Mobile Agent Based Ad Hoc Routing Technology

Ad hoc network is a completely wireless no-center network, in which the topology rapidly changes due to the movements of mobile hosts. Therefore, how to detect the variable topology and find an appropriate route among nodes is the essential problem of Ad hoc network. Current routing protocols for Ad hoc networks are on demand routing protocols which have route discovery latency. A great number of data transport from limited nodes may lead to sudden packet losses and delays. Non-balanced traffic load may quickly consume the power of the higher loaded nodes, and shorted the lifetime of the network. So it's important to monitor the overhead and congestion status of a routing path to achieve traffic-load balancing.Mobility and autonomy are the main characters of mobile agent, the mobile agent and mobile Ad hoc network have the same nature. This paper proposes a mobile agent based congestion control AODV routing protocol to avoid congestion in Ad Hoc network. We add some mobile agents in Ad Hoc network, which carry routing information and nodes congestion status. Each node maintains a relatively less-loaded one-hop neighbor set by broadcasting HELLO packet, which includes the congestion level. When mobile agent travels through the network, they can select a less-loaded neighbor node as its next hop, and update the routing table using the node in history records which has lager sequence number and lower multiple congestion level. With the aid of mobile agents, the nodes can get the dynamic network topology in time and avoid congestion. Before leaving the node, mobile agent can determine to transfer or delay depending on the current congestion status. Though this method we can control the mobile agent's number in the network, and avoid agent flooding. Finally, the thesis has done an extension to AODV protocol, and a lot of simulation experiments under NS2. Simulation indicates that this mobile agent based congestion control AODV routing protocol reduces the end-to-end delay and the average number of route discovery requests, balances the traffic load, prolongs the lifetime of network, and improves the performance of Ad hoc network.