Switch fabric architecture and techniques for implementing rapid hitless switchover

摘要

A switch is provided that receives user information through a plurality of framer circuits, which group the user information into frames. The frames are fed to a switch fabric including an array of switch elements, each having a switch matrix for routing each frame to a desired output in accordance with configuration data stored in a first table coupled to the switch matrix. If different outputs are desired, i.e., the switch matrix is to be reconfigured, a switch control circuit supplies additional switch configuration data to the frames through the inputs along with additional user information to be routed through the switch. While the additional switch configuration data is stored in a second table, data flow remains uninterrupted through the switch matrix. Once storage of the additional configuration data into the second table is complete, however, the switch control circuit inserts a table select signal into the frames, to thereby couple the second table to the switch so that the switch matrix is configured in accordance with the additional switch configuration data. Subsequent frames are then routed through the reconfigured switch matrix. The first and second tables can thus be alternately updated and coupled to the switch matrix to appropriately reconfigure the switch without affecting existing connections established through the switch. “Hitless switchover” is therefore achieved.