Apparatus and method for redundancy control of duplex switch board

A method for controlling a redundancy in duplex switch boards, the duplex switch boards comprising an own switch board and an opponent switch board, the duplex switch boards having an identical structure and being connected to a communication network system, the method comprising the steps of:

• a) applying an electric power to the duplex switch boards and determining whether there is an error generated in the duplex switch boards;
• b) setting the duplex switch boards as a stand-by mode if there is no error generated in the duplex switch boards;
• c) determining whether an own clock is used or not, setting the own switch board as an active mode if the own clock is used, and determining whether a clock of the opponent switch board is used or not if the own clock is not used;
• d) recognizing a switch operation failure by a clock fail and perform the step b) if the clock of the opponent switch board is not used, and determining whether the clock of the opponent switch board is normal or not by requesting a clock state response of the opponent switch board if the clock of the opponent switch board is used;
• and
• e) recognizing a switch operation failure and performing the step b) if the clock of the opponent switch is not normal, and checking a state of the opponent switch board and determining whether there is an error detected in the opponent switch board if the clock of the opponent switch board is normal.