Oddness with IP profile & bt-tester

[SSK]

This isn't a complaint of any sort. I'm quite happy with the speeds I'm get, but I'm just hoping someon can explain some odd observations.

For about 800 hours I had a synch rate of 17912 Kbps. During all that time the BT speed tester was showing an IP profile of 16000 and download speeds mostly well over 16000. That was the first odd observation because according to the kitz.co.uk the IP for that synch rate should have been only 15000. 

About 4 days ago, in the early hours of the morning, the synch was reset, presumably by the exchange (the router wasn't rebooted). The new synch rate since then has been 18424, but according to the BT-tester the IP profile has dropped to 15000. The BT tester hasn't been able to complete the test recently, however, because it either won't load the page at all or stops after 10% of the download test saying the server is busy. So I can't get a throughput from it. Other tests, though, indicate that the IP profile is indeed 1500 because max throughput is 14232.

Anyway, I wonder why for about 800 hours the IP profile remained 'too high' for the synch rate and why after resetting to a higher synch rate the IP profile is now stuck 'too low' for the new synch rate.

Also, has anyone else been having the same problems with the BT tester - i.e. it won't run at all with Safari and with Firefox it is very slow to load and gives up part way through the download test?

Sean

[Rik]

The BT tester is always a bit of a lottery, Sean.

Your profile vs sync speed doesn't make any sense. Has your noise margin changed at all? If not, give support a ring after five days if it hasn't adjusted. I suspect you had a brief low-sync period which triggered the drop, but that's just guesswork.

[SSK]

Yes, Rik, over the last few months I've seen for myself how much the bt test is very much a lottery!

As my download speed is more than adequate, I'd be reluctant to bother support even if the IP stays at 15000 for more than 5 days. They surely have more urgent problems to deal with! The reason for my query here was to try to clear up the mystery (to me) of the strange relationship between IP and synch.

For a long time I had a synch speed that 'justified' the IP of 16000 then about 1000 hours ago synch speed dropped.  I always thought IP dropped quickly after a decrease in synch speed but for over 800 hours after my synch had dropped below the level required for an IP of 16000 it remained at 16000. That seemed very odd to me, but obviously, I didn't complain about it!

The fact that I'm now on a lower profile despite an increased synch is probably easier to explain - as you say, it could be caused by a brief period of lower synch that occurred without me spotting it. It's more than 965 hours since my router was last rebooted, so it's nothing I've done.

To answer the question about SNR margin: over the approx 800 hour period it varied between 8 and 10 dB. Now it is 7dB, which is the lowest I've had for months. Does that give any clues?

Sean

[Rik]

I ran on an overfast profile for a while till BT's system spotted it. I just kept quiet and hoped.

The lower NM suggests the higher sync speed which you now have, so I think everything is well.

[SSK]

The connection reset on its own again last night (around 1.30am).
The synch and SNR margin haven't changed (18424 Kbps & 7dB).

The BT speed tester now says the IP is 16000, but I still can't get a throughput from it. The download test gets to 100% but then it just says "An Error Has Occurred!" and stops. I suppose that's an improvement on yesterday when it stopped at only 10 or 20%. 

Sean

[Rik]

Consider it akin to a miracle, Sean.