| Popis: |
In vehicular ad-hoc networks, vehicles move at a very high speed which makes data communication among vehicles difficult. VANET applications can be classified into safety and non-safety applications. Safety applications mainly focus on reducing the number of accidents and helps in improving the travel efficiency. An accident in heavy traffic roads leads to traffic jam. This information, of an accident happened should be multi-casted to the vehicles nearby, thereby they can change their route plan. So there is a need to multicast the emergency data to nearby vehicles with reduced packet loss and less delay. In this paper, we propose a fault tolerant multicasting technique with one primary parent and a secondary parent. A parent peer located near the accident is responsible for multicasting the data to other moving vehicles. If a parent node fails, the secondary parent starts multicasting the data. Simulation is done in NS-2 with 100 moving vehicles. Simulation results show that packet loss rate is decreased by 64.2%, end-to-end delay is reduced by 31% and control overhead is decreased by 9.91% in the proposed overlay structure than the tree approach. |
