An
interconnection between fully synchronous networks of the prior art and next generation frame communications networks, which is required for the shift to next-generation packet networks and a broader-based connection service, is realized. Here, the first point is that a means of bidirectional frame format conversion between a synchronous
multiplexing system and a logical
multiplexing system is provided, and a method of transmitting data between different networks on a path as if it was being transmitted in the same network. The second point is that when converting
network control information in an STM network into data suitable for a packet network, even across the boundary of a synchronous
multiplexing system and a logical multiplexing system, a unified communication management means is provided over the whole path. For this purpose, a hierarchized logical path control method is used wherein, in a network comprising two or more information
relay devices having one or more line interfaces, this network performs communication between information
relay devices using data packets, and has a means, when performing communication between any two points in the network, to control the path via which the packets pass between arbitrary end points, and the
communication control means has a first communication path management function which performs communication management at the connection level which is terminated at the end point of a communication section, and a second communication path management function which performs communication management for each section of a physical circuit or
logical circuit which is terminated at each communication section between any adjacent information
relay devices in the communication section.