It's interesting to me that people who know better often confuse basic
routing (which I'll call next-hop-reachability) with policy. Most of
todays routing systems are only concerned with next-hop-reachability.
They don't address policy at all. To me policy looks like "you go in
the slow lane because you're not paying as much as the guy who goes in
the fast lane".
Most of the routing policy discussions I've seen recently seem to have
gotten side tracked on some form of tag-switching. The tag-switching
seems like a way to prop up slow Ethernet switches and dumb ATM
switches instead of addressing the real policy issue.
I think ISP's will (or do) want to charge different rates for different
levels of service. This means policy should determine what path the
packets take, not reachability. I don't think the policy has to be very
complex, but it has to tie together the policy mechanism at a router
port (like bandwidth limiting and fair-share) with the end-to-end path
(like you take the oc-3 and the other guy gets the oc-12).