Installing the Ryu controller:
1.
2.
To begin with ensure your system has python installed, by executing python on the terminal,
which would turn into the python shell, besides displaying the version. You may then exit from
the prompt using Ctrl+D.
Install Ryu dependencies:
 sudo apt-get install python-pip python-dev libxml2-dev libxslt-dev zlib1gdev
Install Ryu using pip:
 sudo pip install ryu
 If the system already contains Ryu (one can check this using whereis Ryu and which Ryu and
from the output of the previous commands), then add the --upgrade option to the above
command, to avoid a potential "version conflict" error.
The Ryu controller gets instantiated using a script called ryu-manager. We next add this to the
python path variable, so that we don't need to give the complete path to invoke the controller at all times:
 PYTHONPATH=. ./bin/ryu-manager ryu/app/simple_switch.py
Next to test your installation, open up two terminals:

In the first one, get the controller up and running:

ryu-manager --verbose ~/ryu/ryu/app/simple_switch.py
This starts the controller with a simple_switch script that pushes down rules to the
switches to enable them as simple switches.
In case of your own NetApp (Ryu application), replace simple_switch.py with your own
.py file, with its complete path.

In case you see an oslo.config error, try, as shown here:


sudo pip install oslo.config
In the second one, set up the Mininet topology, with a remote controller. An example could be the
following:


sudo mn --topo single,3 --mac --switch ovsk --controller remote
Finally run the pingall command on the second terminal, to see if all hosts can reach every other
host in the network.
Next we upgrade OpenvSwitch switches so that they are good to go with OpenFlow version 1.3 scripts that we
may run later. Use the command: ~/mininet/mininet/util/install.sh -V 2.3.1