High-speed facility protection in a digital telecommunications system

A cross-connect system having facility protection capability, comprising:

• a plurality of ports, including n east input port and a west input port for receiving a facility from east and west lines in a telecommunication system, and including a head output port for communicating the facility received at one of said east and west input ports to another network;
• a central processing unit, coupled to a bus;
• a cross-connect matrix of the Clos type, having first, center and third stages, said cross-connect matrix coupled to said bus;
• and
• an interface processing unit coupled to said bus and to said east and west input ports, comprising:
• a first interface processor coupled to a first stage of said cross-connect matrix associated with said east input port, for connecting a facility received thereat to a center stage of said cross-connect matrix, and for monitoring the received facility for an errored condition;
• a second interface processor coupled to a first stage of said cross-connect matrix associated with said west input port, for connecting a facility received thereat to a center stage of said cross-connect matrix, and for monitoring the received facility for an errored condition;
• and
• a third interface processor coupled to a third stage of said cross-connect matrix associated with said head output port, for coupling the third stage to one of said first stages to receive the facility from a first one of the east and west input ports, and for controlling the third stage to switch said head output port to receive the facility from a second one of said east and west input ports responsive to the monitoring performed by the interface processor associated with the first one of said east and west input ports indicating an errored condition.

A digital telecommunications system, comprising:

• first and second transmission lines;
• and
• a first cross-connect, comprising:
• a plurality of ports, including first and second input ports for receiving a first facility from said first and second transmission lines, respectively, and including a head output port for presenting the first facility;
• a central processing unit, coupled to a bus;
• a cross-connect matrix of the Clos matrix type, having first, center and third stages, and coupled to said bus;
• an interface processing unit coupled to said bus and to said first and second input ports, for connecting the facility received at one of said first and second input ports to said cross-connect matrix, for monitoring the first facility to detect an error condition, and for switching to connect the other of said first and second input ports to said cross-connect matrix responsive to detecting the error condition, comprising:
• a plurality of interface processors;
• and
• a plurality of first/third stage circuits, each coupled to an associated one of said plurality of interface processors;
• wherein said first input port corresponds to a first one of said first/third stage circuits, controlled by a first one of said plurality of interface processors so that a facility received at the first input port is monitored for detection of an

A method of providing line protection for a telecommunications system including a fiber optic line in such a manner as to eliminate the need for providing a redundant fiber optic line, comprising:

• providing a redundant route relative to the fiber optic line;
• broadcasting a facility over the fiber optic line and the redundant route to a cross-connect configured as a switching matrix of the Clos type, the cross-connect having first and second ports coupled to the fiber optic line and to the redundant route, respectively, the cross-connect having a head port for presenting the received facility, the head port coupled via a cross-connect matrix to the first port;
• monitoring the received facility at a first stage of said switching matrix associated with the first port to detect an errored condition;
• and
• responsive to detecting an errored condition, connecting the head port to the second port to receive the facility thereat by switching a third stage of the switching matrix which is associated with the head port and which is coupled to the first and second ports by way of center stages of the switching matrix.