Let’s Build Your Own SDN

You must have heard a lot about SDN. But, do you know you can make it yourself? If not then this post will help you in knowing that. So, let’s start:

For this, you will need an OpenFlow controller. We are using RYU. It is written in Python and is very convenient with vast documentation. You can even get many options regarding how to run it in Mac or OSX. You can also go for another option that is using a VM.

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SDN Architecture

Source:Open Networking Foundation

After the installation of the controller, connect to Zodiac Fx and you are good to go towards your first SDN. The Zodiac Fx has Port 4 in its default settings that is “non-openFlow”. It is used for the communication between controllers. While using a VM, a physical port has to be assigned by you for the connection. Its IP address by default is You can set it as the controller’s IP address or change it accordingly.

Let’s talk about simple_switch_13.py that is installed with RYU. It creates layer 2 switching. Firstly, it creates a flow for sending traffic towards the controller and then after seeing a packet flow is created again for sending traffic to the connected port. Resultantly, a flow is created continuously no direct sending of traffic to controller.

The basic command in RYU used is:

PYTHONPATH=. ryu-manager –verbose /Library/Python/2.7/site-packages/ryu/app/simple_switch_13.py

If all connections are done properly you will see nothing in the debugging output as there is no traffic now.

As the traffic starts to move “Packet In” message will be seen on the output and actual flow can also be analyzed at CLI.

If you don’t know anything about SDN then let me tell you that this is the demand for current and future times. But, don’t worry its never too late. If you want you can still grab the opportunity of learning about SDN. Logic Finders will be sincere with you. To get more about our offerings do check the link below: