Re: NAT v6->v4 and v4->v6 (was Re: WG Action: Conclusion of IP Version 6 )

[Randy Bush <randy () psg com>]

> MPLS as well as the IETF softwires techniques (the MPLS model without
> using MPLS i.e. tunnel from ingress to egress via automated setup
> tunnels - gre, l2tp, or native IPv4 or IPv6) can or will shortly be
> able to be used to tunnel IPv6 over IPv4 or vice versa. softwires in
> effect treats the non-native core infrastructure as an NBMA layer 2.
>
> The advantage of these techniques verses dual stack is that they push
> the complexity of dual stack to the network ingress and egress
> devices.
>
> Dual stack isn't all that complicated, however when you think about 
> running two forwarded protocols, two routing protocols or an
> integrated one supporting two forwarded protocols, having two
> forwarding topologies that may not match in the case of dual routing
> protocols, and having two sets of troubleshooing methods and tools, I
> think the simplicity of having a single core network forwarding
> protocol and tunnelling everyting else over it becomes really
> attractive.

huh?  and your tunnels do not have *worse* congruency problems than dual
stack?  gimme a break.

randy