Line speed has changed.

[#1]

I'm hoping someone can shed some light on this for me.
Since moving to 21CN (8mb), my sync rate went from a stable 8128 (interleaving off) to 7616 (interleaving on) with an increase in upload causing interleaving to be applied automatically. My download speeds were now lower at 765kps but with the higher upload speed it seemed a reasonable compromise.
As of yesterday morning, my download speeds have dropped again by over 40kps to a max of 717 on any site I use. My sync rate remains the same as does my profile at 6500, the only difference I've noticed, and it may not be relevant, but if I run a speed test, the figure, which has been steady at around 6250 since the beginning of Feb, now shows at 5900-6000. I know 40kbps may not seem that important to some, but 40kps is 40kbps when you have several machines accessing the same connection.
Can anyone explain what might have caused this drop and if there's anything I can do about it?

[#2]

Anyone?

[#3]

Hi esseff,
Sorry for the delay in getting back to you - I'm just taking a look now and will let you know what I find. 6041kb/s looks about right for a 6500 profile though.

[#4]

Well I can't see any disconnects that might have caused this though the records show that interleaving was applied on the 15th March (somewhat after the move completed). There was a lower sync event just before that but nothing to explain the lowered profile.
I'm not sure what to suggest to be honest, unless you've recently changed phones or plugged something new into the line?

[#5]

Do you mean interleaving was applied on 15th Feb? Otherwise your records are not correct. Interleaving was applied immediately the move completed (see first post).
Nothing has been changed at this end. I have the router plugged directly into the BT socket. No additional or new phones have been added. As I said, it's not that 6041kb/s is unreasonable per se, but it's been consistently at 6250 for the last 2 months, and a drop of over 40kps in actual download speed has to be caused by something.
After the move completed, I'd been intending to request my upload speed put back to 448 and have interleaving turned off again, as on the whole, having a higher download speed is far more useful. But, I've been uploading to my websites quite a bit and have enjoyed having the higher upload speed to do so, and the download speed I was left with after the move of 765 wasn't that much lower that the 795 I'd had previously. I'd rather not lose the upload knowing that this exact configuration gave me those figures rather than this being me just thinking they should. So it makes me loathe to change it as a means of solving the problem.
I did try replacing the filter this morning, just in case, which actually resulted in a higher 1056kb/s upstream figure, but it seems I definitely have this lower download figure now as my norm. It makes no sense that there's no explanation for it. It's such a stable and consistent change. However, if you're sure there's nothing else to be done, then I can't see any other solution except to lower the upload to 448, turn interleaving off which should reduce the extra noise and let me sync back at 8128. Obviously I've not had that config on 21CN before, but I assume that as I synced at 8128 on 20CN there's no reason that I shouldn't again?
Simon

[#6]

If interleaving is turned off your downstream sync speed should increase to 8128kbps (the reduction to 7616kbps with interleaving on is due to the way certain router chip-sets communicate with the equipment at the exchange).
With interleaving off you might find the higher upstream sync speeds cause some instability in your connection; if that proves to be a problem asking for upload to be capped at 448kbps might help.

[#7]

One last thought. Isn't the speed of my download dependant on my sync speed? The higher my sync the faster my download? If my sync speed, after dropping to 7616 gave me a download of 765 for weeks, and nothing has changed at my end to cause the sync rate to alter, how can my download speed suddenly lower to 717? Something has to have been turned down somewhere doesn't it?
Strangely, Matt stated that PN records show interleaving wasn't applied until 15th March - my router clearly showed interleaving on from the moment the move was completed in Feb. I'm just interested if someone at PN can confirm that as it doesn't make sense.
Anyway, if I ask you nicely, could someone please cap my upload and turn interleaving off again or do I have to raise a ticket?
Thanks.

[#8]

How does your modem report interleaving? If it's by interleave depth and the value is 1 then interleaving is off.

[#9]

It says 'Interleave Path' as opposed to 'Fast Path' when interleaving is turned off.
As I said, if I ask nicely, could someone at PN please cap my upload and turn interleaving off again or do I have to raise a ticket?

[#10]

Hi there esseff,
I have just raised a modify order for you to remove interleaving and cap the upload speed at 448kbps. The order should complete before 1pm tomorrow so please reboot your router after that point and see how things go.