An alternative to 6to4 and teredo

[Erik Nordmark <Erik.Nordmark@sun.com>]

A long time ago Joshua wrote:

> This is a chicken and egg problem. That is why transition tools are 
> important. Apple could develop and ship a system that implemented 6to4 
> and shipworm/teredo to fall back on when IPv6 wasn't immediately 
> available. Apple could also ship an application that made use of IPv6. 
> Microsoft is in a similar position. Once that's done, third party 
> developers can take advantage of that, assuming all of the transition 
> mechanisms work. Shooting down 6to4 eliminates one transition 
> mechanism. Not even acknowledging Teredo is another shot at transition.

I argue that using tunnel broker and extending it to support UDP tunneling
across NATs is much better than 6to4 and Teredo when considering the space
of temporary solutions until the ISPs provide native IPv6.

I think tunnel brokered tunnels provide better incentives for deployment
than 6to4 relays because they are visible to the user - the provider
can throw in some content and adds as part of the web page you visit,
and the can claim "we have x,000 users". A 6to4 relay provider can not
do this. The "connect to IPv6" icon on the desktop also helps drive
IPv6 awareness - folks will see that enabling that allows them to run
their IPv6 peer to peer games even across an IPv4 NAT box, thus they
are more likely to ask their ISP for native IPv6 than if this is
completely automatic as is envisioned for Teredo.

The only downside of the tunnel broker schemes is potentially less efficient
routing. But if the services are popular this might be a self-correcting
problem. And if they are not popular it is either because there is sufficient
native IPv6 access or that IPv6 is not being widely used.

The upsides for tunnel broker (with UDP tunneling across NATs, or even PPP
over  TCP over NATs for those so inclined) in addition to the incentives above
is that it avoids the security issues around 6to4 and Teredo, and is
operationally much much simpler to trouble-shoot.
And there isn't any risk of creating separate IPv6 native and 6to4
universes since it is all IPv6 native addresses with regular IPv6 routing.

  Erik