APPLICATION OF HARDWARE-BASED MAILBOXES IN NETWORK TRANSCEIVERS AND DISTRIBUTED APPROACH FOR PREDICTABLE SOFTWARE-BASED PROTECTION SWITCHING

摘要

A line card in a network node having a local memory coupled to a local controller and local logic circuit. The local memory in the line card stores state information for signals processed by the line card itself, as well as state information for signals processed by other line cards. The logic circuit and controller implement a same fault detection and signal processing algorithms as all other line cards in the group, to essentially effectuate a distributed and local hardware based control of automatic protection switching (APS) without interrupting a central processor. The line card also performs error checking and supervisory functions to ensure consistency of state among the line cards.