Abstract: A communication network system includes a plurality of networks interconnected via a plurality of relaying stations each performing a program controllable process to relay communication data, the program controllable process comprises a routing table having route information for determining a route to transfer the communication data, a learning processing unit exchanging the route information contained in the routing table among the individual relaying stations in accordance with the route information of the routing table to acquire the route information by the exchange, and a route information transform processing unit for transforming the route information contained in the routing table as acquired by the learning step into route information non-exchangeable among the individual relaying stations.