This is a very interesting direction that will come about as the next-generation broadband Internet service evolves.
At the moment, a typical next-generation broadband service will be based around central-office exchanges that serve and support copper and fibre-optic infrastructure for all communications. This allows for integration with copper-technology services such as PSTN voice / ADSL data.
The newer fibre-only exchanges will operate on fibre-optic infrastructure only with Fibre Ethernet backhaul and FTTH / FTTP fibre-optic service to the customers. The primary advantage of this setup would be to achieve higher throughput for the data that the high-bandwidth technology would provide.
The BT Openreach trial is primarily focused on new exchanges rather than converting existing exchanges to fibre-only operation. It is to assess how much it would cost to switch to fibre-only operation for existing exchanges or go “all-out” fibre-only for new or replacement exchanges. Such a trial could also be used for “infill” exchanges in dense urban areas or to satisfy new developments in potential “Silicon-Valley” areas around universities.
A good question about these exchanges is whether a “fibre-only” exchange could work with a part-fibre part-copper setup like a VDSL2-based fibre-to-the-cabinet or fibre-to-the-building setup.