Hi Robert,
At 05:22 AM 4/20/2003 +0700, Robert Elz wrote:
But if you assume that there are people (and there most probably are) who are so sold on the "benefits" of NAT, that they're going to use NAT no matter how much you show them that there is in fact no benefit at all (which for a site with an IPv6 global /48, and site locals, is certainly true) then why would you care what address they're using behind the NAT? That is, whether it is SL, LL, or some random "global" prefix they calculated by tossing coins.
Actually, it isn't true that an IPv6 global /48 prefix plus site locals would provide all of the "benefits" of NAT.
In particular, you would still need to renumber your local network (the global prefixes) when your provider-allocated global addresses change. Having extra addresses available for internal traffic (the site-locals) does not make renumbering the global prefix any easier or less expensive.
Although NAT causes various problems, it does offer a high degree of provider-independence for internal nodes. You won't get this using provider-allocated global addresses in IPv6, no matter how many other addresses you add to each node.
Of course, this isn't why NAT is most often used... NAT is most often used to extend a single address to cover multiple systems in a home or small office environment. For that environment, an IPv6 /48 (without site-locals) would suffice to replace NAT.
I find it almost inconceivable to believe that anyone is deciding the fate of SL addressing by reference to NAT - that's simply too ludicrous (and sad) to contemplate.
I am similarly disturbed that there are people who want to specify site-local addressing because they think it will offer the provider-independence currently offered by NAT.
Margaret
