Patent ID: 6657952
Filing Date: 2003-12-02
Classification: H04J

Abstract:
A communications network comprising:a plurality of transmission links; and a plurality of nodes for interconnecting said transmission links to form first and second working rings and first and second protection rings in a ring topology, and establishing a plurality of working paths on each of said working rings and a plurality of protection paths on each of said protection rings corresponding to said plurality of working paths in response to a failure of said working paths, said ring topology having an insertion point for inserting a signal from an external source into the ring topology and a termination point for terminating the inserted signal, a first one of said working paths of said first working ring spanning across first and second nodes of said plurality of nodes for transmission of a signal in a first direction of said ring topology, a second one of said working paths of said second working ring spanning across the first and second nodes for transmission of a signal in a second direction of the ring topology opposite to the first direction, a first one of said protection paths on said first protection ring spanning across the first and second nodes transmission of a signal in said direction of said ring topology, a second one of said protection paths of said second protection ring spanning across the first and second nodes for transmission of a signal in said first direction of said topology, said first and second respectively serving as said insertion point and said termination point of the ring topology and normally using said first and second working paths, respectively, and responsive to said second node detecting a failure of one of said first and second working paths, transmitting a command signal from said second node to said first node for instructing said first node to switch from one of said first and second working paths on which failure was detected to a corresponding one of the first and second protection paths for using said corresponding one of the first and second protection paths instead of the failed working path.