Visualization of OpenFlow Data-plane Abstractions
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Flowsim is a tool that helps you learn OpenFlow quickly. It is a completely self-contained web application, no system configuration is necessary. In minutes a user can configure an OpenFlow switch and single-step a packet through the OpenFlow pipeline. At each stage of a simulation, internal data structures are visible, so a user can see exactly how the OpenFlow pipeline operates.

Most people are interested in learning new technologies, tools, and techniques. However, the grind of their daily lives sets a limit on the amount of time they have, and levels of frustration they are willing to tolerate. If learning a new technology is tedious or time consuming, adoption will often stall.

Flowsim is designed with time concerns in mind. We want to teach people OpenFlow without requiring them to rack and stack equipment, or even configure a virtual machine. Flowsim allows users to do 'something interesting' in a matter of minutes with only a few button clicks.

Another key design goal is to visualize the OpenFlow pipeline, and all the internals of packet processing. We want to let users play with different OpenFlow abstrations, change configuration, and see how packets flow through the system.

Flowsim appeals to a diverse group of people: network engineers, system adminstrators, software developers, and hardware engineers. By learning the foundational abstractions of OpenFlow, users are better prepared to write applications, troubleshoot networks, and even implement the OpenFlow specification.


Flowgrammable is a nonprofit organization comprised of students, researchers, and professional engineers, who are focused on network systems education and research. Originally founded to compete in the Open Networking Foundation's (ONF) OpenFlow driver competition, Flowgrammable has evolved into a mentoring, research, and education organization. The organization mentors undergraduate and graduate students in SDN research, conducts original research, and actively develops educational and training material.


The Flowsim project is organized into the following subdirectories:

  • 3rdparty
  • doc
  • backend
  • flowsim-ui

Our project uses a 3rd party tool called Flyway for SQL database migrations. This tool depends on Java 1.6, or higher, and certain environment variables being set. The tool is located in the '3rdparty' directory.

Drawings and documentation about the design of the system can be found in the 'doc' directory. At the moment this is just a collection of notes and not yet fully organized.

The RESTful API for the service is located in the 'backend' directory. This is an HTTP/S server using the Restify JavaScript framework to modularly serve RESTful API services. This is our persistence layer for Flowsim.

The bulk of the application runs in a modern JavaScript capable broswer and the code is located in the 'flowsim-ui' directory. The frontend relies on the angularjs UI framework and the bootstrap css styling library.