Mobile Ad-hoc network (MANET) is one of the high tech communication mechanism. A MANET is defined as a network that has many nodes composed of mobile devices that can arrange themselves in various ways. Mobile Ad-Hoc Networks is integrated with wireless nodes that can communicate anywhere. MANET are categorised into three types: VANET, InVANET and iMANET.
A Vehicular Ad-Hoc Network or VANET provides communication between vehicles and between vehicles and road-side base stations with an aim of providing efficient and safe transportation. A vehicle in VANET is considered to be an intelligent mobile node capable of communicating with its neighbours and other vehicles in the network. VANET can achieve affective communication between moving node by using different ad-hoc networking tools such as Wife IEEE 802.11 b/g, WiMAX IEEE 802.10, Bluetooth, IRA.
Each vehicle of VANET device can receive or transmit message through the wireless network in ad-hoc mode. Such mechanism provides collision, traffic conditions, road sign, alarm etc. The device is equipped with multimedia and internal connectivity facilities for the wireless coverage vehicles. VANET provides automatic vehicle parking and toll collection facilities. There are three possibilities of communication in VANET:
• Vehicle-to-Vehicle (V2V) ad hoc network: allows the direct vehicular communication without relying on a fixed infrastructure support and can be mainly employed for safety, security, and dissemination applications.
• Vehicle-to-Infrastructure (V2I) network: allows a vehicle to communicate with the roadside infrastructure mainly for information and data gathering applications
• Hybrid architecture: combines both Vehicle-to-Vehicle (V2V) and Vehicle-to-Infrastructure (V2I). In this scenario, a vehicle can communicate with the roadside infrastructure either in a single hop or multi-hop fashion, depending on the distance, i.e., if it can or not access directly the roadside unit. It enables long distance connection to the Internet or to vehicles that are far away