Vehicular Ad hoc Networks (VANETs), a subclass of mobile ad hoc network (MANET), is a promising approach for the intelligent transport system (ITS). VANET allows vehicles to form a self-organized network without the need for a permanent infrastructure. As the VANET has a potential in improving road safety, real time traffic update and other travel comforts, it turns attention of the researcher. Though VANET and MANET shares some common characteristics like self-organized network, dynamic topology, ad hoc nature etc, VANET differs from MANET by challenges, application, architecture, power constraint and mobility patterns, so routing protocols used in MANET are not applicable with VANET. New routing strategy for VANET has been proposed by many researchers in recent year. This paper provides focus on the various aspects of VANET like architecture, characteristic, challenges, glimpse of routing protocols, and simulation models used for VANET.