In a communication system using an IP tunnel for communication between application processing apparatuses (hereinafter, processing apparatuses), an application can be moved to an arbitrary processing apparatus, update of tunnel tables included in the respective processing apparatuses is quickly performed, and a buffer for waiting for packets during the table update is made small. A redundancy managing apparatus manages a correspondence between a virtual IP address (VIP) of an application in a communication system and an IP address (RIP) of an processing apparatus to execute the application. The processing apparatus notifies the VIP of the communication partner application of the application to the redundancy managing apparatus. The redundancy managing apparatus notifies the VIP of the communication partner application of the moved application and the RIP of the processing apparatus to execute the communication partner application to the processing apparatus of the movement destination (failover destination) of the application.