Can FTTC handle speeds above 80 Mbps?

The reason I have asked this question is that the Open Reach engineer I saw today said that FTTP is unlikely to come to my area but at the end of the summer FTTC will offer up to 120 Mbps. I thought only FTTP offered this sort of speed. Can the 'fountain of knowledge' people advise!?

In reply to a post by shalom2005:

The reason I have asked this question is that the Open Reach engineer I saw today said that FTTP is unlikely to come to my area but at the end of the summer FTTC will offer up to 120 Mbps. I thought only FTTP offered this sort of speed. Can the 'fountain of knowledge' people advise!?

Depends on the distance. Last I heard on very short cable runs it can do up to 200Mb/s in the lab. Perhaps BT are going to roll out a new profile that increases speeds for those on short lines. There is also something called 'vectoring' that is rumoured to be coming soon. This works in a similar way to noise cancelling headphones to counteract cross-talk between cables in a bundle. In theory it will give almost everyone a boost. There's an Ofcom document floating around that is very speculative but suggests than 1Gb/s might eventually be possible.

Alternatively (and perhaps more likely) the engineer was talking out of his [censored]. That's something BT engineers seem adept at.

Edited by Andrue (Wed 17-Apr-13 18:54:14)

Thanks Andrue - that's why I posted here. I've not read anywhere about what he said & if it was going to launch at the end of the summer I would have thought it would be heavily advertised.

Anyway if I get around 60 Mbps on a 80 Mbps profile I doubt my speed would increase to 90 Mbps

More down to the line cards not being able to handle anything above 17a profile.

In reply to a post by lockyatlrg:

More down to the line cards not being able to handle anything above 17a profile.

Can you explain more fully ?

These are the Huawei VDSL2 linecards, taken from the Smart MA5616 Hardware Guide V800R310:

http://www4.picturepush.com/photo/a/12715522/img/Hua...

Profile 17a is limited to an Actual Net Data Rate (ACTNDR) of 100Mbps Down 60Mbps Up. And Openreach imposes an IP Profile of 80/20 on top of that.

Profile 30a potentially supports an ACTNDR of 200Mbps Downstream. That is only on the very shortest loops though. And the port density of the 30a linecards is only 16, so they're not very cost-effective.

SFAIK, the highest port density of VDSL2 card is currently 48, for both the ECI M41 DSLAM and the Huawei MA5616.

cheers, a

A year ago the max attainable speeds on my line were 102/32 Mbps on an 80/20 profile. As FTTC take up has increased, my max attainable speeds have fallen to 93/28 Mbps. Home to cabinet distance is about 300 Metres. If BT has plans to roll-out higher speeds then my guess is that they will also roll-out vectoring.

Quote: In vectoring, the VDSL signal is optimized for the subscriber line by compensating for interference between adjacent lines. Even when many subscribers use the line, this allows a transfer rate of over 100 Mbit/s for each connection. Unquote Source AVM Berlin

AVM Berlin is already producing vectoring capable modem/routers for German consumers. To work, the network also has to be vectoring-enabled.

Ah - I think I'm qualified for this one

Yes - FTTC can go over 80Mbps in 3 different circumstances:
- Short distances to the cabinet - probably within 200 metres.
- Medium distances to the cabinet (between 400 and 500 metres), but with vectoring applied to remove crosstalk
- Longer distances with multiple pairs bonded together, probably alongside vectoring

Reading stuff about the recent suggestion that the Aussie NBN should consider FTTC, I saw an article summarising the Openreach rollout. In there, Mike Gavin said that Vectoring would be deployed later in 2013.

There were no other details, in particular the headline packages that they're going to offer. But I suspect they'll be keen to match Virgin's offers.

Alcatel-Lucent have a self-aggrandizing white paper on the current state of Vectoring/Bonding, with the more recent trials suggesting that 100Mbps is a straightforward goal to distances of 400 or 500 metres - presumably depending on matters such as the diameter of the copper used in the access network - and that 120Mbps may be possible to around 300 metres.

Of note is the fact that the more recent trials are getting better speeds out of vectoring, suggesting lessons are being learnt.

The use of Vectoring generally means that more people can get closer to the theoretical speed for their distance, giving Openreach a bit more licence to set a higher headline package. I was expecting them to set 100Mbps packages, rather than 120Mbps.

The use of bonding alongside vectoring can give speeds of 200Mbps out to 400 metres. I wonder if we'll ever see BT making use of this in a reasonable fashion, rather than with a BET-like kludge.

Yes - Deutsche Telekom have just been given approval by their Ofcom-equivalent to roll out vectoring.

It is a contentious decision for a regulator, as it means the end of meaningful physical sub-loop unbundling.

In reply to a post by WWWombat:

It is a contentious decision for a regulator, as it means the end of meaningful physical sub-loop unbundling.

Do we have any co-located SLU ? Openreach evaded a Rutland cab deployment, I guess SYDR is the most likely. So was it "meaningful" in the first place.

Mind there's enough about cross-vendor or multi-DSLAM vectoring to suggest that it may not have the suggested consequence.