VDSL 2 Pair Bonding

Just wondering if anyone had thoughts on pair bonding via FTTC?

It's used in a number of other countries, largely to extend the reach of the speeds as sold although in some cases purely to boost speed but Openreach have thusfar been quiet on the subject.

Especially for the Openreach bods, any ideas why Openreach haven't publicly looked at this solution yet?

With vectoring and phantom pair technology a couple of pairs would be more than a match downstream for Virgin's 120Mb service for many people and would leave anything Virgin can release any time soon in the dust for upstream capacity.

I'm wondering if there are regulations causing issues with it due to the lack of voice over FTTC and the requirement to allow operators to unbundle anything copper related, so Openreach taking a part of a loop and keeping it to bond with another loop would be a no-no.

The alternative is of course that it threatens Ethernet in the First Mile / leased line revenues hence CPs don't want it and Openreach won't offer it if they aren't asked for it.

speculative guesses?

1 - consumer freindlyness, adds complexity and cost. This appears to be BTs primary market for FTTC. With FTTPoD been aimed at the small business market.
2 - BT seem to not feel a need to market US speeds of higher than 20mbit/sec and a speculative guess has the bulk of infinity customers on the 40/10 not 80/20 service (this is backed up by that sky dont seem too bothered to sell their sky fibre pro product), so lack of demand for speeds higher than 40/10.
3 - Extending reach probably not their priority at the moment with the rollout still in progress.

I think vectoring needs to be seen to be effective first and foremost, as pair doubling adds crosstalk, there is stories eg. of people having 2 FTTC lines in one property and when the 2nd is activated the 1st loses a ton of sync speed.

With BT they are not frontrunners on tech and dont roll out things just because they better, they need to see it as a profit making machine.

http://blog.thinkbroadband.com/2013/05/so-how-fast-a...

Shows the spread of people using our tester and a good proportion on 80meg product. Probably because Infinity1 only gained unlimited option fairly recently.

fair enough seems reasonably healthy demand then.

Fluidata can bond up-to 3 VDSL lines.

http://www.fluidata.co.uk/connectivity/purefluid/

Giving up-to ~200Mbps download and ~60Mbps upload.

I think that eventually openreach will 'need' to offer a bonded VDSL solution that doesn't need two phone lines all the way to the exchange and therefore two rentals. Instead providing a second line from the cabinet only for a bonded connection. This is perhaps the only way they will be able to compete with VM and other providers. And if vectoring is used as well this could be a way of getting 100~200Mbps to a reasonable number of people.

I think there are a few issues at play here.

Firstly, VDSL2 bonding is probably seen as a product to extend reach - to get the 30Mbps speeds out beyond the current distances, rather than getting 160Mbps to properties within 300 metres.

The second issue is vectoring, which (from BT's apparent statements) seems to have the same role - reach extension.

Third is the limitation of resources. Many properties may well have 2 pairs in the dropwire back to the DP, but are there 2 pairs for every property in the cables from DP back to PCP?

I think all three link together. Chrysalis is right that two pairs bonded will cause crosstalk, and reduce each other's speed - so bonding is a better solution after vectoring arrives.

The (possible) lack of spare pairs to allow bonding to be available for everyone means that BT are likely to reserve it strategically - which means I think they will leave it to solve the reach-extension cases that vectoring alone cannot solve. Another reason it is going to wait until we know how far vectoring actually extends the reach of 30Mbps services.

I suspect that it will become part of the mix in BDUK2, in the 2016-2017 timescales, as part of the drive to extend coverage from 90% to 95%.