Last week, Jasson Casey presented a tutorial on Flowgrammable’s visual OpenFlow simulator, Flowsim. Jasson Casey is a PhD candidate at Texas A&M University and the founder and executive director of Flowgrammable.org. Flowsim enables a detailed view of the OpenFlow protocol in action using real switch configurations. The presentation covered the some of the problems in current OpenFlow application development and how Flowsim helps to solve them. The Flowsim application also serves a starting point for people wanting to learn about the OpenFlow protocol and how it works. The application can be also used to test switch configurations in production networks.
The presentation covered an overview of OpenFlow, including the packet processing pipeline model that the Flowsim application uses. The pipeline model helps explain how OpenFlow packets move through a switch data plane. Another key point in the presentation was the explanation of OpenFlow primitives, and how they be generalized over any switch data plane. These primitives include instructions, actions, groups, ports and queues, which together enable the user to describe basic network functions. Another key point brought up was feature discovery. Between versions of OpenFlow, new optional features are added, which means the switch needs to be queried for them before those new features are used. Flowsim will let users pick real switch configurations, making feature discovery for that switch much easier.
Jasson Casey is a research associate with the Open Networking Foundation, and a research affiliate with the Center of Secure Information Systems at George Mason University. His research includes topics in programming languages and networking, specifically centered on SDN.