PURPOSE: To reduce a primitive between layers and to simplify the configuration of a master set by locating an aborted frame based on monitor number information identifying an area of management information positioned to a layer without transmission reception of information between the layers.
CONSTITUTION: A master set 1 extracts a frame synchronizing signal and a timing in a network management information frame received by a reception circuit 11 and a network management information extract circuit 12 extracts network management information. Furthermore, a monitor number extract circuit 13 reads a monitor number among the extracted network management information. A monitor number received before is stored in a memory 14. A difference calculation circuit 15 calculates a difference between a monitor number received precedingly and a monitor number received at present and an area location circuit 16 locates the aborted and lost frequency based on the difference. The network management information included in the aborted frame is extracted from the frame received at present. Furthermore, a network management information area designation table is stored in the area location circuit 16.
TSUBOI TOSHINORI
HAYASHI KAZUHIRO
MAEDA YOICHI
