Mobile ad hoc networks (MANET) comprise mobile hosts in a network bereft of base stations and characterized by a highly dynamic network topology. The MANET environment contains unpredictable obstacles, such as mountains, lakes, buildings, or regions without any hosts, impeding or blocking message relay. This study proposes geocasting protocols for sending short message from a source host to single or multiple geocasting regions in ad hoc networks. The proposed protocols keep messages away from unpredictable obstacles and create a small flooding region. Experimental results show that a source host can send a short message to all hosts located in single or multiple geographical areas with a high success rate and low flooding overhead.
