CONGESTION CONTROL DEVICE, CONGESTION CONTROL METHOD AND PROGRAM THEREOF

PROBLEM TO BE SOLVED: To execute congestion control which permits control to start quickly when congestion occurs and makes the most efficient use of net resources.SOLUTION: First, in its initial action when congestion occurs, a congestion control device 10 transmits control directive information for the prefix-matched exchange numbers (short digits) subject to restraints among those accommodated by a congestion session control device to a call origination restraint session control device (step S302). Next, the congestion control device 10 extracts an exchange number which would cause congestion on the basis of traffic condition information received from the call origination restraint session control device (step S305). And the congestion control device 10 expands the low-order digits of the extracted exchange number which is the cause of congestion (step S306), and transmits control directive information including control directives for the exchange numbers derived from number expansion which are subject to restraints to the call origination restraint session control device, whereby it executes restraint control of the call origination restraint session control device.