Quote:
Originally Posted by Turkey Machine
ADSL2 usually comes before the FTTC deployment, as it relies on the 21CN backbone to provide it. So chances are yes.  |
Not really.
As I mentioned above also where an exchange has FTTC cabinets but no 21CN it's usually a small exchange and the headend for those cabinets, where their fibre goes, will be a larger exchange for cost purposes. It's actually cheaper for Openreach to blow fibre from a larger exchange than to set up every exchange with an FTTx headend so there's a fair amount of consolidation going on.
21CN is only used for BT Wholesale services. These are the majority but FTTC itself isn't dependent on BT Wholesale in any way, it's backhauled from cabinet to exchange with dedicated 10Gb links.
Where an exchange has a headend but no 21CN BT Wholesale can choose to use an extension circuit to connect the neared 21CN exchange to the FTTC headend but these will be unlikely. The exchanges that are 21CN are, naturally, going to be the most economical for a fibre head end.
As a case in point Northern Ireland has wide FTTC coverage, all exchanges have an FTTC presence. It has one 21CN exchange.