Analytical review and study on multipath routing protocols

Vehicular Ad Hoc Networks (VANET) constitute a promising technology for Intelligent Transport Systems (ITS). VANET are highly dynamic in their nature because of the movements of vehicles, which are acting as nodes. The routing protocol must be designed for dealing with multiple limiting conditions, like link failures, handoffs, and long congestion periods, which is very challenging. The survey of different routing protocols in VANET provides a significant information for building smart ITS. Accordingly, the present survey is devoted to the existing distinct multipath routing protocols. This review article provides a detailed account on 50 research papers, presenting the different kinds of multipath routing protocols, namely proactive routing protocols, ad-hoc-based routing protocols, Greedy Perimeter Stateless Routing (GPSR), hybrid routing protocols, as well as geographic routing protocols. Besides the classification and cursory description, the present study addresses also several of the important parameters, like evaluation metrics, implementation tool, publication year, datasets utilized, Peak Signal to Noise Ratio (PSNR), and packet end-to-end delay with respect to various techniques considered. Eventually, the research gaps and issues of various multipath routing protocols are presented with the intention of pointing out directions for future research.