For those interested in this topic, there is a (non-technical) article in this month's Internet Protocol Journal by Geoff Huston. It pretty well summarizes the issues and suggests different approaches to solve them. Highly recommended. http://www.cisco.com/web/about/ac123/ac147/archived_issues/ipj_11-3/113_ipv4... or in pdf http://www.cisco.com/web/about/ac123/ac147/archived_issues/ipj_11-3/ipj_11-3... Patrick