Subscriber B relays subscriber A to subscriber C who relays A and B to the AP at D. Separate accounting is needed for A, B and C’s data.
The only way I can think of doing it is to have a PPP server at B for A, route A’s traffic from B to C through a VLAN with a PPP tunnel B<>C for B, and have a PPP tunnel for C<>D with C<>D VLAN for A and B’s traffic.
Thanks for trying but I can’t see what you’re gettting at - perhaps because I have looked several times at Mt’s attempt at an explanation of EoIP in the manual and still have no idea how it works or what it’s for.
Note that I want to set up the accounting tunnel from CPE to AP, not from the subscriber’s computer to the AP, which I think your scheme entails.