Patent ID: 7855979

Claim:
A control device controlling separability of a node device from a tree-type delivery system formed by participation of a plurality of node devices by connecting the plurality of node devices in a tree-like shape through a communication unit while forming a plurality of hierarchy levels placing a delivery device at a top thereof to enable content data delivered from the delivery device to be sequentially transferred from the node device on an upper hierarchy level to another node device on a lower hierarchy level, the control device comprising: a first acquiring unit that acquires a number of the plurality of node devices participating in the tree-type delivery system, a determining unit that determines an upper limit number of the node devices that are permitted to separate simultaneously from the tree-type delivery system, based on the number of the participating node devices acquired by the first acquiring unit; a receiving unit that receives separation request information of requesting separation from the tree-type delivery system from any one of the node devices; a judging unit that judges whether or not the number of the node devices currently under a separation process reaches the upper limit number, based on the separation request information received by the receiving unit, and a notification unit that sends a separation permission notification of permitting the separation process to the node device being a separation request information sending source in a case where it is judged by the judging unit that the number of the node devices currently under the separation process does not reach the upper limit number, and that does not send the separation permission notification to the node device being the separation request information sending source in a case where it is judged by the judging unit that the number of the node devices currently under the separation process reaches the upper limit number.