Some years ago there was a discussion on here as to whether or not the BT speedtester used a "normal" route or bypassed the ISP completely and went direct to the relevant serverů but I can't find the thread. It may be that I've used the wrong search terms, though more likely it was scrubbed off long ago.
As I recall, it was said that some connections went direct to the server but most didn't, ie it was a standard http request via the ISP. I can't remember what determined the difference, my recollection may well be wrong and anyway things may have changed since then!
Can anybody elucidate the current position?
I'm specifically interested in the BTw tester on an FTTC connection with IDNet, but if the general case can be reasonably simply explained I'd appreciate the information.