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Trema

Full-Stack OpenFlow Framework in Ruby and C

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Trema is a full-stack, easy-to-use framework for developing OpenFlow controllers in Ruby and C.

“ I poked through Trema recently. It looks like a *great* project. Very clean. ”
-Martin Casado, Nicira CTO

Install

Installation is very easy. Run gem install trema and straight away you have a working Trema installation.

$ gem install trema

If you prefer manual installation, download .tgz or .zip from the link in the upper right corner and build it as follows:

$ tar xzvf trema-xyz.tar.gz
$ cd trema-xyz/
$ bundle install
$ ./build.rb

Writing Your Own Controller

Trema OpenFlow Controller are simple Ruby scripts. Write your own OpenFlow controller by adding message handlers to your controller class just like Rails.

class MyController < Controller
  def packet_in dpid, message  # packet_in message handler
    ...
  end

  def features_reply dpid, message  # features_reply message handler
    ...
  end

  ...
end

Running Your Controller

You can test your controller right away without compilation:

$ ./trema run mycontroller.rb

This one simple trema run command enables the closed loop of "Coding, run, and debug".

Network Emulator

With Trema network DSL, you can describe the network topology in which the controller is executed.

# One virtual switch + two virtual hosts.
vswitch { dpid "0xabc" }
vhost "host1"
vhost "host2"
link "0xabc", "host1"
link "0xabc", "host2"

Then you can pass the network configuration to trema run.

$ ./trema run mycontroller.rb -c network.conf

Sample Code

[trema]/src/examples/ directory includes some simple samples demonstrating Trema API usage. They are good references for understanding both Ruby and C APIs.
Trema Apps repository includes practical/experimental controllers developed on top of Trema. It is a good starting point for developing real-world controllers.