OpenFlow Tutorial

Theophilus Benson

Outline

• Components in an OpenFlow testbed• Setting up a testbed• Writing a new component– C++ components version– Python components version

OpenFlow Components• Controller• Openflow switches• Traffic generators

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OpenFlow Controller

OpenFlow Enabled Switches

Virtual Testbed

• Directions available online– http://noxrepo.org/manual/using.html#setting-

up-a-noxnetwork• Requirements– Linux system– Qemu – Python– Nox code– Other linux libraries

Testbed Setup

• Compile Nox code• Set up virtual machines• Connect topology• Start controller– Use appropriate components

• Connect switches to controller

Writing Components• Two languages; c++ and python– More information found:

http://noxrepo.org/manual/app.html• Components are stored in src/nox/apps– Separate each component into a distinct directory

• Component Structure– You must inherit from class Component– You must include a call to the REGISTER_COMPONENT

macro – You must include the following methods

• Void configure(const Configuration *)• Void install()

Component Paradigm• Register for events and specify handlers– register_handler<eventtype>(boost::bind(handling_metho

d, this, _1));– register_handler<Packet_in_event>(boost::bind(&Hub::ha

ndler, this, _1));• All work done in handler– Return either CONTINUE or END– NOTE: you can start the controller with a list of

components, event get passed from one to the other– Returning CONTINUE means the next component handles

the packet– Returning END means no other components handle the

packets

Demo

• Run component in openflow controller• Ping from endhost A• Should observe printouts in controller’s

console

Resources

• Nox website– http://noxrepo.org

• OpenFlow Site– http://www.openflowswitch.org/wp/documents

Questions