VANET is a form of network that provide vehicle to vehicle and vehicle to infrastructure communication. The main goal of VANET is to provide the road safety. Various wireless communication technologies used for VANET, the IEEE 802.11p is to support the medium range communication characteristics of vehicular environments. One of the main issues of VANET is handover process. It can be commendably accomplished through FHP mechanisms .The handover algorithm for IEEE 802.11p depend on the vehicular

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... ommunications. It is also characterized as autonomous, self-configured wireless network which has dynamic topology, variable network size and also constrained mobility. Due to these characteristics it needs an effective and efficient routing protocol to fit into an environment. The emergency alert message information are transferred through V2V communications, so the parameters like hub determination, delay, high mobility and frequent data disconnections plays vital role for communications. There are numerous VANET data dissemination strategies were applied, however it truly doesn't give sufficient transmission speed emergency oriented data transmission administrations. In a large portion of the circumstances it prompts sudden traffic congestion and accidents. To limit the equivalent, VANET network need insightful and powerful routing protocols for intra vehicle communication. The different data dissemination procedures used to share the information in highway and urban climate with great nature of services, rebroadcast and the confirmation of message when it arrives at the destination are considered and assessed with various exploration authors papers. It covers application areas, challenges, different dissemination techniques and security issues widespread in the VANET.