I never believed IPv6 will be NAT free, but as idealist I hoped there is good chance there will be mostly only 1:1 NAT and each and every connection will get own routable network, /56 or so, residential DSL, mobile data, everything
Unfortunately that ship has sailed, it's almost certain majority of residential/non-business products will only contain single directly connected network, since we (as a community, I don't want to put all the blame to IPv6 kooks) failed produce feasible technical way to do it and spent too much time arguing on irrelevant matters. I'm reviewing two ways to provide INET access on DSL, no PPPoX, as it's not done in my corner of the world, and show why it's not practical to provide the end customer routable network
Statically configure per customer interface
At DSLAM (or other access device) customer would be placed in unique virtual-circuit (Q, QinQ...) all would terminated on unique L3 logical interface in PE router. Interface would have static /64 ipv6 address and ipv6/56 network routed to say ::c/64. IPv4 could continue to be shared subnet via 'unnumbered' interface.
This is by far my favorite way of doing residential IPv6 it, it supports customer owned and provider owned CPE, it supports routing and bridging in CPE, if CPE is bridged, CPE doesn't even need to be updated and it requires no magic features in DSLAM, IPv6 will just work.
But why this in practice does not work, is because there isn't PE router supporting 100k logical interfaces in single physical port, which would be needed for most non-trivial size operators today. Of course you could always buy more L3 termination points and terminate fewer (or even just one DSLAM) per PE, but the CAPEX isn't justifiable just to produce IPv6. Maybe due to organic network upgrades L3 goes closer to the edge and this will become feasible.
Routing in CPE, DHCP-PD
Customer CPE would use shared linknet with other customers, and some magic feature in DSLAM would stop CPEs from reaching each other in L2 (like they do today in IPv4), for LAN address customer would use DHCP-PD, which would be distributed by CPE as SLAAC to LAN interface, this is supported and works today.
But there is no supported way to provide static route to CPE, there is draft-ietf-mif-dhcpv6-route-option-03 which would add needed functionality, but I don't think there is much chance it'll materialize in time, as SPs are already busy defining how their residential V6 is produced.
Problems here are, apart from not being supported, is that new CPE is needed, DSLAM vendors need to develop IPv6 specific magic features (ND, RA, DHCP) to workaround shared LAN problems.
Conclusion
So all I can say is sorry, again users need to pay for premium product to get routable network and ad-hoc network sharing from random available 3G mobile or DSL still means setting up NAT (or ND proxy to lie that you're on connected net, when you're not). It's damn shame, as it's really trivial technical problem which seems just to be completely ignored.
