Welcome to another exciting installament of "mode has fucking weird connection issues".
Since a couple of days back my ping on servers has hovered around 300ms. Those who played in scrims with me then will have noticed this.
The issues carried on overnight. I didn't sleep and was keeping an eye on it, which probably rules out flatmates hogging the connection.
It sorted itself out about quarter to nine in the morning, then went back to this state about quarter past one in the afternoon, and I haven't seen it stabilise since.
A snippet of a ping graph in HLSW screenshotted today:

The blue arrows point at where I tried connecting an ethernet cable between to my computer from the router to rule out wireless issues. The connection gets better for a few seconds before going completely rubbish again.
A traceroute to the WDG server looks like this:

The only change in my computer configuration between the evening it messed up and when I played previously was installing Filezilla. I've tried uninstalling this and restarting but my connection's no better.
I can browse the internet without issue.
The relevant programs (Steam, HLSW) are allowed in my antivirus (AVG), and traffic on the ports is set up to allow on the router firewall.
Ideas? I'm stumped.
