Patent ID: 8630166
Filing Date: 2014-01-14
Classification: H04L

Abstract:
1. A ring network comprising: plural network relay devices connected in a ring shape, wherein the plural network relay devices comprise a first network relay device and a second network relay device, the first network relay device comprises a first control port, the second network relay device comprises a second control port; wherein the first control port and the second control port to be transitioned into either a forwarding state that permits relaying information, or a blocking state that prohibits relaying information; and wherein the first network relay device comprises a first ring protocol control unit for transmitting a first connection confirmation information generated by the first network relay device indicative of communications being possible between the first control port and the second control port from the first control port to the second control port at a first predetermined time interval, and wherein the second network relay device comprises a second ring protocol control unit for transmitting a second connection confirmation information generated by the second network relay device from the second control port to the first control port at a second predetermined time interval, and wherein, in an event that the first control port does not receive the second connection confirmation information, the first ring protocol control unit transmits a first failure information indicative of communications being not possible between the first control port and the second control port, from the first control port to the second control port, and, wherein, in an event that the second control port does not receive the first connection confirmation information, the second ring protocol control unit transmits a second failure information from the second control port to the first control port, wherein the first ring protocol control unit transitions the first control port into the blocking state when the first control port receives the second failure information, and into the forwarding state when the first control port transmits the first failure information, and wherein the second ring protocol control unit transitions the second control port into the blocking state when the second control port receives the first failure information, and into the forwarding state when the second control port transmits the second failure information; wherein after a first predetermined period of time passing from a point of transmitting the first failure information from the first control port, the first ring protocol control unit transitions the first control port, from which the first failure information has been transmitted, into the forwarding state, and wherein after a second period of time shorter than the first predetermined period of time passing from a point of receiving the first failure information in the second control port, the second ring protocol control unit transitions the second control port, in which the first failure information has been received, into the blocking state; wherein said transmitting the first failure information from the first control port to the second control port and the second failure information from the second control port to the first control port includes, transmitting the first failure information and the second failure information via at least one another network relay device.