I'm having some weird issues with my fibre service with the pattern below:

Sunday both internet and phone service stopped working sometime during the afternoon. Note that phone is connected directly to the ONT. In addition I tried a different working phone and a different router and Ethernet cable. This initially showed up as a red error LED on the optical indicator but seemed to change (see below). Both Sunday and Monday were fairly wet and miserable days here.
Tuesday working sometime 1300-1430. Stopped sometime between 2300 – 2350. Tuesday was sunny with little rain.
Wednesday working about 1215. Wednesday had a bit of rain but was also fairly sunny.
Thursday stopped about 0147. Thursday was another very wet day.
Friday working about 1349. Stopped at 2144. Friday was another fairly sunny day.

I've finally gotten through to MyRepublic who have notified Chorus. Presuming it continues a similar pattern and Chorus pay attention, they just have to make sure they come in the morning. I'm assuming they also have access to more stats like attenuation and optical error rates that I don't have access to. (Maybe MyRepublic do but they haven't said anything.) Just in case and also since I don't know that much about fibre I'm wondering out of personal interest if my guess could be right. (I'm not sure if the details will be revealed even after it's fixed.)

I'm thinking a temperature and/or moisture related issue. Maybe water has somehow gotten somewhere it shouldn't (I guess one of the connections/splice points) and is condensing during cold weather and attenuating the signal enough to make problems? Alternatively a classic expansion/contraction problem.

The MyRepublic rep doesn't seem to think it's weather related (I appreciate it's Chorus reps that should know) but the pattern looks a lot like it to me. I know fibre optics are fairly different from metal cables, e.g. their expansion under temperature is a lot less. But I've found suggestion these sort of problems can still arise if there's an improper installation or defective cable.

Could be electronic equipment. I don't think it's the ONT since I've tried heating the area around the ONT on Thursday when it was not working and this didn't help. So Chorus's equipment further afield, but I would have thought this would affect someone else as I know there are at least 3 people with fibre near me (albeit haven't asked if they were having problems).


Another interesting point is the ONT itself seems to have 3 failure modes.

1 optical light shows red, LAN1 port is normal (orange for GbE provided the router is connected). Think this happens after been in state 2 or 3 for while, but it's also changed to 2 or 3 after being in 1.
2 optical is green light, but no light on the LAN1 port. Router also doesn’t detect connection on the WAN port. Tried restarting the router, connecting to a different router or even replacing the Ethernet cable but LAN1 port never lights up except briefly during startup of the ONT.
3 all lights on the ONT indicate a normal connection (optical green & LAN1 port light orange). Router does detect connection on the WAN port but doesn't receive an IP. (Restarts, diff router etc don't help.)

P.S. Initially I did try restarting the ONT, even leaving it off for hours. I've stopped that as it doesn't seem to help and the service comes back without that.

Cheers