IP Profiles GRRRRR

[#1]

Rant
I recently had to turn off the router, for some electrical work to be done, router had been synced for over 60odd days, perfectly stable at 5Mb profile.  After I switched on, synced at approx 6800, but I knew my line would not hold this, and after a day it resynced to 5664.  Where the hell did BT pick these profiles from, thin air!!!.  Why does a sync of 5664, give me a 4.5Mb profile!!!!!!  Its syncing closer to 6Mb.  I realise the need for profiles, but surely they could have chosen some that bear more of a resemblace to the profile you might get. Unluckily, I appear to be only 1kb off a 5Mb profile, which is rather annoying to say the least, seeing as I had a stable 5meg profile before.  Damn you BT  >:(.  I sincerely hope that the WBC profiling is far better than this.
Rant over.

[#2]

The IP Profile is an approximation to the idealised maximum throughput capability when ATM, TCP and IP transmission overheads have been allowed for. For a sync at 5664kbps the idealised maximum throughput is around 4980kbps which is under 5000kbps. Unfortunately BTw chose to round values down in 500kbps steps which leads to an IP Profile of 4500kbps.
In fact if you manage to re-sync just 32kbps higher (5696kbps) you will get an IP Profile of 5000kbps. If you restart your router when the noise margin is a little over its target value (say 6.5dB) you might find you achieve the slightly higher sync speed you need. However experience shows this is very hit and miss. The main thing is not to restart your router repeatedly or several times per hour; doing that is likely to lead to the monitoring kit at the exchange increasing your target noise margin, which will reduce the achievable sync speed by 750kbps or more.

[#3]

Quote

The main thing is not to restart your router repeatedly or several times per hour; doing that is likely to lead to the monitoring kit at the exchange increasing your target noise margin, which will reduce the achievable sync speed by 750kbps or more

Too right, if you get stuck in this route like i am at present, trying to solve it and return to a speed that you have been stable at for months if not years is like trying to part an ocean.
Been suffering reduced speed because of this now for over a month and there is no end in sight to get back to my stable speed. Currently appear to have an enforced noise margin of 12-15db meaning a sync of 992, would love to have your problems mate 
Spent most of the last week looking for a window to jump out of !!! 

[#4]

992? I would love to have your problems 8). I am getting 160 at the moment, with about two disconnections a week. Still trying to work out what is causing it.
Is 5M to 4.5M really worth complaining about?

[#5]

Port	Status	   TxPkts	   RxPkts	 Collisions	Tx B/s	Rx B/s	Up Time
LAN	10M/100M   10797568  6591057	    0	     38	     253	     917:51:57

That's 38 days uptime and counting . . . now you know why I won't risk a re-sync! 

[#6]

Oh Penfold, how I sympathise. I drop 1M if I re-sync at the wrong time of day and to wait 3 days to get the profile back up makes me mad. Perfectly stable connection, just don't like leaving the router on 24/7 if I'm not using it for a couple of days.