At about 15:00 on 1st November 2022, my FTTP broadband disconnected. Upon looking at the BT Openreach ONT, I saw the following light condition.
| Power | Green (Solid) |
| LOS (Loss of Service) | Red (Solid) |
| PON | Off |
| LAN | Green (Solid with blinking occasionally) |
Unfortunately I don’t have a video or picture of this state, but needless to say, this shows that the ONT is unable to see light to the Exchange via the fibre. This could be a problem at the exchange end, or it could indicate a line break.
Next Step
So first things first, switch it off and on again, so I powered off the ONT (with its power switch) and powered off the Plus.net Two Router, left it for about 30 seconds and then powered it all back on again, I was then left with this light condition on the ONT.
| Power | Green (Solid) |
| LOS (Loss of Service) | Off |
| PON | Green (Flashing) |
| LAN | Green (Solid with blinking occasionally) |
Now, the PON light flashing means it is trying to authenticate the ONT to the exchange, this is normal to see when you’ve first had your line provisioned, while settings are made and changed.
However, it not normal to see this normally after installation, because if your ONT is not able to authenticate to the exchange, neither will your router. At this point the router was disconnected and I could not get it to connect, I was seeing the following error listed within the logs over and over:
PPPoE send PADI
Also notice that one of the flashes of the PON light is longer than the rest of the flashes, somewhere in the middle of the video, according to this post, it indicates that the ONT is unable to authenticate because it is connected to the incorrect SASA at the splitter node.
Of course, this could happen at installation, just a simple mistake, but why would by fibre suddenly swap in normal operation, unless someone had accidentally unplugged my fibre, realised what they had done and then patched it back in wrong? Perhaps?
Weirdness
So I restarted things a few more times, but after leaving the ONT and router alone for about an hour, it was still in this state and the broadband router was not reconnecting.
So called up Plus.net and reported the fault, after a bit of troubleshooting, an engineer was scheduled to attend on Friday 4th November to fix the line that appeared to be faulty.
However, at about 07:00 on Friday 4th November, the ONT then started to show a solid PON light, this indicated that the ONT had successfully authenticated to the exchange, however my broadband router was still unable to connect and was showing the following in the logs:
PPP LCP Receive Termination Request (Failed to authenticate ourselves to peer)
PPP LCP Send Termination Request (Failed to authenticate ourselves to peer)Resolution
I use the standard Plusnet Two router which I got in August when getting FTTP, logging onto the web interface, I could see it was still disconnected and the log entry as above.
I checked the connection details settings which can be found under “Advanced Settings” and “Broadband”, it all on the face of it appeared to be fine.
However, I noticed this post on the Plusnet community forum, it talked about a disconnection of the router causing the password field to be blanked out.
Well, that would explain the log entry about being unable to authenticate, if it was trying to login with a blank password!
So, re-entered the password and hey-presto, back connected again.
The BT Openreach engineer then turned up and I said it had all started to work again, he’d done some tests from the exchange end when picking up the job, but also ran some more tests on my line directly, all within normal tolerances and no loss visible.
So it was a bit of a mystery, but sounds like a simple case of someone re-patching something by mistake.
Normal light situation would be for the ONT:
| Power | Green (Solid) |
| LOS | Off |
| PON | Green (Solid) |
| LAN | Green (Solid with blinking with activity/traffic) |
Anyway here is the video of the ONT working in normal operation:
Additional Links
https://community.plus.net/t5/My-Router/Further-observations-on-the-Plusnet-Hub2/td-p/1874115
https://forums.thinkbroadband.com/bt/4655391-full-fibre-ont-pon-light-flashing-after-connection.html
https://www.ispreview.co.uk/talk/threads/fttp-installation-what-am-i-waiting-for.36578/
Additionally I seem to be up on my speeds, I pay for the 150/30 package, but at most got 100-120/30, after these disconnections I get a solid 150/30, perhaps the IP Profile got updated as well by the disconnect and reconnection?