Sdn-based service chaining system

An SDN controller connected to a plurality of SDN-based switches via OpenFlow protocol and controlling the plurality of switches, the SDN controller comprising:

• a switch communicator configured to receive a first packet-in message from a first switch of the plurality of switches, which has received a service request packet from a user, to indicate that the first switch does not have a corresponding entry in a field extracted from the service request packet;
• an identifier extractor configured to extract from the packet-in message both a service identifier that identifies a type of a service requested through the service request packet and a user identifier that identifies the user;
• a service table enumerating services available to be provided;
• a user table comprising a plurality of user list, each user list being associated with each available service in the service table;
• a network function table comprising a plurality of network function lists, each network function list being associated with each user list of the user table;
• a topology table comprising information about a network topology;
• an entry DB configured to store entries that define packet forwarding to be performed in the plurality of switches;
• and
• an entry manager configured to determine whether an entry list that enables the service request packet to be forwarded to a network function list that corresponds to both the service identifier and the user identifier is present in the entry DB, with reference to a service table, a user table, and a network function table which are associated with one another.