The factory reset of the ONT made no difference, dropped after a few hours. So I followed the advice given here, I pulled a new Ethernet cable in parallel with the original. (Probably should have pulled 2 in when I did it). I added a new punchdown outlet at each end and used 2 new patch leads, one at each end. I also replaced the ONT PSU so everything is new. Been up for 3 days so far so time will tell. If it stays up for 10 days I'll tempted ro start swapping bits back in as I'd like to know which part is faulty.

I wasn’t very hopeful on the ONT reset. If there is a fault with these it’s generally hardware and not firmware/software.

See how it goes with the new cabling. If it drops again you’re back to the ONT and router ports. Either one will likely be the culprit.

Assuming your camera didn’t work / spot any drops on the fibre side of the ONT / LOS light…

Thanks for reminding me, yes the camera caught the LAN LED pulsing hence the cable replacement. If anyone wants to lose a minute of their life you can watch it here.

Video

In reply to a post by RichG63:

Thanks for reminding me, yes the camera caught the LAN LED pulsing hence the cable replacement. If anyone wants to lose a minute of their life you can watch it here.

Video

The LAN light WILL flash intermittently with data transfer, even if nothing appears to be going on.

Flashing/blinking is fine as you say, but completely off is not good. Should default back to solid green when link is up (no data passing).

No red visible on 2nd LED (LOS) so that is good but I don’t think Ethernet is completely in the clear…

The ethernet led will go off if the router is rebooting which may have absolutely nothing to do with the ONT and fibre line.

Will wait for the OP to elaborate, but there was no suggestion of a router reboot. What was clear from the log snippet was that the PPP session was dropping, but it did not look like there was any sort of reboot going on.

On the other hand a port flapping on either the router or ONT could cause a loss of link. Lower layer events like this are typically not logged in consumer routers like this. It’s just not clear from the grainy video necessarily either.

Edited by Pheasant (Tue 06-Oct-26 07:47:40)

In reply to a post by Pheasant:

Flashing/blinking is fine as you say, but completely off is not good. Should default back to solid green when link is up (no data passing).

No red visible on 2nd LED (LOS) so that is good but I don’t think Ethernet is completely in the clear…

Not sure how a Ethernet cable can go bad unless it is treated badly. I have cables here that are years old and still working, one of them was rolled up in a way it should not be and stored for a couple of years and yet when i got it out, it still worked.

A mate have one that goes outside the house and is not protected and been out there for over 10 years and still works.

Edited by zyborg47 (Tue 06-Oct-26 08:30:59)

Any cable can be borderline on performance and still appear OK. Hardware faults do happen. It’s all within the realms of possibility.

In reply to a post by Pheasant:

Any cable can be borderline on performance and still appear OK. Hardware faults do happen. It’s all within the realms of possibility.

also borderline cables, may work fine on one device and not on another ......