Design and Analysis of the Gateway Discovery Approaches in MANET

The demand for any time anywhere connectivity has increased rapidly with the tremendous growth of the Internet in the past decade and due to the huge influx of highly portable devices such as laptops, PDAs etc. In order to provide the users with the huge pool of resources together with the global services available from the Internet and for widening the coverage area of the MANET, there is a growing need to integrate the ad hoc networks to the Internet. Due to the differences in the protocol architecture between MANET and Internet, we need gateways which act as bridges between them. The gateway discovery in hybrid network is considered as a critical and challenging task and with decreasing pause time and greater number of sources it becomes even more complex. Due to the scarcity of network resources in MANET, the efficient discovery of the gateway becomes a key issue in the design and development of future hybrid networks. In this paper we have described the design and implementation of the various gateway discovery approaches and carried out a systematic simulation based performance study of these approaches using NS2 under different network scenarios. The performance analysis has been done on the basis of three metrics - packet delivery fraction, average end-to-end delay and normalized routing load.