I recently ran into a task that had me setup PPPoFR between two routers. The task stated not to use DHCP but to negoiate the address (IPCP). So, using the peer default ip command I did just that, and the remote side received the address through IPCP negoiation and reachability was fine. Now the next part is where it got tricky, the next task had me layer OSPF on but the two sides never established a neighbor relationship because the negoiated side had a /32 so OSPF never allowed the neighbor relationship to establish.
I realize there are solutions out there that place the address on the loopback and use ip unnumbered on the virtual-template intoferace to solve this problem. However, in this case, the task gave specific restrictions that implied this was not allowed (ip must be negoiated and must not be done using DHCP). Any thought how this would be done?