Abstract: A loop-back recovery technique used when a failure takes place in a ring network, for transmitting information to a path indicated with a path ID number or the time slot position from a periodic frame. This is achieved by establishing working paths on one of the dual ring line between a transmission node and a receiving node thereof, establishing ring-formed protection paths in a ring line of the direction opposite to the working line, and making a loop-back from the working paths to the corresponding protection paths at a node which detected the failure. The receiving node multiplexes the working and protection paths to receive data from either.

Abstract: Packet transfer is controlled by using an acceleration rate of packet transfers or by using a packet transfer rate acceleration ratio to predict that congestion will occur at a prescribed time in the future. Congestion avoidance in packet integrated networks is thereby achieved in a network having both variable rate terminal nodes and fixed rate terminal nodes. A future packet transfer rate is predicted in a congestion prediction circuit on the basis of a pre-established upper limit for the packet transfer acceleration or acceleration ratio. When it is predicted that the packet transfer rate will exceed a permissible value, a congestion prediction signal is output or a rate increase request indication is deleted. The invention prevents packets from being discarded in the packet network, allows buffer memory capacity of nodes in the network to be decreased, and avoids the generation of new packets when signal congestion is predicted.