JPH05292113

PURPOSE:To avoid cell abort by providing a generating means of path supervisory information with identification information representing a source redundancy system inserted thereto to a generation point of path supervisory information and providing a termination means used when its own system is dissident with the source redundancy system based on the identification information to an intermediate detection point. CONSTITUTION:A Pi generating means 21 at a generation point A of path supervisory information (Pi) generates the information Pi including identification information representing a source redundancy system of the Pi. A 2nd normality discrimination means 22 placed at an intermediate detection point B of the Pi discriminates whether or not a path is normal based on the detected Pi. A 1st Pi termination means 23 terminates the detected Pi when its own system and a Pi source redundancy system are dissident based on the identification information included in the detected Pi. A 2nd normality discrimination means 24 at a Pi final detection point C discriminates whether or not a path is normal based on the detected Pi and a 2nd Pi termination means 25 terminates the detected Pi. Thus, one Pi is supplied to the points B,C and cell abort due to concentrated Pi information sets is avoided.