A communication signal sent out by an application is transferred to a communication signal control unit, and then is controlled or processed by a communication signal control module. Then, the communication signal is sent out to a network after being sequentially passed to a next communication signal control module. A communication control adjustment module included in a communication control adjustment unit, based on request conditions from a user, determines an execution position of the communication signal control module used for the control of the communication flow. The communication signal control module and the communication control adjustment module can change their structure even during communication.