Nathan Ward wrote: ...
2) If Teredo relays are deployed close to the service (ie. content, etc.) then performance is almost equivalent to IPv4. 6to4 relies on relays being close to both the client and the server, which requires end users' ISPs to build at least *some* IPv6 infrastructure, maintain transit, etc. When you consider that this infrastructure and transit is quite likely to be over long tunnels to weird parts of the world, this is a bad thing. Putting relays close to the content helps for the reverse path (ie. content -> client), however the forward path (client -> content) is likely to perform poorly.
Not quite correct. 6to4 does not require transiting a relay if the target is another 6to4 site. What this means is that a clueful content provider will put up a 6to4 router alongside whatever native service they provide, then populate the dns with both the native and 6to4 address. A properly implemented client will do the longest prefix match against that set, so a 6to4 client will go directly to the content provider's 6to4 router, while a native client will take the direct path. The only time an anycast relay needs to be used is when the server is native-only and the client is 6to4-only. Tony