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

marcelo bagnulo braun marcelo at
Mon Oct 11 08:30:20 CEST 2010

  El 11/10/10 2:48, Truman Boyes escribió:
> On 10 Oct 2010, at 11:43 PM, marcelo bagnulo braun wrote:
>> 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, so it would allow a v6 
>> node to access a v4 server.
> Yes, however devices would need to be able to tunnel IPv4 inside IPv6.
mmm, why is that?
I mean, i agree that some devices will need this and for that, some form 
of tunelling as dslite would the right tool.
However, i fail to see why this will be the general case. I mean, if we 
are supposedely migrating to a v6 only deployment, then i would assume 
that there would some interest to deploy networks that only run v6 and 
no v4 is involved. In that case, you need translation

> It's not translation, but the tunneling support is the key to 
> traversing an IPv6 network.
>>> NAT64 is simple, but it presents issues with tethering v4 devices 
>>> among other issues.
>> nat64 is the right tool for this particular problem, afaict
> I am not so sure about this being the right tool. Let's say that you 
> have a mobile subscriber handset that is IPv6-only. The SP can turn on 
> NAT64 and for the most part, the device would not need to care about IPv4.
right, that is what i was talking about

> However, if you wanted to use the phone as a tethered modem/gateway on 
> an IPv4 host, it would not work.
sure, for that you need a tunneling technique, such as dslite, but i 
understood we were talking about a v6 only deployment scenario

Regards, marcelo

>> 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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