Changes between Version 11 and Version 12 of GEC21Agenda/iMinds

10/10/14 11:41:55 (5 years ago)



  • GEC21Agenda/iMinds

    v11 v12  
    5959In a second part of the tutorial, we will demonstrate how to use OMF/OML & Labwiki to run wireless experiment on the w-iLab.t testbed, including mobile nodes. Using the graph plotting capabilities of Labwiki, you will be able to see the throughput impact of moving the mobile node around the testbed.
    61  Instructions will follow soon...
     61 Instructions below are not final yet...
     63== Part 1: Wireless & mobile experimentation at w-iLab.t ==
     65 === Reserve 3 wireless nodes using jFed ===
     67All of the w-iLab.t nodes have been previously reserved for the "GEC21" project. You should join this project prior to running the tutorial.
     69Every group has 3 wireless nodes (2 fixed and 1 mobile) which you have to activate using jFed. You should choose specific nodes in jFed by right clicking the node.
     70Name them: ap, client and backup. See the table on the group sheets to see which nodes you can use.
     72 === Configure the access point (on the mobile node) ===
     74Before running the experiment, we will use the shell script option in the RSpec to install hostapd.
     75Go to the Raw RSpec view and add the following in the node part of the ap (first line is already there):
     78<sliver_type name="raw-pc"/>
     80     <execute shell="sh" command="sudo apt-get update ; sudo apt-get install hostapd ; "/>
     84 === Configuration of Access Point (on your mobile node) ===
     86SSH to your mobile node (from jFed). Become root:
     88$ sudo su
     91Create a config file for the hostapd program:
     93$ nano /root/hostapd.conf
     96Add the following content to the config file (X=group number, Y=channel, Z=mode lines should be left aligned):
     106Replace X with your demo number. Replace Y with your channel and Z with the WiFi mode.
     107Start hostapd. The above config will setup an AP on wlan0 using 802.11a or g, channel Y, with SSID demoX:
     109$ hostapd /root/hostapd.conf
     112Open a second ssh terminal and give an IP address to the wlan0 interface so we can test the connection to the clients (in the next steps). Be sure to replace X with your group nummber:
     114$ sudo su; ifconfig wlan0 192.168.X.1/24
     117 === Configure the client (on one of the fixed nodes) ===
     119Become root:
     121$ sudo su
     124Put the wireless interface into managed mode and specify the SSID so it knows to which AP it should connect
     126$ iwconfig wlan0 mode managed
     127$ iwconfig wlan0 essid demoX
     130Specify an IP address and bring up the interface:
     132$ ifconfig wlan0 192.168.X.10/24 up
     135Check if you can ping the AP:
     137$ ping 192.168.X.1
     140 === iPerf measurement ===
     142Start an iPerf server instance (UDP in this case) on the mobile node (AP):
     144$ iperf -s -u -i 1 &
     147Configure the iPerf client:
     149$ iperf -u -c 192.168.X.1 -b 40M -i 1 -t 6000
     152If the iperf reports an actual 40Mbit/sec throughput, you probably lost the connection.
     153By tweaking the transmit power (values of 0 to 20dBm) of the access point, you should be able to see a difference in throughput of the iPerf stream:
     155$ iwconfig wlan0 txpower <0-20>
     158For this tutorial, leave the txpower to 20 for the first experiment runs. If the effect of moving the mobile node is too limited, you can try lowering the txpower.
     159Note that each antenna at the w-iLab.t is equipped with a 10dB attenuator (so 20dB attenuation per link).
     161 === Move the mobile node ===
     162Once everything works fine, you can start driving the mobile node and check the impact on the iPerf throutput.
     163The robot control software can be accessed at [].
     164You can log in with the demoX accounts. For example, the demo5 account will give you the rights to move mobile5.
     165Instructions on how to use the framework: [] , scroll down to “Setting up paths”.
     166VERY IMPORTANT : You will only be able to SSH to the mobile node while it is docked. (If you want an SSH connection during your experiment, you will have to set up a wireless connection to a fixed node and SSH over the wireless.)
     169== Part 2: Mobile experimentation using Labwiki ==
     171In this part, you will learn how to run experiments using the Labwiki tool. This tool uses the OMF framework in combination with the OML measurement library.
     173 === Prepare your experiment ===
     174Go to [], click the prepare text field and type "gec21iperf". You should see a drop down list with some files. Select the gec21iperf.oedl file.
     175Since this version of labwiki only has one user account at the moment, you should copy the contents of this experiment file and create a file with your group number in the file name. Click CTRL-A, followed by CTRL-C and then click the wheel icon. Choose a name for your file (without the .oedl extension), select OEDL and click Create.
     176Now paste (CTRL-V) the contents of the experiment in the field below and click the Save button.
     178The presentation at the beginning of the session should have given enough explanation to understand this experiment description file.
     180Change the properties "sender" and "receiver" so they reflect the hostnames of your resources.
     182 === Prepare your mobile scenario ===
     183Go to [] and start drawing a scenario for your mobile node.
     184If you are done, click the Save button and copy the list of coordinates.
     188Be sure to issue the following command when you dock the robot again, otherwise you will not be able to run more experiments.
     190$ /usr/bin/killall ruby ; /etc/init.d/omf_rc start