High-availability secure communication system

A very high-availability secure communication system for a mobile terminal for establishing local and remote communications, comprising:

• a mobile terminal connected to a communication box, said communication box comprising at least four physical communication interfaces comprising a first physical communication interface, a second physical communication interface, a third physical communication interface, a fourth physical communication interface, wherein
• the first physical communication interface serves to establish communications via Narrowband Asynchronous Transfer Mode (NATM) with the mobile terminal,
• the second physical communication interface is a first physical remote communication interface and the third physical communication interface is a second physical remote communication interface, wherein the first physical remote communication interface and the second physical remote communication interface serve to establish remote communications via mobile networks,
• the fourth physical communication interface serves to establish local communications with another box by direct communication and according to an IP protocol according to a predetermined addressing plan;
• wherein the communication box uses the fourth physical communication interface when the first physical remote communication interface and the second physical remote communication interface are defective;
• wherein the mobile terminal communicates with an application server as follows:
• the communication box is connected to an access server by a first link of a Virtual Private Network (VPN0) established through the first physical remote communication interface and by a second link of a Virtual Private Network (VPN1) established through the second physical remote communication interface;
• the application server is connected to the access server, the mobile terminal and the application server communicate through the communication box and the access server using one of the first link (VPN0) and the second link (VPN1);
• the communication box is a network gateway of the mobile terminal;
• the communication box:
• maintains a local routing table based on a 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 are using a same link at a same time.