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Migration to 21CN

Hamster
Dabbler
Posts: 13
Registered: 24-01-2011

Migration to 21CN

On 14th November 2011 I was advised by e-mail that my service would be transferring to 21CN "within the next 5 weeks" and that a new 10-day training period would occur. The 5-week period ended on 19th December and I have still not seen any changes nor any down time and am still syncing at a rather high 12dB noise margin which I always seem to have been on.  Could a moderator advise whether I am still to be switched or whether I am not to be switched!  As my line is long (61dB attenuation) and speeds rarely go above 1700kb/sec, a change to 21CN may not, in fact, offer any advantages.  Would appreciate a progress report if possible!
Many thanks
'Hamster'
4 REPLIES
Community Veteran
Posts: 38,460
Thanks: 1,027
Fixes: 62
Registered: 15-06-2007

Re: Migration to 21CN

Obviously I don't know what has happened in your case (only staff have access to that information) but I can offer a few generalities.
When moving from 20CN to 21CN but on ADSL1 then from my experience the previous line settings - noise margin, interleaving, etc. - are carried over.
It is only when you move from ADSL1 to ADSL2 or ADSL2+ does the line retrain.
With an attenuation of 61dB the automated move should keep you on ADSL1 as ADSL2 would give no advantage and could well cause a reduction in speed
Superuser
Superuser
Posts: 9,465
Thanks: 814
Fixes: 52
Registered: 06-04-2007

Re: Migration to 21CN

You might well have been migrated to 21CN but probably placed on ADSL1 since as Oldjim says ADSL2/2+ is beneficial only if sync speed is above 4000kbps.
However I think current line settings are also carried over even if the move is to ADSL2/2+ (though uncapped upstream sometimes appears to be selected for those close to the exchange).
If you do a speed test (full test, not beta) at http://www.speedtester.bt.com does it give you an IP profile which is not a round number, and does it test upload speed? The presence of these would indicate you are on 21CN.
David
David
machare
Grafter
Posts: 135
Thanks: 1
Registered: 13-01-2011

Re: Migration to 21CN

I hope to be in much the same  situation in a couple of months time.  My plan is to try out ADSL2+ anyway.  It it makes matters worse that I thought that I might be able to force ADSL by chaing the settings in my router.
Hamster
Dabbler
Posts: 13
Registered: 24-01-2011

Re: Migration to 21CN

I've just carried out a BT Speedtest and it still gives my IP profile as the 'old' 1250kb/s rather than the 21CN '88.2%' method so I can't have been changed over to 21CN yet.  So why I am wondering was I sent an e-mail back in November last year saying that I would be within 5 weeks?  Will it still happen?  I can't sleep until I know!!
Regards
Rod