Protection-switching apparatus and method in asynchronous transfer mode system with ring topology

摘要

The present invention discloses a protection-switching apparatus and method in an asynchronous transfer mode (ATM) system with ring topology. In the invention, the ONU detects a trouble, or abnormal states, of an optical path connected with the ONU itself; the ONU performs the protection-switching function by receiving an ATM cell from the opposite direction of the optical path having the trouble; the software unit of the ONU inserts a node identification data (NID) of the ONU to the APS register of the optical path of normal states; and the hardware unit of the ONU generates the APS cell by performing mirroring of the APS register to the VCI area of the APS cell, and transmits the APS cell in the same direction as the direction of the optical path of abnormal states. Therefore, the protection-switching apparatus and method in an ATM system with ring topology of the present invention have the advantage of reducing switching delay time and switching load.