FTTP off and on every 15 mins or so

[#1]

My FTTP appears to be disconnecting and reconnecting all the time. Seems to be getting worse. Both the router's connection to the FTTP drops and also the wireless signal from the router vanishes. Is this a symptom of a faulty zyxel router?
I've looked at the router logs and there is nothing obviously wrong.
What normally happens is that on my 3 devices I notice wifi has disconnected, soon as I reconnect it says limited service e.g. no internet but connected to router OK, and then after a very short while I get internet access back.
Works ok for a while and then rinse and repeat 
Any ideas?

[#2]

What are the ONT lights doing?

[#3]

No idea as I have a bookcase in the way. I will have to video it 

[#4]

Quote from: AndyH

What are the ONT lights doing?

All are normal, with PON light on steady, port 1 that is connected to the zyxel is flashing with traffic and power light is on.
Likewise, nothing odd occurs on the zyxel with the power light on, internet LED on and WIFI LED on
I can see the WAN status on the zyxel admin page go down and up though.

[#5]

It could be the router is on the way out...have you tried resetting the router or updating the firmware (if newer is available)?

[#6]

yes firmware was checked a couple of weeks ago and I have powered of all kit for 30 mins last weekend, I may have another router here I can try now that I've thought about it!
adie:quote

[#7]

It's definitely worth trying another router if you have one.
What does it say in the router log when you lose connection?

[#8]

Got the new router plugged in now thanks. Will keep an eye out on reliability
There's nothing in the routers logs showing disconnects/drops or reconnects. Every couple of seconds it justs puts in information message up saying "WAN, start TR-Agent" - no idea what that is, google is not much help either.
adie:quote