Bob Braden wrote: > > Within the ARPA-funded Internet research program that designed IP and > TCP, Jon Postel and Danny Cohen argued strenuously for variable length > addresses. (This must have been around 1979. I cannot name most of the > other 10 people in the room, but I have a clear mental picture of Jon, > in the back of the room, fuming over this issue. Jon believed > intensely in protocol extensibility.) > > However, Vint Cerf, the ARPA program manager, rules against variable > length addresses and decreed the fixed length 32 bit word-aligned > addresses of RFC 791. His argument was that TCP/IP had to be simple > to implement if it were to succeed (and survive the juggernaut > of the ISO OSI protocol suite). I'm quite OK with both, IPv4 fixed-length 32-bit addresses and IPv6 fixed-length 128-bit addresses, and consider fixed-length addresses reasonable. What I really don't like is that IPv6 was not made to be transparently backwards compatible (on the IPv4 address range), but instead a completely different protocol that requires non-trivial translation IPv4<->IPv6. One the one hand, the IETF was frowning upon NATs when they were developed outside of the IETF. But if you look at the IETFs (lack of) migration plan, the translation that you need in order to make old-IPv4 interoperate with new-IPv6, is actually worse than an IPv4 NAT. -Martin _______________________________________________ Ietf mailing list Ietf@xxxxxxxx https://www.ietf.org/mailman/listinfo/ietf