A communications network system comprising a control unit, one or more wireless systems (4, 4a), and application equipment, wherein the control unit comprises: a data information acquisition unit to acquire information about data that the application equipment communicates via the wireless systems (4, 4a); a wireless environment information acquisition unit to acquire information about a wireless environment that has an impact on communications by the wireless systems (4, 4a); a policy generation unit to generate a plurality of communications policies that are delivered to the wireless systems (4, 4a); a policy management unit to manage the communications policies that are executed on the wireless systems (4, 4a); and a network control unit to carry out data communications with the wireless systems (4, 4a), and wherein the wireless systems (4, 4a) at least comprise: a policy agent unit (41, 41a) to store the plurality of communications policies delivered from the control unit, and to detect a status of communications by the wireless systems (4, 4a) and change the communications policies, wherein the policy agent unit (41, 41a) is configured: to change to one of the plurality of stored communications policies, without inquiring the control unit in advance, to deliver the plurality of changed communications policies to the control unit after the change, and maintain the communications policies until a communications policy is delivered again; and a wireless system control unit (42, 42a) to control information about data that the application equipment communicates via the wireless systems (4, 4a) based on the communications policies. wherein the control unit comprises: a data information acquisition unit to acquire information about data that the application equipment communicates via the wireless systems (4, 4a); a wireless environment information acquisition unit to acquire information about a wireless environment that has an impact on communications by the wireless systems (4, 4a); a policy generation unit to generate a plurality of communications policies that are delivered to the wireless systems (4, 4a); a policy management unit to manage the communications policies that are executed on the wireless systems (4, 4a); and a network control unit to carry out data communications with the wireless systems (4, 4a), and a data information acquisition unit to acquire information about data that the application equipment communicates via the wireless systems (4, 4a); a wireless environment information acquisition unit to acquire information about a wireless environment that has an impact on communications by the wireless systems (4, 4a); a policy generation unit to generate a plurality of communications policies that are delivered to the wireless systems (4, 4a); a policy management unit to manage the communications policies that are executed on the wireless systems (4, 4a); and a network control unit to carry out data communications with the wireless systems (4, 4a), and wherein the wireless systems (4, 4a) at least comprise: a policy agent unit (41, 41a) to store the plurality of communications policies delivered from the control unit, and to detect a status of communications by the wireless systems (4, 4a) and change the communications policies, wherein the policy agent unit (41, 41a) is configured: to change to one of the plurality of stored communications policies, without inquiring the control unit in advance, to deliver the plurality of changed communications policies to the control unit after the change, and maintain the communications policies until a communications policy is delivered again; and a wireless system control unit (42, 42a) to control information about data that the application equipment communicates via the wireless systems (4, 4a) based on the communications policies. a policy agent unit (41, 41a) to store the plurality of communications policies delivered from the control unit, and to detect a status of communications by the wireless systems (4, 4a) and change the communications policies, wherein the policy agent unit (41, 41a) is configured: to change to one of the plurality of stored communications policies, without inquiring the control unit in advance, to deliver the plurality of changed communications policies to the control unit after the change, and maintain the communications policies until a communications policy is delivered again; and a wireless system control unit (42, 42a) to control information about data that the application equipment communicates via the wireless systems (4, 4a) based on the communications policies.