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[JGO]

http://forums.thinkbroadband.com/fibre/4230912-can-fttc-handle-speeds-above-80-mbps.html#Post4230912

This thread sets me wondering if BT has set an end date for ADSL/VDSL techniqies or is it being stretched indefinately by accountants who can't accept very large capital outlay however justified  ?  Or is the "alternative explanation" correct ?!

[asbokid]

G.Vector will have limited use in bundles which include non-vectored lines.  For example, in cases where pairs carrying VDSL2 lie in the same bundle next to pairs carrying ADSL2+  served by DSLAMs in the exchange.   Since the crosstalk on those ADSL2+ lines wont be included in the VDSL2 vectoring FEXT matrix, it will be seen as alien crosstalk that can't be identified or compensated.

Unless BT does something draconian like forcing people off ADSL2 from the exchange (and to hell with LLU, would the regulator allow that?), vectoring is going to be a disappointment for many.

At best it's going to claw back bandwidth lost to far-end crosstalk but it's not going to actually increase the throughput beyond its maximum limits (i.e. on Profile 17a that is 100Mbps downstream actual net data rate).

cheers, a

[ryant704]

By the time vectoring is being rolled out I expect us to be on the 30a profile.

[asbokid]

Because of frequency-dependent attenuation, those higher subcarriers, the DMTs using frequencies 17MHz up to 30MHz, are only utilisable for loops of a few hundred metres or less though. Vectoring won't change that. And the port density of 30a cards is very low.  The maximum 30a subscriber port per Huawei linecard is 16.   And Openreach doesn't want low density linecards.  Because it either means fewer end-users, or more cards, more powerful DSLAM controllers and larger cabinets. Which serves to lower revenues while adding to the capital costs.

[guest]

http://forums.thinkbroadband.com/fibre/4230912-can-fttc-handle-speeds-above-80-mbps.html#Post4230912

This thread sets me wondering if BT has set an end date for ADSL/VDSL techniqies or is it being stretched indefinately by accountants who can't accept very large capital outlay however justified  ?  Or is the "alternative explanation" correct ?!

I'm 100% certain that the techie peeps at Adastral view FTTC as a stopgap which is maybe good for 5-10 years in the current marketplace. Frankly FTTP or FTTB is an expensive proposition in the UK so FTTC was an understandable midpoint. BT won't recoup the costs of FTTC IMHO as they will be forced to FTTP/B much much faster than they'd wish.

The problem from my perspective is that both FTTC and Virgin cable are being presented to Joe Public as "fibre" which as we all know is nonsense. So when real fibre arrives everyone goes "had that rubbish its nothing special"....

We'll see, its not going to be any sort of panacea thats for sure - some BTO guys ought to pick up REALLY transferrable skills working with VDSL anyway.

I suspect in 2023 those of us still around will be moaning about when FTTP is coming - ironic really that BT in the 1980s wanted to fibre up most urban areas. Monomode cable to the premises IIRC but I think I'd probably be comfortable with that

[guest]

Amusingly Andrew over at TBB has linked up something on this on their front page article about vectoring/self-install.

Somewhere in amongst all that is a BT guy saying its going to take 10-15 years (he uses the phrase late "tweens" IIRC) to recoup the current cost of FTTC.

Dream on boys, if you get 10 years out of it before being forced to deploy FTTP/B in a widespread manner then I'll be astounded.