Thursday 19 April 2012

FTTC Install - What's involved



Firstly, what is FTTC, Fibre To The Cabinet is a service that BT is rolling out throughout the UK to provide stable, fast broadband to home users without requiring additional equipment to the customer premises (* ignoring BT VDSL modems). The service to the client premises is still delivered over the standard copper pairs used for PSTN provision, in the same way ADSL and ADSL2+ are, and it uses the same basic technology of frequency shift to 'shift' the data bits into a higher frequency range. The separation of this at customer premises takes place within the BT master socket, which is replaced during the installation of FTTC by a BT engineer. At the other end of your line things change quite dramatically.

In ADSL/ADSL2+ the BT copper pairs go from your master socket to a junction box in the street (the street cab), this then can pass through other street cabs/junction boxes (as mine did) and then eventually ends back in a BT exchange on a Main Distribution Frame (MDF). From here your line goes into an ADSL line card which is part of the DSLAM and provides the mo-dem part (modulation, de-modulation). This then turns into a 'regular' ethernet-like connection and will be fed back to BT Wholesale via their fibre connections to the exchange.

In FTTC the street cabinet is upgraded and takes a fibre connection from the exchange. The street cabinet then has the fibre-to-copper hardware inside it and this then uses the copper pairs to your premises to transmit the broadband. This reduces the distance the copper pairs are transmitting the data signal, and therefore provides much higher quality and therefore potential speeds. It is this key change that provides the improvements to the broadband provision, stabilises the connection and generally offers a higher quality service. The downside is that BT have to 'blow' fibre to the street cabinets, and upgrade the cabinets to support the active (i.e. powered) equipment to do the work (which was previously in the exchange).

The actual install to the end-user is pretty painless (your mileage may vary!). In my instance my current ADSL2+ service dropped around 20-30 minutes into the engineer visit window that had been scheduled (BT engineer had phoned confirming his attendance at the alloted time), and shortly afterwards he turned up to change the faceplate and do his work. The install was pretty quick. Removal of the existing BT master socket. Installation of the new socket. Connection of test equipment the BT engineer could then verify the signal quality and the potential speed of the circuit. Then installation of the BT supplied VDSL modem, and finally checking that I could authenticate over PPPOE.


The new installed BT master socket with integrated VDSL socket:

 Top socket is the VDSL socket, and the one parallel to the screws is for your PSTN phone (Which I don't use)

This is a snap of the tester the BT engineer uses, it shows the line sync and status on there and gives you your first indication of what your speeds should be like, etc.


This is the BT Openreach modem that the BT engineer supplies and for now is required to be installed. This isn't a router or anything smart, its a very simple modem, the LAN1 port presents a PPPOE connection for you to handle authentication, etc, to your ISP. All other ports are blocked off and not in use on the device.

Note this is the newer BT VDSL modem that is now being supplied in most installations. Earlier models were common to overheating, and had also had their firmware cracked open so the average user could log into them and view line stats, tinker about, etc. BT therefore started to replace their shipped/installed modem (generally cited as due to the overheating fault). Also note that most installs BT will attach this modem to a wall to help with cooling/circulation. You generally should NOT run it sitting on a carpet like you see in my pic! But as you can see its not powered on in the pic. The unit does get warm pretty quickly so beware of this!

An attempt at a close-up of the sockets:

My phone didn't do a very good job of this picture. Basically the ports are: DSL in, LAN1, LAN2 (blocked off), RESET, BBU (blocked off).


You would then plug your router in supplied by your ISP into the LAN1 port and wait for it to auth up.

Since I like to tinker, I went a little further and have removed the BT modem and installed my own, this allows me to view line stats, and generally have a closer view of what is going on over the VDSL connection. I'm using the vigor 2750n which I've found to be a very capable little router. Setup is a little more in-depth than defaults so here are the settings you'll need if you're doing the same.

Firstly, firmware update. I'm running 1.5.2_Beta so you need that or newer (Older ones don't always sync up correctly and will sit with their DSL light flashing constantly).

Then go through the Quick Start Wizard, this steps you through the usual stuff. When it comes to WAN, DO NOT CHOOSE DHCP (This is a little confusing), you want to choose PPPOE, as it will then give you the chance to put in your login and password provided from your ISP.

You then need to login to the web interface again, choose WAN and Multi-VLAN. In here you need to enable Multi-VLAN setup and in the WAN VLAN ID box put in 101. This is a BT wholesale FTTC setting, so I can only comment on this install. You might need something different if you are with a LLU or other provider.

Save it all up and you're good to go. By default the Vigor will do NAT, DHCP and all the other usual stuff. In my case I get a /30 allocated and run a server behind my connection so I want to remove NAT and do routing. This is pretty straight forward on this router too, just go into LAN and General Setup, and in the "For IP Routing" enable that and enter in your public IP address allocated by your ISP along with your subnet mask. Disable DHCP (not needed) and save that. This will then setup your router to route! One thing to bear in mind though, the router will still answer on on the LAN and will still do NAT for this range, you can tweak this and lock this down further in the setup but most Vigor docs recommend against this for some reason.

I hope this has helped you setup FTTC or at least given a bit more info. If you've got any questions feel free to comment/drop me an email.


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