FTTP ONT Speed Problems - reboot appears to resolve ?

Hi,

I've been on Sky FTTP 150Mb service for a few months and recently noticed with various speed tests and more accurately newshosting multi threaded downloads I was never getting more than 80Mb/s - note I am fully wired ethernet, not WiFi.

I rebooted my 3rd party router (Netgear running Openwrt) and didn't see any improvement, so powered ONT and router off and reconnected Sky router - I then saw 150Mb/s speed within 30 mins.

Bit weird I thought, so reconnected my 3rd party router and still speeds are good.

Now a few weeks later notice I have the same problem again with never going above 80Mb/s, just power cycled my router but still issue remained.

So, rebooted my ONT and within 30 mins speeds back up to 150Mb/s.


This implies rebooting the ONT is resolving the issue (for a period of time) - anyone had this issue or know what could cause it?

Thanks!

Before you call up Sky to get Openreach to replace the ONT (fairly sure this is it), try replacing the Cat5e/6 fly lead between the ONT and the router with a fresh new lead.

Sorry forgot to mention I swapped the CAT5 lead between ONT and router when I tried the Sky one.

Thanks for your insight, I will wait to see how long it runs at 150Mb/s before dropping again and definitely prove again an ONT reboot resolves it - don't relish having to explain to Sky technical support ....

Just seems weird, I would have thought the ONT woudl either work or not - didn't know if there were FTTP "speed profiles" like VDSL2 and maybe I was for some reason getting moved to a slower one.

It’s worth trying the basics first 👍

There are definitely speed tiers / profiles on Openreach FTTP. Seventeen to be precise. However they are provisioned by the system when the ONT first powers up/is rebooted. They don’t dynamically alter on the fly or “retrain” based on line conditions or any copper-based broadband concepts like that.

This is unusual for FTTP. Worth getting Sky to check you FTTP provisioning speed/profile matches what you ought to be getting and explaining what is occurring with the fault.

Sounds to me this could this just be randomness of connecting to different gateways? So just a coincidence you happened to land on a less congested gateway after rebooting the ONT, this led you to believe the ONT has a problem when it might not.

If it happens again, rather than reboot the ONT, get your router to drop and reconnect a few times testing the speeds. You should be able to see the gateway IP address in your router settings somewhere, and can see if when that changes it correlates to changes to your speed test results.

Edited by E300 (Thu 10-Feb-22 08:53:10)

I don't know how it works at that level.

If it is a "gateway" issue then this implies I am getting switched to different gateways without me actively doing anything OR the one I am on degrades in speed badly and stays like that - wouldn't multiple people be affected by a congested gateway?

And by chance when I reboot the ONT I always get on an uncongested one...



For now I think I will keep monitoring and see how long it stays on 150Mb/s.

I do think "never going above 80Mb/s" and a reboot of the ONT fixing it is significant.

I am talking purely from a layman's point of view so I would give Sky a call and make it their problem to fix it if it reoccurs.

In reply to a post by starfire:

I don't know how it works at that level.

If it is a "gateway" issue then this implies I am getting switched to different gateways without me actively doing anything

Yes. If it's PPPoE, there's a "discover" phase and multiple BRASes may offer service.

In reply to a post by starfire:

OR the one I am on degrades in speed badly and stays like that - wouldn't multiple people be affected by a congested gateway?

Yes to that too.

In reply to a post by starfire:

And by chance when I reboot the ONT I always get on an uncongested one...

That's what seems to suggest it's not the problem. Equally, restarting the router without touching the ONT should be able to switch you between BRASes.

Does your router have any sort of interface monitoring? Can it tell you whether its WAN port is running at 1000/1000 or 100/100? A bad cable or a bad port on the ONT or router *could* cause the ethernet connection to drop down to 100/100. It has been known to happen, so it's good if you can rule it out (i.e. if you can see that the WAN port is definitely 1000/1000 when the speed is slow).

In reply to a post by dect:

I do think "never going above 80Mb/s" and a reboot of the ONT fixing it is significant.

I am talking purely from a layman's point of view so I would give Sky a call and make it their problem to fix it if it reoccurs.

Except the problem so far is only reported with the third-party router, and putting the Sky router in place has fixed it. (Aside: OP should make sure they don't touch the ONT in future when doing that).

And of course, Sky will say it's the third-party router which is at fault. Which it certainly could be.

In reply to a post by candlerb:

Does your router have any sort of interface monitoring? Can it tell you whether its WAN port is running at 1000/1000 or 100/100? A bad cable or a bad port on the ONT or router *could* cause the ethernet connection to drop down to 100/100. It has been known to happen, so it's good if you can rule it out (i.e. if you can see that the WAN port is definitely 1000/1000 when the speed is slow).

Yes, I can see the WAN link up at 1000Mbps full duplex. I have already tried a different cable.

But will monitor it.

I was thinking similarly with a possibly faulty cable pegging the speeds to Fast Ethernet, much as as faulty GigE port on either the ONT or the Netgear router - but then I thought 80 Mbps is a very coincidental speed to be pegged to for a hardware fault…usually if the port is flapping or faulty the speed will be close to the limit of Fast Ethernet ie 94-ish Mbps

In reply to a post by candlerb:

Except the problem so far is only reported with the third-party router, and putting the Sky router in place has fixed it. (Aside: OP should make sure they don't touch the ONT in future when doing that).

And of course, Sky will say it's the third-party router which is at fault. Which it certainly could be.

The issue has occurred with my 3rd party router, rebooting it didn't help, rebooting the ONT did.

Yes I strongly suspect Sky will tell me to go away without their router attached.

I would use it, but you can't even port forward to a different internal port...


edit: forgot to mention Sky don't use PPPoE, its IPoE

Edited by starfire (Thu 10-Feb-22 10:59:20)

I have to reboot our TTB router about once a month, one time after several reboots and not getting any better speeds I rebooted the ONT, although at time this restored the speed since then a router reboot has solved the problem, so might have been just chance.

I don't disagree that Sky will blame the third party router as you would expect them to do, as so many things have been rebooted its hard to tell exactly but I agree maybe next time first reboot third party router to see if that resolves it then switch with sky router and see if that fixes it.

Sky and no PPPoE.

Doesn't work that way with PPPoE - sessions are steered to a BRAS usually via RADIUS, not a race. The link is point to point, not broadcast.

Thanks for the correction.

I'd guess: the session is being delivered as a VLAN to some sort of routing device, which might be applying an IP profile dynamically as part of session setup, e.g. DHCP -> RADIUS, and they may have a screw-up here where it's wrongly applying an 80M profile sometimes.

These problems are annoying when they are not consistently repeatable

In reply to a post by dect:

I do think "never going above 80Mb/s" and a reboot of the ONT fixing it is significant.

I am talking purely from a layman's point of view so I would give Sky a call and make it their problem to fix it if it reoccurs.

Yes sir.

Folks are working to the assumption that the Sky router is golden here - but the OP hasn’t clarified if the Sky router has previously been in situ for a long-ish enough period (several weeks) as the Netgear router has when it experienced the issue.

So the problem may well be inherent even with the Sky router in place…

It might be helpful to set up a BQM via Thinkbroad if you can. This may give some extra information when speeds drop to what is happening, i.e. does it look like congestion?

Doesn't do any harm, but I would think it's unlikely if it's flatlining at 80M.

In reply to a post by Pheasant:

Yes sir.

Folks are working to the assumption that the Sky router is golden here - but the OP hasn’t clarified if the Sky router has previously been in situ for a long-ish enough period (several weeks) as the Netgear router has when it experienced the issue.

So the problem may well be inherent even with the Sky router in place…

Sky router has never been in place for more than 2 days at the start of service.

In reply to a post by E300:

It might be helpful to set up a BQM via Thinkbroad if you can. This may give some extra information when speeds drop to what is happening, i.e. does it look like congestion?

I've set this up now, additional data is always good.

In reply to a post by starfire:

In reply to a post by Pheasant:

Yes sir.

Folks are working to the assumption that the Sky router is golden here - but the OP hasn’t clarified if the Sky router has previously been in situ for a long-ish enough period (several weeks) as the Netgear router has when it experienced the issue.

So the problem may well be inherent even with the Sky router in place…

Sky router has never been in place for more than 2 days at the start of service.

OK not really long enough to replicate the issues you’re seeing using the Netgear then.

I don’t suppose you have the detail/MI to see if there is a pattern when the speed drops / becomes capped at c. 80 Mbps? Such as duration since the router was rebooted? Time of day?

There is a a command line version of the speedtest.net app, which could be scripted to run at intervals on a spare machine to see if you could gather this info….

My Broadband Ping

Not sure why I am getting breaks in the green minimum latency, the help pages don't seem to cover that ?

Edited by starfire (Fri 11-Feb-22 12:54:56)

In reply to a post by starfire:

My Broadband Ping

Not sure why I am getting breaks in the green minimum latency, the help pages don't seem to cover that ?

are you using your IP or a dynamic DNS

DDNS via Duck DNS, but it's not renewed/changed in last 15hrs.

maybe make a second one with your IP directly and keep them both going at the same time.
I think others have previously said that sometimes DDNS causes issues with thinkbroad BMQ
if you do that and share it then we can see if that is the case.

Let us know how that goes

Well, this issue is still ongoing.

Now I'm down to around 60Mbps and router/ONT reboots aren't helping.

Sky technical support say they can't find an issue, they contacted Openreach who apparently ran a test to my ONT and said it was reporting 150Mbps.

Can anyone confirm, this test that OR did presumably runs only from the OLT in the exchange to my ONT, correct ?

Personally I think the issue is elsewhere on Sky's network.

In reply to a post by starfire:

Well, this issue is still ongoing.

Now I'm down to around 60Mbps and router/ONT reboots aren't helping.

Sky technical support say they can't find an issue, they contacted Openreach who apparently ran a test to my ONT and said it was reporting 150Mbps.

Can anyone confirm, this test that OR did presumably runs only from the OLT in the exchange to my ONT, correct ?

Personally I think the issue is elsewhere on Sky's network.

I know its been some time since you started this thread but what happens if you use the Sky router as Sky will expect that as a minimum before they start looking at their backhaul.

In reply to a post by dect:

In reply to a post by starfire:

Well, this issue is still ongoing.

Now I'm down to around 60Mbps and router/ONT reboots aren't helping.

Sky technical support say they can't find an issue, they contacted Openreach who apparently ran a test to my ONT and said it was reporting 150Mbps.

Can anyone confirm, this test that OR did presumably runs only from the OLT in the exchange to my ONT, correct ?

Personally I think the issue is elsewhere on Sky's network.

I know its been some time since you started this thread but what happens if you use the Sky router as Sky will expect that as a minimum before they start looking at their backhaul.

All my tests with Sky were with their router only, they logged in remotely to it via TR069.

In reply to a post by starfire:

All my tests with Sky were with their router only, they logged in remotely to it via TR069.

Sky will probably want to go through the pointless motion of getting Openreach to replace the ONT before they look at investigating their own backhaul. Can't believe its Openreach's PON to be honest but trying to convince Sky is another matter.

In reply to a post by dect:

Sky will probably want to go through the pointless motion of getting Openreach to replace the ONT before they look at investigating their own backhaul. Can't believe its Openreach's PON to be honest but trying to convince Sky is another matter.

Unfortunately Sky say there is nothing they can do and cannot send out an OR engineer as their system will not allow it as no fault is shown.

Specifically though, do you know if the OR speed test is between OLT and ONT omitting Sky's network ?

Yes

In reply to a post by Pheasant:

Yes

Thanks, what I thought.

In reply to a post by starfire:

Unfortunately Sky say there is nothing they can do

I've heard them say this before and I found that if you raise a high level complaint with Openreach they should then pass it to Sky high level complaints to deal with and so far this has ended up with a resolution from Sky. I cannot make a guarantee yours will go the same way.

You need to check the link status between the router and the ONT. A faulty port at either end could cause it to drop to 100Mbps, or become intermittent. The Openreach test won't have picked that up.

Ideally, when the router is connected to the ONT, you'd go to the router's web interface and ask *it* whether the WAN port is running at 1G or 100M. But most routers are too dumb for that.

If you're lucky, the following might work:

1. Plug in a PC with ethernet port, directly into the ONT, with a CAT5 cable. Check the NIC status on the PC to see whether it says 1G or 100M.

2. Then plug the PC's NIC directly into the router WAN port, also with a CAT5 cable. Do the same NIC status check.

If either of those shows 100M, it shows where the problem is. But if they both say 1G, you're none the wiser.

In neither case will you get Internet access. However you can in case (1), PC to ONT, if you configure a PPPoE client on your PC. If you do that and run a speedtest, it gives you another way to try to narrow down the problem, by ruling out a problem with Sky's router.

In reply to a post by dect:

I've heard them say this before and I found that if you raise a high level complaint with Openreach they should then pass it to Sky high level complaints to deal with and so far this has ended up with a resolution from Sky. I cannot make a guarantee yours will go the same way.

How do you raise a high level complaint with OR though? I thought consumers always had to go via their ISP ?

In reply to a post by candlerb:

You need to check the link status between the router and the ONT. A faulty port at either end could cause it to drop to 100Mbps, or become intermittent. The Openreach test won't have picked that up.

Ideally, when the router is connected to the ONT, you'd go to the router's web interface and ask *it* whether the WAN port is running at 1G or 100M. But most routers are too dumb for that.

If you're lucky, the following might work:

1. Plug in a PC with ethernet port, directly into the ONT, with a CAT5 cable. Check the NIC status on the PC to see whether it says 1G or 100M.

2. Then plug the PC's NIC directly into the router WAN port, also with a CAT5 cable. Do the same NIC status check.

If either of those shows 100M, it shows where the problem is. But if they both say 1G, you're none the wiser.

In neither case will you get Internet access. However you can in case (1), PC to ONT, if you configure a PPPoE client on your PC. If you do that and run a speedtest, it gives you another way to try to narrow down the problem, by ruling out a problem with Sky's router.

Yes, I run OpenWRT firmware on a 3rd party router and it confirms 1Gbps connection from router to ONT.

Haven't thought about my laptop directly into the ONT but I can try that.

I have tested from the router to my laptop using iperf and it consistently reports just under 1Gbps transfer rate.

In reply to a post by starfire:

How do you raise a high level complaint with OR though? I thought consumers always had to go via their ISP ?

Use the email address [removed by tbb] which high level complaints monitors, explain you have an issue and what speed your paying for and what you're currently getting and say the ISP is unwilling to sort the issue out for you.

Edited by seb (Mon 02-Feb-26 21:39:46)

In reply to a post by starfire:

Well, this issue is still ongoing.

Now I'm down to around 60Mbps and router/ONT reboots aren't helping.

Sky technical support say they can't find an issue, they contacted Openreach who apparently ran a test to my ONT and said it was reporting 150Mbps.

Personally I think the issue is elsewhere on Sky's network.

Do you have a Sky Q TV box with mini boxes maybe?

If you do then power off all the Sky TV boxes and reboot the router only and do another test. DO NOT reboot the ONT.

Had a few faults with random slow speeds or even connection drops and turning off the Sky Q set top boxes clears it.

No idea what causes it, but something to do with the Q boxes for sure, and even being hard wired makes no difference.

In reply to a post by TheInstaller:

Do you have a Sky Q TV box with mini boxes maybe?

If you do then power off all the Sky TV boxes and reboot the router only and do another test. DO NOT reboot the ONT.

Had a few faults with random slow speeds or even connection drops and turning off the Sky Q set top boxes clears it.

No idea what causes it, but something to do with the Q boxes for sure, and even being hard wired makes no difference.

Don't have mini boxes.

We tested by changing the WiFi SSD so only one device was then configured and connected, and wired we had everything disconnected apart from my laptop direct into a router port.

In reply to a post by deleted:

Use the email address [removed by tbb] which high level complaints monitors, explain you have an issue and what speed your paying for and what you're currently getting and say the ISP is unwilling to sort the issue out for you.

OK ta, will keep that one in the back pocket

Edited by seb (Mon 02-Feb-26 21:39:53)

Just to update, after escalation and complaints one of their support staff saw a network issue and sent around an OR engineer - they couldn't find any issue with my connection.

After begging them to check with their network team turns out there is a known issue with the Sky network affecting 60K customers and causing slow speeds....

Why that couldn't have been highlighted much earlier on in the troubleshooting process who knows..

Anyway, got to wait for that to be resolved or I can leave contract without penalty as I get as low as 50Mbps on my 150Mbps service some days.

The solution in these instances is to arrange for the device to break, say one of these with the RJ45 adaptor

https://usbkill.com/

It will be properly dead with no visible traces. You can DIY this stuff pretty easy if you have a bit of experience in electronics.