FTTC technical question...

Hi guys, I was just wondering if someone could clarify how FTTC works...

So before FTTC is it a bundle of 50 or so pairs to a cabinet which is basically a big junction box?

And after FTTC is the cabinet now like some kind of mini exchange with only 1 fibre for 40 houses? Or is it 40 fibres for 40 houses?

Is the voice line then still on the old copper network, or is it then put down the fibre from the FTTC cabinet?

Thanks, JF.

Voice remains exactly as it is now, so over copper.

The FTTC is a bundle of fibres, with the number used being down to the bandwidth rather than number of properties. With fibre you could push 100 Gbps with no problem down one fibre if you wanted to.

So from the main exchange, a bundle of fibres, with usually 1 to 4 serving the FTTC cabinet, which has electronics in it, to create the VDSL signal, which is then sent down some copper wires that link back to the old green cabinet where it is combined with your existing telephone line.

So linking the two green cabinets is a bundle of copper wires, usually enough to handle a full fibre cabinet, which is either 144 (for smaller ones) or 288 for the standard size one.

The 288 line cab I looked at had 6 line cards each for 48 lines and each card had a 1 gigabit Ethernet fibre pair to it.

Ah right, thanks for the explanation.

So FTTP will be 1-4 fibres from the exchange to a fibre cabinet, then an individual fibre from the cabinet to each premises? leaving the old copper pairs in place purely for the phone?

JF.

FTTP fibres could be split in a chamber or on the side of a pole - they need not go anywhere near the cabinet as theyre fed from the exchange.

In reply to a post by 405mi16:

So FTTP will be 1-4 fibres from the exchange to a fibre cabinet, then an individual fibre from the cabinet to each premises? leaving the old copper pairs in place purely for the phone?

No FTTP works completely differently and has no cabinets. The copper system is completely ignored - the fibres from the exchange are "split" at a point probably in an underground chamber, and then individual fibres fed to each property.

This gives a brief description of the FTTP network

Just out if interest, are the fibres the go between the exchange and FTTC cabinet straight through connections (obviously made up of many seperate lengths spliced together) or is there any other equipment between the exchange and FTTC cabinet?

Are the tubing that the fibres go dedicated to each cabinet so at the exchange you would end up with one or more for each cabinet, or do they branch off as they gradually get further away from the exchange?

I'm finding the rollout in our area very interesting

Nothing else between the head end , which will often be in another exchange , and the cabinet. FTTC uses point to point fibre, a dedicated fibre from exchange to cabinet.
The fibre spine cable (244 fibres) will go to a node (aggregation point) where it's branched off in tubes to cabinets or fibre splitters in mixed FTTC/FTTP areas. The node maybe close to the local exchange or further out into the network

interesting, thanks.
One last question, is there any redundancy built into the FTTC network? If a cabinet has multiple fibres, are they for capacity or redundancy? do they take the same route?

Same route and single fibre per card, but spare fibres so if one breaks they can swap over.

Diverse routing gets very expensive

A bit more about how FTTC gets to the premises.

In reply to a post by RobertoS:

A bit more about how FTTC gets to the premises.

One of the things that surprised me there was this: - The initial FTTC street cabinets can handle only 288 connections each.

Is that right? Even for now? I just know that there is one cabinet in Bridgeton which is serving what must be over 400 properties.

What happens in this scenario?

when you get 20% takeup of FTTC there are no great dramas. They initially aren't fully equipped for 288 either.

280 is 70% of 400, so the FTTC cab is about right for all of the broadband users.

In reply to a post by jparnell82:

interesting, thanks.
One last question, is there any redundancy built into the FTTC network? If a cabinet has multiple fibres, are they for capacity or redundancy? do they take the same route?

if you want diverse routing, you're into business territory and probably should be buying a circuit.

If they do fill up they can add a second cabinet anyway.

In a year or two that may be a mute thing, as businesses moving to FTTPonDemand may free up FTTC ports.

In reply to a post by Ribble:

This gives a brief description of the FTTP network

Just reading through that...

It appears that the phone is supplied through the fibre as well (page 22), could someone explain how this works please?

Also, if a neighbour (business or residential) orders up fibre in a non fibre area, and their fibre passes by your property, what are the chances of being able to get FTTP easier? Also, if anything fibre related were to happen, would it be acceptable to bury your own single mode armoured fibre for BT to connect to (I have my doubts), or would it just be easier to dig the trench for them to lay their own conduit/fibre?

Thanks, JF.

The phone can be supplied via the Fibre using a product called Fibre Voice Access

A bit more towards bottom of http://www.thinkbroadband.com/guide/fibre-broadband....

In reply to a post by 405mi16:

Also, if a neighbour (business or residential) orders up fibre in a non fibre area

That would be a leased line, like schools, hospitals, libraries and the like have. There is no chance of consumer products being fed from that fibre.

In reply to a post by RobertoS:

In reply to a post by 405mi16:

Also, if a neighbour (business or residential) orders up fibre in a non fibre area

That would be a leased line, like schools, hospitals, libraries and the like have. There is no chance of consumer products being fed from that fibre.

Hmm, fair enough, I did think there would be something to prevent it.

I don't suppose an exchange serving 150 properties will really be anywhere on BT's list of priority's for being fibre enabled... But would there be any chance if they were offered outside investment to do it?

Thing is this area is so sparsely populated over such great distances, fibre is the only way we'd ever get anything over 1meg (apart from satellite, but that's not ideal either...).

Thanks for the info anyway, JF.

In reply to a post by 405mi16:

Thing is this area is so sparsely populated over such great distances, fibre is the only way we'd ever get anything over 1meg (apart from satellite, but that's not ideal either...).

Your best hope I suspect is the LTE 800mhz licence that O2 just won in this week's auction. That licence (out of the 5 sold) has a condition that it cover a serious amount of the country.

800mhz has quite good propagation, so one central mast, and external antennas and you might see speeds that my work colleagues in the US are getting on their 700mhz LTE. e.g. 40meg download and 10meg uploads.

I suspect that is the Govt's hope for rural areas, as wireless technologies are a lot cheaper to deploy than cabling areas, either through digging or running on poles.