Book Image

OpenFlow Cookbook

Book Image

OpenFlow Cookbook

Overview of this book

Table of Contents (17 chapters)
16
Index

Processing a packet-in asynchronous message from the switch

Packet-in messages are sent from the switch to the controller to transfer a packet received from one of the switch ports to the controller for further processing.

Getting started

There are three ways in which the switch can send a packet-in event to the controller:

  1. Table-miss entry. When there is no matching flow entry for the incoming packet, the switch can send the packet to the controller. Refer to the Sending a switch configuration message to the switch recipe in Chapter 1, OpenFlow Channel Connection Establishment (Part 2), for the switch configuration required to send a table-miss packet to the controller.
  2. TTL checking. After decrementing the TTL value in the packet, and if the TTL value reaches zero, the switch can send the packet to the controller. Refer to the Sending a switch configuration message to the switch recipe in Chapter 1, OpenFlow Channel Connection Establishment (Part 2), for the switch configuration required to...