> Tony is right -- any registration process costs resources. agreed, though the cost of registering a domain name should serve as a useful upper bound. at least with address blocks you don't have to worry about I18N, trademark infringement, etc. > But, if these addresses are assumed to be not routable, then there > shouldn't be any routing table bloat. Put differently, once can > conceive of three ways to get addresses: > > * From an RIR, as PI space > > * From an ISP, as PD CIDR space. > > * From some other process, as long-prefix, almost > certainly unroutable, isolated space. actually it's highly desirable if such addresses *are* routable by private agreement, just not by default. I don't see why we shouldn't be able to choose from the above three options.