OK, I will perform the test once I get back home this evening.
Thanks.

OK, here are the results :
Input :
Sync speed 4224 Kbps
Attenuation 44 dB
Noise Margin 5.9 dB
Output :
Your maximum line connection speed using an ADSL (up to 8Mbps) service is:
4224 Kbps
If using a BT Wholesale Max product, then your expected IP Profile (sometimes called BRAS Data Rate) will be :
3.5 Mbps
If your service provider uses ADSL2+ the maximum line speed likely is:
8750 Kbps
With ADSL2+ the maximum IP throughput (result from a speedtest) is likely to be around:
7743

Line stats (straight line distance to the exchange roughly 900m) :

BEFORE upgrade (so on ADSL Max) :

telnet :

Down Up
SNR (dB): 5.9 21.0
Attn(dB): 44.0 22.0
Pwr(dBm): 18.8 12.1
Max(Kbps): 4800 1104
Rate (Kbps): 4224 448

MIB Browser :

MIB Name Raw Value
adslAtucCurrSnrMgn 210
adslAtucCurrAtn 220
adslAtucCurrOutputPwr 180
adslAtucCurrAttainableRate 1104000
adslAturCurrSnrMgn 60
adslAturCurrAtn 440
adslAturCurrOutputPwr 121
adslAturCurrAttainableRate 4800000
adslAturChanCurrTxRate 488000

AFTER upgrade (so on ADSL2+) :

telnet :

Down Up
SNR (dB): 6.2 7.3
Attn(dB): 42.5 22.3
Pwr(dBm): 18.9 12.4
Max(Kbps): 4700 888
Rate (Kbps): 4655 888

MIB Browser :

MIB Name Raw Value
adslAtucCurrSnrMgn 75
adslAtucCurrAtn 223
adslAtucCurrOutputPwr 189
adslAtucCurrAttainableRate 888000
adslAturCurrSnrMgn 63
adslAturCurrAtn 425
adslAturCurrOutputPwr 124
adslAturCurrAttainableRate 4700000
adslAturChanCurrTxRate 8992000

The downstream sync appears to be low for the attenuation. It might be worth checking the stats from the test socket (within modern BT master sockets) and removing the ring wire if it is connected.

See http://www.dslzoneuk.net/socket.php?type=html

The only thing that happens in the first 10 days is that two figures are recorded and stored - the MSR (Maximum Sustainable Rate), which is only referred to during fault finding, and the FTR (Fault Threshold Rate), which is 70% of the MSR. BT will not normally accept that there is a fault unless your line sync speed consistantly drops below the FTR.

After the 10 days, your line will continue to rate adapt, in accordance with the line conditions.

http://www.thinkbroadband.com/news/2693-bt-wholesale...

Edited by deleted (Fri 23-Oct-09 08:27:27)

In reply to a post by zebedeee:

The only thing that happens in the first 10 days is that two figures are recorded and stored - the MSR (Maximum Sustainable Rate), which is only referred to during fault finding, and the FTR (Fault Threshold Rate), which is 70% of the MSR. BT will not normally accept that there is a fault unless your line sync speed consistantly drops below the FTR.

After the 10 days, your line will continue to rate adapt, in accordance with the line conditions.

http://www.thinkbroadband.com/news/2693-bt-wholesale...

zebedeee, many thanks. I think I understand. So within this famous "10-days-long training" period only the above two values are recorded. Other parameters (limits) can adapt to changing circumstences with time so one can see an improvement, or a degradation, of speeds etc if the line quality changes over time. This is how I understand your reply.

Is there a way to find MSR and FTR values from the line stats ?
The telnet response does not seem to contain this data.
Then MIB Browser info has hundreds of lines of data so I am not certain what to look for ...
On other hand, as you tend to suggest, these two parameters (MSR & FTR) are not very interesting from the user's / consumer's point of view.

In reply to a post by rmaciag:

OK, I will perform the test once I get back home this evening.
Thanks.

Here are the results from the yesterday's test :

Download speedachieved during the test was - 3261 Kbps
For your connection, the acceptable range of speeds is 600-7150 Kbps.
Additional Information:
Your DSL Connection Rate :4447 Kbps(DOWN-STREAM), 1005 Kbps(UP-STREAM)
IP Profile for your line is - 3500 Kbps

Well, I am a bit disappointed.

I reset the router, left it on overnight and then rerun the test this morning.
Results are not much different :

Download speedachieved during the test was - 3257 Kbps
For your connection, the acceptable range of speeds is 600-7150 Kbps.
Additional Information:
Your DSL Connection Rate :4418 Kbps(DOWN-STREAM), 1048 Kbps(UP-STREAM)
IP Profile for your line is - 3500 Kbps

What puzzles me now is why the Best Effort speed achieved is only c. 45% of the max acceptable speed ?
What are the likely factors causing this effect ?
Could internal house wiring have impact here ?
Do the line stats cover the entire length of the line from the exchange upto the router i.e. including internal house wiring ?

On an ISP reselling the BT product your maximum speed is limited by your IP profile (in your case currently 3500kbbs). You are getting 93% of that which isn't bad.

Your IP profile is governed by your worst recent (less than a week say) downstream sync rate (currently 4447kbps).

Poor internal wiring may drag down your downstream sync rate.

In reply to a post by rmaciag:

Well, I am a bit disappointed.
What puzzles me now is why the Best Effort speed achieved is only c. 45% of the max acceptable speed ?
What are the likely factors causing this effect ?

I've put some notes here of understanding adsl max - there's an IP Profile table at the bottom of the page.

You need to sync/connect at 4544kbps to move into the next IP Profile step of 4000.

BT's rules!

In reply to a post by rmaciag:

What puzzles me now is why the Best Effort speed achieved is only c. 45% of the max acceptable speed ?

What is not clear to me is the relation between internal wiring, line stats and the max achieveable speed.
My understanding is very limited. That is clear.
I assume that max achieveable speed is based on line stats (when I feed line stats data through the speed estimators I get 8-9Mbps range of max speeds so the max achieveable speed of 7150kbps as returned by BT's test is not very far from the estimates).
I also assume that line stats cover entire length of the connection from the exchange to the router so they cover internal house wiring (in my case). Am I wrong here ?
However the Best Effort speed is so much lower than the max achieveable.
Clearly I am missing something fundamental in my basic analysis.

PS
I will try resyncing the router from the master socket (I did it once while still on ADSL Max but found hardly any difference).
I am thinking about disabling all firewalls, antivirus software etc. Does it make sens ? I am concerned other traffic is causing the tests to return lower than expected results.

The relationship between your internal wiring, line stats and achievable speed is basically this.

Depending on the state of your internal wiring it may be slowing down your connection - that's why the BT TEST socket within the Master Socket should be used to see if your wiring is causing problems.

The connection speed or sync will change immediately when you connect via the test socket or an extension. BUT your actual usable speed won't change (in an upward direction) until your IP Profile catches up - this can take 'up to' 5 days. A lower sync will give you a lower IP Profile within a couple of minutes!

Yes the line stats are for your whole line - including your extensions etc. Obviously there isn't a lot you can do about the phone line to the exchange but you can ensure you've made the most of your internal wiring which is why you see it mentioned so often. It's often also your internal wiring that's picking up a lot of interference - see references to ring-wire tweak etc.

As has been mentioned earlier your tests are correct for your IP Profile.
Firewalls etc. won't effect your router sync...

Hope that helps

Edited by b4dger (Fri 23-Oct-09 13:37:05)