Re: [Softwires] 4rd-u tunnels and stateful NAT64s

[Maoke <[e-mail]>]

i understand NAT64 makes translation between arbitrary IPv6 address to
arbitrary IPv4 address. i don't understand how you make CNP in any IPv6
address. in other words, we cannot limit NAT64 stateful service only serve
those IPv6 addresses with CNP. - maoke

2012/3/15 Rémi Després <[e-mail]>

>
> Le 2012-03-15 à 10:59, Rémi Després a écrit :
>
> > Maoke,
> >
> > Thanks for this question.
> > This subject being new, I take it on a new thread.
> >
> > 2012-03-15 10:38, Maoke:
> > ...
> >> i didn't understand the how the stateful NAT64 benefits from CNP.
> >
> > The point is that if a NAT64 is upgraded to support 4rd-u tunnels (thus
> becoming a NAT64+) it can take IPv6 payloads as valid IPv4 payloads.
> > Any protocol that this NAT64 supports is then supported e2e for 4rd-u CEs
> > These CEs need not being dependent on which NAT64 supports which
> protocols.
> >
> > Note that the NAT64 doesn't need to have CNP code. It just happens that
> host IPv6 addresses it sees are checksum neutral. (Thus, IPv6 and IPv4
> payloads are the same for all protocols that have ports at the same place
> as TCP/UDP/..., and the same checksum algorithm)
>
> Oops.
> This is only true for the IPv6 host address. To construct an IPv6 address
> when transmitting to  a 4rd-u CE, the NAT64 should compute a CNP. (This is
> to maintain the property that that middleboxes can treat tunnel packets as
> valid IPv6 packets. Not a big deal, but necessary).
> Sorry for having hastily added this sentence.
>
> RD
>
> >
> > RD
> >
> >
> >
> >
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>