Ofs in-band communication method and ofs

An OpenFlow Switch (OFS), comprising:

• a processor, a memory, and a communication interface, wherein
• the memory is configured to store one or more controller list entries, wherein the controller list entry comprises a MAC and an IP of a local OpenFlow controller (OFC), and a port number that is corresponding to the MAC and the IP of the local OFC and is used when the OFS receives a Link Layer Discovery Protocol (LLDP) data packet sent by the OFC;
• the communication interface is configured to receive the LLDP data packet, wherein the LLDP data packet comprises a MAC, an IP, and a role sub-field of a sender, wherein the role sub-field is used to identify a sender type;
• and
• the processor is configured to create a controller list entry or update the controller list entry when it is determined, by using the role sub-field, that a sender type of the received LLDP data packet is OFC, wherein the created controller list entry or the updated controller list entry comprises a MAC and an IP of the local OFC that are carried in the LLDP data packet, and a port in_port through which the LLDP data packet is received;
• and
• the communication interface is further configured to:
• acquire a first-time TCP handshake packet used for establishing a TCP connection;
• check, according to a destination MAC and a destination IP that are carried in the TCP handshake packet, whether a corresponding controller list entry exists in the controller list;
• and if yes, update a flow entry according to a MAC, an IP, and an in_port in the corresponding controller list entry in the controller list, so that the OFS can forward, by using a flow table, a packet to be sent to an OFC to the OFC.