# Future Wireless Networking Experiments Escaping Simulations
## 5 Our Wireless Experiment on Each Testbed  
W-iLab1.t, W-iLab2.t, and POWDER are Emulab-based testbeds. Currently, Emulab testbeds provide a simple way to create wired networks topologies using an Ethernet switch. All the different types of wired topologies--linear, ring, grid, mesh--can be created. However, there have not been many studies performed on how to set up wireless ad hoc network topologies in Emulab. For wireless experiments, Emulab installs real wireless devices on a building space. Most of these wireless devices contain IEEE 802.11 a/b/g Wi-Fi interfaces (Atheros and INTEL chipset), and are located at various places in a large building or in a city. Further, all these wireless devices contain only two Wi-Fi interfaces. The problem is that not all the nodes/Wi-Fi interfaces support the ad hoc mode. Therefore,we create the ad hoc network topologies (linear, ring, grid, and mesh) using the access-point mode and use different non-interfering frequencies to create different links.  
Our method for creating a wireless ad hoc network topology on a linear topology is shown in Figure 4. In the diagram, node 1, node 2, node 3, and node 4 with Wi-Fi interfaces are shown. Since all Wi-Fi interfaces support the Access-Point (AP) mode, we created ad hoc network topologies using this mode. The links are created using non-interfering frequencies (f1, f2, and f3). In the first link, WiFi1 and WiFi2 are connected via frequency f1 where WiFi1 serves as a station and WiFi2 acts as an access point. Further, frequency f2 is used for the second link, where WiFi4 is the AP and WiFi3 is the station. Moreover, the third link is created by using frequency f3, where Wi-Fi5 acts as an AP and Wi-Fi4 acts as a station. We enabled Optimised Link State Routing (OLSR) in each node so that nodes can communicate with each other.  
The hardware details of all used nodes are presented in Table 3. According to Table 3, all nodes used on the CityLab testbed include AMD processors with a frequency of 1 GHz on each of the four cores available. Moreover, nuc0-3, nuc0-5, nuc0-6, nuc0-8, nuc0-9, nuc0-10, nuc0-11, nuc0-14, nuc0-15, nuc0-17 of Wi-Lab1.t contain Intel processors with 1.3 GHz frequencies in each of the four cores while apuW2, apuW4, apuW5, zotacK6, apuV5, apuU6, zotacI6, apuT5, zotacH6, apuS2 of Wi-Lab2.t contain Intel processors with 1.8 GHZ frequencies in each of the four cores. In POWDER, there are four nodes supporting wireless setups and it contains Intel processors with 2.3 GHz frequencies in each of four cores. Table 3 also shows that the RAM of CityLab nodes is 4 GB, as opposed to 8 GB for W-iLab1.t, W-iLab2.t, and POWDER. All the testbed nodes are selected based on their availability at the time of the experimentation. The information on topologies with respect to each testbed is provided below.  
\begin{table}
\begin{tabular}{l l l l l} \hline \hline
**Testbed** & **Name** & **Location** & **CPU** & **RAM (Memory)** \\ \hline \multirow{6}{*}{W-iLab1.t} & nuc0-3, nuc0-5, & \multirow{6}{*}{} & Intel(R) & \multirow{6}{*}{8 GB} \\  & nuc0-6, nuc0-8, & & & Core(TM) \\ \cline{1-1}  & nuc0-9, nuc0-10, & & & i5-4250U CPU@ \\ \cline{1-1}  & nuc0-11, nuc0-14, & & 1.30 GHz & \\ \cline{1-1}  & nuc0-15, nuc0-17 & & Quad-core & \\ \hline \multirow{6}{*}{W-iLab2.t} & apuW2, apuW4, & \multirow{6}{*}{} & AMD G-T40E & \multirow{6}{*}{4 GB} \\  & apuW5, zotacK6, & & & \\ \cline{1-1}  & apuV5, apuU6, & & & Intel(R) \\ \cline{1-1}  & zotacI6, apuT5, & & & Atom(TM) CPU \\ \cline{1-1}  & zotacH6, apuS2 & & & D525 @ 1.80 \\ \cline{1-1}  & & & & GHz Quad-core \\ \hline \multirow{6}{*}{CityLab} & node71, node72, & \multirow{6}{*}{} & AMD GX-412 TC & \multirow{6}{*}{4 GB} \\  & node73, node74 & & & \\ \cline{1-1}  & & & & Quad-core \\ \hline \hline \end{tabular}
\end{table}
Table 3: Hardware resources used in the single-testbed experiments.  
Figure 4: Wireless ad hoc network topology creation at Emulab (W-iLab1.t, W-iLab2.t, and POWDER).