ATM SVC DUPLEX SYSTEM

PROBLEM TO BE SOLVED: To improve the service reliability of an ATM(asynchronous transfer mode) network using an ATM exchange, etc., by continuing with no interrupt the supply of the ATM main signal information via the SVC(switching virtual connection) even when a working system is switched to a standby system. SOLUTION: A working switch part 2a and a standby switch part 2b share the same routing set and also a working storage medium 6a and a standby storage medium 6b share the SVC information. If the switching is carried out by some reason between the working and standby systems under such conditions, the SVC exists or disappears between the ATM subscribers 10 and 11 since the first routing set of the part 2b is already shared with that of the part 2a by a call processing control function 4b. Thereby the transmission service of the ATM information is continuously supplied with no interrupt via the SVC.