Patent ID: 7139286

Claim:
A method of inserting and extracting overhead in SONET/SDH in which an interface system interfaces between each of a plurality of ports for transferring transmission frames between a high-speed line and an ATM device, and between the high-speed line and an external device that performs lower-speed processing, the interface system inserting overhead for network operation and management into the transmission frames and extracting overhead from the transmission frame, the overhead including transport overhead and path overhead with respective data and control signals, the method comprising: generating a basic timing signal based on a framing pulse; storing the transport overhead, the path overhead, and the control signals in a plurality of storing means in response to the basic timing signal; transferring the transport overhead, the path overhead, and the control signals to and from the external device; and controlling the plurality of storing means commonly, and said interface system including a first frame processing unit that is connected between the ATM device and the high-speed line and performs frame processing for inserting the overhead, and an overhead insertion interface unit that is connected between the first frame processing unit and the external device and performs transport overhead processing and path overhead processing for the insertion of the overhead.