Deployment Guide

52
The controller communications channel goes through the OpenFlow connection handshake protocol (shown
below) and should end up at HANDSHAKE_COMPLETE/CONNECTED with communications established.
Next you need to verify that the switch shows up on the controller as an OpenFlow node. For the Ryu
controller, in order to verify that the controller sees the switch and to obtain the unique datapath ID, you can
use the controller’s REST API. To start Ryu with the REST API enabled, use the Ryu ofctl_rest.py script included
with the controller package. From the Ryu server command line:
> ryu-manager –verbose ofctl_rest.py
You can then use the Ryu REST API’s to communicate with the switch via OpenFlow. The first API shown here
wil allow you to test the controller connection and the controllers visibility into the switch node:
/stats/switches
Accessing this URL on the controllers IP address through a web server will allow you to see the Datapath ID
(DPID) of the switches known to that controller: