Book Image

OpenFlow Cookbook

Book Image

OpenFlow Cookbook

Overview of this book

Table of Contents (17 chapters)
16
Index

Sending a packet-out message to the switch

Packet-out (OFPT_PACKET_OUT) messages are sent from the controller to the switch when the controller wishes to send a packet through the switch data path via a switch port.

There are two ways by which the controller can send packet-out message to the switch:

  1. Construct the full packet. In this case, the controller generates the complete packet and adds an action list field in the packet-out message. The action field contains a list of actions defining how the packet should be processed by the switch. It may include packet modification, group processing, and an output port. It can also specify the OFPP_TABLE reserved port as an output action to process the packet through the OpenFlow pipeline.
  2. Use a packet buffer in the switch. In this mechanism, the controller uses the buffer that was created at the time of sending the packet-in message to the controller by the switch. While sending the packet_in message to the controller, the switch adds the buffer_id...