Summary

Requirements document:
try to clarify options we have
Pretty different from IPv4 case

RADIUS attribute: 
for static clients, static address assignment
protocol used internally in ISP backend

Prefix assignment protocol (to be done):
for roaming clients, dynamic address assignment
a protocol to assign prefix dynamically, from an ISP to a customer

Related documents
draft-itojun-ipv6-dialup-requirement-00.txt
draft-itojun-ipv6-dialup-radius-00.txt
draft-aboba-radius-ipv6-02.txt