An OFS in-band communication method and an OFS are disclosed. The method includes: receiving an LLDP data packet; creating a controller list entry or updating a controller list entry when it is determined, by using a role sub-field, that a sender type of the received LLDP data packet is OFC; acquiring a first-time TCP handshake packet used for establishing a TCP connection, and checking, 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 a controller list; and if yes, updating a flow entry according to the MAC, the IP, and the in_port in the corresponding controller list entry in the controller list, so that an OFS can forward, by using a flow table, a packet to be sent to an OFC to the OFC.