[Ignitionnet]

It should be mentioned that this is basically how almost all BT FTTC services work. You connect via a PPPoE tunnel to a server that delivers IP.

Latency increase can be kept to a minimum by having the terminating services close to the same path the traffic would take anyway.

In the case of VM they can put the servers where their core sites are. The CMTS are each homed to 2 or more core routers in the same POP site, so putting a BRAS in the same site as those core routers will add very minimal latency as all traffic would be going through that site anyway, just the last hop to the CMTS has GRE / L2TP headers added rather than being native IP.

Using this are as an example the CMTS serving it are in Leeds South, VM code lee2, and all of them backhaul through Leeds Seacroft, VM code leed's core routers.

Place a BRAS in Leeds Seacroft and you're good to go to serve all hubsites homed from there. Seacroft had BRAS for the old VM National ADSL service anyway, so could trivially repurpose those.

It's a bit of a headache but is the only way to deliver truly static IP addresses over a cable platform without wasting a bunch of them, and they are a pretty valuable commodity now.