topic Re: Constant High Latency Spikes; Frequent Dropped Connection in Broadband

Constant High Latency Spikes; Frequent Dropped Connection

danielw — Mon, 17 Jun 2024 11:27:42 GMT

Hi all,

I am new to Plusnet (approx 1 month)

I am on a 23mbps package - 'minimum guarantee' 16mbps.... but I am getting no more than 4 to 5 mbps (6 to 7 on a very good day)

Worse - there are constant frequent all day every day spikes in latency making my connection for remote work unreliable.
Around certain times (6pm and 10pm) the connection is almost unusable.

And overnight, in various bursts, the latency is extreme, with significant packet loss. To the extent that my Unifi router/gateway believes the ADSL connection is dead and I fail over to my 5G backup

Please see attached BQM when I am at home, and when I am away on holiday (note that the extreme latency and packet loss does not occur when I am not at home - so the only difference is that our mobile phones are present overnight)

My set up:
Plusnet hub -> Unif Gateway Max -> Unifi switch -> Unifi wifi access points

Diagnostic/fix attempts:
1) If I 'failover' to (or manually choose) my 5G backup connection, my devices can get 80mbps+ speeds, so my setup (router/switch/wifi) is not a slowing-down factor.
2) I have tried a replacement Plusnet hub - this reduced the disconnects but did not increase speed or improve latency
3) I have tried a Draytek Vigor 167 modem - this helped increase speed by ~1mbps but did not improve latency
4) Connecting Plusnet hub in PPPoE mode made latency worse
5) I have tried a different phone-modem cable and a different filter splitter, this did not improve the latency or speed

So:
Do I have a bad line? How can I diagnose this? How can I fix this?
Does Plusnet's network beyond my modem have a problem? How can I diagnose this?
Why does PPPoE make things worse?

Re: Constant High Latency Spikes; Frequent Dropped Connection

Dan_the_Van — Mon, 17 Jun 2024 12:18:09 GMT

@danielw welcome to the forum.

Have you reported your issue? Follow the instructions on this link https://www.plus.net/help/report-a-problem/

Re: Constant High Latency Spikes; Frequent Dropped Connection

danielw — Mon, 17 Jun 2024 12:21:52 GMT

Yes - the only suggestion was to replace the modem

Re: Constant High Latency Spikes; Frequent Dropped Connection

Anunnaki — Mon, 17 Jun 2024 12:25:15 GMT

Using your DrayTek Vigor 167, can you post here the following screenshots from the modem's web console menu -

System Maintenance > System Status (showing the installed firmware version)

Diagnostics > DSL Status (showing all the DSL line statistics)

Hardware Acceleration (confirming that 'Acceleration' is set to "Disable')

Internet Access > General Setup (showing the chosen DSL Mode and modem code)

Internet Access > MPoA (showing your ADSL bridge characteristics)

Re: Constant High Latency Spikes; Frequent Dropped Connection

corringham — Mon, 17 Jun 2024 12:49:37 GMT

Even your PlusnetAway graph is pretty bad - I'd see that as a problem.

Just to see if the at home issues are prompted by your phones doing back-ups you could try disconnecting them from the wifi overnight, and see if the issues still appear - it may be that one phone backs up at 1am and the other at 5am.

I'd suspect that the upload is being maxed out. You could try setting a max upload rate for your phones on your UXG-Max (it is pretty flexible so you can limit all kinds of things) and see if that changes things.

Even if it is your phones backing up (what needs so much backing up daily?) it shouldn't be that bad, and as I mentioned the PlusnetAway looks bad to me too. I'd get whatever stats you can from your plusnet router and report that as suggested above.

Re: Constant High Latency Spikes; Frequent Dropped Connection

danielw — Mon, 17 Jun 2024 18:11:51 GMT

Hi @Anunnaki ,

Thanks for getting back - here's the info.
WIth the exception of Hardware Acceleration and MPoA mode - can't find those, where should I look?

System Maintenance > System Status (showing the installed firmware version)

Can't find the "System Status" section within "System Maintenance", but firmware shown in Dashboard is 5.2.4 (most recent - I updated it)
Attached Dashboard.png

Diagnostics > DSL Status (showing all the DSL line statistics)

Attached Diagnostics.png

Hardware Acceleration (confirming that 'Acceleration' is set to "Disable')

I don't know where to find this?

Internet Access > General Setup (showing the chosen DSL Mode and modem code)

Attached ModemCode.png and OperationMode.png

Internet Access > MPoA (showing your ADSL bridge characteristics)

Don't know where to find this?

Re: Constant High Latency Spikes; Frequent Dropped Connection

Anunnaki — Mon, 17 Jun 2024 18:45:33 GMT

Oh ! sorry for the wild goose chase !, I had assumed that the Vigor 167 had a similar web interface as the nearly identical Vigor 166 (that I have), but clearly from your screenshots it is completely different and unlike any DrayTek web interface I've seen before.

Most DrayTek devices have a menu that looks like some variation of this -

OK - plan B

Can you do a screenshot of your UniFi Gateway Max's webpage for its "QoS" setting ?

Re: Constant High Latency Spikes; Frequent Dropped Connection

MisterW — Mon, 17 Jun 2024 18:50:26 GMT

@Anunnaki that's because it's in modem mode,

Re: Constant High Latency Spikes; Frequent Dropped Connection

Anunnaki — Mon, 17 Jun 2024 19:05:15 GMT

I'm not convinced, my Vigor 166 is in "modem mode" and only shows traditional style DrayTek menus.

It looks to me that DrayTek have done the modern thing of showing a new pretty but dumbed down user interface on the 167.

If needed later, I might get @danielw to try getting the modem DSL stats using Telnet

but in the mean time figuring out how to get the UniFi to apply QoS to the VDSL upstream, and get that TBB BQM plot looking better.

Re: Constant High Latency Spikes; Frequent Dropped Connection

danielw — Mon, 17 Jun 2024 21:33:10 GMT

Sorry not sure what you mean by "how to get the UniFi to apply QoS to the VDSL upstream"

Googling for Unifi QOS gives a few disparate results, feels like there used to be something called QoS but now it's been renamed maybe?

Do you mean "Smart Queues"? https://help.ui.com/hc/en-us/articles/12648661321367-UniFi-Gateway-Smart-Queues

That gives me the option to set a downrate and an uprate.

Re: Constant High Latency Spikes; Frequent Dropped Connection

corringham — Tue, 18 Jun 2024 08:59:52 GMT

Ubiquiti are a bit irritating in that they seem to reorganise the interface with almost every update.

I've not used smart queues, but I have used a bandwidth limit on individual WiFi networks, and on VLANs, and there is now a "Flow Control" setting in the Networks settings which claims to reduce network congestion by pausing traffic (I've not tried that as I have no congestion).

There are probably at least half a dozen ways of implementing QoS for specific devices, but I expect it will take a little experimentation to find which works best for your case.

Re: Constant High Latency Spikes; Frequent Dropped Connection

Anunnaki — Tue, 18 Jun 2024 21:29:33 GMT

@danielw wrote:

Do you mean "Smart Queues"? https://help.ui.com/hc/en-us/articles/12648661321367-UniFi-Gateway-Smart-Queues

That gives me the option to set a downrate and an uprate.

If that's all it can do, then lets try that.

When your connection isn't otherwise being used, first run this test - https://www.waveform.com/tools/bufferbloat

then under the results, find "Share Your Results:", click on the "Copy" button, and paste that link into your reply here.

That will give us a starting point for how your connection is behaving.

Watch the following YouTube video showing how to get to the Smart Queue settings - Ubiquiti UniFi Quality of Service (QoS)

Navigate to your UniFi's Smart Queue settings page.

From your "Dashboard.png" image in Reply #6 your connection speeds were 1269Kbps UP, and 13833Kbps DOWN.

We'll first set the actual connection speed, then set the Smart Queues to approximately 85% of those speeds.

This will be a guess at a starting point for further speed and latency optimisations, depending on what happens !

In the section "Expected ISP Speeds" -

Change the "Download" to 13833, and change the units from "Mbps" to "Kbps"
Change the "Upload" to 1269, and change the units from "Mbps" to "Kbps"
Click on the <Apply> button

Run the waveform.com/tools/bufferbloat test again, and post the resulting link here, to see whether anything changed.

In the section "Smart Queue" -

Check the "Enabled" tick box
Change the "Download" to 11750, and change the units from "Mbps" to "Kbps"
Change the "Upload" to 1075, and change the units from "Mbps" to "Kbps"
Click on the <Apply> button

Run the waveform.com/tools/bufferbloat test again, and post the resulting link here, to see whether anything changed.

Post back here a screenshot of your UniFi's Smart Queue settings page AFTER all your changes.

Good luck !

Re: Constant High Latency Spikes; Frequent Dropped Connection

Mustrum — Tue, 18 Jun 2024 22:14:27 GMT

@corringham wrote:

Even your PlusnetAway graph is pretty bad - I'd see that as a problem.

Just to see if the at home issues are prompted by your phones doing back-ups you could try disconnecting them from the wifi overnight, and see if the issues still appear - it may be that one phone backs up at 1am and the other at 5am.

I'd suspect that the upload is being maxed out. You could try setting a max upload rate for your phones on your UXG-Max (it is pretty flexible so you can limit all kinds of things) and see if that changes things.

Even if it is your phones backing up (what needs so much backing up daily?) it shouldn't be that bad, and as I mentioned the PlusnetAway looks bad to me too. I'd get whatever stats you can from your plusnet router and report that as suggested above.

@danielw

you really do need to pay attention to this reply. Before going off on possible wild goose chasing, you need to check your own environment to see if that is causing the large amount of traffic depicted in your away graph. Depending on the PN router, connect that with nothing else connected, but with settings that the BBQM can report on. The congestion is either on your home LAN, or on the equipment in the exchange - then you can direct your efforts appropriately

Re: Constant High Latency Spikes; Frequent Dropped Connection

Anunnaki — Tue, 18 Jun 2024 22:45:55 GMT

@Mustrum wrote:

...check your own environment to see if that is causing the large amount of traffic depicted in your away graph.

? what ?

There is no "large amount of traffic" on the away graph.

Large amounts of traffic on BQM plots are depicted by significant periods of BLUE lines.

I agree that there is more traffic than the connection can cope with on the home graph - particularly overnight.

The yellow lines on the away graph, are just delayed ping responses due to having a low upload bandwidth, and will likely be improved by applying QoS.

Re: Constant High Latency Spikes; Frequent Dropped Connection

Anunnaki — Tue, 18 Jun 2024 22:49:02 GMT

@Mustrum wrote:

Depending on the PN router, connect that with nothing else connected, but with settings that the BBQM can report on.

Wrong again !

@danielw isn't using a Plusnet router, they're running a UniFi "Gateway Max" as the router

Re: Constant High Latency Spikes; Frequent Dropped Connection

Anunnaki — Tue, 18 Jun 2024 22:56:59 GMT

@Mustrum wrote:

The congestion is either on your home LAN, or on the equipment in the exchange

Sigh !

No, congestion occurs at the slowest link in the data chain, on xDSL connections, this will always be at the modem.

That is why it is essential to apply QoS BEFORE data reaches the modem, so that latency is correctly managed.

Re: Constant High Latency Spikes; Frequent Dropped Connection

Mustrum — Wed, 19 Jun 2024 00:14:06 GMT

You can sigh all you like, but the away graph tells a different story.

Re: Constant High Latency Spikes; Frequent Dropped Connection

Anunnaki — Wed, 19 Jun 2024 07:47:06 GMT

So this is the away graph in question -

and below is the explanation from the ThinkBroadband BQM FAQ -

Re: Constant High Latency Spikes; Frequent Dropped Connection

corringham — Wed, 19 Jun 2024 08:11:37 GMT

I used to have an ADSL (not ADSL2+) connection with a low upload, and I never had a graph with latency as bad as the away graph. I may be that I was using a more competent router, but the amount of traffic generated by the BQM isn't enough to swamp the upload unless other traffic is present too.

The TBB info was written some years ago (the 585 is ~14 years old) - most routers are much better than they were then, so I wouldn't expect any relatively modern router to produce a graph that bad when the connection is quiescent.

Re: Constant High Latency Spikes; Frequent Dropped Connection

Champnet — Wed, 19 Jun 2024 08:15:57 GMT

I'd be seriously concerned about either of those two graphs.

As @Mustrum commented : "The congestion is either on your home LAN, or on the equipment in the exchange"

The router not only moves traffic internal to external, and external to internal, but also internal to internal.

Gven the very low internet speed any traffic is going to affect the graph even a simple camera writing to a storage device. The ICMP reply is going to be delayed and show as busy................