Ping doubled overnight

OK, not overnight, but in the middle of the afternoon.

Coupled with losing about 7Mb/s from my sync, my latency went from approx 10ms to 20ms during a resync. I'm on an 80/20 Plusnet line, and usually get 79 down and 20 up. But I've dropped to around 77 for some unexplained reason.

I'm more confused about why this would happen than wanting an immediate fix.
I'm using a TP-link router, which 'helpfully' tells me that my Max Rate is 87133, but my current rate is 73006. I'm confused!

Do you have other stats available? Minimum would be SNR and Attenuation but if you can also get interleaving depth that might help. It sounds like your line has been hit with a burst of noise and DLM has increased the interleaving depth to compensate.

Apologies - I mean to post my BQM graph and totally forgot

My Broadband Ping

Up / Down
snr: 9.3 / 6.4
Attenuation: 18.2 / 11.8
Current rate: 20000 / 73006
Max rate: 25773 / 87187

It's a TP-link router, so other stats are thin on the ground.

I'd go for interleaving kicking in as well.

There is a hack on TP-Link routers to allow you Telnet access, from which you can get more detailed stats.

I'm not a TP-Link owner for this very reason, but I'm sure someone will help you out.

We're also on Plusnet on a rural adsl EO line

Yesterday at the exact same time our ping halved:

BQM: 8th Jan 2018

this morning at just after 4am normal service resumed:

BQM: 9th Jan 2018

DLM may have switched you onto fastpath thinking your line could take it and then went back to interleaved presumably by detecting high error rates.

As a bit of a follow up - am I seeing congestion here?
My Broadband Ping

It may be worth noting that something has been knocking my router out recently. I think it's the Chromecast issue (I have two Chromecast audios) but I've not bottomed that out yet.
I can't decide if the router is being stressed and is dropping packets, or if the connection is struggling at peak times.

Many thanks!

Chromecast issue could cause that as router CPU is overloaded dealing with the flood of traffic from the chromecasts, only way to know is unplug the chromecasts does issue go away

If I unplug the Chromecasts, and then reboot the router, it goes back to normal.

Hopefully that's all it is, and the devices pull down fixes soon!

Thanks!