Patent ID: 8694643

Claim:
A contents delivery server comprising: a processor; a memory; a load information exchanging unit which collects other server information from each of other contents delivery servers in a network and stores the other server information, wherein the other server information comprises load information of said other contents delivery servers, a determination unit which determines the presence of free resources of own contents delivery server based on own server information, wherein the own server information comprises load information of own contents delivery server; a delivery server selection unit which selects one or more other contents delivery servers with a lower load than own contents delivery server from among said other contents delivery servers based on said own server information and said other server information when said determination unit determines that there exist no free resources; a redirection unit which requests to said selected other contents delivery servers delivery of contents which are targets of a contents delivery request to a user terminal which transmitted said contents delivery request; and a number of redirection calculating unit which calculates a maximum value of a number of requests of delivery by said redirection unit during a fixed period of time P based on an average resource usage rate of all said contents delivery servers and an average resource usage rate of said own contents delivery server obtained from said other server information and said own server information received during a fixed period of time T just before said fixed period of time P, wherein the memory is configured to store the above units and the processor is configured to implement the above units, wherein said contents are composed of one or more segments, wherein said redirection unit further determines whether or not said number of requests during said fixed period of time P reaches said maximum value and, in case said number of requests reaches said maximum value, does not request to said other contents delivery servers selected delivery of contents, and wherein said number of redirection calculating unit calculates said maximum value, Rmax, by using an average resource usage rate U of said all of the contents delivery servers, an average resource usage rate Ui of said own contents delivery server, an average number of concurrent connection Ci of said own contents delivery server, and an average segment size S during a fixed period of time T obtained just before said fixed period of time P and during a fixed period of time T as if U>=Ui , then R max=0 (1) if U<Ui , then R max=( Ui−U )× Ci×T/S (2).