Date: Fri, 2 Dec 2011 15:20:34 -0800 From: Ted Hardie <ted.ietf@xxxxxxxxx> Message-ID: <CA+9kkMAJnUp60NCzWCtokZStcTk1LrdVRfQJZmbzPFBgoo5A5Q@xxxxxxxxxxxxxx> | Big enterprises buy small ones; sometimes at a great rate. And this itself is a good argument that 1918 space is sufficient (one way or another), not the reverse. What you have there is two 1918 spaces (typically, if it isn't, it is irrelevant here) colliding - with just the same possibilities of collisions as are being mooted here - and yet as you say, this happens all the time, and I don't see the big enterprises clamoring for a dedicated address block for their use, so they can avoid clashes when swallowing smaller ones. This also raises another problem with the proposal - it assumes that there are two distinct classes of networks, the carrier ISP networks that get to use CGNs, and the new network block, and end users, who are supposed to use 1918 space. While I agree in many cases it is easy to categorise users as one or the other, I believe that there are very many ambiguous cases, ISPs who believe themselves to be carriers where most of the rest of us would treat them as end users, and others (like just big enterprises like above that have swallowed lots of little ones) that are acting more like a big ISP, even though their only customers are their acquired enterprises. I still believe that there are just two types of addresses (multicast etc aside) - routable ones, and non-routable ones, and attempting to set aside pieces of either of those spaces for one use, as opposed to another, is just futile. kre _______________________________________________ Ietf mailing list Ietf@xxxxxxxx https://www.ietf.org/mailman/listinfo/ietf