Why Are FTTC Connections Speed Capped?

[#1]

Does anyone know why Plusnet, and other FTTC providers, cap their highest speed FTTC connection at 80 down / 20 up?

For example, because I live only 50 metres from "our" cabinet, my hub always indicates that the "Maximum Data Rate" is in the region of 105 down /  35 up, but the actual data rates are "capped" at the contracted 80, (shown on hub as 79.999), down / 20 up.

I understand that the sync speed has to be slightly lower than the maximum possible to maintain the stability of the connection, but why not let it find its own "safe" maximum, as it would if my maximums were less than 80/20?

There is a, (sort of), precedent for this:

About 35 years ago, I started working in the Outside Broadcast department at BT. One of the products that we supplied at the time was "high quality" audio circuits over the same copper network that now carries ADSL/FTTC and telephone connections. These lines were used for football commentaries etc.

Special amplifiers etc were used to increase the available audio bandwidth. The minimum specification for these lines was "up to 6.5kHz", but the bandwidth was not deliberately restricted, and the spec specifically stated that "the broadcaster is free to use any extra bandwidth available".

So, why aren't FTTC connections allowed to "free run", and find their own maximums?

[#2]

@Mr_Paul 

80/20 & 40/10 speeds are the products that OpenReach offer through BT Wholesale. End of story.

Brian

[#3]

@bmc 

Thanks for the reply, but all it does is modifies my question to:

Why does Openreach set a limit of 80/20 for their maximum FTTC offering, and not let "free run" and find their own limits?

I don't know what the theoretical maximums are for FTTC, but as I said before, I am only 50 metres from the cabinet, and in theory could sync at just under 105/35 with a safety margin - so I'd guess that the actual possible maximums of FTTC aren't much more than this?

What are the speeds of Openreach's minimum FTTP offering? Maybe they are concerned about taking business away from their lowest speed FTTP products?

[#4]

I don't know the answer of why speeds are capped at 80/20, but I'd guess it was to make sure that there is enough backhaul bandwidth for everyone - if the few people very near cabinets maxed their connection out it could end up restricting the available bandwidth to people further away with already slower connections.

As far as FTTP goes, I think they want to move as many people as possible over to that - the available bandwidth is far higher. But they restrict upload on FTTP to avoid competing with leased lines - which are much more profitable than FTTP.

[#5]

@Mr_Paul 

I would guess it's to do with quality control so they didn't get snowed under with complaints about "poor" speed due to the line. 80 down was probably the maximum they could go for while maintaining a stable line for the majority of users. Yes, some could have got better speeds but OR have to "define" their product offering.

FTTP offers the same speeds at the the lower end (although PN no longer do FTTP 40/10).

Brian

[#6]

@corringham @bmc 

Thanks both for your replies.

"FTTP offers the same speeds at the the lower end (although PN no longer do FTTP 40/10)."

Do Plusnet offer 80/20 as an FTTP service then? I'm not offered that as an option because Openreach haven't installed FTTP in my area - nor will they do so for a few years yet, I don't think.

FTTP has been available here for about 3 years though via CityFibre, though take-up doesn't look to be too high: they have a box opposite my house, and when an engineer opened it up recently as I was passing, it looked like there were only about 3 or 4 connections.

It looks like Vodaphone offer 82, 100, 200, 500 and 910 Mbps download speeds via FTTP, (but with guaranteed speeds only half that in each case). Oddly, at the moment, 910 is cheaper than either 500 or 200, (£29/month vs £32/month)!

[#7]

@Mr_Paul 

Yes, PN have a 80/20 product though it's called Full Fibre 74 (FF74). I suspect this is what can be reasonably guarenteed on an 80/20 product allowing for overheads. For once the marketing appears to be in line with the speed!!!

If CityFibre is available then, as you say, it could be a while before you get OR FTTP as Ultrafast Internet is available in your location. Have you looked at their website - they wholesale their network so other ISP's are available eg Zen Internet use them.

Brian