Using mobile agents for off-line communication among mobile hosts in a large, highly-mobile dynamic networks

In dynamic networks such as packet radio and ad-hoc wireless networks, each node acts as a mobile router, equipped with a wireless transmitter/receiver, which is free to move about arbitrarily. In this configuration, even if two nodes are outside the wireless transmission range of each other, they can still be able to communicate with each other in multiple hops, if other intermediate nodes in the network are willing to participate in this communication process. However, the dynamics of these networks as a consequence of mobility and disconnection of mobile hosts pose a number of problems in designing routing schemes for effective communication between any source and destination. Thus, even off-line communication between source and destination (E-mail, for example) would be inefficient, if not impossible, in a large dynamic network structure where hosts are highly mobile. This paper introduces a scheme using mobile agents to address this issue. A mobile agent in this context would act as a messenger that would migrate from a source and carry the message from a source to a destination. The scheme utilizes the location information (using the Global Positioning System, for example) and relies on the fact that the mobility of hosts in ad hoc networks is not totally random but follows a pattern of movement. A mobile agent can migrate off a source node with a message and navigate autonomously throughout the network to find out the destination in order to deliver this message. If the destination is disconnected from the network for some duration, the delivery of the message will be deferred and the agent waits for its reconnection in an appropriate intermediate node. From the performance evaluation, it is concluded that the proposed scheme consumes much less network resources compared to other routing schemes proposed in the context of a highly dynamic large ad hoc network