Long Reach VDSL trial in Isle of Lewis

I see 20 houses on North Tolsta on the Isle of Lewis have been selected for the trial of Long Reach VDSL.


http://www.ispreview.co.uk/index.php/2016/08/openrea...

http://www.islandnewsandadvertiser.co.uk/lewis-test-...

Edited by Nightglow (Thu 18-Aug-16 16:07:42)

Does anyone have any idea on when LR-VDSL will become a widespread solution to long-distance copper connections? Is it just a simple firmware upgrade to the cabinet, or does it require a sophisticated hardware extension like G.fast?

Should be software or at worst a new line card in an existing DSLAM. So less onerous that original VDSL roll-out.

As for widespread - issues around co-existence with ADSL/ADSL2+ signals are a key thing hence the variations in analysis of the effect at http://www.thinkbroadband.com/news/7499-what-will-lr...

The biggest restriction to widespread availability is that it needs regulatory approval.

The technical solution is incompatible with exchange-based ADSL or ADSL2+ services, whether from BTW or LLUs. The solution is to swap all subscribers, of all ISPs) onto a GEA product ... and you can imagine how well that will go down - especially with Sky and TalkTalk.

Ofcom will need to decide whether LLU takes precedence over long-range customers ... and will probably need to set up a scheme where this gets approved on a cabinet-by-cabinet basis.

When implemented, is LR-VDSL likely to only be enabled for lines which receive less than 10mbps through the fibre service, or the majority of lines with less than 20-30Mbps?

It'll be likely to improve every line on the cabinet - both those using standard "short-range" profiles, and all those eligible for the "long-range" profile.

edit: To add this...

The "long-range" profile can be used for any property whose line has electrical properties equivalent to 1.25km of 0.5mm copper, or longer. That cutoff happens to be the point where BT believes lines can achieve 25Mbps.

On cabinets where "LR-VDSL" has been activated, such lines can probably squeeze a little better out, because vectoring will help minimise the effects of crosstalk.

Edited by deleted (Thu 18-Aug-16 16:26:38)

Do you know of any estimated speed versus distance graphs for LR-VDSL? I found a couple, but they're all really vague and only show really far distances, not closer ranges such as 1-2km.

There is a survey on that page about upload speeds, which I took.

The voting results given for actuals may be valid, (influenced by people reporting sync or product speed), but the "NEED" result is ludicrous. Not ISPreview's fault of course, they did their best by the emphasis repeated here, but it is not credible that 36% of users need over 20Mbps upload.

BT supplied the graph on this article:
http://www.thinkbroadband.com/news/7176-long-reach-v...

At the time, we didn't know what the technology behind options 1 and 2 were.

Now, almost a year later, we know that the technology is
- Using the VDSL2 8b profile, which allows a higher aggregate transmit power of 20.5dBm (instead of 14.5dBm), but only over 8.5MHz
- Setting the cabinet's PSD mask to allow maximum power throughout the spectrum (instead of restricting it for ADSL compatibility)
- Adding vectoring

We still don't know whether this technology is option 1, 2 or something else. My best guess would be option 1.

In reply to a post by RobertoS:

The voting results given for actuals may be valid, (influenced by people reporting sync or product speed), but the "NEED" result is ludicrous. Not ISPreview's fault of course, they did their best by the emphasis repeated here, but it is not credible that 36% of users need over 20Mbps upload.

There appears to be not a lot of critical thinking going on for some of those surveys ... some people seem to just ticked the biggest number.

In this case, I have 20Mbps, but I reckon I only actually need 5.