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

marcelo bagnulo braun marcelo at
Tue Oct 12 10:02:17 CEST 2010

  El 12/10/10 1:30, Dan Wing escribió:
>> -----Original Message-----
>> From: at [mailto:ipv6-
>> at] On Behalf Of marcelo
>> bagnulo braun
>> Sent: Sunday, October 10, 2010 8:43 AM
>> To: ipv6-ops at
>> 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!

sorry for the relax phrasing. By translation, i meant protocol (v4-v6) 
translation and not address translation.
So, i guess we agree

Regards, marcelo

>   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

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