I posted a similar thread a while ago but this is an updated one and without the mess of the last thread re discussions.
if this helps please rate the message with a star so I know I am not wasting my time.
You will be on one and only one of the 3 methods although there are some rare exceptions such as fixed rate lines and banded rates. For banded rates due to line issues I have been informed that it can take 3 days to sort itself out if the line remains ok. Additionally for new or reset lines the bedding in period varies between 3-10 days and than can effect the profile used.
1 88.2% method.
This is the newest method and basically removes the concept of a profile as such as matches similar other schemes in place by other providers. Your 'profile' is set to 88.2% of your downstream sync rate (which allows for the overheads needed that are contained wiithin the traffic). Setting change is made with a change in sync speed.
This method is only available on exhanges that have been updated to CN21 and there are no current plans to change this. Not all CN21 exchanges may yet have this method but eventually those that don't (Fujitsu MSANS) will get an update to implement it.
Some lines may have this method, have the new rate applied but then be moved down to the nearest IP profile on the old method a while after connecting until some internal BT software is updated.
If you run a BT speedcheck it will tell you your IP profile, if it is not a nice round value ending on 0 or 5 then you are on this method already, otherwise your profile should fit one of the values in the table further down (unless your speed is greater than I cater for [posts limited to 20,000 chars])
2 Oldest method
Decreases in profile take up to 75 minutes to apply, increases can take up to 3 days from the time of a higher sync.
IP profile value depends on your sync speed.
|Sync speed (incr 32kb stages)||IP profile|
|160 kbps||256 kbps||135|
|288 kbps||384 kbps||250|
|416 kbps||544 kbps||350|
|576 kbps||832 kbps||500|
|864 kbps||1120 kbps||750|
|1152 kbps||1408 kbps||1000|
|1440 kbps||1696 kbps||1250|
|1728 kbps||1984 kbps||1500|
|2016 kbps||2240 kbps||1750|
|2272 kbps||2816 kbps||2000|
|2848 kbps||3392 kbps||2500|
|3424 kbps||3968 kbps||3000|
|4000 kbps||4512 kbps||3500|
3 Adaptive Max
Adaptive max is available on some exhanges and is an attempt to speed up the resets for those affected without resetting it too quickly and causing more issues if there is a line issue.
Change depends on the lowest rate that caused a decrease and the new profile that your current sync would fall within. (decreases are within 75 minutes, the table is for increases only)
The table for the ADSL2+ rates are as follows
Old rate is down the side and new rate along the top, the resultant value is the number of hours for a change to take place.
This is the minimum time and it seems that it may take a few hours longer than expected, probably because I suspect that the process to check/reset the values only runs periodically and so you should probably allow up to 2 hours or so extra.
On my exchange (New Deer) I have found that the change roughly takes place at either 20 minutes or 50 minutes past the hour and at no other time so it seems that the process probably runs twice per hour. The times at your exchange are likely to vary.
I find that under adaptive max my profile still on occassion sticks, when this happens it seems to reset itself often after 3 or 3.5 days, if not reset by them it does not reset without needing BT to arrange it.
Expanded table on profile values for adsl2+ (could not be added to above due to size of post limits)
|Sync speed (incr 32kb stages)||IP profile||bRAS ATM bit rate profile||Maximum Throughput speed|
|160 kbps||256 kbps||135||138||Up to 135 kbps|
|288 kbps||384 kbps||250||256||Up to 0.25 Mbps|
|416 kbps||544 kbps||350||370||Up to 0.35 Mbps|
|576 kbps||832 kbps||500||512||Up to 0.5 Mbps|
|864 kbps||1120 kbps||750||768||Up to 0.75 Mbps|
|1152 kbps||1408 kbps||1000||1024||Up to 1 Mbps|
|1440 kbps||1696 kbps||1250||1280||Up to1.25 Mbps|
|1728 kbps||1984 kbps||1500||1536||Up to 1.5 Mbps|
|2016 kbps||2240 kbps||1750||1792||Up to 1.75 Mbps|
|2272 kbps||2816 kbps||2000||2048||Up to 2 Mbps|
|2848 kbps||3392 kbps||2500||2560||Up to 2.5 Mbps|
|3424 kbps||3968 kbps||3000||3072||Up to 3 Mbps|
|4000 kbps||4512 kbps||3500||3584||Up to 3.5 Mbps|
|4544 kbps||5088 kbps||4000||4096||Up to 4 Mbps|
|5120 kbps||5664 kbps||4500||4608||Up to 4.5 Mbps|
|5696 kbps||6208 kbps||5000||5120||Up to 5 Mbps|
|6240 kbps||6784 kbps||5500||5632||Up to 5.5 Mbps|
|6816 kbps||7360 kbps||6000||6144||Up to 6 Mbps|
|7392 kbps||7936 kbps||6500||6656||Up to 6.5 Mbps|
|7968 kbps||8096 kbps||7000||7168||Up to 7 Mbps|
|8128 kbps||9087 kbps||7150||7320||Up to 7.15 Mbps|
|WBC ADSL 2+ Profiles|
|9088 kbps||10207 kbps||8000||8192||Up to 8 Mbps|
|10208 kbps||11359 kbps||9000||9216||Up to 9 Mbps|
|11360 kbps||12479 kbps||10000||10240||Up to 10 Mbps|
|12480 kbps||13631 kbps||11000||11264||Up to 11 Mbps|
|13632 kbps||14751 kbps||12000||12288||Up to 12 Mbps|
|14752 kbps||15903 kbps||13000||13312||Up to 13 Mbps|
|15904 kbps||17023 kbps||14000||14336||Up to 14 Mbps|
|17024 kbps||18175 kbps||15000||15360||Up to 15 Mbps|
|18176 kbps||19295 kbps||16000||16384||Up to 16 Mbps|
|19296 kbps||20415 kbps||17000||17408||Up to 17 Mbps|
|20416 kbps||21567 kbps||18000||18432||Up to 18 Mbps|
|21568 kbps||22687 kbps||19000||19456||Up to 19 Mbps|
|22688 kbps||23839 kbps||20000||20480||Up to 20 Mbps|
|23840 kbps||-||21000||21504||Up to 21 Mbps|
Adaptive max liits (from Kitz web site)
Adaptive max percentage calculation.
In case your speeds are outwith my table the calculation is as follows.
( new-profile-value minus old-profile-value) / new-profile-value and then multiply by 100.
It is important to note that it is the profile values used and not the sync rates.
How to tell if you are on adaptive max or the old method
As far as I know there is no way to tell directly, I have yet to find anyone at BT who can say for sure.
At one stage a figure of 40% of lines was quoted for adaptive max but this is now widely out of date, I know that my exchange has been updated since then and with Infinity a large number of people now don't use IP profiles at all so the percantage of lilnes on adaptive max instead of the old method is by default now higher probably.
The only way I know to tell is by observation, if you run the bt speedtester every now and then when under adaptive max you would expect a speed change and you find it has changed then you know you are on that method but please bear in mind that a change due in 12 hours could take nearer 14-15 hours to be appllied.
It is also vital that you know you have not had a lower sync in the meantime, if you sync below the targer profile band then the count will restart.