Patent ID: 6639893
Filing Date: 2003-10-28
Classification: H04L

Abstract:
A communication network system that has multiple switching devices connected on a ring transmission line, including first and second ring networks that perform communication via the multiple switching devices;first and second ring networks comprising: first and second between-ring connection devices, within the first ring network, each connected with a facing one of first and second between-ring connection devices within the second ring network by a between-ring transmission line that includes a duplex line, each of the first and second between-ring connection devices having a between-ring communication means that performs, between facing ones of the between-ring connection devices, mutual communication of first control information, and performs line switching control with the other one of the first and second ring networks through the between-ring communication means so as to make one of the duplex between-ring transmission lines to be a current use system and other one to be a standby system; and a control device that performs switching control for operating one of the between-ring connection devices as the current use system, and the other one as the standby system, the control device having a ring internal communication means that performs, between the first and second between-ring connection devices, mutual communication of second control information; wherein, between the first and second ring networks, current use communication is performed via the between-ring transmission line that connects the between-ring connection devices that operate as the current use system, and the between-ring transmission line that connects the between-ring connection devices that operate as the standby system is used as a standby line.