Hi all! Over the past couple of days my ADSL connection (provided by Vispa) has been very up and down. Most of the time it's very slow - speeds in the 56k modem range, however there are periods where it'll be somewhere near normal. This graph, which I've nerdily produced, shows ping times to Google - as you can see, the ups and downs are very regular (the spikes are timeouts).
I've been on to Vispa who state there's nothing wrong with the line and that my stats seem fine. (They don't traffic shape or ought, and anyway I've used way more in previous months than I have this month and I'm nowhere near my limit). I've tried the engineer's socket and replacing the filter, none of which has made anything any happier.
Anyone have any idea what could cause this? I've not had an internet connnection behave like this before. It's the same on all the computers and mobile devices in the house. The next step is to get a BT engineer out but that'll cost me if they don't find anything wrong at the exchange, so I want to rule out any other potential problems.
Thanks for any help!