How to run a Virtual Mobility experiment on ORBIT

Goal

This tutorial designed to teach you how to run a virtual mobility experiment on Orbit after creating VM*.txt files and setting up the experiment. (In order to find out about VM*.txt files and their creation, refer to the How to code and use Various Mobility Model Scripts to Emulate Mobility on ORBIT and also, in order to find out some more detail about setting up an experiment, refer to Mobility Emulation using Spatial Switching).

Running an Virtual Mobility Experiment

The virtual mobility on orbit depends on the configuration of click router files and their activation times at specific grid nodes. Therefore, running an experiment means successful configuration of the click router files for all the used nodes during the experiment and installation of these click files.

It is an option to create the click router files and run manually, but this process may get complicated. Therefore, there are scripts at the vmss2.tar.gz file to ease the job.

In order to create the click router files automatically, you need to extract vmss2.tar.gz file to your orbit.grid account after logging in with your user name and password. vmss2.tar.gz compressed file includes several useful scripts that make the creation of needed router files easy using VM*.txt mobility path files (The difference between vmss.tar.gz used at Mobility Emulation using Spatial Switching and vmss2.tar.gz is the latter has additional build-in mobility models and a script for running the experiment automatically).

Steps

1) Log to grid.orbit-lab.org with your user name and password and extract vmss2.tar.gz
2) Run your own mobility model script or build in models and create VM*.txt files
3) Run perl ./runVM.pl Perl script (Only vmss2.tar.gz has this file)

IMPORTANT: This script above assumes all grip nodes are running without any problem. However, this may not be the case all the time. Some nodes may fail during imaging step and may not respond to your calls. Therefore, the click router file installation to these nodes will fail, so will the experiment. To avoid this case, after finishing step 2, be sure that the nodes that you are using during the experiment are working properly. You may do this by checking “system_topo_failed_grid.rb” file at the root.

During step 3, the script will automatically perform these actions,

1) Image all grid nodes —> Takes approximately 7-8 minutes
2) Turn all grid nodes on —> Takes a few seconds
3) Run CreateMobilitySetup script—> Takes a few seconds
4) Install ath0 ports to nodes and turn them up —> Takes a few seconds
5) Copy the Click files to nodes —> Takes a few seconds
6) Run the loaded Click files on nodes —> Takes a few seconds

Step 6 completes the initialization process and then nodes get active sequentially in a predetermined order and emulate mobility.

Total running time of your experiment is depended on the durations that you specified at your mobility model and the above mentioned durations.

You can see the details of runVM.pl script above.