> I agree with Keith that the logical conclusion is that whenever a site-local > and global address are returned the only non-ambiguous decision to take is > to prefer the global address. But that means we lose the nice property of > prefering site-locals intra-site to help maintain long-standing connections > (e.g. NFS) through external renumbering or connectivity events that alter > global prefixes seen within the site. > > It seems the only way around that is to either use a special unique > "site-local global" prefix internally (plucked from some method as yet > undefined, Keith's ideas to date there are "woolly" at best :) or to use a > parallel/split DNS naming structure internally (be it foo.site or otherwise, > indeed in my own NATed v4 home network I use .home in the scope of my home > network for that purpose on Net10, not pretty but it works), or to use only > site-local literals. Are there other solutions?
I actually think that all applications that expect to keep associations around more than some well-known (and explicitly chosen) lifetime need to have mechanisms for surviving renumbering. And unless/until we introduce renumbering support into TCP, UDP, and SCTP, this means providing that support in layer 7. I also think there needs to be a minimum overlap time during renumbering (during which both prefixes are valid), which is greater than or equal to the max reliable association lifetime above. That way, if an application gets a valid prefix when it starts, that prefix will remain valid for at least the max reliable association lifetime. In other words, I'd rather make a distinction between applications with long associations and applications which don't need long associations than between site-local applications and applications that might need to cross site boundaries. In practice I don't think there are many inherently site-local applications. Keith p.s. offhand I suggest that that lifetime should be 10 days. -------------------------------------------------------------------- IETF IPng Working Group Mailing List IPng Home Page: http://playground.sun.com/ipng FTP archive: ftp://playground.sun.com/pub/ipng Direct all administrative requests to [EMAIL PROTECTED] --------------------------------------------------------------------
