NAPT DEVICE, COMMUNICATION SYSTEM, AND PORT NUMBER GRANTING METHOD USED FOR THE SAME, AND PROGRAM FOR THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a NAPT device for making it possible to effectively use limited port number resources by granting n consecutive port numbers, in performing a grant request for port numbers in multiples of n.SOLUTION: A NAPT device (11) comprises: granting means (port number granting unit 116) for granting n consecutive port numbers from unused port numbers in response to a grant request when a NAPT management device performs the grant request for port numbers in multiples of n; and means (transaction management unit 112 and port number grant response creation unit 117) for transmitting the granted port numbers as a grant response to the NAPT management device.