Vehicular Ad hoc Networks (vanet) are a special kind of Mobile Ad-Hoc Networks (manet) adapted to the communications between vehicles. Several specific protocols to vanets have been developed to improve performances and satisfy vehicular application needs. To evaluate a protocol for vanet, some realistic mobility models are needed. Unfortunately, such models are not provided by Opnet Modeler. In this work, we propose a framework that enhances Opnet Modeler simulation scenario using realistic vehicular mobility models. This framework makes use of the open source software called "Simulation of Urban MObility" (sumo) and the "input trajectory files" feature of Opnet Modeler.

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Abstract-Vehicular Ad hoc Network in a highway is composed of high speed vehicles or nodes which induce fast topology changes in their configuration. In order to solve the connectivity and scalability problems of VANETs, we introduce the architecture of a Vehicular hybrid ad hoc network (VHANET). Using some routing protocol extensions, the VHANET allows ad hoc islands to be interconnected among each other using a infrastructure network. Our simulation results show that the performances, compared to a flat network, are greatly enhanced. In addition, we study a nearly optimal AP density for the use of our architecture.I. VEHICULAR AD HOC NETWORKS AND ROUTING Vehicular Network is a new capability for drivers to enhance safety on roads and then, to provide Internet access services. Vehicular Networks can be formed either by deployment of a telecommunication network infrastructure or by using Ad Hoc communications between vehicles. In the first case, some access points are distributed along the road, each one connected to other through a wired network allowing the vehicles to connect to the AP (Access Point). The main drawbacks of a complete road coverage are prohibitive costs and inefficient use in case of light traffic. On the other hand, a Vehicular Ad Hoc Network (VANET) is a special kind of Mobile Ad-Hoc Networks (MANET), where vehicles equipped with wireless devices constitute a network without any additional infrastructure.In VANET [1], the vehicles act both as hosts and routers, being either packets source, destination or forwarder. VANET networks can be used for two kinds of applications: safety applications like alert diffusion, road foreseen, and user oriented applications like Internet access, VoIP, file transfers or advertising services. Both types of applications have different constraints in terms of delay, bandwidth and reliability. For user oriented applications, data rate will usually be greater than for safety applications. Safety applications are mainly interested with reliability and delay guarantee. Moreover, we consider safety and user-oriented applications which use unicast communications. For these unicast communications, a routing protocol is required. MANET routing protocols were designed to establish paths even with a dynamic network topology. With VANET, the difficulty comes from the nodes high mobility because the paths have to be more often established and a lot of signaling messages are broadcasted. The second problem comes from the convergence delay which has to be less than the topology change interval in order to achieve an accurate routing process.For these main reasons, several studies have shown that it is not reasonable to use a proactive routing protocol for VANET where the vehicles speed implies a highly dynamic topology. In contrast, either reactive or geographical protocols are more robust to frequent topology changes. Particular routing techniques are thus studied for the VANET [1], [2] but other studies has demonstrated that DSR (Dynamic Source Routing, a reactive ad hoc p...

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Mobile ad hoc networks are characterized by their highly dynamic, multi-hop, and infrastructure-less nature. Due to limited computing power, scarce bandwidth, high mobility and the lack of a central coordinating entity, service discovery in these network is a challenging task. The great majority of service discovery protocols developed for MANETs deal with the above issues at the application layer.In this paper, we discuss the fact of implementing service discovery at the routing layer instead of the application layer, in order to reduce Service Discovery (SD) overhead and to limit resources consumption. We develop an integrated service discovery protocol, called BF-SD-ZRP, utilizing a combination of different optimization techniques: piggibacking of SD information on the routing messages, compact description of SD using Bloom filter (BF) and service caching. Our simulation results allows to validate our scheme and demonstrate its efficiency in terms of overhead reduction and service discoverability.

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