Suitability of MANET Routing Protocols for Vehicular Ad Hoc Networks

In this paper, the suitability of the existing MANET routing protocols for VANETs has been evaluated. Even though a VANET is a subset of MANET, it has unique characteristics and message delivery requirements. VANETs are characterized by a very dynamic topology with partial infrastructure support, patterned mobility, mobile nodes with sufficient resources, intermittent connectivity and varied channel behavior. In addition to these characteristics, the network traffic requirements are also different. Safety messages need reliable, accurate and timely delivery in a few hops neighborhood whereas other types of messages may have other requirements. MANET protocols, in contrast, are designed for resource constrained wireless environment. The message delivery constraints are not stringent and movement of nodes is slow and random. Thus, there is a need to ascertain whether, the basic MANET routing protocols like AODV and DSR can satisfy VANET needs like timely delivery of messages especially when the vehicles move at high speeds. Simulation studies show that AODV and DSR are not able to satisfy the requirements and specific VANET routing protocols are needed.