Geographical addressing is a key communication paradigm in emerging Intelligent Transportation Systems (ITS). In this paper, we address the issue of how to direct messages to roadside units (RSUs) in order to have them forwarded by the RSUs to the on-board units (OBUs) of vehicles in a certain specified destination area. For that purpose, we have extended the Domain Name System (DNS) to support geographically scoped queries. A query with specified geographical coordinates will be resolved by

more »

... extended DNS system to the IPv6 addresses of those RSUs that cover the area described by the geographical coordinates. In this paper, we further extend the proposal by introducing delegation of geographical queries to DNS servers lower in the hierarchy. Furthermore, we demonstrate the feasibility of the proposal by implementing and experimenting with a prototype.