Book Image

Mastering Python Networking

Book Image

Mastering Python Networking

Overview of this book

This book begins with a review of the TCP/ IP protocol suite and a refresher of the core elements of the Python language. Next, you will start using Python and supported libraries to automate network tasks from the current major network vendors. We will look at automating traditional network devices based on the command-line interface, as well as newer devices with API support, with hands-on labs. We will then learn the concepts and practical use cases of the Ansible framework in order to achieve your network goals. We will then move on to using Python for DevOps, starting with using open source tools to test, secure, and analyze your network. Then, we will focus on network monitoring and visualization. We will learn how to retrieve network information using a polling mechanism, ?ow-based monitoring, and visualizing the data programmatically. Next, we will learn how to use the Python framework to build your own customized network web services. In the last module, you will use Python for SDN, where you will use a Python-based controller with OpenFlow in a hands-on lab to learn its concepts and applications. We will compare and contrast OpenFlow, OpenStack, OpenDaylight, and NFV. Finally, you will use everything you’ve learned in the book to construct a migration plan to go from a legacy to a scalable SDN-based network.
Table of Contents (22 chapters)
Title
Humble Bundle
Credits
Foreword
About the Author
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface
12
OpenStack, OpenDaylight, and NFV

OpenFlow operations with Ryu


To begin with, let's look at two basic components of Ryu code that we have seen in the switch application:

  • ryu.base.app_manager: The component that centrally manages Ryu applications. ryu.base.app_manager.RyuApp is the base class that all Ryu applications inherit. It provides contexts to Ryu applications and routes messages among Ryu applications (contexts are ordinary Python objects shared among Ryu applications). It also contains methods such as send_event or send_event_to_observers to raise OpenFlow events.
  • ryu.controller: The ryu.controller.controller handles connections from switches and routes events to appropriate entities:
    • ryu.controller.ofp_event: This is the OpenFlow event definition.
    • ryu.controller.ofp_handler: This is the handler of an OpenFlow event. A Ryu application registers itself to listen for specific events using ryu.controller.handler.set_ev_cls decorator. We have seen the decorator set_ev_cls as well as CONFIG_DISPATCHER and MAIN_DISPATCHER...