Re: Simplified NAT-PT

[Hiroshi MIYATA <miyata@tahi.org>]

Thanks Brian for your comment.



On 2008/02/07, at 11:05, Brian E Carpenter wrote:

> Miyata-san,
>
> I haven't completely studied this yet, but I have two
> quick comments.
>
> >   The prefix PREFIX::/96 is advertised in the IPv6 network by the
> >   NAT-PT gateway, and packets addressed to this PREFIX will be routed
> >   to the NAT-PT gateway. The pre-configured PREFIX only needs to be
> >   routable within the IPv6 network and as such it can be any routable
> >   prefix that the network administrator chooses.
>
> This seems to assume that the NAT-PT is at the boundary between
> a closed IPv6 routing realm (where it's OK to advertise a /96)
> and the IPv4 network. What happens if someone needs to put
> a NAT-PT between a closed IPv4 routing realm and the open
> IPv6 network?

I think advertising /64 is enough.
Prefix for routing should be 64-bit.
And following 32-bit is indicator used by host to detect the translator.
Sorry, my description maybe confusable.

> >   The following 32-bit, represented as IDENT MUST be an value  
> > assigned
> >   by IANA to indicate that translator would exist in the path.
> >   More requirement for IDENT is described in Chapter 13.
>
> Why is this useful?

IDENT can help end-node to know the existence of translator.
And it must be unique.
Then the end-node can have some options.
Put dialog to user, quit the session, search other address, etc...
If the end-node does not have function to detect the translator,
like existing implementation, it would connect to the address.

Regards,

...miyata


>    Brian