, but the only other possibility is a fault with/in the modem?

Re: Strange disconnects on adsl

Dan_the_Van — Wed, 02 Apr 2025 09:52:59 GMT

@markangeltruema

The router log is only going to show the details of the PPPoE connection through the modem, to make sense of DSL disconnects you'd need access to any DSL connection logs the Openreach modem may or may not have.

Does the modem have any lights that indicate the current DSL status, flashing or off at the time of the issue? Have you considered the modem could be the issue.

Have you a plusnet supplied Hub that can be used for investigation? Hub One would be best.

Re: Strange disconnects on adsl

markangeltruema — Wed, 02 Apr 2025 09:59:43 GMT

The modem is a pretty old OpenReach ECI 061513. Its pretty locked down as far as i know. You cant even get line stats off it, let alone logs. I havent checked the lights during the problem, but my router is showing the line synced and the connection is still up (even though it has effectively hung). I'll make sure i double check next time it happens.

You are right though, maybe its time for a new modem.

Not even sure i have a plusnet router any more. The last one i had from them was probably more than 10 years ago.

Re: Strange disconnects on adsl

Mustrum — Wed, 02 Apr 2025 10:52:57 GMT

@markangeltruema what is it on your network that is generating so much traffic even at night when you would expect things to be quieter?

Your TBB graph looks very busy.

Re: Strange disconnects on adsl

markangeltruema — Wed, 02 Apr 2025 11:51:50 GMT

I'm pretty new to interpreting those graphs. Are you saying that something I'm uploading/downloading is causing the yellow spikes in latency because i'm pretty sure i'm not downloading anything excessive at any time of the day? I'm at home alone most days with just teams meeting traffic and emails etc, and in the evening maybe a bit of youtube but nothing OTT.

The TBB site says this kind of graph is normal. It could be things such as my home automation devices calling out i guess? My blue section stays pretty stable it seems.

Re: Strange disconnects on adsl

Mustrum — Wed, 02 Apr 2025 12:11:06 GMT

@markangeltruema your graph shows higher levels of yellow spikes than the example, and they continue through the night when I expect you are asleep. You can probably tell when you are on Teams, or watching 4K streaming, but inbetween those times I would expect there would be no yellow spikes - so I would first be looking to see what is causing it.

Re: Strange disconnects on adsl

markangeltruema — Wed, 02 Apr 2025 12:13:14 GMT

my guess is something on my extensive home automation setup/homelab. I'll try turning some things off overnight and see if things calm down at all.