> -----Original Message----- > From: Brian E Carpenter [mailto:[EMAIL PROTECTED] > > ... > > we would ideally also have corresponding IPv6 subnets that are > > algorithmically derived from the IPv4 subnets. > > I used to think that was a good way to design an initial > IPv6 addressing plan. But from helping people design a real > addressing plan for a real campus with many years of IPv4 > history, I've reached the conclusion that it's a really bad idea. > It's much better to design a clean IPv6 plan from the ground up, > rather than sweeping up the messy history of the IPv4 plan. > > If you design a clean IPv6 plan that way, there doesn't seem to be > any incentive whatever to use anything other than /64 as > subnet prefixes (except for the router-router links, as Pekka > mentioned). There's a strong incentive in favour of /64, > i.e. the ability to use SLAAC, privacy addresses, and CGAs.
I second this. My approach has been (rather, is being) to retain the same number of separate subnets as I was using in IPv4, but to allow each one to become far bigger now. Using the /64 prefix. And I'm creating these out of the /56 blocks I'm being assigned. Seems like a low risk way to go dual stack, and not run into any unnecessary restrictions wrt IPv6 clients. The incentive for greater than /64 prefix would be to prevent wanton waste for such things as firewalls or serial links, I suppose. Bert -------------------------------------------------------------------- IETF IPv6 working group mailing list [email protected] Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
