Target SNM not dropping

I had a few problems with my line a while back and my TSNM went up to 15db. After 5 solid weeks of sync to the exchange I restarted my router only to find its still at 15db.Between resyncs I usually have a period of about 3 or 4 weeks. Surely after this length of time it should have made at least one drop of 3db? Im tempted to regrade to a fixed speed product for a month then change back to max to force a re-train. getting a bit cheesed now with my line not achicving what it should be. Current IP profile is 3000k as opposed to the usual 4000-4500k
Any opinions?

Thanks

Edited by chrimbow (Tue 01-Sep-09 16:59:20)

Try leaving it switched off for at least 20 minutes. It should have happened at 10-14 days though if it was going to. Were you using DMT though? I don't recommend that in these circumstances although some say it doesn't matter.

If switching off doesn't fix it give send me a PM .

Just left router turned off for an hour or so, TSNM is 15 db synchronised at 3584db Attn48db.

Edited by chrimbow (Tue 01-Sep-09 17:52:44)

Few weeks old this thread now, but I was just wondering if anyone would like to hazard a guess what would happen if I did a re-sync this week after over a thousand hours of solid connection?
My bet is stil stuck at TSNM of 15db

Can't do any harm at all to do a daytime re-sync.

If I know Im going to force a re-sync, I always wait until I have a chance to do it during mid morning.
Just done one now after over 1000 hours of solid connection and surprise surprise its still 15 db...
I give up!
It was suggested that the easiest way of sorting this was to regrade to the old fixed 2mb speed for a month then go back to max to force a line re-train.
Do you think thats the way to go?

PM MrSaffron and ask if he can help.

your ISP can get it put back through the retraining process from 6dB and should also be able to have it set to a specific value.

It is possible your line has errors at a rate that falls outside the parameters for reducing the target margin, AIUI there's a fairly wide deadband between the level of (in)stability that kicks it up and that that is deemed good enough to drop it (purely to avoid it oscillating).

I did that a few weeks back and Mr S had a reply which basically said that there had been large fluctuations in margin and that if they lowered the TSNM this could cause "retrains".
I would agree that in the past there has been massive variations in margin which I posted about on here but these problems vanished a while back. I still momitor the line with router stats but havent seen any problems for a while.
I had interleaving turned off by my ISP, is it worth putting it back on to see if that helps?

here is the ticket I raised with my ISP (ADSL24)

i had issues with my line a while ago with large fluctuations in SN margin. When i was with BT their response was to raise my target SN margin. This is currently 12db on router start up which causes me to synch at about 4000k. I have to manually alter the margin to achieve a sycnch of above 5696kps to achive a 5k profile. Could my target SN be lowered by BT wholesale to the default 6db please to save some messing about for me?

My line is attn 47down 26.5 up
target SN 12db
IP profile is usually 5k (with manipulating SN margin, without manipulating it is 3.5k)
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I am afraid that BT Wholesale will not accept any faults in regards to SNR. They will not manually reset the SNR as it could interfere with the RAMBo Dynamic Line Management that handles your IP profile and the SNR.

The only way to bring the SNR down is by turning interleaving off or using DMT tool and a compatible router to lower it that way.

If we disable interleaving your sync rate should increase and your latency should drop. You may potentially suffer packet loss if interleaving is turned off but this only tends to be on bad lines. It can take in excess of 20 days for the SNR to drop and it drops in 3db steps but I am afraid these are the only ways of dropping the SNR.

Would you like me to turn Interleaving off for you?
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Thanks
I will leave it for now and see how it goes, I know I have had solid synchs for longer than 20 days though (although I do lose connection to adsl24 fairly requently accoding to my router and logs) without the snr being affected noticably.
Cheers anyway
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We need to turn Interleaving off though for the SNR to drop. Would you like me to place this for you?
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ok I will try it. Is it a major hassle to put it back on once my snr has reduced or does it not work like that (ie turniong it back on will increase the snr again)?
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t can be turned on next day if you want it to be. I have placed the modify to turn interleaving off, and turning it back on if it is required will not make the SNR increase.