Sdn, method for forwarding packet by sdn, and apparatus

A software defined network, wherein the software defined network (SDN) comprises an SDN controller and an SDN switch, the SDN switch comprises a processor and a data path, and the SDN switch further comprises:

• a first transceiver, configured to:
• receive a first packet, determine that the first packet is to be sent to the controller, and forward the first packet to a channel agent;
• and
• the channel agent, configured to:
• add address information of the SDN controller to the first packet, encapsulate the first packet into a second packet, and send the second packet to the controller, wherein
• the first transceiver is further configured to:
• receive a third packet sent by the SDN controller, and forward the third packet to the channel agent;
• and the channel agent is further configured to:
• delete control information and address information in the third packet, convert the third packet into a fourth packet, and send the fourth packet to a corresponding port or flow table according to at least one of a port number or a flow table number that is carried in the control information in the third packet.