[tardedmeme]

Would it help at all? You can't just send IPv6 packets down the equivalent IPv4 path because that bext-hop router probably xoesn't understand IPv6 packets. In fact there could be no IPv6 path at all between you and the destination, so knowing where they are still wouldn't help you forward packets. If it understood them, it would have given you an IPv6 route anyway. Updating BGP to support IPv6 routes wasn't an actual problem.

[zadikian]

There are lots of services I can't send v6 to, not because some router in the middle only understands v4 but because the service operator decided not to deal with v6.

[tardedmeme]

So the idea is to surreptitiously install software on the service operator's machines that they can't disable?

It's already a bit like that, but they can and do disable it. You can see the other comments in this thread: many people disable IPv6 upon any sign of a networking problem.

[zadikian]

No, the idea is you can turn v6 on/off, but doing so only changes the packet format and nothing else at first. There's no separate place to configure v6-specific settings because there are none. You use the same address, routes, DHCP, NAT, DNS, etc as v4, but you're limited to 32-bit addrs at first. The point is to just get people off v4.

Once v6 has reached enough adoption, you can turn off v4. Those who want to keep the addrs from v4 can, except now they get way more addresses under those too. Others can start building a clean new topology under the other prefixes without worrying about compatibility.

[Ekaros]

I don't see why anyone would change all the bits you actually need to change for some nebulous future gains. Still have to deal with new sockets and new routing decisions at least. To not really gain much from new features.

To me it looks like something that would have gained nearly no actual adoption outside some toy examples. Later you will need to anyway get new DNS, DHCP(or alternative) and so on.

[zadikian]

That's a legit concern. If that's not interesting enough to the kind of user that wants all-new v6, instead start from today where some users are on the new v6 network, and say they added the 4:: prefix as a way to pick up the kind of user that doesn't want to change much. They'd still be compatible eventually. Though the reason I was thinking 4:: from the start would've been attractive enough is, a lot of people did use 6to4 and other halfway measures despite having no immediate gain.

Today's DNS6 DHCP6 etc are totally incompatible with v4. 4:: buys backwards-compatibility. Each can be updated to support longer addrs without caring whether you use it with v4 or v6.