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Training period on moving to 21CN on Value

nozzer
Hero
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Registered: ‎04-08-2009

Re: Training period on moving to 21CN on Value

Quote from: Joanne
Hi there,
there would be a 10 day training period but  shouldn't reset the SNR. As for tweaking the noise margin we would not recommend that you do this at all. the DLM could do allsorts because of this and if any tweaking took place it could lead to banded profiles and increased noise margins which are much harder to change on 21cn.
Jojo Smiley

I was "converted" yesterday and before I was running at a totally stable 9dB, synced at 8096kbps.. Immediately after the changeover the SNRM went up to 16.8dB, synced at 7617kbps. but was again completely stable. Over the intervening 24 hours it has slowly reduced to 12.8dB and still stable. Will the training process force a resync at some point to try to squeeze as much as poss out of it?
Oldjim
Resting Legend
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Re: Training period on moving to 21CN on Value

Mine hasn't and I am now out of the training period - going to start reducing the default noise margin myself
Oldjim
Resting Legend
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Re: Training period on moving to 21CN on Value

Dropped the noise margin using DMT - set at 50% - which should have dropped it to 9dB but it dropped it to 9.9dB and a speed of 3808kbps.
I will leave it at that for a few days to see how it performs - unfortunately still a 3,000kbps IP profile - and then try to get a sync speed speed of just over 4,000kbps (3,500kbps IP profile)
nozzer
Hero
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Re: Training period on moving to 21CN on Value

So, are we saying that the SNRM should have sorted itself out automatically (with a resync or two) and in your case it hasn't? Or does the system not work like that? I must admit it's still not clear as to how it's supposed to be working.  Huh
Oldjim
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Re: Training period on moving to 21CN on Value

A change of default noise margin, in my experience, is always accompanied by a resymc initiated from the exchange (usually at the dead of night).
In my case nothing changed after the initial increase from 9dB to 12dB as part of the changeover.
My opinion, for what it is worth, is that the so called training period only looks for instability problems. Having said that I am not entirely convinced that there actually is a 10 day training period when the previous settings were carried over.
nozzer
Hero
Posts: 3,298
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Registered: ‎04-08-2009

Re: Training period on moving to 21CN on Value

Quote from: Joanne
Hi oldjim,
Yes, you wouldn't be able to request a reset until the 10 days had elapsed. A request for this would have to be done through the faults process and there is no guarantee it would get done; or if it did and the SNR was to increase, they would not reset it again. That said, we are hoping towards the end of the year to be able to reset this from our end.
Jojo Smiley

Eenteresteeeng!!  http://www.btwholesale-briefingportal.com/brief/view/8c81aa12577e7e64903e228f53da97c9
In this case "customer" is the ISP. Am I reading this correctly???
Also this...  "adsl2+ on 21cn does not have a 10 day training period as the nature of the product is 21cn systems so should stabilise if incorrect IP profile has occured within a max 72 hour window" found here...   http://forums.moneysavingexpert.com/archive/index.php/t-1915665.html.  Not necessarily definitive but sounds about right to me!
[Moderator's note by Jim (Oldjim)  link fixed - the forum software didn't like it ]
Oldjim
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Posts: 38,460
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Re: Training period on moving to 21CN on Value

That is correct and from what Jojo said it looks like it hasn't been rolled out yet.
Oldjim
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Re: Training period on moving to 21CN on Value

Forced the noise margin down to the minimum I could using DMT yesterday (6.9 dB) with the following results after 24 hours
The first graph is CRC per 15 minutes
MisterW
Superuser
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Re: Training period on moving to 21CN on Value

It will be interesting to see how the DLM responds to the increase in error counts.

Superusers are not staff, but they do have a direct line of communication into the business in order to raise issues, concerns and feedback from the community.

Oldjim
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Re: Training period on moving to 21CN on Value

After over 2 days at the higher speed I did a bit more fiddling and after 2 resyncs with different settings on DMT I have achieved this which is exactly where I want the sync speed to be (default noise margin now about 9dB so a 3dB noise margin drop by the automatic system won't cause too many problems)
Noise Margin:    9.1  dB
Connection Rate:  4000  Kbps
Line Attenuation: 51.0  dB
Power:            19.2  dBm
Max Rate:        4448  Kbps