topic Re: New full fibre connection issues in Full Fibre

New full fibre connection issues

gj972639 — Fri, 27 Feb 2026 11:10:14 GMT

New FTTP install showing persistent packet loss (4–16%) to multiple public IPs.

Reproducible on Windows and Linux
Reproducible across two routers
Reproducible with multiple Ethernet cables
0% packet loss on LAN
WAN link stable at 1000 Mbps
ONT synced (Power + PON solid, LOS off)
Latency stable at ~7–9 ms

Issue appears upstream of customer equipment.

Engineers don't know what packet loss is, and plusnet supports only solution is to make me wait for more engineers to come out. Is there anything at all I can do on my end or am I just stuck wasting my time with broken internet?

Re: New full fibre connection issues

jab1 — Fri, 27 Feb 2026 14:33:49 GMT

Purely out of interest, @gj972639 , is this issue actually causing you any real issues? My ThinkBroadband monitor shows packet loss for most of the day, but it does not appear to be slowing anything down.

Re: New full fibre connection issues

gj972639 — Fri, 27 Feb 2026 14:37:26 GMT

I use my internet mostly for gaming and streaming, both are severely affected.

Re: New full fibre connection issues

jab1 — Fri, 27 Feb 2026 14:47:30 GMT

Understood. As I do very little of that, it isn't something that worries me, but I understand it can be disruptive in your case. Unfortunately, unless you can pinpoint where the loss is, it is nigh on impossible to suggest a possible remedy, but more engineer visits will be pointless.

Re: New full fibre connection issues

gj972639 — Fri, 27 Feb 2026 15:04:42 GMT

Best I can tell after testing, speaking to a friend and double checking with chatgpt the issue is at a plusnet ip.Support just says "maybe openreach will send a better engineer next time as it's a second visit"

Re: New full fibre connection issues

jab1 — Fri, 27 Feb 2026 15:13:29 GMT

I would suggest that 'speaking to a friend' - unless they have in-depth knowledge, with all due respect - and asking chatgp, is not likely to give you conclusive answers.

It is pointless sending out Openreach engineers for this type of issue, as it is not a network issue.

The only suggestion I can make, as this is not my area of expertise, is to run traceroutes to a number of the affected destinations, and post the results on here for investigation/analysis.

Re: New full fibre connection issues

PhilipHeyes — Sat, 28 Feb 2026 10:14:18 GMT

Share a screenshot of the results from :

https://speed.cloudflare.com/

Re: New full fibre connection issues

gj972639 — Sat, 28 Feb 2026 10:53:24 GMT

First

Re: New full fibre connection issues

gj972639 — Sat, 28 Feb 2026 10:54:36 GMT

Second. Not sure why it only lets me upload one at a time, that's a bit annoying. But anyway, 4% packet loss is on the lower end of how it gets, but still quite tragic for my particular usages

Re: New full fibre connection issues

gj972639 — Sat, 28 Feb 2026 10:59:00 GMT

The friend is a network engineer, just in another country, and chatgpt I'm mostly using for specific info on how to test the problems and get all the information I can, not for specific answers.

I've run a traceroute and tried to explain what I saw there to plusnet customer support as the screenshot I posted yesterday shows. But they just insist on sending more engineers around.

Re: New full fibre connection issues

PhilipHeyes — Sat, 28 Feb 2026 11:33:17 GMT

I am unable to Ping or to Trace Route to your Public IP.

Re: New full fibre connection issues

Dan_the_Van — Sat, 28 Feb 2026 13:10:52 GMT

@gj972639

I would suggest setting up a BQM (broadband quality monitor) details found here

https://www.thinkbroadband.com/broadband/monitoring/quality You will need to enable ICMP on the router.

This will give a view from the outside of you connection state, just be warned as you have a dynamic IP Address, you would need to make allowances for that.

Have you checked the Fibre cable is fully connected to the ONT, hopefully something Openreach would have done.

As a last resort if you think you are getting the run around from support I would suggest raising a complaint.

https://www.plus.net/help/legal/complaints-code-of-practice/

Re: New full fibre connection issues

Ian06 — Sat, 28 Feb 2026 15:27:10 GMT

In my limited experience the router has a significant impact on connection performance... I use my own router on my full fibre connection and setting for Traffic Control (or QOS) affects the bandwidth applied to the internet connection. Overloading the network connection will cause packets to be dropped, so setting the QoS (or Traffic Control) can have a significant impact on connection quality.... this will depend on the router you are using and what settings it allows you to control.

Re: New full fibre connection issues

LatencySlayer — Sat, 28 Feb 2026 21:33:11 GMT

@gj972639

Your MTR test in Message #5 shows the worst case ping between your PC and router as 5ms !.

Either you have a LAN problem, or the router is doing something CPU intensive and delaying replying.

Have you checked to see whether your router has the latest firmware installed ?

ASUS TUF-AX3000 V2 Firmware version 3.0.0.4.388_23947

If the latest router firmware doesn't fix it, try connecting your Linux PC directly to the ONT, configure the network port for PPPoE, and repeat your tests (having bypassed the router). If the packet loss disappears then the problem is with the router.

Re: New full fibre connection issues

LatencySlayer — Sat, 28 Feb 2026 22:59:20 GMT

@gj972639

It would be worth considering using the alternative "ASUSWRT-Merlin" firmware on your "TUF-AX3000_V2" router, as users claim that latency issues are much improved, along with better performance and enhanced features, compared to the stock Asus code.

See - https://github.com/gnuton/asuswrt-merlin.ng?tab=readme-ov-file

Re: New full fibre connection issues

LatencySlayer — Sat, 28 Feb 2026 23:23:23 GMT

@Dan_the_Van wrote:

@gj972639

I would suggest setting up a BQM (broadband quality monitor) details found here

https://www.thinkbroadband.com/broadband/monitoring/quality You will need to enable ICMP on the router.

This will give a view from the outside of you connection state, just be warned as you have a dynamic IP Address, you would need to make allowances for that.

Fortunately @gj972639's "TUF-AX3000_V2" router supports a DDNS client, therefore a 'hostname' can be configured so that the ThinkBroadband BQM follows any WAN IP address changes.

Re: New full fibre connection issues

LatencySlayer — Sun, 01 Mar 2026 00:17:17 GMT

@gj972639

For what it's worth here is my MTR test to Cloudflare DNS, to compare your result with my 80/20 SoGEA connection. As you can see there is no packet loss on any hop, so your dropped packets are likely to be your router or somewhere between you and Plusnet's gateways.

My MTR test -

$ mtr -w -c 1000 -r 1.1.1.1 HOST: Loss% Snt Last Avg Best Wrst 1.|-- GA-J3455N-D3H 0.0% 1000 0.2 0.2 0.1 0.2 2.|-- ??? 0.0% 1000 5.7 5.7 5.6 5.9 3.|-- ??? 0.0% 1000 5.8 5.7 5.5 5.8 4.|-- 141.101.71.244 0.0% 1000 6.7 6.7 6.5 6.8 5.|-- 141.101.71.107 0.0% 1000 6.6 7.0 6.4 7.9 6.|-- one.one.one.one 0.0% 1000 6.4 6.4 6.2 6.5

@gj972639 's MTR test -

Re: New full fibre connection issues

Dan_the_Van — Sun, 01 Mar 2026 07:56:37 GMT

@gj972639

Take a look at this thread https://community.plus.net/t5/Full-Fibre/Just-had-it-installed-as-of-27th/m-p/2039034#M29962

A TUF-AX3000 V2 router is also being used.

Re: New full fibre connection issues

LatencySlayer — Sun, 01 Mar 2026 11:11:32 GMT

@gj972639 wrote:

New FTTP install showing persistent packet loss (4–16%) to multiple public IPs.

Reproducible on Windows and Linux

Reproducible across two routers

@gj972639

From your MTR test result, one of your routers appears to be a "TUF-AX3000_V2"

What other models of router have you tried ?

Re: New full fibre connection issues

gj972639 — Sun, 01 Mar 2026 12:42:05 GMT

I set up the BQM and it just shows the same thing, consistent up to 20% packet loss but in every other way it's fine.
https://www.thinkbroadband.com/broadband/monitoring/quality/share/5d17b01f29c226124c599e61a4667cce30499cb1

And yes, the fibre cable is solidly in the ONT, and the ONT lights are showing everything is fine.

@LatencySlayer The ASUS router is fully up to date, I made sure of that before I started using it. But the same issues happen the exact same way on the Plusnet router I was sent when I joined. Also over a selection of ethernet cables ranging from cat 6 to cat 8.

I've also tried plugging directly into the ONT (which is why the BQM shows a brief period of 100% packet loss) But the same problem persisted in the traceroute at the same point in the connection. Roughly 10% loss starting at the ip 172.16.17.205

The router/cables aren't the issue as the problem is still apparent even when entirely bypassing them. The problem begins at the ONT or further along the connection somewhere.