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SNR Margin

mot
Grafter
Posts: 52
Registered: ‎25-02-2010

SNR Margin

Would it be wrong of me to think that a 16db margin is unacceptable?
Yesterday, my margin was 6db and synced at a smidge under 12mbps, I checked this morning as I'm in my training period and we now have a whopping 16db SNR margin, reducing our speed considerably!
I've rebooted my router and it syncs with the same figures.
I've also adjusted the margin to 50% in my router which used to work a treat with ADSL in the past but has made no difference with ADSL2+, it syncs at the same speed.
Should I put a call into support and ask to have my margin dropped?
Router is a DG834GT with DGTeam firmware BTW.
I can't do a BT speedtest to check my IP Profile as it errors with something like "could not confirm details, please contact your ISP"
We probably get a 1.5db drop in the evening but nothing the router can't hang onto, I've seen it drop near 0 and hold sync in the past!
42 REPLIES
itsme
Grafter
Posts: 5,924
Thanks: 1
Registered: ‎07-04-2007

Re: SNR Margin

With ADSL2+ it's best to leave your modem on 24/7 do no reboots and do not do any tweaking of the SNR margin and let the DLM do it's business.
mot
Grafter
Posts: 52
Registered: ‎25-02-2010

Re: SNR Margin

ah, right..I was kinda hoping sync wouldn't drop so low Sad
How can it sync at a higher rate without a reboot?
easty
Newbie
Posts: 9
Registered: ‎11-03-2010

Re: SNR Margin

FWIW -- I have the same router and similar behaviour - previously low SNR margin, now very high and now on a banded profile.
See: http://community.plus.net/forum/index.php/topic,84209.0.html
itsme
Grafter
Posts: 5,924
Thanks: 1
Registered: ‎07-04-2007

Re: SNR Margin

Quote from: mot
How can it sync at a higher rate without a reboot?

The DLM will do it. You will find that it will try different SNR and interleave levels. This can be several in a day or every 3 days for the first month. Then after that every week/month especially when banded.
grahamt
Rising Star
Posts: 567
Thanks: 13
Registered: ‎05-04-2008

Re: SNR Margin

With a downstream sync speed of 6656 it looks like you're on a banded profile - this would also explain the high noise margin.
You'll probably just have to be patient. Eventually you'll come off it. The problem is that if the problem with your line that caused the original banding returns you'll be put back on the banded profile and it'll take longer to get off again the next time. If the problem was just a one-off then your noise margin will be lowered and your speed will rise.
Graham
mot
Grafter
Posts: 52
Registered: ‎25-02-2010

Re: SNR Margin

It's been determined that after one day on 21CN I've been moved back to 20CN for some unknown reason.
I have to wait to be regraded again now..
Explains my high SNR margin though!
Plusnet Help Team
Plusnet Help Team
Posts: 13,724
Thanks: 265
Fixes: 76
Registered: ‎27-04-2007

Re: SNR Margin

Hi mot,
I've just checked your account and can see that when you moved over to us we had to place your service on 20CN briefly. An order to put you back on to 21CN was placed on the 17th and is due to complete on the 24th. Let us know if you see any issues following on from there please.
If this post resolved your issue please click the 'This fixed my problem' button
 Adam Walker
 Plusnet Help Team
mot
Grafter
Posts: 52
Registered: ‎25-02-2010

Re: SNR Margin

Nothing as of yet, although my upstream is now 450kbps rather than 448, would that mean I'm on 21CN with the upstream cap removed?
Still experiencing a huge SNR margin, and a resync last night but no idea why as the line figures are fine..
I'm hoping I'm not on a capped profile!
Any chance of an update on the current status or is it just sitting with BTO?
Plusnet Help Team
Plusnet Help Team
Posts: 13,724
Thanks: 265
Fixes: 76
Registered: ‎27-04-2007

Re: SNR Margin

Hi again mot,
It looks like the order has not gone through yet. Please bear in mind that these can complete at any time on the due date. I'll see what I can find out in the meantime and will report back here shortly.
If this post resolved your issue please click the 'This fixed my problem' button
 Adam Walker
 Plusnet Help Team
Plusnet Help Team
Plusnet Help Team
Posts: 13,724
Thanks: 265
Fixes: 76
Registered: ‎27-04-2007

Re: SNR Margin

Right,
I've just checked with BT and there are no reasons to indicate any delays on your order so we expect it to complete at any point between now and midnight. Please check your ticket tomorrow if you can and let us know if you see any issues.
If this post resolved your issue please click the 'This fixed my problem' button
 Adam Walker
 Plusnet Help Team
mot
Grafter
Posts: 52
Registered: ‎25-02-2010

Re: SNR Margin

Hi Adam, No change this morning..still on 20CN Sad
Either that, or a banded profile, ha!
mot
Grafter
Posts: 52
Registered: ‎25-02-2010

Re: SNR Margin

I've just updated my ticket with the above - could you call my mobile with any correspondence please?
I can access my router remotely from work if you need me to for any reason.
mot
Grafter
Posts: 52
Registered: ‎25-02-2010

Re: SNR Margin

Could you take a look at this please, my ticket has been closed but I'm still seeing a high SNR margin..maybe indicating that I am, indeed on a banded profile?
Looking through my logs each morning I see that I generally have a disconnect over night. I'm not sure why and I certainly didn't get it with my last ISP so maybe it's the DSLAM?
itsme
Grafter
Posts: 5,924
Thanks: 1
Registered: ‎07-04-2007

Re: SNR Margin

If it's the DSLAM you will still be on 20CN as 21CN use MSAN  Grin
From my experience ADSL2+ in the training period the DLM use to try different settings between 6 to 8 in the morning.