In reply to a post by jabuzzard:

Except XGPON requires new ONT's as well OLT's.

that's not entirely correct XGPON can coexist on the same fibre and PON splitter as it uses different wavelengths, so while the head end would need an additional XGPON OLT (or card) there is no service change to users on lower tier connections - they can remain on the existing OLT and keep the same ONT in their property.

I only ever remember a BT Integrated Services Digital Network (ISDN) product called ISDN2 (rather than just ISDN) which was referred too as 2B+D (2 bearers + 1 delta) and had 2 x 64Kbps telephone lines (they could be either aux/stroke or separate numbers). We used an iMate tester when installing and detecting faults on them. I remember a lot of them being used for video conferencing and as a backup for data circuits as most data circuits in those days were BT Kilostreams and Megastreams.

Edited by deleted (Fri 15-Feb-19 09:59:16)

In reply to a post by jabuzzard:

In reply to a post by TechServ:

As soon as the PON circuit reaches capacity it can be upgraded to XGPON - customers paying for Gigabit services are already contributing towards that future upgrade.

. I find it hard to believe they only pull a single fibre to each DP point (it would be madness to do so).

Saw a brand new cable in a duct going to a pole (there were no poles beyond it) in a Fibre Cities area. It had a label on it that said 3x BFT (blown fibre tubes). It�s not my area of expertise so I can�t really discuss this point. So I�m merely passing on what I saw.

Could just be a couple of spares in case of faults though.

Edited by deleted (Fri 15-Feb-19 19:06:23)

Pleasantly surprised to find they've already done my road - which is strange, cos I've never seen any roadworks. Does make sense though looking at the maps, the areas they cover are those that aren't getting Gfast.

Now just need to find a cheap provider. BT 60/mth seems a lot.

If ducts and chambers are in place already and in good condition then may not require any road works at all

In reply to a post by Thinker27:

Sorry I sounded like a schoolmistress, frustration got the better of me. I do have the greatest respect for those who give up their time to help, and I appreciate everyone is busy.

I try and note snippets of information to build up a picture, and also research new concepts via google.

If I may set out my understanding of how it all works, perhaps others could correct it and add the proper names for the parts and more detail.

In the telephone exchange (does it have to be a telephone exchange? are there other places? presumably it is usually here because of the existing ducts. what is the proper name for this part of the network?) there is some electronic equipment, essentially a router (called a?) for connecting subscribers' data to the Internet backbone (operated by Openreach?) via "backhaul". The backhaul medium is optical fibre.

Does the ISP (internet service provider) have any physical equipment here of are they just billed for the connection and throughput?

All routing is done by electronics and all transport is done through fibre, so the router has an electronic to optical converter on its output and vice versa on its input. There are always two connectors on each interface, one for upstream data and one for downstream. (Is this true? I imagine there are standard lasers and phototransistors and the two directions would interfere if on the same fibre. Or at least it is easier to provide only a single converter on each connector.)

The data is all IP packets, unchanged between the fibre and the router, and the packets to/from different users are all mixed together in the routers to get them through the system as efficiently as possible. Each packet contains a destination IP address, a source IP address, and the payload (user data) and the routers look at the addresses to route the packets from node to node through the internet.

Fibre cables radiate from the exchange into the community. What does a cable look like? How big, how many fibres? Any copper in it for power? They go in a tube about 25mm diameter with a yellow stripe called a subduct, and through larger ducts. They may run up and between poles. Are there joints in this path, or are great lengths pulled out from a reel? If jointed, how and in what housing? Are there any cabinets? What and where are splitters and aggregators? Is any electricity used?

In the destination building is an ONT (optical network terminal), also called a modem, which is an optical-electronic interface. There may be a TP (termination point) or BFP (building flexibility point) that anchors the end of the external cable, with a fibre link to the ONT. The ONT presents an Ethernet socket for a copper cable to connect to a router.

Hyperoptic deliver a fibre cable to a router in a multi-unit building and then Cat 5E copper cable to individual flats. Openreach provide a fibre to each flat.

There are a number of different topologies of fibre network, one (name?) being a single fibre (pair?) that runs all the way from the exchange to the premises and another being a passive optical network where a fibre is split by prisms into multiple branches to separate premises (GPON?) The consumer doesn't get to choose or know which system they will be provided with.

Hi Thinker27

I am at a lose how to correctly respond to your post, imagine being in an exam and turning over the question paper and not knowing where to start

You have so many questions and I can tell from above a very confused/mashed up understanding of how everything fits together currently.

I thought by leaving it a day I may be able to come up with a way but I am really sorry I simply can't respond with anything that's going to help you. Another poster has suggested a few good places to start so I would trying them and see how you get on.

Edited by deleted (Sat 16-Feb-19 08:55:51)

In reply to a post by arfster:

Now just need to find a cheap provider. BT 60/mth seems a lot.

It is, although there's often a £150 cashback available. Sky have said they will be reselling FTTP - if you can wait for that it might shake things up a bit. Otherwise there are few other providers like Zen you can look at.

Remember you don't need to take the Ultrafast speeds on fibre - if all you want is a rock-solid 80/20 (or even 55/10), you can buy that instead.

Pretty sure Sky is quietly selling FTTP at the two FTTC speeds in areas where FTTP is the only superfast option.

Suspect its a loyal customer thing e.g. have bundle and moving to area i.e. done on a very low volume while they get support staff up to speed

In reply to a post by candlerb:

It is, although there's often a £150 cashback available. Sky have said they will be reselling FTTP - if you can wait for that it might shake things up a bit. Otherwise there are few other providers like Zen you can look at.

It's not a market I'd kept up to date on at all, so was a little surprising how few providers offer it yet. I guess there simply aren't that many lines.

Anyway, as you say, cashback! Can get 150 from a cashback site atm, + 130 reward card from BT, plus a free Amazon echo. That takes the sting out of the price a bit

As for alternatives, I absolutely don't need it, already have 80/20. Just a luxury.

my city completely void of colour so cityfibre aka vodafone for me then, I just hope by the time cityfibre are ready vodafone fix their backhaul issues.