In an IPv6 future, how will you solve IPv4 connectivity?

[Dan Wing]

> -----Original Message-----
> From: ipv6-ops-bounces+dwing=cisco.com at lists.cluenet.de [mailto:ipv6-
> ops-bounces+dwing=cisco.com at lists.cluenet.de] On Behalf Of marcelo
> bagnulo braun
> Sent: Sunday, October 10, 2010 8:43 AM
> To: ipv6-ops at lists.cluenet.de
> Subject: Re: In an IPv6 future, how will you solve IPv4 connectivity?
> 
> 
>   El 10/10/10 16:10, Truman Boyes escribió:
> >
> > On 10 Oct 2010, at 10:05 PM, Roger Wiklund wrote:
> >
> >> Let's say for arguments sake that the prophecy is true, and in late
> >> 2011/2012 a new user can only get an IPv6 address.
> >>
> >> Have you guys concidered/tested how you will solve these users
> >> connectivity to the IPv4 Internet?
> >>
> >> I guess NAT-PT is out of the picture,
> >> NAT64?
> >> DS-Lite?
> >>
> >> Also, as these new users are IPv6 only, how can IPv4 hosts
> communicate
> >> with them? 4to6 NAT?
> >>
> >> Thanks for your comments,
> >>
> >> /Roger
> >
> > I think the answer to this question depends upon the type of network
> > (ie. mobile, internet application hosting, fixed line broadband,
> etc).
> > DS-LITE would scale well, but would require CPE that obviously
> > supported this feature.
> mmm, dslite, is about v4 hosts accessing to v4 servers (and using v6 in
> the ISP), so no translation is involved, 

DS-Lite absolutely does translation!  DS-Lite includes a NAPT44 function
in its "AFTR" element, which is a carrier grade NAT (a big NAT operated
by the carrier).  This is how DS-Lite shares one IPv4 address among 
several subscribers.  Combining the NAPT44 function with an IPv4-over-IPv6 
tunnel and it's then called "Dual Stack Lite".  DS-Lite is both a 
tunnel (IPv4 over IPv6) and a carrier grade NAT44.

> so it would allow a v6 node to
> access a v4 server.

DS-Lite does not allow an IPv6 node to access an IPv4 server; DS-Lite
does not translate between IPv6 and IPv4 (nor between IPv4 and IPv6).
With DS-Lite, IPv6 traffic stays IPv6.  With DS-Lite, if a node wants 
to access an IPv4-only server, that node needs to run IPv4.

-d

> > NAT64 is simple, but it presents issues with tethering v4 devices
> > among other issues.
> nat64 is the right tool for this particular problem, afaict.
> 
> About how to enable access for communications initiated from the v4
> land
> to the v6 servers, NAT64 is compatible with current nat traversla
> techniques, so, that would one way to do it (i.e. use STUN, TURN, ICE
> and the like)
> 
> Regards, marcelo
> 
> 
> > It is quite possible that dual stack to subscribers will be common,
> > with private IPv4 and public IPv6. The service provider would
> natively
> > route IPv6 and perform NAT44 for IPv4.
> >
> > Truman
> >