Method of transmission of a signal and ring network

A method of transmission of a signal using a ring network that includes a plurality of transmission devices, any one transmission device of the plurality of transmission devices being set as a first blocking portion, and any another transmission device of the plurality of transmission devices being set as a second blocking portion, the method comprising:

• receiving, by a first transmission device of the plurality of transmission devices, a first signal;
• setting, by the first transmission device, first information in the first signal;
• and
• transmitting, from the first transmission device to a second transmission device of the plurality of transmission devices, the first signal in which the first information is set, wherein
• when a value of the first information is a first value, the first blocking portion passes the first signal and the second blocking portion blocks the first signal, and
• when the value of the first information is a second value, the second blocking portion passes the first signal and the first blocking portion blocks the first signal.