Patent ID: 7937489

Claim:
A port hopping flow detection system comprising: a storage section configured to store flow data for each of past flows of packets which have been transmitted from application programs and an application data for each of the application programs; a receiving unit configured to receive a new flow of packets; and a detecting unit configured to extract a flow data for the new flow to store in said storage section, calculate an application data for the new flow from the extracted flow data for the new flow, to compare the calculated application data with the application data stored in the storage section, and determine from the comparison whether the new flow has been subjected to port hopping, wherein the application data includes a port change time difference which is calculated from the first packet reception time of the new flow and a last packet reception time of an existing flow, wherein said storage section further stores band control policies, said port hopping flow detection system further comprises: a band control unit configured to restrict a band for the packets of the new flow, which are sent from a flow separating section, based on said band control policies; and a transmitting unit configured to transmit the packets of the new flow whose band is restricted.