'Upgrading' NAT64 to 464XLAT?

[Marco Sommani]

On 26/nov/2013, at 10:31, Lorenzo Colitti <lorenzo at google.com> wrote:

> On Tue, Nov 26, 2013 at 5:55 PM, Doug Barton <dougb at dougbarton.us> wrote:
> Which uses more IPv4 addresses, a traditional IPv4 NAT or 464xlat? At the end of the day the PLAT still has to talk to the v4 net.
> 
> Oh, I forgot - the answer to that question is that the traditional IPv4 NAT uses much more IPv4 space. This is because the traditional IPv4 NAT needs private IP addresses to number the endpoints.
> 
> If you have fewer than 10M subscribers this might not matter, but if you're, say, a mobile operator with 50M subscribers, you either number endpoints using RIR space, or you number them with bogon space, or you have to use overlapping RFC1918 realms. RIR space is about to run out. Bogon space is risky, and overlapping RFC1918 is painful for operations and causes application breakage.

Well, I understand that there is value in moving towards an IPv6-only backbone, but, even in that case, I find it safer to provide IPv4 via DS-Lite rather than via 464xLAT. In my view, translating between different IP versions can only produce more problems.

-- 
Marco Sommani
Consiglio Nazionale delle Ricerche
Istituto di Informatica e Telematica
Via Giuseppe Moruzzi 1
56124 Pisa - Italia
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mailto:marco.sommani at iit.cnr.it

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