Narrow Results

The management of increased demand for the utilization of available road infrastructure thanks to urbanization that has attracted the interest of researchers in the domain of Intelligent Transportation System (ITS). This helps the commuter to travel in congestion-free, accident-free, and efficient road scenarios. Vehicular ad hoc networks (VANETs) form a vital element of the ITS. VANET is defined as a subcategory of mobile ad hoc networks (MANETs) with some predefined distinct properties. Unlike MANET, VANET has no constraint on the node’s battery life, but there is a bandwidth constraint in this scenario. VANET supports two types of communication: either among vehicles or among vehicles and infrastructure. The key objectives of VANETs are to modify public safety and transportation efficiency in the highly dynamic and mobile scenario. This chapter provides detailed information regarding the VANETs and their characteristics, network layer-wise communication protocols, shortcomings, features, and applications, and finally the challenges and future scope.

In this paper, a new communication model to describe the controller placement problem of software-defined networks is proposed. Previous solutions to the problem only focus on the switch to controller latency, without paying attention to the latencies between controllers. In this study, both of these latencies were comprehensively studied, based on which the theory was raised. The simulation results show that the algorithm which suited the new model has better delays in most topologies.

In IEEE 802.11 based WLAN system; the mobile nodes (MN) are connected through access points (APs). During mobility a MN leaves one AP and is associated to new APs, A handoff process will occur. To provide a better seamless connectivity, Handoff process latency should be very small. Handoff latency is a combination of scanning, re authentication and reassociation latency. Reauthentication latency is major contributing factor that affects the performance of handoff and increase the handoff latency. In this paper we present a novel approach for reducing the Reauthentication latency, and network overhead. For reducing the re-authentication latency we apply pre-authentication mechanism which is preceded by the mobility prediction to consider the user mobility behavior as the contributing factor in the pre-authentication. With the help of mobility predication the central server sends a pre authentication key to the APs and also sends the Ids of AP to the MN and MN store into their buffer. The simulation results show a good factor of improvement over the latency values in WLAN environment.