Service providing system

A server device group comprising:

• a plurality of “k” (“k” shows plural) server devices respectively coupled to a network with a routing function;
• each of the plurality of “k” server devices being configured to receive one access via the network, wherein
• each of the plurality of “k” server devices is assigned at least one of “n” (“n” shows an integer greater than or equal to “0”) addresses, each of the addresses being different from each other capable of being assigned to any of one of the plurality of “k” server devices,
• the server device group is configured to change a destination of assignment of 1 through (m−1) addresses out of “m” addresses, “m” showing an integer greater than or equal to “2”, having been assigned to a first server device toward a second server device with a lower load than the first server device, and
• the second server device is configured to receive an access via the network directed to the 1 through (m−1) addresses having been assigned thereto.

A network system comprising:

• a server device group including a plurality of “k” (“k” shows plural) server devices respectively coupled to a network with a routing function, each of the plurality of “k” server devices being configured to receive an access via the network, wherein
• each of the plurality of “k” server devices is assigned at least one of “n” (“n” shows an integer greater than or equal to “0”) addresses, each of the addresses being different from each other capable of being assigned to any of one of the plurality of “k” server devices,
• the server device group is configured to change a destination of assignment of 1 through (m−1) addresses out of “m” addresses, “m” showing an integer greater than or equal to “2”, having been assigned to a first server device toward a second server device with a lower load than the first server device,
• the second server device is configured to receive an access via the network directed to the 1 through (m−1) addresses having been assigned thereto, and a name resolution device,
• the name resolution device is configured to, when each of the 1 through (m−1) addresses which is an object to be changed has not been used,
• manage the “n” addresses with classifying into two or more groups, and
• switch, in a predetermined timing of period, a group of addresses between one or more groups of addresses from which an address for an answer to the request is selected and the other one or more groups of addresses in which an address for the answer is not included.