Indian Journal of Science and Technology

Abstract

Objective: The main objective of this paper is to find an efficient and reliable path for routing data packets in vehicular ad hoc networks using hybrid routing. The hybrid routing protocol, Geo-Reactive, comprises of geographical routing and reactive routing with stable links. Method/Analysis: An analytical model has been derived for selective forwarding of Route Request (RREQ) packets through stable links. The mobility trace is generated using SUMO (Simulation of Urban Mobility) tool. This trace file is fed to NS-2 (Network Simulator) to compare the performance of our proposed protocol with GPSR in terms of packet delivery ratio, packet drop ratio and end-end delay. Findings: The simulation results obtained have been compared with GPSR and the results were promising in terms of packet delivery ratio, packet drop ratio and average end-end delay. The packet delivery ratio of Geo-Reactive increases when compared with GPSR as packets are forwarded only through stable links. This avoids frequent link failures thus improving the packet delivery ratio. This is also reflected in packet drop ratio. In Geo-Reactive protocol the Sequence number in the packet header of the reactive phase ensures that packets never get into loops which forces packets to be dropped after the Time-To-Live (TTL) expires. Also reduction in frequent link failures reduces packet drop ratio. As Geo-Reactive establishes a path with stable links, end to end communication delay is also reduced. Thus Geo-Reactive outperforms GPSR. Improvement: Geo-Reactive protocol definitely improves the performance of position based greedy forwarding technique by adopting a reactive protocol with stable links as recovery strategy. This hybrid mechanism of forwarding data packets using stable links outperforms GPSR.
Keywords: Geographic Routing, Greedy Forwarding, Link Stability, Reactive Routing, Recovery Strategy, VANET