Troubleshooting with the briefest of details

I got sent this question last night:

"Anyone know why an ISP would say broadband issues are our wiring if the VDSL is rock solid and we only have PPP/IP connection drops, basically VDSL and phone are perfect and Internet drops connection with no errors counted. I can't see it being anything but router hosed. Wiring implies VDSL dropping too."


ISP is talktalk, using their 2 year old supplied router. Apparently the sync remains on the line remains constant, but the connection is dropped.

"It's [censored] the logs don't tell much apart from error counts (zero).
It drops in batches and then stays stable for ages, it last dropped at 7am yesterday it dropped 4 times in an afternoon"

Sadly no spare router to test with. I'm going to assume this issue has only started recently, although I can't confirm that. I've suggested PSU issues and using the Test socket, but have no first hand experience of TalkTalk's routers (not even sure what they supply).

Some routers may drop sessions based on transient errors that recover quick enough to avoid the need for a resync, and looking at the web interface will not be fast enough to determine that, but if this were the case you'd usually also get the odd longer full resync issue too.

Most likely is the network is blipping and support don't see that or just say the VDSL2 is dropping.

A BQM monitor should be pretty clear as VDSL2 sync is fairly slow (minute) but PPP/IP drops should be a much shorter time.