Abstract-Inter-Vehicular Communications (IVCs) are now considered as a way to realize active safety, for example, by providing the position information of each other or the potential danger warning by wireless communications.We have worked on a flooding protocol over vehicular ad hoc networks (VANETs) to efficiently disseminate the information for the sake of active safety applications, such as the positions and the velocities of the vehicles. We propose a flooding protocol with (i) Congestion Detection algorithm which suppresses unnecessary packets due to vehicular congested traffic and (ii) Backfire algorithm which efficiently forwards the packet through the network by selecting the adequate receiver node based on the distance from the original node.In this paper, we show simulation results over NS2 (Network Simulator 2). They show that the proposed flooding protocol significantly improves the performance of data dissemination over VANETS.

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Abstract-A Mobile Ad-hoc NETwork (MANET) is a selfconfiguring network of mobile nodes connected by wireless links, which can form an arbitrary topology. We have worked on a new protocol, RSVconf, to ensure the IP address self-configuration of MANETs, with a special focus on the ITS (Intelligent Transportation System) context which is indeed the most mobile scenario. The RSVconf protocol manages the creation, merger and remerger (merger after part of the network temporarily separated) of networks at IP layer. It is stateful, distributed and routing independent. The simulation results show its capability to react fast and correctly to the rapid topology changes of mobile networks without a waste of bandwidth. In this paper we present the current status of our research, open aspects and future directions. I. BACKGROUNDAutoconfiguration is the procedure used by MANET nodes to get automatically a unique IP address. The protocol must be able to create a new network, assign addresses to newcomer nodes, and treat network mergers and partitions. Our target is the ITS context where the number of nodes is limited (less than 1000 nodes), the mobility speed is high, the mobility is defined by the other factors like driver behavior and traffic rules. The wired network address assignment mechanisms (manual configuration or DHCP) are not suitable for wireless highly mobile networks. New specific protocols must be conceived and optimized to achieve a fast convergence to support the mobility. One of the most interesting protocols presented is MANETconf [1] which proposes a reliable Duplicate Address Detection (DAD) requiring an answer from all nodes. A new arriving node (the requester) looks for a configured neighbor (the initiator) in order to obtain its configuration information. The initiator broadcasts an address for the requester on the MANET. All nodes have to answer to the request to avoid using the address of a node that has been temporarily disconnected from the MANET. If a node does not answer after, it is considered as having left the MANET and its address becomes available. This implies that each node of the MANET keeps a list of all assigned addresses in his MANET. Mergers and partitions are managed with Network Identifiers (NID [3]. EPDI uses the concept of the epidemic dissemination of information: single nodes form an abstract global entity which has global network knowledge. Each node has a partial view of the network; to have a global sight all local databases must be collected and consolidated. The protocol easily supports the network creation and the newcomers joining. Mergers and remergers are supported only for few nodes (about 25 nodes). These protocols are not suitable for the targeted scenarios. MANETconf requires too much messages, traffic to maintain the statefulness, avoiding the scalability and sometimes detects wrong partitions. DACP, like other centralized approaches, is fragile because too much importance is given to few nodes. Furthermore mergers are slower because the leader has to manage all th...

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