On 2011-12-01 09:28, Chris Grundemann wrote: ... > It is more conservative to share a common pool. It suddenly occurs to me that I don't recall any serious analysis of using 172.16.0.0/12 for this. It is a large chunk of space (a million addresses) and as far as I know it is not used by default in any common CPE devices, which tend to use the other RFC 1918 blocks. I realise that ISPs with more than a million customers would have to re-use this space, whereas a /10 would only bring this problem above 4M customers, but at that scale there would be multiple CGN monsters anyway. Sorry to bring this up on the eve of the telechat. Brian _______________________________________________ Ietf mailing list Ietf@xxxxxxxx https://www.ietf.org/mailman/listinfo/ietf