Line Rate

[codsallandy]

When I first joined IDNET at the beginning of October my router immediately achieved a Downstream Line Rate of 7616 kbps.
However following three mains power interuptions in the house (nothing to do with my computer) the Downstream Line Rate is now 6976 kbps which produces a downstream speed of 6248 kbps on Speedtest.net.
Please can anyone advise me if the Line Rate will eventually rise back to 7616 kbps? Is there anything I can do to get back to 7616 kbps?
Sorry if any of my terminology isn't quite right but I'm not very technical.
Many thanks for any help or advice you can give.

[Simon]

Hi Andy (?) and   Have a welcome karma!

Someone more technical than me will be along later to confirm this, but I think that the power interruptions would have caused the BT software to decrease your line rate, in at attempt to stabilise the connection.  Assuming you suffer no more outages, your line rate should improve in a few days. 

[Sebby]

As Simon says, the likelihood is that, in response to the power interruptions (which, to BT's systems, are a sign of instability), your target signal-to-noise ratio margin (SNRM) has been increased. The effect this has is to force your router to sync a bit lower, the aim being to offer more stability.

In general, it takes 14 days without a drop in sync for this target margin to be reduced to the next notch down. The default and lowest SNRM is 6dB; you've probably been increased to 9dB. 12dB and 15dB are also options.

This is the most likely explanation, though it might not definitely be the case. Which router do you have? Could you post the line statistics? If you're not sure where these are, let us know what router you have, and someone will be able to guide you.

I hope this helps. 

[Rik]

I couldn't have put it better myself.

[Lance]

Welcome to the forum

The other thing is that you may want to try a re-sync early on in the morning. The reason for this is that if the last power outage was in the evening, there is a lot more noise on the line and you sync at a lower speed. Re-syncing in the morning, there is less noise so you may be able to sync at a higher speed.

[codsallandy]

Hi Everybody
In reply to Sebby I have a U.S. Robotics 9105 router. If I have understood what you want to see these are the ADSL statistics:


Mode: G.DMT 
Type: Interleave 
Line Coding: Trellis Off 
Status: No Defect 
 
Total ES: 1458 
Total SES: 0 
Total UAS: 17 
 
  Downstream Upstream
SNR Margin (dB): 11.9  19.0 
Attenuation (dB): 16.5  10.0 
Output Power (dBm): 11.9  19.7 
Attainable Rate (Kbps): 7520  936 
Rate (Kbps): 6976  448 
K (number of bytes in DMT frame): 219  15 
R (number of check bytes in RS code word): 16  16 
S (RS code word size in DMT frame): 1  8 
D (interleaver depth): 16  2 
 
Super Frames: 4406987  4406985 
Super Frame Errors: 1946  0 
RS Words: 299675169  37459372 
RS Correctable Errors: 5154  1230 
RS Uncorrectable Errors: 23440  N/A 
HEC Errors: 1788  0 
OCD Errors: 0  0 
LCD Errors: 0  0 
ES Errors 0  0 

Unless these change things and your collective advice changes I'll keep my fingers crossed for 14 days!
Andy

[Lance]

It looks like your target has been raised two steps to 12db, rather than the one step to 9db.

Hopefully it will drop to 9 in 14 days, giving a slightly higher sync, and then 6db after another 14 days, increasing your sync further still.

[Rik]

I'm with Lance, Andy, you need to keep a stable connection for 14 days, then 14 days again and you should recover fully.

[Sebby]

It does looks like your target margin has been increased to 12dB, so just hang in there, and hopefully it will decrease itself. I'd suggest leaving it for 14 days then rebooting the router.

One thing you'll realise is that BT's IPstream Max can be an annoying system! 

[Rik]

BT's IPstream Max can be an annoying system! 

Can Sebby?? 

[Sebby]

Can Sebby?? 

I'd actually written is annoying, but then I changed it, because I thought it can't be annoying for everyone! 

[Lance]

I think it is, just not everyone realises it!

[Sebby]

I think the target SNRM system works well in theory, but in practice it's a pain.

The bRAS profile system really is a pain, on paper and in practice. 

[codsallandy]

Thanks everyone. I'll let you know how I get on in 14 and 28 days.
Andy

[Rik]

The bRAS profile system really is a pain, on paper and in practice. 

The annoying thing is that it's not technically necessary, it just reduces the amount of computer power BT need to run the system.