Introduction: ------------- There have been several suggestions on the nanog list recently about ways to clean up the IP address "swamps" created by prior, piecemeal allocations of class C addresses. I understand the PIER Working Group of the IETF, with the approval of the IANA and Internic, are currently surveying those swamps to provide data for evaluating proposed solutions. Before making addtional proposals one might then do well to ask, "What criteria should a 'good' solution meet?" Here's my list: - Impose few administrative costs on end users. Approaches involving renumbering or installing IP tunnels won't meet this criterion until much better tools are available. - Depend only on voluntary participation by Internet providers. - Gain for participating providers smaller route tables. - Assure that no customer of a provider is unduly harmed by the provider's participation. Can a solution be found that includes all these criteria? Perhaps not, but here's a "straw" proposal nonetheless. Proposal: --------- Participating providers divide a swamp into sections. For example, four providers could divide 192/8 into 192.0/10, 192.64/10, 192.128/10, and 192.196/10. Each provider continues to announce its customer /24 routes, but in addition each announces to the others one of the four /10 routes. For the /10 route which it announces, each provider accepts and keeps all the /24 routes it hears. For the other three, it keeps only the /10 route and filters out any /24 routes it hears. The resulting routing might be inefficient: provider A might deliver packets to provider B that are eventually destined for a customer of provider C. But packets do continue to reach their ultimate destinations. Providers get smaller route tables, while customers remain blissfully unaware (and thus continue to pay for service ;-). Note that four is not a magic number: any two providers could bilaterally enter into an agreement of this type and get reduced route table sizes. Personal Note: -------------- As an observer on the sidelines of nanog activity, I certainly lack the experience of the "older, wiser heads" who operate the major providers' backbone networks. Those with that experience, and the knowledge accrued therefrom, may well find gaping holes in this straw proposal. I look forward to their criticism, either in traffic on the list, in private email, or in person at the upcoming San Diego meeting. -- Sean Shapira sds@jazzie.com +1 206 443 2028 <a href="http://www.jazzie.com/sds/">Sean's Home Page</a> Serving the Net since 1990.