So, Openflow doesn’t do shortest path forwarding? How can a network architecture NOT do shortest path forwarding? SDN is BS.
Yes, Openflow doesn’t do shortest path forwarding by itself, in fact, it doesn’t do anything by itself. Openflow is a tool that allows you to programmatically control your network devices.
However, it gives you the power to do it. In this post I’ll guide you through the development of a shortest-path forwarding network application using the RYU Controller and Openflow. Hopefully I’ll post a few thoughts on different forwarding schemes and Openflow.
For this tutorial, I’m assuming you are familiar with Openflow, Mininet and RYU. If you are not, go ahead and check this other posts. I’m using RYU, which is an OpenFlow Controller written in python with support to OpenFlow 1.3. To know more about it visit their website
To install RYU you can easily do
pip install ryu and BOOM! If it doesn’t work you can try using the Mininet installation script with the -y option.
The network application will be organized in three blocks:
- topology discovery
- network view construction
For the topology discovery we’ll use a RYU module/library called topology. For network view construction we’ll use an awesome python graph library called networkX. For forwarding we’ll use OpenFlow.