[Pierre]

Originally Posted by MrIca

Interesting post I'll grant you that. Could you explain what you mean by "fibre tails in BT's access ducts". Surely if they have BT fibre connected to the mobile masts then it'll be going back to a BT exchange? (as they don't share ducts). Do you mean that at the exchange it then switches to another provider's core network?

You have an "interconnect" or "meet-me" chambers where you have a handover. Virgin Media run a fibre to this chamber then it is jointed onto a BT fibre and run to wherever, a mast or an exchange. These tails are generally less than a km or two in length.

So the traffic doesn't go via the BT Core but straight onto the VM Core.

But there are other combinations as you suggest. In really outlawing areas where there is absolutely no way of getting onto any VM fibre, then the traffic can be taken back to the BT exchange and VM can pick it up from there.

I take your points though, but it is just strange as round here is very built up, VM have a cable network and ducting everywhere. There's C&W ducting right up the A-Road. However, I can think of a Vodafone mast that is fed by two overhead fibre cables from BT. There's another mast that's off the main road and also fed by overhead BT fibre. I can't fathom why they aren't just using C&W for these masts.

There can be lots of reasons, but just because there is BT fibre running into that mast doesn't mean that BT are the sole carrier serving that site. There may be other fibres running into there.