On Fri, 15 Jan 2010 20:13:16 +0900, Arifumi Matsumoto <[email protected]> wrote: > * Fred's proposal. > - A host tries each pair of src and dst addresses to establish > a connection in a short time period. > - A host can make use of ICMP error messages indicating that the > src address should be this, or the src address is simply wrong. > - A host can have cache for the reachability status, which stores > which src and dst pair should be used to reach a certain dst.
This is awfully complicated. It might be implemented properly in some high-profile apps, but it will be implemented incorrectly in many apps, and it won't be implemented at all in others. To this day, there are still applications that won't even try to fall-back from IPv6 to IPv4. Also, as you mention, this simply doesn't fly for connection-less protocols. So IMHO, source address selection should be hidden from apps into the operating system as much as possible. That of course does not preclude writing advices for robust applications on what intelligent things they can and can *not* do. That could definitely include trying all potential pairs in parallel instead of trying them sequentially, if the application-layer protocol would handle it properly anyway. -- Rémi Denis-Courmont http://www.remlab.net http://fi.linkedin.com/in/remidenis -------------------------------------------------------------------- IETF IPv6 working group mailing list [email protected] Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
