Performance Evaluation and Analytical Validation of Internet Gateway Discovery Approaches in MANET

The integration of MANET and Internet extends the network coverage and also increases the application domain of the MANET. The connection of ad hoc networks to the Internet is established via Internet gateways, which acts as a bridge between them. One of the key overhead components affecting the overall performance of this integration is the discovery and selection of Internet gateways as discovery time and handover delay have strong influence on packet delay and throughput. In this paper, the three Internet gateway discovery approaches have been implemented and then the impact of node mobility for two different cases have been examined in terms of performance metrics throughput, end-to-end-delay and routing overhead using network simulator NS2. Our simulation results reveal that the reactive Internet gateway discovery approach scale poorly with increase in number of traffic sources and node mobility to access Internet as compared to the proactive and hybrid gateway discovery approaches. However, reactive gateway discovery results higher throughput and lower end-to-end delay for the same situation than proactive and hybrid approaches. Hybrid Internet gateway discovery approach performance was always observed in between reactive and proactive approaches. The simulation results have also been analytically verified.