Patent ID: 6633537
Filing Date: 2003-10-14
Classification: H04J,H04L

Abstract:
A hitless path switching ring network comprising at least two node devices connected in ring form through a work transmission line and a protection transmission line, wherein at the time of normal operation a signal is transmitted with said work transmission line; at the time of failure occurrence in said work transmission line the signal can be transmitted with said protection transmission line in the opposite direction from the direction in which the signal was transmitted before failure occurrence in said work transmission line;in order to cause the signal to be received from one of said node devices to the other of said node devices without instantaneous hitting of the signal at the time of failure occurrence in said work transmission line, said one node device includes a first memory section for storing the signal being transmitted onto said work transmission line at the time of normal operation, and a first read control section for reading out the transmitted signal held from said first memory section before failure occurrence in said work transmission line and sending out said transmitted signal through said protection transmission line in said opposite direction at the time of failure occurrence in said work transmission line; and said other node device includes a second memory section for storing the signal received through said work transmission line at said time of normal operation, a third memory section for storing the signal received through said protection transmission line according to said first read control section of said one node device at the time of failure occurrence in said work transmission line, and a first phase adjusting section for matching a time phase of the received signal stored in said, second memory section after failure occurrence in said work transmission line with a time phase of the received signal stored in said third memory section before failure occurrence in said work transmission line and outputting said received signal to the outside.