Desperately need help: Massively fluctuating FTTP speed to router (not devices)

[Lowrys]

Hi BT community, 

I desperately need some help and this is my last resort. I'm a disabled and autistic customer and seem to have such an unusual problem that BT seem completely unable to diagnose let alone fix it. I rely heavily on my broadband for my wellbeing so this really matters to me.

I have FTTP on the Halo 3 package and for 18 months was getting a stable d/l speed of around 950mb. The minimum speed guarantee was 450mb, which I queried at the time as being too low. Like all connections, it dropped a couple of times in those 18 months, but otherwise was basically flawless.

Two months ago, the speed to the router (as measured on the BT app and by BT tech support) started varying from as low as 60mb to the usual 950+mb. It varies seemingly randomly and minute by minute. I can measure it five times in ten minutes and get five different speeds.

I have spent countless hours and countless calls with BT tech support, and have explained the problem countless times. I feel like I'm trapped in a nightmare. 

I live alone and the problem isn't my devices. Most are LAN connected, aside from my ipad and phone, of course. I have a simple network switch for my hardwired devices. That's not the problem either.

The issue is the speed the router is getting from the connection coming into my house. I've had three Openreach engineers out. They've measured the light level and said it was 18db, and said that was good and indicated no problems with the infrastructure. They also changed the ONT (?) white box in my property twice, with no improvement. 

BT have refreshed my profile (whatever that means) with no improvement. They also raised my stay-fast guarantee to 700mb (which is what it should have been originally), but again with no improvement.

I have spent countless hours pleading with BT to get their heads together with Openreach and troubleshoot to identify the cause of the fluctuating speed, but they are no closer to solving it. There must surely be A reason why this is happening, and presumably it must be possible to go methodically through every part of the connection/chain to find it, but they haven't been able to.

One thing they've suggested but haven't done yet is a cease/reprovide on the service to see if that fixes it.

So I'm posting here as a last resort. If anyone has any ideas or can help me, please, please let me know. Because I honestly don't know what else I can do at this point. I'm desperate for help.

Thank you in advance for reading this. I really appreciate it.

[36ULW]

A Cease and Reprovide won’t help if it’s a Network Fault because you’ll still have exactly the same Fibre and ONT.

Have any Openreach Engineers run an OTDR Trace to see if they can see any fluctuating splices in the Network?

[Lowrys]

Thanks @36ULW for helping me. 

I'm not sure if they've done an OTDR trace; I'm OK with home networking but my knowledge ends where my property begins! 

All they've told me when they came out was that the light levels looked fine. I assume the splices are the "joints" in the network where the signal splits? Maybe I'm wrong there.

Another Openreach person is coming tomorrow morning, so I can ask them then. BT told me to ask them to check the exchange, whatever that means, to see if there's any issues there.

In my rudimentary understanding, surely they should be able to check at various points along the network to see if the speed is fluctuating at those points? And that should help them pinpoint it. But again I don't understand the outside stuff so I could be wrong.

Because the problem is fluctuating, I'm assuming if they do a light reading at one point it might be fine, but might not be fine if they do a few over a period of time.

Everyone I've dealt with (3x Openreach, endless people at BT tech support) doesn't even have any conception of what could be causing the issue, even theoretically. Which I find hard to believe; surely there must be something, because we know for sure the speed is massively fluctuating.

Is there anything else I should ask the Openreach person tomorrow?

Thank you again for helping me.

[36ULW]

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A Light Loss Test just sees the Light Level as it is in that moment.

If there’s a Bad Splice causing the Light Loss to fluctuate then a prolonged OTDR Test needs to be performed.

The ONT actually sends Light back to the Head End and any drops in connection would be recorded. An Engineer call to his/her DCoE Helpdesk should be able to confirm and drops in connection to the ONT.

In regards to the OTDR Test, not all Engineers get an OTDR, especially a Tri-Band one, which the Engineer will need.

[Lowrys]

@36ULW thank you again. I'll ask them to do that. And I presume that this test should help them diagnose the problem? 

The connection doesn't seem to be dropping completely (as in disconnecting); it just massively varies in speed from one minute to the next.

From what Openreach and BT have said to me so far, no one seems to have ever come across this issue before. But surely I can't be the only person. They seem to have no frame of reference for what could even theoretically be the problem (and solution). Which is frustrating, to put it mildly.