Hiya all, I would like to see some capability for reservation/hierarchy/delegation in such a tool. For example at Viag Interkom we have small ranges loosly reserved to each of 10 or so locations. These loose reservations can be aggregated and only exceptions need to be announced to all routers in our network. From our experience I would say that up to about 30% of an allocation can be reserved with current IPv4 policies, but that could be less depending on the likely assignment types. the reservation can be later shrunk if necessary (not yet needed). Typically a single /24 per site is used for small assignments. If a reservation gets full, another is made - two route announcements are better than no aggregation. Despite this reservation we are able fairly easily to reach the 80% utilisation required from RIPE for further allocations. Hierarchy/reservation is also very important in networks where addresses are in somewhat greater supply (RFC1918 and maybe IPv6). I have moderate perl experience and, after my left upper arm heals from a double fracture last Thursday :) , I may be able to help with some coding. Dave Pratt Viag Interkom