Let me play Devil's Advocate here for a moment... Why do you need a -policy-? Why do you need anything other than what 1597 already says? 1597 was VERY careful to be general and leave implementation of policy up to the users. The RA, NAPs, IXs, and others do not need to concern themselves with how or when these suggestions are implemented. The thing to understand is that the 1597 network addresses are not unique throughout the entire Internet. There use and administration is done on a local basis, but it behoves us to not get parochial about the term local. Actually, there's a really interesting point here that's about to give you a big whopping ulcer. I hate to do this to you but... You, as RA, need to support your customer's routing policies. If, for instance, someone at Sprint and someone at MCI get together and decide jointly that they want to share network 10 "privately" for their BGP loopbacks or their porno FTP servers, they could form the Sprint/MCI net-10 consortium and you'd need to carry an advertisement for net 10 in your RA database so the two sites could exchange routes. Here's where the fun comes in... now say Alternet and PSI get together and want to share network 10 "privately" for their BGP loopbacks or their porno FTP sites and form the Alternet/PSI net-10 consortium... :-) The long and the short of it is that as RA, not only do you need to not block 1597 advertisements in your database, you need to correctly implement virtual private networking for 1597 advertisements. Remember Bill, that the RA needs to not get bogged down by parochial definitions of "local." I bet now you're wishing you hadn't brought this up and got me thinking... Sorry...I'll buy you a drink in Danvers to make it up to you. Best regards, Paul p.s. the B block of 1597 has 12 bits of prefix-signifcance, not 20 (32-20=12...)