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FTTC Question
JSemple3
Posts: 8,652 Forum Member
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Curious about something about FTTC. I got it installed 2 weeks ago today via BT (It really is a lifechanger) best thing that ever happened to me I think. But anyway how does it actually work at exchanges? I know that old ADSL worked via the main exchange and I figured out that FTTC works via a cabinet (I'm about 800 metres away from my cabinet) My line can do 52.18 and about 20 down. Is there not a main main FTTC cabinet beside the old ADSL cabinet or is it all done via the street cabinet (sorry if I not making sense) just very curious about it all
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There is no such animal as an ADSL street cabinet. All the ADSL gear is in the exchange. With ADSL the pair of wires from your phone socket goes all the way back to the exchange where it is split into two paths. One goes to the phone equipment for the phone service and one goes to the ADSL kit for the broadband service.
With FTTC the split is performed at the roadside cabinet instead of the exchange. Your phone service is still connected as it always was all the way back to the exchange but your broadband is connected to the kit in the cabinet.
This allows higher speeds because the length of copper between your home and the cabinet is very much shorter than the distance to the exchange (usually) and line length is a determining factor in how fast your broadband can go. Long lines equal low speeds generally.
Although the distance from phone socket to cabinet is usually much shorter than the distance back to the exchange this is offset by FTTC pushing more data into the copper wires than ADSL.
If it was only poking 2Mb down the wires then I doubt a person 100m from the cabinet would see much difference to someone 2m from the cabinet. But because it's poking much higher data rates the length of cable has a greater effect. So the person 100m from the cabinet is likely to see lower speeds than the person 2m away. All other factors being equal.
If the 2m connection is on some really ropey bit of wire with loads of really badly repaired breaks then it could be worse than the 100m cable!
Bit of a difference that. i know people who have gone for FTTc and glad they have, but then like you they was getting naff ADSL speeds. If you get decent ADSL to start with then the choice is a bit more difficult to make.
Yeah, if you was closer to the fibre cab, you would get a better speed, but then it still depends where the copper wires go from and to.
The maximum length of an Ethernet cable, for example, is limited to @ 100m.
Fibre, on the other hand, is very good at carrying a high-speed signal over considerable distances, a single-mode fibre carrying light with a wavelength of 1550 nm has an attenuation rate of @ 0.2 dBm/km.
The advantage of this, as chrisjr has explained, in terms of FTTC is that instead of the data having to be carried over a ropey old copper cable for a couple of miles from the exchange, meaning that with all the noise and attenuation on the line meaning the final data rate is very low, with FTTC the copper cable is only going from the customer premises to the cabinet, which may be only a few yards away. maximizing the data rate available to the end user.
Yes, for example, being able to upload an 800 MByte HD video to Youtube in 6 minutes instead of 2.5 hours really is a game changer, the whole process is very efficient these days with a good FTTC connection.
If you need that speed up of cause. i know a mate of mine is more bothered about his upload speed than download.
Not that i have put much up on YouTube, I can start it off at night and let it carry on, my upload is still faster than what I had on ADSL. My mate who uploads a lot to You tube makes a lot of use out of FTTc faster upload.
No, I specifically asked for BT infinity 2, but both the online checker and the woman I spoke to at BT said the maximum for the line was 38mb, even with infinity 2. She suggested I just went for BT infinity.
At first it struck me as really odd given I'm only 600m from the cabinet and have had good connection speeds on adsl2 which is slightly further away than the exchange - but I read somewhere that the drop off as you get further from cabinet/exchange is steeper on vdsl than adsl, so perhaps that explains that.
Heskethbang,
Tomorrow will be my 1st year of having FTTC on an 80/20 profile and I am about the same distance as you of 600m from the FTTC PCP. Here is what I can tell my experience from having it for the last year.
I to am still quoted as getting the maximum speed of around 37mb/s on BT Wholesale checker but these are only estimates. Before I got FTTC when I was on ADSL2+ for only 11 months I was getting around 15mb/s, as the exchange only got upgraded in 2012. Before that on an ADSL 8mb/s frequency I got around 7.2mb/s at 1200m from the exchange.
A year ago when I went live with FTTC I was the first one on my fibre cabinet as I knew it had been switched on and I got 65mb/s dl & 13mb/s ul for about 3-4 months then it started to slow down to 60 & 55mb/s and stayed at 50mb/s for about 7-8 months but it has now started to increase again over the last 6 weeks to 53mb/s. This maybe all due to more and more people being added or removed from the same FTTC cabinet as me over the year.
I am also an accredited FTTC installation engineer and last year I was installing it all over East Anglia & in London. From an installation point of view if the fibre cabinet is more than 1km from your house then you will only get a very slight increase in speed, as the minimum speed BT are required for a working FTTC line is 15mb/s.
Some installations that could not be completed due to the regulations went under that. On one particular installation the customer was 1.6km away from the fibre cabinet the broadband increased from 4mb/s to 9mb/s which for some people is quite an increase. But according to the BT training manual this FTTC installation shouldn't be completed.
I am not a FTTC installer anymore so the regulations may of changed since.
Many thanks for this useful insight. I did wonder if BT were being conservative with their estimates. If there was some way of trialling the service then it might be worth doing but as I'd have to get sockets moved and sign up to a lengthy contract, it's not worth it for a service that may not even be as good as my Virgin Broadband service.
The sync speed will drop slightly as more people are added to the fibre cabinet but this isn't a capacity issue it is caused by interference on the copper side (cross talk). That is why BT's speed estimates are conservative, to take this drop into account. Vectoring is currently being tested and this will help a great deal in reducing this interference and people will see their sync speed increase as a result.
It seems that until something changes with telephone line based broadband services the speed you get will always be a bit of a lottery depending on how far you happen to be from the exchange/cabinet. This seems rather unfair given that everyone pays the same for a given level of service e.g. ADSL, Infinity 1, Infinity 2 etc.
I guess that in a few years time we'll all have fibre optic lines right into our homes, delivering not just broadband but also cable TV (if you want it) and telephone aswell!
Parts of the country do have fibre to the home from BT. Not many, but it exists here. Later in the year you can order it if you're in a FTTC area but its expensive.
BT announced in their end of year presentation (that's on the website) that the long term plan is to go faster, using vectoring initially and then g.fast. They will just keep bringing the fibre closer to the house, eventually to the pole.
BT have been working on the above strategy for a number of years now but the implementation of that strategy is basically down to the commercial viability of it from either BT Retail or via BT Wholesale to other potential ISP's.
redcar1 - using the currently implemented last mile technology - copper - currently is the most commercial way of offering the service. New estates and building complexes will have either coax or fibre implemented because the cost of "pulling" it through the ducting with the cost of the actual cable is these days almost the same as cooper. If you think about how many copper connections the BT Group has implemented over the years - I think it's about 24 million currently - then the cost of using "new technology (fibre / coax etc.)" is very high and would make the cost of "broadband" unacceptable.
Infinidim :cool:
I understand that we are really stuck with telephone wire to carry broadband in many places unless you're in the ca. half of the country that Virgin covers or one of the few places where direct fibre connection is available. In fact I still find it quite amazing that twisted pair telephone wire can carry a complex data signal as well as it does! However, I don't think it's fair that people in rural areas (or even towns where large exchanges may be some distance from your home) have to pay the same price for a broadband service that may be 10 or more times slower than what others are getting.
I don't know for sure but I get the idea that with Virgin cable's hybrid fibre-coaxial system speeds are more consistent regardless of where you are on their network.
Yes that's right the signal defrades less over coax. BT's system does have its advantages though, there's a fair bit of sharing of coax in Virgin's HFC network, you don't have a dedicated run of coax all the way back to the fibre cabinet. Whereas with BT's network you do have your own copper pair back to the fibre cabinet. This causes congestion in VM's network.
The density of cabinets is different too, in a Virgin cabled area there's loads of coax cabinets, but not many fibre ones. You're more likely to be closer to a BT fibre cabinet than you are a Virgin Media fibre cabinet So BT already have fibre closer to more people in urban areas which puts them in a good position for FTTH deployment in the future.
*MikeB* - The one thing that I wish that the BT Group would do is put more fibre out and therefore FTTC into the country areas. I know that BT are researching other technologies (for higher speeds) for these areas but some of that won't be available for a while.
Infinidim :cool:
That is not going to happen unless they are sure they will get their money back.
They are still trying to get more people to have FTTC here by all accounts as a lot of people are staying as they are, so they are not making as much money as they want from the installation.
Wireless no doubt, something like 4G, but it have to be a good price. The ISP I am with is covering parts around here that have awful broadband and have very little chance of FTTC. Pretty good considering that they are not a ISP, they are in fact a payment service.
I assume that your ISP is using either the point to point or point to multipoint Cabium's Canopy equipment to service your area.
BT looked at this type of service a few years ago and I was involved in implementing it in some countries as well. Seems to work well but does sometimes get effected by weather conditions - especially in the countries I implemented it in.
Given that Allpay has about 20 access points for there broadband and a couple more planned it is a good solution for a country demographic area. It is also very easy to upgrade - you just add another access point to the mast / location you need more connections.
Which frequency have they implemented to deliver the service?
Infinidim :cool:
That they are, equipment by Motorola
Weather here have never been a problem, but then from where I am I can see where the access point is and if I use the zoom on my camcorder I can see the access point equipment itself and I am in direct line of sight. In fact the signal strength is around 97%
It is a great system for rural areas, ok it have some downfalls, the one is now and again it gets a bit busy and the speed is a bit lower than it should be, but not really that much of a problem and I have only been affected a couple of times.
That is not the fault of the system, that is just that they did not realise how well it would do and did not have the bandwidth. they solved that now.
The second problem is if you are at the edges of the signal, I know someone who can only get 5Mb/s, because they are right at the edge until Allpay do a update later this year, but it is still better than the 1Mb/s ADSl service they had, when it worked.
The other problem that can happen and this is the way All pay does it, a lot of the access points is on churches and even on Farms, so they can be switched off, but they all got a battery backup system
but I still think the system is great and I am very happy with it and I certainly know people out in the sticks who love it. they just need to expand a bit more.
Don't quote me on it, but I think it is around the 5 Ghz.
The way FTTC works is that it is copper to a roadside cabinet, then fibre back into the BT cloud. If it is BT Infinity than the fibre back-haul goes into one of their BRAS sites then the BRAS links into the 21CN network and then into the main internet in the UK - very simplified. Copper also goes from the FTTC cabinet to the old copper cabinet net to it and back via copper to the exchange for the voice side. Here is a URL for the generic Openreach FTTC http://www.openreach.co.uk/orpg/home/products/super-fastfibreaccess/fibretothecabinet/fttc/downloads/GEA_FTTC_4.pdf
Infinidim :cool: