Re: An alternative to 6to4 and teredo

[Pekka Savola <pekkas@netcore.fi>]

On Thu, 16 Jan 2003, Erik Nordmark 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 agree, to some extent.  Definitely so for Teredo (complexity).
 
> 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.

That's not all.  6to4/Teredo offer an automatic configuration using 
anycast addresses.  Much easier than trying to figure out the closest 
tunnel broker, configuring to use that etc.
 
> 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.

I agree, but there is a cost to a tunnel broker model, that is, not so 
simple configuration..

-- 
Pekka Savola                 "You each name yourselves king, yet the
Netcore Oy                    kingdom bleeds."
Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings