A system for high-availability secure communication between a mobile terminal and an application server. The terminal is connected to a communication box having at least three physical communication interfaces, a first interface used for communicating with the terminal. The communication box connected to an access server by first and second links through corresponding first and second physical remote communication interfaces. The application server connected to the access server. The terminal and the application server communicating through the communication box and the access server using one of two previously established links. The communication box is the network gateway of the terminal. The communication box: maintains a local routing table based on the routing performance of at least one physical remote communication interface; maintains a remote routing table on the access server so that the communication box and the access server use the same link at the same time.