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Openreach vectoring trial to expand to 100 cabinets
Friday 30 January 2015 15:09:31 by Andrew Ferguson

For those who have VDSL2 (FTTC) installed already and have seen the speeds drop off as more people upgrade in an area (this drop off is often the result of crosstalk) then news of the vectoring trials expanding will be welcome. We understand that Openreach is to start enabling vectoring on more DSLAMs as of February 2015 with the aim of having 100 cabinets running in vector mode by the end of March 2015.

The cabinets involved will be spread across the UK, and we presume would be picked to give a sample of the varying cable densities and lengths that different areas will have.

The trials will closely monitor the speeds that people receive, but it is possible that some people who have seen speeds drop from 74 Mbps to 62 Mbps might see that loss totally recovered, the effect of vectoring is generally thought to be less for longer lines, but for those just under the 24 Mbps mark at say 21 Mbps the improvements might just boost speeds enough to earn a superfast label. The 1 to 2% who have line lengths to their cabinet of over 1500m are likely to see minimal improvements, but predictions are much harder for these lines, hence trials to help Openreach understand real world performance.


Posted by adslmax about 1 year ago
And where the list for the 100 cabinets?
Posted by andrew (Favicon staff member) about 1 year ago
Obviously if I had the list I would have published it, have asked for one, so do not panic.
Posted by neifo about 1 year ago
I'm on the end of a 1200m line and my speed has dropped from 30Mbps to 12Mbps and I've been told by OR that the drop is a result of crosstalk. Am I likely to see a speed increas if vectoring is enabled on my cab?
Posted by 19nbg71 about 1 year ago
BT will start testing this summer in roughly 4,000 homes and businesses in two locations -- Huntingdon in Cambridgeshire and Gosforth in Newcastle.
Posted by andrew (Favicon staff member) about 1 year ago
If the drop off is down to crosstalk then yes. The impact is going to vary a lot based on where the other lines are in the bundle, rather than just a simplistic 20% boost for all.
Posted by TheEulerID about 1 year ago
Since I had a line fault fixed (about 8 months ago), I've had no loss of sync speed. Indeed, following a firmware update to my HH5 at the beginning of the month, my line is now syncing in both directions slightly faster than before. (About 6-7% both ways).
For a couple of weeks after this Interleaving got slapped on, which more than undid the good effect downstream, but it's back off now. Increased x-talk hasn't really affected me.
Posted by Blackmamba about 1 year ago
Hi Openreach and others
I hope Exchange HDJ Cab 12 will be in this 100 Cab Programe because it will get a few more over (Surreys 15 meg download target) all the other customers on this 3000 line exchange have service over 15 meg.
Posted by Keef1977 about 1 year ago
Yeah, mine started out at 75Mb, but as soon as everyone started ordering, mine is now down at 50Mb... I'm guessing I'm about 200 - 250m away from my cabinet, so a 25mb hit on the line is quite disgusting. If it keeps going, then being on Infinity 2 will be pointless.
Posted by timmay about 1 year ago
Excellent news. Hopefully this'll restore my sub-100 meter line to the full 80Mbps again... and allow for a possible further increase in speed if BT up the speed of FTTC.
Posted by timmay about 1 year ago
Shocking! Just looked at my Sync. I originally got 80,000Kbps now after ~18 months I'm getting 63,012Kbps.
Posted by TheEulerID about 1 year ago
Are we going to be told which cabinets are going to be included in the trial? The odds are against it of course for any one person (500:1 or worse), but it's conceivable there's a member of this site who is.
I suppose BT might want it to be a "blind" trial as far as the customers are concerned, as I don't suppose they'll want a bunch of people doing resyncs all the time to try and gain an improvement.
Posted by andrew (Favicon staff member) about 1 year ago
Have asked for a list, but suspect it might only appear as and when cabinets go live.
Posted by Blackmamba about 1 year ago
Hi Broadband Watchers.
As from the above report 100 Cabs in 8 Weeks shows it will be either a Card Change or software but it could be all ready done.
Posted by TheEulerID about 1 year ago
I would sincerely hope it doesn't involve a card swap as that would surely scupper the economics of the exercise. I suppose it might be for a firmware update, but surely that is done remotely.

I would expect the delay is more likely to be about the degree of pre-planning that's required as I imagine there are different configs, more data to collect and so on.
Posted by WWWombat about 1 year ago
Good to see something happening with vectoring. It was strange to see the long term vision with G.Fast this morning without any mention of vectoring.

Perhaps they really are going to stick with the same speed packages.
Posted by Ixel about 1 year ago
I wonder if this was why I saw two people working inside the fiber cabinet here recently, they had lots of equipment and there was no capacity issues reported on BT Wholesale's DSL availability checker.

Fingers crossed some cabinets on SDESTBR get this.
Posted by Blackmamba about 1 year ago
Hi Broadband Watcher. EMLC
If the upgrade on the 100 Cabs is data or card I think it will be refreshed on the monthley routine on the EMLC so it could be loaded in sections after reading the notes.
Posted by rtho782 about 1 year ago
What happens where customers have replaced the CPE with devices that do not support vectoring? (e.g. some Draytek models, etc).

My opinion is that these lines should be disabled until the customer rectifies the situation by putting their openreach modem back in place, but I have a feeling such users will just be left to interfere with everyone else's line.
Posted by Ixel about 1 year ago
@rtho782: As I understand it, the policy will be that non-vector capable modems will run in 'vector friendly' mode. This likely means a significantly reduced power, sync rate, and such to not cause much crosstalk to those vectored. The reason I say this is because the current JDSU's that engineers use have a SIM module that isn't compatible with vectoring either. As such, in order to test the VDSL2 connection they will be able to connect in a 'vector friendly' state instead.
Posted by Ixel about 1 year ago
... continued

This is the cheapest approach for BT Openreach and I'm fairly certain they'll do this instead of replace all the SIM modules to a more expensive SIM module that supports vectoring. Current SIM modules in use have an Infineon chipset, where the more expensive vectoring capable SIM module has a Broadcom chipset in.
Posted by TheEulerID about 1 year ago
One important thing to note about is that the relevant SIN specifically says Vectoring must be supported (and it's up to the ISP to enforce that). What will probably happen is those running non-vectoring capable modems will find a loss of throughput as a low output "vectoring-friendly" mode is enforced on those.

Be warned when choosing a modem/router.
Posted by WWWombat about 1 year ago
Some of the studies on vectoring show that alien disturbers - non-vectoring lines - can be made to have reduced impact on the vectored groups by being "managed" - or made to run at reduced speed.

I suspect BT will enforce this through banded line profiles via DLM, with a curt reference to the SIN when anyone complains.
Posted by WWWombat about 1 year ago
Interesting on the JDSU.
I wonder how they'd intend for engineers to test & fix lines if their test equipment can't work at the full potential of the line.
Posted by TheEulerID about 1 year ago

I rather suspect it would be during the negotiation time that any "vectoring-friendly" psd will be imposed on non-cooperative modems. I would have thought that would be a standard feature of the vectoring management software in the cabinet MSANs (suitably customisable of course). DLM would be a rather clunky way of doing it.
Posted by WWWombat about 1 year ago
Good point. I guess it depends whether "the solution" can be figured solely at sync negotiation, or needs some feedback - possibly from other lines - during showtime.
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