topic Re: Fibre speed suddenly capped? in Full Fibre

Fibre speed suddenly capped?

ccxphoenix — Thu, 27 Mar 2025 09:13:56 GMT

Hi,

Apologies for creating another thread, I wasn't sure whether to piggy back off another or not.

I have all of a sudden noticed that my 900Mb fibre connection seems to be capped at around 500/600Mb and has been since the 10th March. I've always (for a couple of years now) had nearly the full speed, so I am wondering if my line has been capped due to me moving around some network stuff at home, and I noticed it has happen to a couple of others.

Can anything be done to uncap my speed again?

I've attached a screenshot showing my historic speed, and you can see the drop around the 10th March.

Thanks!

Re: Fibre speed suddenly capped?

MisterW — Thu, 27 Mar 2025 09:16:59 GMT

Are you measuring that from a wired connection ?

Re: Fibre speed suddenly capped?

ccxphoenix — Thu, 27 Mar 2025 09:23:40 GMT

Hi @MisterW ,

Yes, this is all on a gigabit ethernet connection.

Re: Fibre speed suddenly capped?

MisterW — Thu, 27 Mar 2025 09:31:48 GMT

Very strange then! Have you made any software changes to the device used for speed tests e.g AV/Firewall ?

Have you tried different speed test sites ?

Re: Fibre speed suddenly capped?

ccxphoenix — Thu, 27 Mar 2025 09:52:41 GMT

Not that I can think of. I moved my router to a different location in my house (it might not have even been that day), but that's about it, and as I've said my main pc using the tests is wired in, just passing through one switch as it always has.

Yeah I have tried a few, the screenshot was from my Home Assistant measuring a couple of times a day, but I've also tested on Speedtest.net and Fast I think it's called, and both come up with 500-600Mb. I've also tried resetting my router a few times, and leaving it off overnight in case it was an IP issue, but nothing seems to have changed.

Re: Fibre speed suddenly capped?

Baldrick1 — Thu, 27 Mar 2025 09:56:26 GMT

Moderator's note:
Thread moved from Broadband to Full Fibre

Re: Fibre speed suddenly capped?

jab1 — Thu, 27 Mar 2025 10:00:30 GMT

@ccxphoenix I'm no FTTP expert, but that graph looks very unstable to me. I'm only on a 100/20 connection, but my weekly checks(via the TBB speedtester) are always within 1-2Mbps (101-103).

Re: Fibre speed suddenly capped?

ccxphoenix — Thu, 27 Mar 2025 10:06:12 GMT

@jab1 Yeah it might be taking reading more often than I realise, but overall whenever I've done manual checks using normal websites, its usually a rock solid 850/900Mb. And I mean you can still see the drop on average from what I have been getting so something is up somewhere 😁

Re: Fibre speed suddenly capped?

Baldrick1 — Thu, 27 Mar 2025 10:11:41 GMT

@ccxphoenix wrote:

Not that I can think of. I moved my router to a different location in my house (it might not have even been that day), but that's about it, and as I've said my main pc using the tests is wired in, just passing through one switch as it always has.

This suggests that you have used a different Ethernet cable. Is it CAT5e or better? Have you tried a different cable? Alternatively, horror of horrors, you're not using IGhz powerline devices anywhere in the network?

Re: Fibre speed suddenly capped?

jab1 — Thu, 27 Mar 2025 10:12:03 GMT

@ccxphoenix I see what you mean about 'apparent' reduction. What does a manual check show now, and, unless I have missed it, where is this 'historic' data from?

Re: Fibre speed suddenly capped?

ccxphoenix — Thu, 27 Mar 2025 10:33:45 GMT

I haven't replaced any of my Ethernet cables, just sort of re-routed them. I believe they are all CAT5e at a minimum, but I will double check.

I basically have my pc cabled into a switch, which then runs up into my loft where my router is which then has a ethernet to from the WAN port to where the fibre ONT (?) box is. It could be I've messed up and either my cable to the router isn't CAT5e or potentially the one that is WAN to ONT might not be. I will double check those and see, though I am planning to upgrade those to CAT6 or CAT6e as some point in the near future anyway. I have yet to try a different cable due to where they are running and the plan to replace them anyway. Nope not using any powerline at all, all cable are trunked running where they need to go.

Re: Fibre speed suddenly capped?

ccxphoenix — Thu, 27 Mar 2025 10:36:28 GMT

@jab1 Current speed test is 512 down, 109 up - which is also weird as I've not lost any speed on the upload, which might point to a cable issue as mentioned above.

The 'historic' data is from speed test on my home assistant, which now looking at is run once per hours, hence the lines being quite sharp as that's a 30 day view.

Re: Fibre speed suddenly capped?

jab1 — Thu, 27 Mar 2025 10:40:43 GMT

Fair enough, @ccxphoenix . It does look as though something has upset your connection, but as I said, I'm no FTTP expert, so I'll leave further comment to those with more knowledge.

Re: Fibre speed suddenly capped?

RobPN — Thu, 27 Mar 2025 10:52:22 GMT

@ccxphoenix

Have you tried a PPPoE connection from a PC connected directly to the ONT? Doing so would verify what speed you're actually getting, provided the Ethernet cable (and PC) used was adequate.

Re: Fibre speed suddenly capped?

Baldrick1 — Thu, 27 Mar 2025 11:11:29 GMT

@ccxphoenix wrote:

I've also tried resetting my router a few times,

By resetting do you mean factory resetting by pushing a paperclip or similar in the reset hole and holding the switch closed until you get a green light? Also. have you tried the same on the ONT?

Re: Fibre speed suddenly capped?

ccxphoenix — Thu, 27 Mar 2025 13:09:02 GMT

I did manage to do this briefly and the download was 177Mb which is weird, because I've since put it back to how it was and its now at 550Mb again. So not sure what that is about.

Can confirm that all my ethernet cables are in fact CAT5e also.

Re: Fibre speed suddenly capped?

ccxphoenix — Thu, 27 Mar 2025 13:10:13 GMT

I had done a factory reset recently yeah, but also just turning it off and on again when trying to get the IP to change. I haven't factory reset the ONT, is that worth trying?

Re: Fibre speed suddenly capped?

Marsh — Thu, 27 Mar 2025 16:48:29 GMT

Hey @ccxphoenix,

I haven't factory reset the ONT, is that worth trying?

If you can please do it is worth trying I have conducted a line test and I have found not faults affecting your service please let us know if this manages to resolve the issue.

Re: Fibre speed suddenly capped?

outcast — Thu, 27 Mar 2025 16:53:31 GMT

@Marsh wrote:

... I have conducted a line test and I have found not faults affecting your service

@Marsh did your tests confirm that the sync rate at @ccxphoenix's ONT was 900Mbps ?, if not what was it ?

Re: Fibre speed suddenly capped?

Marsh — Thu, 27 Mar 2025 17:02:25 GMT

@outcast,

For FTTP lines we do not get the line sync speed however the line is profiled at 1000Mbs with no caps