METHOD OF SETTING SHORTCUT PATH, ITS PROGRAM AND RECORDING MEDIUM, AND SHORTCUT PATH SETTING SYSTEM, AND ROUTER

摘要

PROBLEM TO BE SOLVED: To efficiently scatter shortcut paths used for avoiding congested states in a network. SOLUTION: When layer 2 transfer sections 16-1 to 16-3 are used for setting shortcut paths instead of routing control sections 13-1 to 13-3 in order to avoid the occurrence of line congestions in routers 1-1 to 1-3, shortcut path control sections 15-1 to 15-3 recalculate the costs indicating the easiness of line transfer after the shortcut paths are set, and increase the costs by updating the costs of lines held by the routers 1-1 to 1-3 to the recalculated costs. When the routers 1-1 to 1-3 set next shortcut paths, the concentration of the shortcut paths to a specific line is avoided in such a way that the routers are caused to almost simultaneously perform route selection for the shortcut paths upon receiving information on a congested state when the congested state occurs, by gradually performing such shortcut path setting in steps that makes already set shortcut paths to be selected hardly by causing the routers 1-1 to 1-3 to select the routes of shortcut paths based on the increased updated costs.