DSLMax - Speed and Potential for improvement

I everyone. Hopefully this will be in the right forum.

I'm trying to understand what speeds I can possibly get out of my ADSL 8mb connection.

We've been experiencing periodic line crackle and broadband issues since last Autumn. During that time I was with Plusnet and then switched to Zen with no real difference in speed performance. Over the last few months sync speeds have varied from 5/6MB down to less than 1MB when we experience line issues. Whenever we got the line crackles I tested the line via the master socket (behind front of master socket) and the crackle always seemed to go. Zen performed a couple of remote line tests but nothing ever came up. The general consensus was it our internal wiring.

I've finally got the wiring looked at by an ex BT engineer who has disconnected all redundant extension sockets and re-done all wiring from master socket to the one extension socket we now use.

My Router (Billion 7800dxl) is connected to master socket via XTE-2005 Master Faceplate. Since re-wiring was done I know get a consisted sync speed of around 4480kbps. Whilst the engineer was here we tried using the BT iplate instead of the XTE-2005 to see if that was different and again sync speeds where around 4400. We then left the master socket with the XTE-2005.

The line is now clear (no crackling) and connection is now stable with no dropped ADSL connection. I'm just wondering from my stats on whether I can expect anymore of more out of the speed. I've had BBC iplayer and lovefilm break up and would obviously like to squeeze everything I can out of the Ashurst exhange we are connected to. I also never get up into the 5's and 6's with sync speeds and I guess this is due to the new wiring?

Current stats:
xDSL
Mode ADSL_G.dmt

Traffic Type ATM
Status Up
Link Power State L0

Downstream
Line Coding (Trellis) Off
SNR Margin (dB) 12.5
Attenuation (dB) 37.0
Output Power (dBm) 19.9
Attainable Rate (Kbps) 5092
Rate (Kbps) 4480

Upstream
Line Coding (Trellis) Off
SNR Margin (dB) 23.0
Attenuation (dB) 23.0
Output Power (dBm) 11.9
Attainable Rate (Kbps) 1088
Rate (Kbps) 448

http://www.thinkbroadband.com/speedtest/button/13711...

You should be getting over 7 Meg Sync.

The highish 12.5dB NM is damping your speed somewhat. Do a reboot in daylight and see if it improves. Try test socket.

Actually at home today and tried test socket and several reboots.


Mostly getting the same stats. Did get:
SNR: 12.5
Attainable Rate (Kbps) 5164
Rate (Kbps) 4544

and now back to:
SNR: 12.3
Attainable Rate (Kbps) 5004
Rate (Kbps) 4480


Attenuation stayed on 37.0 throughout

Insignificant difference.

Attenuation is a pretty much fixed value, unless you manage to rip out 500m of wiring.

The expected range of speeds for your attenuation is shown at
http://www.coolwebhome.co.uk/calc/calculator.php?par...

Also it has calculated that if you got the target margin lowered to 6dB you would fall into the normal range just about. As this is an older IPStream Max style connection don't reboot too much or you might be slowed down even more.

I think that's the issue with the constant reboots and re-connections over the last few months it takes an age for the profile to reset.

anyone know if this something I can my ISP (zen) to look at?

I've fiddled with the Billion SNR parameters and set it from -1 (auto) to 2, which has resulted in an SNR margin of 8.3 and the following:

Attainable Rate (Kbps) 6156
Rate (Kbps) 5536

trouble is my BRAS profile according to ZEN is adsl4000. Subsequently actual downloads and speed tests are still around 3 to 3.4 MB

As you are on the older IP profile system it can take up to 5 days for the IP profile to increase if the sync speed improves.

Not sure on the effect of forcing down the noise margin and the BT systems spotting if line is stable or not. Feeling is that by forcing it lower you are making the wholesale side think there is nothing for it to do even if the line is very stable.

Zen could put it request for the target margin to be set lower, but will get confused if you are using tweaked hardware to force it lower as data their end will look like you are doing relatively well already.