Method for resuming topology of single loop network and switch network system

A method for resuming a topology of a single loop network, wherein the single loop network comprises at least one first network switch and a second network switch, each of the at least one first network switch comprises a first port and a second port, and the second network switch comprises a third port and a fourth port;

• each of the first port, the second port, the third port, and the fourth port is in an enabled state or a disabled state by default so as to form a single loop network, and the method comprises:
• in response to that one of the at least one first network switch detects that the first port is abnormal, setting the first port to the disabled state by the first network switch and transmitting a recovery control frame through the second port by the first network switch;
• in response to that the second network switch receives the recovery control frame, setting the third port in the disabled state to the enabled state by the second network switch;
• in response to that the first network switch detects that the first port is resumed, transmitting a block control frame through the second port by the first network switch;
• in response to that the second network switch receives the block control frame, setting the third port in the enabled state to the disabled state by the second network switch and transmitting a forward control frame through the fourth port by the second network switch;
• and
• in response to that the first network switch receives the forward control frame, setting the first port in the disabled state to the enabled state by the first network switch.