Abstract: A primary and secondary card are coupled to protect and working paths, respectively providing a redundant connection to a node. The primary and secondary cards implement an inter-card path that is a working path for the primary card and a protect path for the secondary card. Responsive to a fault in the working path, the secondary card generates a simulated error condition on the inter-card path, causing the primary card to make the protect path the active path. When the protect path is the active path and goes down, the primary card generates a simulated error condition on the inter-card path, causing the secondary card to make the working path the active path. Switching of packets to the active and protect paths on the primary and secondary cards and is performed by an FPGA that maintains its own state machine subject to instructions from software executed by the cards.

Abstract: A primary and secondary card are coupled to protect and working paths, respectively providing a redundant connection to a node. The primary and secondary cards implement an inter-card path that is a working path for the primary card and a protect path for the secondary card. Responsive to a fault in the working path, the secondary card generates a simulated error condition on the inter-card path, causing the primary card to make the protect path the active path. When the protect path is the active path and goes down, the primary card generates a simulated error condition on the inter-card path, causing the secondary card to make the working path the active path. Switching of packets to the active and protect paths on the primary and secondary cards and is performed by an FPGA that maintains its own state machine subject to instructions from software executed by the cards.

Abstract: A primary and secondary card are coupled to protect and working paths, respectively providing a redundant connection to a node. The primary and secondary cards implement an inter-card path that is a working path for the primary card and a protect path for the secondary card. Responsive to a fault in the working path, the secondary card generates a simulated error condition on the inter-card path, causing the primary card to make the protect path the active path. When the protect path is the active path and goes down, the primary card generates a simulated error condition on the inter-card path, causing the secondary card to make the working path the active path. Switching of packets to the active and protect paths on the primary and secondary cards and is performed by an FPGA that maintains its own state machine subject to instructions from software executed by the cards.

Abstract: A primary and secondary card are coupled to protect and working paths, respectively providing a redundant connection to a node. The primary and secondary cards implement an inter-card path that is a working path for the primary card and a protect path for the secondary card. Responsive to a fault in the working path, the secondary card generates a simulated error condition on the inter-card path, causing the primary card to make the protect path the active path. When the protect path is the active path and goes down, the primary card generates a simulated error condition on the inter-card path, causing the secondary card to make the working path the active path. Switching of packets to the active and protect paths on the primary and secondary cards and is performed by an FPGA that maintains its own state machine subject to instructions from software executed by the cards.