Sudden drop in Fibre Broadband Speed

[Ian]

When we first switched to FTTC Fibre Broadband we got speeds of around 22Mbps, which dropped slowly year on year down to 18Mbps. We're at the end of a long cable run and a lot of other people have switched to Fibre, so it's not entirely surprising.

However, a couple of weeks ago our sync speed dropped down to 15Mbps, which is below the "minimum" download speed from our ISP/BT Openreach - i.e. it's a lot lower than they would expect. I'm currently chatting to Zen's tech support team to see what looks to be the problem.

We've not changed any wiring or added anything new recently.

Has anyone experienced Fibre broadband speeds lower than the "minimum" as suggested by the line provisioning stats? Below these speeds, ISPs will cancel/refund the contract - but it won't fix my problem. I wonder how likely they would be to send an engineer out?

 

[V_R]

The 22-18 drop is likely to be crosstalk unfortunately, sod all you can do about that I'm afraid.

BT Broadband

What is the Downstream Handback Threshold showing on that site? That is the fault threshold, if you're lower than that then they should send and engineer out to investigate.

 

[Ian]

Yeah, the 22-18Mbps drop I can handle - it's the sudden drop to 15Mbps that puzzles me.

VDSL Range A (Clean) Downstream Handback Threshold(Mbps): 16.5
VDSL Range B (Impacted) Downstream Handback Threshold(Mbps): 11.8

Do you know if they go off "clean" or "impacted"? If it's clean, then I'm below the minimum.

 

[V_R]

Who knows! Hopefully Zen will push OR to visit.

Any noise on the phone line?

 

[Abarbarian]

Has anyone experienced Fibre broadband speeds lower than the "minimum" as suggested by the line provisioning stats?

Nope still getting 37 Mbps from my crappy Talk Talk 38 Mbps service,

Sorry I could not resist.

 

[Ian]

Who knows! Hopefully Zen will push OR to visit.

Any noise on the phone line?

No noise on the line and I've done the usual checks, however my sync speed is now (as of last night) spot on the minimum. I think I'm just going to have to suck it up and wait it out for a while and hope it improves . If it drops again, I'll push for a further check.

 

[V_R]

Well, that sucks. What have ZEN said?

 

[Ian]

Just the usual stuff about using master socket, swap cables, swap modem etc... all stuff I've tried already. Until it drops back below that threshold, I don't think there's much they'll do about it in reality. I'm going to monitor sync over the next month or so.

 

[P.B.]

There are two sets of figures to compare; there are the line data speeds that the router/modem reports which should be the maximum possible, so look at your router status to see what these are. Then there are the figures that a broadband speed test will give you, which will normally be slightly less than the line data rates due to overheads. If the router figures are not good, then it definitely appears to be the providers domain where the problem lies, if it is not a faulty router, otherwise if your speed test is so much slower than the line data reported rate, the problem could be in your system. When I suffered from a 75% drop in download speed on my fibre broadband, it turned out to be a faulty Ethernet switch in my system which was only connecting to my PC at 10 Mbps instead of 1000 Mbps.