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RE: 6to4v2 (as in ripv2)?

2011-07-29 16:32:19
Christian,

-----Original Message-----
From: ietf-bounces(_at_)ietf(_dot_)org 
[mailto:ietf-bounces(_at_)ietf(_dot_)org] On 
Behalf Of Christian Huitema
Sent: Friday, July 29, 2011 12:17 PM
To: Michel Py; Rémi Després
Cc: ietf(_at_)ietf(_dot_)org; Keith Moore
Subject: RE: 6to4v2 (as in ripv2)? 

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.

I think this is well said. Another way of saying the
same thing is that 6to4 is an inter-site solution while
6rd is an intra-site solution when considering the
provider network as a "site". With extensions, ISATAP
can also satisfy this provider network intra-site
requirement (see draft-templin-isupdate) while enabling
the desired IPv6 services for end-user sites.

Thanks - Fred
fred(_dot_)l(_dot_)templin(_at_)boeing(_dot_)com

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(_at_)ietf(_dot_)org 
[mailto:ietf-bounces(_at_)ietf(_dot_)org] On 
Behalf Of Michel Py
Sent: Friday, July 29, 2011 11:38 AM
To: Rémi Després
Cc: ietf(_at_)ietf(_dot_)org; 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.

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