Poor Connection speeds since migrating to ADSL2+

[ShadowHunter]

Hi..

Well, I've had my router plugged into the mains (avoiding the surge protector) for a couple of days now, I did just restart it as I was reading about initial target SNR's displaying after a reboot but anyway.. my stats are as follows:-

Line Mode   ADSL2+       Line State   Show Time   
   Line Power State   L0       Line Up Time   00:00:06:46   
   Line Coding   Trellis Off       Line Up Count   1   
   
   Statistics   Downstream   Upstream   
   Line Rate   7127 Kbps   944 Kbps   
   Noise Margin   21.4 dB   5.0 dB   
   Line Attenuation   30.0 dB   14.2 dB   
   Output Power   20.4 dBm   12.4 dBm   
   MSGC (number in overhead channel data)   59   34   
   B (number of bytes in Mux Frame)   110   29   
   M (number of Mux Frames in FEC Frame)   1   4   
   T (Mux Frames over sync bytes)   2   2   
   R (number of check bytes in FEC Frame)   16   6   
   S (ratio of FEC over PMD Frame length)   0.4961   4.0000   
   L (number of bits in PMD Frame)   2048   252   
   D (interleaver depth)   64   2   
   Delay   7 msec   2 msec   
   Super Frames   25194    25192    
   Super Frame Errors   0    8831    
   RS Words   3275238    428264    
   RS Correctable Errors   0    39138    
   RS Uncorrectable Errors   0    0    
   HEC Errors   0    0    
   OCD Errors   0    0    
   LCD Errors   0    0    
   ES Errors   0    0

I believe my noise margin is still high at 21.4 dB, in fact I thought the highest was 15dB ??

Also, Trellis is still off and I'm sure it used to be on.. it certainly was when I was gettting my high speeds! and other forums have indicated to other users that this is some kind of error correction which would help with noisy lines like (apparently) mine.. even though my line has never had any audible noise on it when listening through the phones handset..

Is there any way to get this Trellis turned back on?




Thanks

[Glenn]

Call support, they maybe able to request it.

[Steve]

Following on from what Glenn said, these settings are negotiated between the router and the MSAN at the exchange. Unfortunately as far as I am aware 'user tweaks' by programs such as DMT tools do not work on BT's line management of adsl2+.

[SSK]

I believe my noise margin is still high at 21.4 dB, in fact I thought the highest was 15dB ??

When I first got ADSL2+ SNR was 6dB then within 24 hours it shot up to 27dB - so it can be greater than 15!   

It did very slowly over a few days come down on its own to 15dB with no sign of coming down further. Then support asked BT to restart the training period and it has been stable on 9dB for over a week now.

Maybe you can ask support to have BT restart the training period on your line?

Sean

[Steve]

We see higher margins greater than 15 with adsl2+ when a banded profile has been imposed.

[ShadowHunter]

Ah right..

So i'm back to being banded again..

Sounds familiar!

I'm going around in circles!

I just don't understand how my sync speeds have dropped from 16247 to 11670 (where it was stable for 6 months or so since my initial posts) then dropped to 11007 and now to 7127.. ??

Slower than my ADSL1 speeds and the reason for my initial post !!

As i've said from the start, my phone line is Crystal clear (and I mean CRYSTAL clear!)

No noise, no hiss, no crackles.. NOTHING !!

What's going on ??

[Glenn]

Have you tried a different router, i didn't see mention of one through the thread? If you haven't, see if you can borrow one from a friend.

[Steve]

In addition to what Glenn said. I can suggest is plug the router into the test socket, leave it on permanently. Use Routerstats or Routerstats lite (if you adsl router supports it) to monitor your connection downstream margin. Collect some connection stats from the router and also collect a few BT speedtests. When this is in hand get onto support and see if they can suggest a reason.

ADSL2+ because of the higher frequencies used on the downstream side is more susceptible to the effects of noise as the signal is more easily disrupted