6rd addresses a different problem than 6to4. 6to4 is a global solution, that relies on pretty much every native IPv6 provider deploying 6to4 relays. If these relays were really well deployed and reliable, 6to4 would allow any router with a native IPv4 address to provide IPv6 connectivity to its local users. That is, 6to4 relies on the kindness of strangers and allows uncoordinated deployments by end-users. 6rd is a local solution, that can be used by providers to easily deploy IPv6 tunnels over their existing IPv4 infrastructure. The provider controls the IPv6 prefix, which effectively defines a specific 6rd "subnet." The provider also controls the deployment of relays between the 6rd subnet and the native Internet. There is no need to rely on the kindness of strangers. In a sense, 6rd is very similar to a tunnel broker deployment, with a key improvement and an important limitation. The key improvement is the ability for 6rd routers in the same domain to send traffic directly at each other. Local traffic stays local, does not need to be relayed by the tunnel servers or the 6rd relays. The key limitation is that 6rd assumes direct IPv4 connectivity between the participating 6rd routers, i.e. no NAT. 6rd is a very good solution for its intended usage, rapid deployment of IPv6 by IPv4 providers. But 6rd is not a replacement for the "global, uncoordinated" 6to4 deployment. Hosts that really need this kind of uncoordinated global solution will have to rely on Teredo if they cannot use 6to4. Whether that's a good thing is clearly a matter of debate. -----Original Message----- From: ietf-bounces@xxxxxxxx [mailto:ietf-bounces@xxxxxxxx] On Behalf Of Michel Py Sent: Friday, July 29, 2011 11:38 AM To: Rémi Després Cc: ietf@xxxxxxxx; Keith Moore Subject: RE: 6to4v2 (as in ripv2)? > Rémi Després wrote: > 6rd is designed to offer native IPv6 prefixes across IPv4-only routing > domains. There is a word for that: oxymoron. In French: oxymore. If it stops working when IPv4 is broken, it is not native. Michel. _______________________________________________ Ietf mailing list Ietf@xxxxxxxx https://www.ietf.org/mailman/listinfo/ietf _______________________________________________ Ietf mailing list Ietf@xxxxxxxx https://www.ietf.org/mailman/listinfo/ietf