# An Efficient Framework Model for Optimizing Routing Performance in VANETs
## 5 Simulation and Performance Analysis  
### Define Urban Network Scenario  
Nowadays, there are different approaches developed to solve the complex problem of VANET simulation. There are numbers of road traffic simulators which generate NS-2 format traces file, but the most comprehensive ones use OpenStreetMap (OSM) [39] such as Simulation of Urban Mobility  
Figure 3: Simulation Flow Diagram of Optimization Model.  
SUMO [40] and VanetMobiSim simulator [41]. These combined approaches allow a direct interaction between the communication network system and the vehicular traffic dynamics to specify the different scenarios, which imports common roads information (XML code) from OpenStreetMap such as road edges, traffic lights, traffic signs, road direction, road conditions, vehicle speed on the roads, etc. The SOMU simulator generates vehicular mobility trace files that is used as input for a mobile wireless of OLSR network. In order to understand the procedures that is needed between two vehicles to create route and exchange data packet. Each vehicle broadcast HELLO-interval and TC messages to detect next hop in its communication range, a symmetric link is necessary to estimate the quality of link and then initiate transmit data packet. The procedures of communications mode between two vehicles in the VANETs uses an ad-hoc way approaches, communication range, control messages, and shortest path method, all depicted in Figure 4.  
In order to obtain results close to the real world, we have defined 10 realistic vehicular mobility scenarios. This scenarios will be evaluated by an existing specific VANET simulator as suggested in [22]. The critical differences between MANETs and VANETs make most of current ad hoc protocols unsuitable to apply in high dynamic environment. The certain characteristics which make most of current ad hoc protocols unsuitable to apply in high dynamic environment. This work take into consideration the relation between the traffic in dynamic mobility and the cost communication network. Thus, we have to define 10 urban scenarios with a specific data flow in which these scenarios represent various possible connections that is presented in the network. A set of cars were defined on specific area to exchange data in an urban environment roads [22]. These vehicles moving with a fluctuating speed and directions throughout the simulation time. Figure 5 shows the conversion stages of road network that was used to evaluate the performance of the proposed method.  
We take into consideration the relation between the number of network nodes and the selected area, vehicle speed movement, limit of covering range, available bandwidth, and simulation time. For example, the number of nodes should be higher in highway wireless network environments. The reason of large scale density is to reduce the likelihood of packets loss due to vehicles traveling at higher speeds than in urban areas environments. In our scenarios, there are 40 vehicles moving and exchange information data about routes in an area of 1400 m \(\times\) 1200 m, and the vehicles travel on the urban scenario with varying speeds of 10-50 km/h, and the transmission power range is adjusted to 250 m. The setting of VANET scenarios are adjusted automatically by SUMO simulator.  
Figure 4: Communications Mode Between Two Pairs of Vehicles.