CONGESTION CONTROLLER, CONGESTION CONTROL SYSTEM, AND CONGESTION CONTROL METHOD

PROBLEM TO BE SOLVED: To improve a call success rate by calculating an optimum control amount for controlling a call amount, in a congestion countermeasure in performing communication service through a network.SOLUTION: A congestion controller 20 comprises: a traffic amount collection unit 23 for collecting the number of generated calls from each session controller 30 to a station number of a predetermined region; a control total amount calculation unit 25 for calculating a next period control amount for the session controller 30 by calculating an adjustment value α by using a ratio of the number of generated calls x obtained by dividing the total sum of the collected number of generated calls by a control total amount to the station number of the predetermined region, and multiplying the adjustment value α by the control total amount to the station number of the predetermined region distributed to each session controller 30 depending on the number of generated calls; and a control instruction unit 26 for instructing each session controller 30 to regulate calls to the station number of the predetermined region by using the next period control amount.