Date: Wed, 15 Nov 1995 15:16:59 -0000 From: Sean Doran <smd@icp.net> Message-ID: <95Nov15.151700-0000_est.20701+5@chops.icp.net> What's important is the routing system. This is certainly true. The fact that you are registered in registry X as being the "owner" of prefix Y is completely irrelevant if pretty much the entire Internet is going to route X towards Z. As is this from a practical sense - but we really need to look a little beyond that. If we simply look at the routing system, we find that longest match preference is the way to go, which argues, very strongly that in order to keep routing working, everyone should inject (at least) /24's (no shorter) prefixes, so they won't be overrideden by a longer prefix from elswhere, to be absolutely safe all advertisments should probably be /32's for every host in every organisation, backed up by /31's /30's /29's ... going back as far as needs routing so the longest possible length will get through any prefix length filters that exist. I don't think that is quite what cidrd is attempting to accomplish. If we step beyond letting the routing system be the sole arbiter of what addresses are useful, so people can be encouraged to advertise shorter prefixes, with consequent greater risk of them being overridden, there really needs to be some way that the controllers of routing policy (who filters what) can determine that they're doing the "right thing" when they refuse to accept a longer prefix, but still not longer than any prefix length limits, and route according to a shorter one instead. Or that they should allow the longer prefix to override a shorter one. History of routes may allow some of that to be automated, but that is never going to be sufficient. What's needed is a list of just where routes should be accepted from - which equates pretty much with address owneship, though says nothing about the permanence of that ownership. kre