On Fri, Apr 04, 2003 at 01:38:28PM +0200, Erik Nordmark wrote: > > Research ships at sea intermittently connect via INMARSAT, or when in > > port, the shipboard network is connected to shore via Ethernet. > > Looking at your resarch ship case a bit more in detail it occurs > to me that even using site-locals plus globals while connected doesn't > necessarily protect the local communication. The introduction of the > global prefix/addresses when the ship is connected might very well > trigger different address selection behaviors in the stack or in the > applications. Thus it seems like the robustness provided by site-locals > only apply to communication established (and addresses selected) > before the global prefix is introduced. Later communication is subject > to any bugs or poor interaction in the address selection domain - something > that is bound to have some corner cases due to its complexity. > (Note that this is a property that applies to #1 in my list that I've > previously not realized.) While the effect of this probably is less than > the effect of renumbering the ships network each time it attaches to the > Internet, it still doesn't isolate the ships internal network from > being attached to the Internet when site-locals are used as you propose.
I think site-locals could be used here, with a single rule that they're simply the least preffered prefix used in address selection. Whilst the boat is in a port, it receives a global prefix which is advertised on appropriate subnets. Before leaving port the prefix is deprecated (but not removed), thus there would be no break in communications. It can be removed several days later safely when it's no longer in use. This doesn't just apply to huge boats, what about a private yacht? This is another zero-conf issue, it has all the same problems as the research boat (getting connectivity via different providers depending on which port they're at) except that the owner may not have his own v6 prefix, or even know what IPv6 is! Finally I don't agree with your tunnelling solution at all (sorry it got <snipped>) . I would rather NAT and have a 10ms RTT insetad of 200ms, and if I would NAT here (I hate NAT!) then I think lots of other people would too. Tunnels are complicated NAT is easy... So I would argue that in this case deprecation of Site-locals *encourages* NAT, now there's something you don't hear every day! :-) Mike -------------------------------------------------------------------- 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] --------------------------------------------------------------------
