Relay device and relay system

A relay system comprising a plurality of relay devices constituting a ring network,

• wherein at least one of the relay devices includes:
• a line card having a ring port connected to the ring network;
• and
• a plurality of management cards which manage the line card,
• the plurality of management cards include an active card operating in an active state and a standby card operating in a standby state and changed to the active card in accordance with a predetermined change instruction,
• the active card determines open or block of the ring port in accordance with an event based on a ring protocol, issues an open instruction or a block instruction of the ring port to the line card, and notifies a block factor representing the event to be that is a basis of the block instruction in addition to the block instruction when issuing the block instruction,
• the line card includes:
• a port control unit which controls open and block of the ring port in accordance with the open instruction and the block instruction from the active card;
• and
• a port management table which retains open/block information of the ring port and the block factor notified from the active card,
• the standby card acquires information retained in the port management table from the line card when the standby card is changed to the active card in accordance with the predetermined change instruction,
• when the standby card is changed to the active card in accordance with the predetermined change instruction, the standby card sets a ring state based on the ring protocol to a pending state, and
• when the block factor is contained in the information retained in the port management table acquired from the line card, the standby card shifts the ring state to a predetermined ring state from the pending state by internally generating an event in accordance with the block factor.