jmccormac - 10:06 pm on Apr 12, 2012 (gmt 0)
Perhaps some IP ranges and their delegation may be associated with the old VPOPs for ISPs. (Virtual Point of Presence). The local exchanges or VPOPs used to have a group of IPs associated with them and these would form a pool of IPs for customers. The problem, from a geographical point of view (especially in Ireland) was that one VPOP could be serving a phone code area that could cover a number of geographical counties or areas.