Communication system with communication route retrieval and selection function

摘要

A gateway (GW) for relaying a communication between a public telephone network and a routing server for managing use status of the GW and a network are provided on the internet. When a connection request is received, the GW issues a request to retrieve a route in which the costs are minimum and a necessary bandwidth can be reserved. The routing server retrieves the route of the minimum costs using the bandwidth reservation status of the internet and the partner's telephone number and notifies the request issued GW of the address of the partner GW. The costs at that time point may be notified to the user and the user selects whether the communication is performed or not. By managing the current connection information established by each GW, if a necessary bandwidth cannot be reserved, an audio compression ratio may be changed.