SDN-based network device with extended function and method of processing packet in the same device

1. A network device comprising:

a plurality of flow tables and a plurality of function modules, executed by a processor, using algorithm, which when executed, causing the processor to search at least one of the flow tables to determine whether a flow entry in the at least one of the flow tables is matched with an input packet and to execute at least one of the function modules to perform least one of various functions, other than searching the at least one of the flow tables, related to packet processing on the input packet; and

an entry module executed by the processor, using algorithm, which when executed, configured to determine which operation, between a flow table search operation searching the at least one of the flow tables and a function module execution operation executing the at least one of the function modules, is to be performed first when the input packet is received,

wherein, in response to a result of the operation determined by the entry module, the processor is configured to designate a next operation until there is no operation to be performed on the received input packet, the next operation being the flow table search operation or the function module execution operation,

wherein when the flow table search operation is performed, the operation to be performed next is designated by an instruction included in the flow entry matched with the input packet, and

wherein the instruction designates, together with the function module execution operation to be performed next, another function module execution operation or flow table search operation to be performed subsequent to the function module execution operation.

2. The network device of claim 1 wherein the function module includes information of an operation to be performed next after the function module is executed.

3. The network device of claim 1 , wherein the instruction is set by a controller over OpenFlow channel or a control channel for performing a similar function.

4. The network device of claim 1 , wherein the instruction designates one or more flow table search operations or one or more function module execution operations to be performed next.

5. The network device of claim 1 , wherein the instruction designates an operation list of a series of combinations of flow table search operations and function module execution operations to be performed next.

6. The network device of claim 1 wherein, when the operation determined by the entry module is the flow table search operation, a first flow table among the plurality of flow tables is searched.

7. The network device of claim 1 , wherein, when the operation determined by the entry module is the function module execution operation, a first function module among the plurality of function modules is executed.

8. A method of processing an input packet in a network device including a plurality of flow tables, an entry module, and a plurality of function modules, the method comprising:

receiving the input packet;

determining a flow table search operation searching at least one of the flow tables or function module execution operation a s an or ration to be performed first on the received input packet by executing the entry module, wherein the function module execution operation is for executing at least one of the function modules to perform at least one of various functions, other than searching the at least one of the flow tables, related to packet processing on the input packet;

processing the input packet by performing the determined flow table search operation or function module execution operation; and

processing the input packet subsequently by performing another flow table search operation or another function module execution operation that is designated as a result of the flow table search operation or the function module execution operation,

wherein as a result of the other table search operation or function module execution operation, still another table search or function module execution operation is designated, and the designation is repeated until an output instruction for the packet is presented,

wherein the operation to be performed next that is designated as a result of the flow table search operation is designated by an instruction included in a flow entry matched with the input packet and

wherein the instructions designates, together with the function module execution operation to be performed next, another function module execution operation or flow table search operation to be performed subsequent to the function module execution.

9. The method of claim 8 , wherein the function module includes information of an operation to be performed next after the function module is executed.

10. The method of claim 8 , wherein the instruction is set by a controller over OpenFlow channel or a control channel for performing a similar function.

11. The method of claim 8 , wherein the instruction designates one or more flow table search operations or one or more function module execution operations to be performed next.

12. The method of claim 8 , wherein the instruction designates an operation list of a series of combinations of flow table search operations and function module execution operations to be performed next.