Thanks Bill, but still odd that it should suddenly start happening a year after the router was installed, with no firmware updates in that time. So something changed somewhere.

I put the HG612 on yesterday & BQM was clean. This morning it showed 20% packet loss kicked in around 1AM & is still present. I'm also running DSLstats on the HG612 & that shows no deviation on the line at that time.

Packetlosstest.com shows zero loss at 15 pings per second with a threshold of 50mS.

Maybe the packets are being dropped at your ISP - perhaps they see them as a DDoS or similar and therefore start dropping them - it isn't necessarily your router dropping the packets and isn't necessarily TBB causing the issue (although either is possible).

In reply to a post by rbz5416:

still odd that it should suddenly start happening a year after the router was installed, with no firmware updates in that time. So something changed somewhere.

True, all I can think of is that the bit "...some routers or networks seem to drop those packets..." also applies to the path between you and the Firebrick, and if that is the cause then it's anybody's guess what's been going on there

In reply to a post by ian72:

Maybe the packets are being dropped at your ISP - perhaps they see them as a DDoS or similar and therefore start dropping them - it isn't necessarily your router dropping the packets and isn't necessarily TBB causing the issue (although either is possible).

Maybe. But given that the 7530 is pretty common (provided by Zen) & the ISP is BT, I'd have thought there would be more instances reported if either were at fault.

Well this is interesting. Just out of curiosity I set one monitor to the IPv4 address & another to the IPv6. In the early hours of this morning (as usual) 30% packet loss started from nowhere on the v4 monitor & continues now. The v6 monitor is completely clean.