Hybrid gateway advertisement scheme for connecting mobile ad hoc networks to the Internet

* This work was supported in part by the Brain Korea 21 project of the Ministry of Education, in part by the National Research Laboratory project of the Ministry of Science and Technology, and in part by the Electronics Telecommunication Research Institute, 2002, Korea. Abstract When a node in a mobile ad hoc network wants to send data packets to the Internet, and therefore outside of its local ad hoc network, it has to obtain information about the available Internet Gateways: i.e. which one to use and how to get there. To accomplish this, nodes can utilize either a solicited gateway discovery mechanism or rely on unsolicited gateway advertisement packets sent by gateways. Obviously, the effectiveness of periodic and unsolicited advertisements depends entirely on the traffic and mobility patterns. The most important factors involved in sending unsolicited gateway advertisements are the time interval between sending two consecutive advertisements and the TTL value of the advertisement packet i.e., the gateway should carefully decide when to send advertisements, and the advertisement flooding area should be limited only to nodes that need to update their gateway information and their paths to the gateway. In this paper, two kinds of advertising schemes are proposed, which are based on the observation of traffic and mobility patterns, and are designed to avoid generating unnecessary packets in the MANET (Mobile Ad hoc Network), in addition to giving mobile nodes more opportunity to use the shortest path to the Internet.