Click Example

1. Obtain Resources

In this step, we are going to setup the experiment. In this tutorial we assume that you are sufficiently comfortable with omni to know when your slice is ready using readyToLogin.

These instructions assume you are using at least omni version 2.6, but it is possible to do the exercise using the tool of your choice. Likewise, this assume Windows users use the git bash emulator distributed with Git for Windows, but the exercise can be completed with other tools.

1. Create a slice

   omni createslice <slicename>
   

   where <slicename> is click<initials>.

2. Create a sliver

   omni createsliver -a AGG_NICKNAME <slicename> <rspec_url>
   

   • In the Portal the RSpec is called Click Router Example Experiment (IG)
   • If you are doing this exercise as part of a tutorial then the aggregate (AGG_NICKNAME below) is given to you.
     • If you are doing this exercise at home use one of : bbn-ig, nysernet-ig, stanford-ig, ucla-ig or utah-ig
   • The rspec_url is: ​http://www.gpolab.bbn.com/exp/ClickExampleExperiment/click.rspec
3. Check the status of your sliver

   readyToLogin <slicename> --useSliceAggregates
   

Install scripts

While you wait for your sliver to become ready, we will see how we can automate the installation of our experiment with install scripts. In this experiment we are going to use software routers in order to write our own forwarding scheme. This means that in any experiment we are going to run we want the basic installation of the software router to always be present. The configuration might change from run to run, but the software should always be installed. The software to be installed, and the scripts to be executed at boot time, are defined in the rspecs. Follow these steps to locate your install script and identify the different parts.

1. Open your RSpec and look for the install tag and copy the value of the URL attribute.
   • RSpec: ​http://www.gpolab.bbn.com/exp/ClickExampleExperiment/click.rspec
2. Look for the execute tag and write down the name of the script to be executed.
3. Download and untar the software. On a UNIX-like system you can do:

   cd /tmp
   mkdir click
   cd click
   wget <software_url>
   tar xvfz <software_name>
   

4. Look in your RSpec and locate the execute tag. Note what script is being executed at boot time.

Question

• Locate the script specified by the execute tag and open it.
  • Can you identify the different parts?
  • What is the purpose of the script?
  • What is the purpose of the installed.txt file?

Tips for using Git For Windows

If you are using the bash emulator in Git for Windows:

• The following commands are available:
  • less
  • cat
  • vi
• The following are not available by default:
  • wget
  • more
  • emacs
• In order to use an ssh agent you need to enter the following additional command in each terminal:

  eval `ssh-agent -s`
  ssh-add .ssh/id_rsa
  

Next: Execute