## 4 Materials and Methods  
The proposed network in terms of the number of testable simulation scenarios are designed according to the simulation environment of this study. Then, the statistics were selected in terms of quality-of-service parameters to run a simulation and analyze the results. This study was implemented utilizing the Riverbed Modeler Academic Edition v17.5. The simulation setup consisted of a number of testable scenarios to test the network performance of the VLAN and the impact of the routing algorithms on the network performance. Each scenario consisted of several workstations linked to two Ethernet switches via Access Points for communication between the workstations and two servers. Two cases were considered in this study (low density and high density) with two traffics (File Transfer FTP, Web browsing HTTP and Email) to investigate the behavior of the designed VLAN network when the load (number of clients) is increased and how the ad hoc routing protocols could improve network performance in terms of the selected quality-of-service parameters. The simulation environments of each of the Riverbed scenarios are as follows:  
* Three access points: named (wirelessethernetslip4 router);
* Numbers of workstations (wlanwkstn) connected by the links to the servers;
* Two Ethernet switches (Ethernet16 switch): each switch had 16 ports for configuration;
* Two servers (Ethernet Servers) to represent two departments;
* Links (100 BaseT) to connect the access points to the switches, links connecting the switches to the servers, and a single link to connect two switches that act as trunks in VLAN scenarios;
* Application definition and profile configuration: to define and assign the application and services to clients and servers in the network;
* In another case, the wireless sensor network was examined as another network. WSNs consist of number of sensors sending data to the controller. These parameters were represented utilizing ZigBee (IEEE 802.15.4) standard connected to WIFI as a gateway. Table 1 shows the simulation environment of the proposed network. In the first case (low-density) Scenario1-Scenario5, 15 workstations were used in the designed network. The scenarios are as follows:  
Scenario 1 (No VLAN): Wireless LANs consists of the following parameters: 15 workstations numbered (PC1-PC15) and connected to two Ethernet switches via three access points connected by a 100 Base-T link. The switches were connected to two Ethernet servers. In this case, each PC could randomly select a server to send and receive data at any time. The scenario is illustrated in Figure 1.  
Scenario 2 (VLAN): VLANs were configured by dividing the network in two VLAN-aware switches with access ports. The VLAN association of these connected end-nodes was identified by the PVID of these ports. The switches with trunk ports were connected to each other to support both VLAN 10 and VLAN 20. VLAN 10 had ten PCs connected via two access points in wireless mode to two switches and VLAN 20 contained five PCs connected via an access point to the first switch. This scenario is shown in Figure 2.  
In this scenario, communication of any workstation cannot be carried out with any server at any time. VLAN 10 Clients selected servers randomly but their linked requests for the server of VLAN 20 were rejected by \"Switch2\", so that service was obtained from the server in their VLAN, minus any problems, as shown in the \"VLAN 10 Dropped Traffic\" graph. In VLAN 2, clients only tried to connect to the server in their VLAN, hence VLAN 20 experienced smaller packet drops than VLAN 10. These could be illustrated as shown in Figure 3. \begin{table}
\begin{tabular}{c c} \hline \hline
**Attribute** & **Value** \\ \hline No. of clients & 15 and 30 \\ \hline Simulation Time & 30 min \\ \hline \multirow{3}{*}{Traffic Flow} & File Transfer (FTP) \\  & Web browsing (HTTP) \\  & Email \\ \hline Network & VLAN and WSN \\ \hline Routing Protocols & AODV, DSR, OLSR \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Simulation Environment.