Many applications and protocols are planned for the so-called Intelligent Transportation Systems (ITS). Most of them are supposed to work in dynamic networks, such as the vehicular ad hoc networks (VANET). However, designing and studying distributed applications and protocols in such networks is not easy. Analytical studies suffer from the lack of pertinent models. Simulations are often far from reality. Road experiments are generally limited, due to their complexity.In this paper, we present an environment that emulates the vehicular networks. It allows to reproduce road experiments without further developments of the studied prototypes. These protocols can be tested with more complex road traffic. The impact of the communication range and the dynamics of the network can be studied. Some comparisons with road tests and simulations show the advantage of such an emulation framework.

The development of the Intelligent Transportation Systems (ITS) highlights the need of connecting vehicles to the infrastructure. Indeed, many ITS applications rely on such connections to offer new on board services. The networking architecture allowing vehicle-to-infrastructure (V2I) communication is then a key challenge for new pervasive applications. In this paper, we present an architecture designed for opportunistic vehicles to infrastructure communication. This light architecture allows to transfer data from the vehicles to the infrastructure through IPv4 or IPv6 connections using 3G networks or WiFi access points, depending on their availability. It relies on any VANET routing protocol like geocast or conditional based routing instead of traditional routing. We use conditional transmissions to benefit from its intrinsic discovery facilities, in order to find a gateway towards the infrastructure. We describe the architecture, its implementation and our road testbeds, allowing to conclude on the interest of such an architecture that allows to exploit already installed networks.

Many applications are designed for vehicular networks, like chat, dynamic map update or touristic information. The need of services used as building blocks for these applications is then emerging: localization, map matching, data collect, and so on. When a unicast communication is required, applications rely generally on naming, localization and routing services. This approach consumes many network resources and leads to poor performances when the network dynamic is high. We then propose an efficient service, named keepalive, to ensure the continuity of a communication that began between two mobile neighbors. The major strengths of our proposal are that it relies only on local exchanges of identifiers and it is less resource consuming than usual networking services. Moreover, it is beneficial for a large set of applications, including download from road side units or follow me application for instance. Road tests and performance study confirm the efficiency of the keepalive service.

Intelligent Transport Systems envision many applications relying only on vehicle-to-vehicle communications. Depending on the application (road safety, driver information, infotainment...), the requirements are different in terms of throughput, delay and loss rate. This paper explores the performances issues of a convoy of vehicles on the road, in order to estimate the capacity of such linear vehicular network. Among other results, we show that, while the loss rate is important, it is possible to rely on the vehicular network to relay informations issued from on-board sensors.