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Any benefit of ADSL2 for long line? Advice please

maranello
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Re: Any benefit of ADSL2 for long line? Advice please

OldJim and Anotherone, thanks for the advice.
The router stats were taken a few minutes before posting, so it is most likely that the changeover occured around 6.00am on Wednesday. As I am away from home now I'll take your advice and over the weekend see if a reboot around midday improves things.
I'll probably stick with the capped upload, as I don't do much for it to be an issue and I would prefer to squeeze as much as I can on downstream speed. The speedtest results may not be rpresentative as I used a wireless connection, I was more interested in what the BT IP profile was in comparison to the PN one (which incidently appears to be unchanging and at 3Mbps).
Other than this I will probably leave things be for a while to see if the stability I was getting on ADSL1 is still apparent on ADSL2. Typically I was remaining in continuous sync for 30 to 60 days, any longer and I would normally aim to manually power down and resync the router. I'm hopeful that my connection could cope with a 3db target snr margin, which could give me an extra 0.5 to 0.7Mbps on d/l speed.
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jelv
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Re: Any benefit of ADSL2 for long line? Advice please

You're getting confused with Annex M which does use some of the downstream for faster than 1.1M upstream. Just uncapping the upstream rarely affects downstream directly - the only risk is that the faster upstream may cause extra errors.
jelv (a.k.a Spoon Whittler)
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maranello
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Re: Any benefit of ADSL2 for long line? Advice please

I've never really understood the significance of the error counts in the router stats, they always seem to be such big numbers, even though the connection has been stable. From the perspective of a total novice, I've always been under the impression that if the errors are too high, this would be symptomatic of uploading/downloading data when the line is suffering from too much noise for the router to maintain sync.
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ejs
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Re: Any benefit of ADSL2 for long line? Advice please

The DLM will consider the error counts when making its decisions to raise, or not lower, the target noise margin. And of course nobody knows exactly what error counts the DLM would consider to be bad.
Pettitto
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Re: Any benefit of ADSL2 for long line? Advice please

A lot of the errors that router logs show also include errors that have been corrected automatically.
maranello
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Re: Any benefit of ADSL2 for long line? Advice please


By way of an update, having monitored the downstream noise margin at various times throughout the weekend, it appears that ADSL2 is slightly worse than ADSL1. Whereas prior to the tranfer to ADSL2, the noise margin hovered close to 6dB with only +/- 0.2dB variation, on ADSL2 the noise margin has never been seen to be above 6db and is typically around 5.1 - 5.8. There has been no loss of sync in the past 5 days. The router is reporting a small increase in attenuation (61dB as opposed to 60.5) and 0.0dBm Output power (is this significant?).
There have been reports of recent problems in parts of Cheltenham following some cable vandalism, although I don't live in the areas where problems have been reported so this may not be a contributing factor.
In summary, it does not appear that ADSL2 offers any benefit over ADSL1 in terms of download speed.
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jelv
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Re: Any benefit of ADSL2 for long line? Advice please

What is the sync speed like?
jelv (a.k.a Spoon Whittler)
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maranello
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Re: Any benefit of ADSL2 for long line? Advice please

Downstream sync speed is 2842kbps, BT profile 2.51Mbps
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jelv
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Re: Any benefit of ADSL2 for long line? Advice please

From your opening posts that suggests you've seen a slight improvement. Correct? If so I wouldn't worry about such a small drop in SNR.
jelv (a.k.a Spoon Whittler)
   Why I have left Plusnet (warning: long post!)   
Broadband: Andrews & Arnold Home::1 (FTTC 80/20)
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maranello
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Re: Any benefit of ADSL2 for long line? Advice please

When I started this thread I has a sync speed of 2914kbps, on ADSL1 over 21CN. Prior to that on 20CN the sync speed was enough to give me a profile of 1.75M.
Soon after there were some issues affecting the BT network, which caused a re-sync to ~2.8Mbps. The change to ADSL2 gave no improvement over those figures, the biggest increase came from being moved onto 21CN.
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ejs
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Re: Any benefit of ADSL2 for long line? Advice please

Although there's been no significant immediate change in your downstream sync speed and noise margin, on ADSL2 you might get fewer errors, or fewer uncorrectable errors, improving the DLM's view of the line's stability.