Speed reducing to set amount at regular interval when downloading files.

[#1]

Thanks for the suggestion, I looked at the posts there and while the problem is similar it’s not exactly the same as they don’t have the up and down yoyo effect for a specific time period and speed. I tried what was recommended in the thread anyway and also started my own here: https://forums.thinkbroadband.com/technical/4738529-reducing-speed-when-downloading.html?fpart=all&v...

Been a couple of days now and no one seems to have any other suggestions I can try so I’ve come back here for help.

No one has said the up and down speed reduction is normal so I assume there is a fixable fault to be found somewhere. I just feel like I’ve ruled out the problem being on my end at this point.

Does anyone have anything else to suggest that I can try that I haven’t already done in the other thread I made on thinkbroadband?

Or advice on what I should do moving forward if I have nothing left to try and this isn’t normal behavior?

The gears grinding in my mind are thinking about how there was a lot of construction work down our road, main street, general town area and motorway the past year or so that led up to FTTP getting enabled. I’m also the very first person in our street to get it enabled so I’m wondering if something wasn’t installed or configured right when the infrastructure got installed or something of that nature since it’s all new stuff and it feels like something is intermittently working and then not, cutting in and out at a consistent regular interval that’s happening either within the ONT or further up the line.

[#2]

Ok, so little disappointed there have been no further replies.

Been going round and round in circles last couple of weeks continuing to try and figure out what’s going wrong and the only new thing I’ve discovered is that when I said previously how the plusnet router didn’t work with the vpn connection and an opnsense router did it turns out they both work with the vpn but only when the pppoe router makes a “good” connection.

By “good” connection I mean that for whatever reason I can restart the pppoe router (plusnet or opnsense) and the vpn connection will give the same speed reduction fault. However, if I restart the pppoe router again and again, usually 3 or 4 times, I eventually seem to stumble onto “something” that works and I can download a file at the vpn’s full speed (usually around 700mbps with the expected internet fluctuation of 30-40mbps higher or lower) without the speed reduction fault occurring.

Of course the first thing I tried when I realised this was to see if I could then download a file on the raw pppoe connection when the vpn had a good connection but alas this didn’t work and it still gave the same drop off a cliff speed reduction.

This has made me start to believe the problem is a gateway/routing problem within plusnets network and when I can get on a gateway that routes well for the vpn connection it permits the full speed with no reduction over the vpn while still having bad routing for everywhere else on the pppoe connection that results in the speed drop.

Just the fact I can get the line and my equipment to support the more expected behaviour of continuous high speed when downloading a file, but only through the vpn connection, suggests to me it has to be some sort of internal problem within plusnets network and when i can get the stars to align and find a gateway/route that works for my vpn connection it is able to bypass the problem.

It’s definitely the pppoe connection that the fault occurs on as once I’ve got the pppoe connection on a good gateway/route I can restart the vpn router again and again and it keeps its full download speed each time and retains those high speeds indefinitely. Restart the pppoe router and it shifts to a bad gateway/route and the vpn router gives the speed reduction fault once again.

Is it possible to get this kind of fault investigated though?

[#3]

@chaoticmess  - Hi Just to check does your pc have a SSD hard drive or a old disk type drive. I'm just making sure that the pc has the capability of saving that amount of data as standard HDD only has a write speed of about 80 MB/s that's about 700Mbps converted not even accounting for bandwidth the OS needs in the first place. The next thing to consider is that the provider you are downloading the file from won't have an endless upload speed, for you to download at 700Mbps the server needs an upload of 700Mbps, and thats just for you to get the file never mind anyone else needing a share of their upload speed. To try and figure out what's going on , I think it's best to at least try it on another bog standard PC with and SSD and try to download a file from elsewhere incase it's being throttled at the servers end. After all it's only in the last 12 months that these speeds were possible for the average population, prior 80Mbps was the fastest on FTTC.

[#4]

Thanks for the reply.

In the thinkbroadband link I gave above I managed to rule out it being a drive issue by using the command: wget -O /dev/null http://90.130.74.153/50GB.zip (The IP of http://ams-speedtest-1.tele2.net)

This doesn’t save the data anywhere ruling out the hard drive being a limiting factor.

Please see the pictures attached below. In them you can see that the hdd stat shows the drive doing nothing both when high or low yet the problem still occurred. This was also done on an i9 10900k using ubuntu 22 and the pppoe connection being setup directly in ubuntu to the ONT so no router was involved at all.

But to answer your question specifically. I have also already tired different computers with different OS’s with old style 7200rpm hdd’s, sdd’s and nvme’s. They all have the same problem. It’s not the computers, OS, Network card, network cable, router or hard drive. I've tried multiples of all of them. The problem starts at the ONT or beyond.

As to the provider not having endless upload speed I solved that being an issue as well because I setup my own dedicated server with a 1gbps connection to let me run an iperf3 test from my server to my plusnet connection so the whole bandwidth was dedicated just to me. The problem still occurred in the exact same specific manner.

If the speed was fluctuating in a manner like this: 710mbps>650>600>500>530>570>620>580>510>480>400>350>300>350>400>390>440>500>490>550>580>610>630>670>710>710>700>720>690>650> etc with each rise and fall happening within a second of each other then I could get on board with that being more typical of the internet being the internet and speeds vary.

However this is not what happens. Instead I get something more like this:

720mbps>770>760>750>760>760>760>760>750>760>350>350>350>350>350>340>350>350>350>350>340>350>350>350>350>340>350>350>350>350>730>740>750>740>760>760>760>730>750>750> etc second to second for a set time period and a max low speed it never goes above, it can still dip lower but never higher during its decreased phase.

Separate to and before I did the iperf3 test I had also already tried downloading from well over at least 50 completely different and independent sites/servers, most offering Linux distribution ISO’s that were mirror sites but not all of them were.

I think it’s highly improbable/impossible that they would all suddenly drop their upload speed to the same precise speed for the exact amount of time as part of an issue to do with them, not to mention my own server which I fully control has the same problem.

Additionally, like I said in my last post, when I can get good gateway/routing my vpn connection has no problem maxing out the speed and sustaining it like it should do. So the servers I’m downloading from have no problem uploading to me at the higher speeds and aren’t the source of the sudden decrease in speed.

The common denominator is the network they are routing into, plusnets. This I feel is further proven by the fact the vpn connection can work at its full speed without the speed reduction occurring because it by passes the plusnet network once it can get a good connection established.