Performance Comparison of Topological Geographical and Clustering Routing Protocols in VANETS

Vehicular Ad hoc Networks (VANETs) represent a specialized form of Mobile Ad hoc Networks (MANETs), where communication takes place among mobile or stationary vehicles equipped with wireless transceivers. These networks support two primary communication modes: vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I), enabling vehicles to exchange critical data either with each other or with fixed roadside units. In this study, we implement and evaluate several topological routing protocols—including AODV, DSR, DSDV, and OLSR—as well as geographical routing protocols such as GPSR, PA-GPSR, and MM-GPSR. The performance of these protocols is analyzed under varying network conditions and packet sizes. Additionally, clustering-based VANET protocols are also examined for comparative analysis. The paper presents a detailed comparison of topological and geographical protocols based on key performance metrics such as Packet Delivery Ratio (PDR), throughput, and end-to-end delay. Furthermore, a comparative evaluation is conducted among topological, geographical, and clustering protocols with respect to PDR, highlighting the relative effectiveness of each routing approach under different network scenarios.