1. A method, comprising: determining, at a network device, a set of routes to one or more reachable addresses in a computer network; determining a set of no-routes to one or more non-reachable addresses in the computer network; recursively aggregating the routes and no-routes into one or more reachable route prefixes within which there are one or more corresponding non-reachable no-route prefix exceptions to exceptions, wherein aggregating includes: creating a bitmap with bits corresponding to each address within a given range, wherein based on the routes and no-routes, the bits of the bitmap are populated with a first bit value for addresses corresponding to a route, and with a second bit value for addresses corresponding to a no-route, and recursively merging each even prefix with its adjacently corresponding odd prefix for each decremented prefix length in a range of available prefix lengths; and utilizing the route prefixes and no-route prefix exceptions.