Virtual Access Point Demonstartion


The objective of this demo is to show the working of a virtual access point as a potential candidate for virtualization of the wireless ORBIT testbed. In this demo three clients are connected to the virtual access point with different essids ie different VLANS. Two clients perform file transfers using simple traffic generators and the third flow comprises of a video streaming. The offered load of the traffic generators in the first two flows is increased gradually and its effect on the quality of the video as a part of the third flow is shown. Once the quality of the video falls enough to make it unsatisfactory, traffic shaping using Click Modular Router is done at the virtual access point. This limits the traffic of the first two flows allowing sufficient bandwidth to restore the video quality.




VAP demo topology


  1. The demo works for a specific set of nodes. Incase one of the nodes is down , certain changes have to be made to the scripts. Presently the following nodes that are fixed for the demo and included in the image are

4,6: Virtual Access point 1,5: Video Receiver/Client 7,5: Video Server

The other nodes can be chosen randomly. The experiment script has to be changed depending upon the nodes used. The experiment script is stored in the home folder rmahindra and its exact location is


I am working on checking in our nodeHandler code. After that the demo can be run using the normal procedure. Presently it has to run using the nodeHandler from my home directory.

  1. Incase one of three above nodes have to be changed.. then just ssh into that node and edit "startitall" script in the root directory of that node. A simple "if" statement would have to be altered to include the new node.
  1. The three nodes that send data to the VAP over the wired network have to have their eth0 configured. This includes the video server node. ssh into these nodes and type in

ifconfig eth0 10.20.0.x netmask up … DONT CHOOSE x TO BE 1,5,6,7,8

Double check by pinging .

  1. Now the nodes are configured and the experiment is ready to be run. Goto rmahindra home folder and type the following commands

cd nodeHandler-3.6.4-plab/src/ruby ruby -W0 handler/nodeHandler.rb -k test:exp:DEMO2

This will run the VAP modified nodeHandler and start the experiment.

  1. The video can be viewed in vlc at http://10.10.x.y:10xy where x,y is the video client node.

The graph for the other data flows can be viewed at


  1. Once the video appears sufficiently distorted, start click on the VAP node.

Last modified 13 years ago Last modified on Jul 30, 2007, 7:29:29 PM

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