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[WWWombat]

Am I right in saying that if I have a resync, vectoring will be removed from my line?

Highly unlikely.

Vectoring is a thing that only works if everyone on the cabinet is included, so it is only ever likely to be removed if it goes from everyone at the same time ... though there will be a resync at that time.

The STIN for "LR-VDSL" being trialled by BT shows they are planning to use vectoring in those trials (so perhaps your cabinet is one of the cabs in the "secret" list), and that all lines (including the lines that aren't eligible for the long-range variant) will be vectored. The only exception is for modems that aren't compatible with vectoring, which will be removed by "rogue line control".

No affect on the upstream though unfortunately

That STIN indicates they aren't using vectoring on the upstream, perhaps adding to evidence that your cab was enabled for part of this trial.

^{Edit: Added response to upstream behaviour}

[niemand]

No point in vectoring some lines but not others so wouldn't surprise if everyone on the LR-VDSL cabinets is vectored.

Good to see this crystalising the earlier comments about deploying vectoring where it would be of most benefit in getting lines into the >24Mb range.

[j0hn]

No point in vectoring some lines but not others so wouldn't surprise if everyone on the LR-VDSL cabinets is vectored.

not just wouldn't be surprised, it's an absolute must have.

2.5  Vectoring Vectoring  (i.e.  “real time”  crosstalk cancellation  [3]) is required to ensure  that the  LR-VDSL signals  do  not  adversely  impact the  existing  VDSL2 signals.  Vectoring  shall be applied in the downstream direction starting  from 138kHz  .  No vectoring  is applied in the upstream direction.  Modems which cannot support vectoring  will  be  manually  removed from the vectoring group.

anyone on those cabinets using an incompatible modem will definitely get a chap at the door from OpenReach. don't know if they'll enforce MCT approved modems only though.

[ejs]

I thought there was some document somewhere which showed vectoring working surprisingly well with vectoring only enabled on some lines but not others in the bundle. What does "removed from the vectoring group" actually mean? Only that they will disable vectoring on the lines with modems that don't support support or have enabled vectoring?

[WWWombat]

What does "removed from the vectoring group" actually mean? Only that they will disable vectoring on the lines with modems that don't support support or have enabled vectoring?

I think it likely means it will disable vectoring for that line. Then, depending on the level of non-support, the rest of the group has to figure out how to deal with the rogue line. Earlier research suggests it has less impact to the vectored lines if you deliberately slow it down (eg banding to half-speed) ... which could be a step taken by "rogue line control". More recent research suggested better ways to cope, but I've forgotten the details.

[S.Stephenson]

Just disable their lines then when they ring up and get an engineer out charge them for not using the correct gear 

[forceware]

 

[ejs]

I suppose it might also depend on if the non-vectoring modem is vectoring friendly, in which case the crosstalk it causes to other lines can be cancelled, but it won't have its own speed improved by the vectoring. However, for something like the TP-Link TD-W9980, I think it doesn't support vectoring and it's not vectoring friendly either.

[j0hn]

I would imagine "Modems which cannot support vectoring  will  be  manually  removed from the vectoring group" means the EU will be made to use a compatible modem. certainly during any trial they would enforce this, otherwise it would impact the trial and affect the results.

what exactly is non-vectoring, vectoring friendly (edit: genuinely asking, not trying to come across as a twat). wouldn't any modem that doesn't support vectoring continue to cause crosstalk? I thought vectoring only worked if all modems supported it.

I thought there was some document somewhere which showed vectoring working surprisingly well with vectoring only enabled on some lines but not others in the bundle.

Was it this by any chance? Managing Unvectored Lines In A Vectored Group - TMCnet
That suggests what WWWombat said, that it's only effective if the non-vectored lines are capped. It uses the example of dlm setting maxSNRM and maxPSD to mitigate the effects of the non-vectored lines.

Seems like more work configuring dlm to work around the very few who have purchased their own incompatible modem. Much easier to enforce MCT approved kit, or at least working vectoring.

[kitz]

Depends if they decide to use something like Zero-Touch technology.

I don't know if there is an equivalent for the Huawei based cabs..  but if there was,  then this could in effect should put non vectored modems into a vector friendly state.
Obviously the non-vectored modems wont see any benefit from vectoring, but it means that one non-vectored modem wont ruin it for all.

See previous discussion on the subject in this thread for more info.

Alcatel-Lucent's unique "Zero-Touch Vectoring" solves this problem by automatically handling all legacy VDSL2 CPEs. Firmware upgrades are not required, so legacy VDSL2 CPEs will be vectoring-friendly without needing to be touched. Only those CPE that are being used to provide higher bandwidth vectoring services will need to be upgraded. This provides a quick and easy way for service providers to introduce vectoring in their network, without having to worry at all about legacy VDSL2 CPEs.

Also vid @ 1:10

[youtube]https://www.youtube.com/watch?v=LouQqdNtMtI[/youtube]

>> manually removed from the vectoring group

Earlier documentation may have mentioned being given a 'vectoring profile' I cant recall now why I would have said profile and am not able to dig any deeper atm.
Other alternatives are spectrum management, PCB or as already mentioned capping the speeds of the non vector friendly lines.   iirc though to be of real benefit some fairly harsh capping may be involved.

Belgacom has their own MCT similar to Openreach's.... and a clause of shutting down lines with non compliant modems.  However iirc they got quite strict and are rate limiting non vector friendly modem lines to adsl1 speeds.

[ejs]

what exactly is non-vectoring, vectoring friendly

There are two different vectoring friendly modes, Annex X and Annex Y, in the 2015 edition of G.993.2 (which got released to the Internet fairly recently).

Annex X is the simplest one for the CPE, there seems to be very little for the CPE to do, besides indicating its support for Annex X to the DSLAM, I think it mainly needs to just ignore the different vectoring-related signals the DSLAM might send down the line. G.vector lines can cancel the crosstalk from Annex X lines for the downstream direction only, not upstream.

Annex Y, "full friendly" operation, allows G.vector lines to cancel crosstalk from the Annex Y line for both downstream and upstream. The CPE needs to do more things to support Annex Y than Annex X, in fact I think it says Annex Y requires everything in G.993.5 except for sending those error samples.

The amusing thing is, that this means that BT could have all lines running in vectoring full friendly mode, and then only enable vectoring on certain lines that the DLM or something decides need it. Then the few lines that get G.993.5 vectoring would still get as much of a speed boost from the crosstalk cancellation as they would if all the lines were doing G.993.5 vectoring. Then we could have the usual watching DSL stats for weeks, hoping the DLM decides to enable something.

[j0hn]

Thanks kitz/ejs. I just spent the best part of an hour reading up on this. Do we know what vectoring friendly mode OR use? I would guess Annex X as it's the easiest to implement, and only works on the downstream.

Then we could have the usual watching DSL stats for weeks, hoping the DLM decides to enable something.

sounds like g.inp all over again!

[ejs]

It was all just speculative, hopefully it won't be done like that, all modems should fully support vectoring anyway. But it appears the technology could allow it to be done that way.

[NewtronStar]

I was under the impression that vectoring on FTTC was shelved by OR and only the current test sites still had it running and is not to implemented any further into their network until G.FAST has started in 2017

[Ronski]

I thought they were using it on selected BDUK cabinets to meet targets.