Patent ID: 9025950
Filing Date: 2015-05-05
Classification: H04B

Abstract:
1. A communication system comprising: a first to a fourth line card each including a user port and a transmission port; a first communication line that connects the transmission port of the first line card and the transmission port of the third line card and transmits a transmission signal from the first line card to the third line card; a third communication line that transmits a transmission signal in a reverse direction to that of the first communication line; a second communication line that connects the transmission port of the second line card and the transmission port of the fourth line card and transmits a transmission signal from the second line card to the fourth line card; a fourth communication line that transmits a transmission signal in a reverse direction to that of the second communication line; a first and a second switch device; a first coupler that divides a transmission signal from the first switch device into two signals, and transmits the signals to receive ports in the user ports of the first and the second line card, respectively; a second coupler that combines transmission signals from transmit ports in the user ports of the first and the second line card and transmits to the first switch device; a third coupler that divides a transmission signal from the second switch device into two signals, and transmits the signals to receive ports in the user ports of the third and the fourth line card, respectively; a fourth coupler that combines transmission signals from transmit ports in the user ports of the third and the fourth line card and transmits to the second switch device; a first backplane that is installed with the first and the second line card, and has a communication path between the first and the second line card; and a second backplane that is installed with the third and the fourth line card, and has a communication path between the third and the fourth line card, wherein in a normal operation, the first and the third line card set the transmit ports in the user ports into an open state, and the second and the fourth line card set the transmit ports in the user ports into a blocking state, and if a failure occurs in the communication path through the first communication line from the first line card, the third line card performs a first process of detecting the failure through a receive port in the transmission port, and then changing the transmit port in the user port from the open state to a blocking state, and notifying the fourth line card of failure existence information obtained from the failure detection through the second backplane, and the fourth line card performs a second process of receiving the failure existence information and changing the transmit port in the user port from the blocking state to the open state.