NETWORK NODE, COMMUNICATION METHOD AND SYSTEM

PROBLEM TO BE SOLVED: To make it possible to provide a network base service such as QoS guarantee, communication reliability, and throughput control by allowing for packet identification in a network comprised of programmable network nodes.SOLUTION: A gateway H131 inserts additional information including measurement information such as a time stamp in a packet at the time of packet transmission, registers packet identification information, the additional information, and header information with tables 141, 142 at the time of input into programs 121, 122 in a network node, searches the tables 141, 142 using the identification information of its packet as a key at the time of output from the programs, and restores the additional information and the header information from elements of the tables when identification is completed. A gateway H132 takes out the additional information from a packet when the packet is received and conducts operation such as measuring.