Brian, On 2009/11/21, at 7:02, Brian E Carpenter wrote:
> > ... >>> My second point is that assumptions like "the best path is through a >>> prefix we both use" are silly. Analysis of a common traceroute will >>> show that two random users tend to use two random ISPs. So a routing >>> policy tat starts from "assume both users are using the same prefix" >>> is a lost cause. Start from the assumption that you're looking for an >>> address pair that works, and as a second choice, works well for a >>> given ISP pair. >> >> I agree. Well, if you happen to have the same prefix, then it makes >> sense. Also, in say an enterprise, most of the communication is probably >> internal where this makes sense. > > Sure, that was always clear to me - longest match only makes sense > when you have already eliminated pretty much every other criterion. > Longest match with other hosts under the same enterprise prefix is > probably the best example. The problem is that there is no universal rule to determine which address is within his (enterprise) network. The prefix length /32, /48 matching is not always beneficial. This is another motivation for distributing site local policy to the user hosts. Regards, Arifumi Matsumoto -------------------------------------------------------------------- IETF IPv6 working group mailing list [email protected] Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
