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Re: NAT v6->v4 and v4->v6 (was Re: WG Action: Conclusion of IP Version 6 )
On Sun, 30 Sep 2007 10:54:34 +0930 Mark Smith <nanog@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > On Sat, 29 Sep 2007 14:45:23 -1000 > Randy Bush <randy@xxxxxxx> wrote: > > > > 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. > > > > I do not understand what you mean. > > The tunnelled traffic takes the same ingress-to-egress path through the > core that it would if the core natively supported the tunnelled payload > protocol. > > This is the basic BGP/MPLS model, using IPv4, IPv6, GRE or L2TP as the > encapsulation, instead of MPLS. > It's also the RFC1772 BGP encapsulation model (section "A.2.3 Encapsulation"), with the difference being the end-node traffic sources and sinks are the ingress and egress peers, rather than an AS worth of them. The model isn't very new at all. > Regards, > Mark. > > -- > > "Sheep are slow and tasty, and therefore must remain constantly > alert." > - Bruce Schneier, "Beyond Fear" -- "Sheep are slow and tasty, and therefore must remain constantly alert." - Bruce Schneier, "Beyond Fear"