A novel strategy to discover Internet gateways in mobile ad hoc networks

Integrating nodes in a MANET to the Internet require either a connection to the Internet or they can connect to the Internet through the Internet gateways or servers. For the second case a node in a MANET has to find out the gateway or server to connect to the fixed nodes in the Internet. End to end packet delay and throughput are strongly dependent on the time needed to discover the gateways. A source node in a MANET can discover a gateway either by broadcasting a gateway discovery message or it may depend on periodic gateway advertisement messages from the gateways. The first one is renowned as reactive gateway discovery strategy and with this one a gateway in a MANET may receive the same gateway discovery message from different intermediate nodes. This paper presents a novel solution for connecting nodes in ad hoc network to the Internet. Here a gateway sends separate reply to the requestor for each request message having the same Broadcast ID it receives from that source in stead of sending only one unicast reply to the requestor. The AODV routing protocol has been used for routing in the MANET domain. We investigated our new strategy of gateway discovery in NS-2. Simulation results show that our one has better performance having lower delay and fewer packets drop.