A SWITCH FABRIC ARCHITECTURE AND TECHNIQUES FOR IMPLEMENTING RAPID HITLESS SWITCHOVER

摘要

A switch is provided that receives user information through a plurality offramercircuits, which group the user information into frames. The frames are fed toa switchfabric including an array of switch elements, each having a switch matrix forrouting eachframe to a desired output in accordance with configuration data stored in afirst tablecoupled to the switch matrix. If different outputs are desired, i.e., theswitch matrix is tobe reconfigured, a switch control circuit supplies additional switchconfiguration data tothe frames through the inputs along with additional user information to berouted throughthe switch. While the additional switch configuration data is stored in asecond table,data flow remains uninterrupted through the switch matrix. Once storage of theadditional configuration data into the second table is complete, however, theswitchcontrol circuit inserts a table select signal into the frames, to therebycouple the secondtable to the switch so that the switch matrix is configured in accordance withtheadditional switch configuration data. Subsequent frames are then routedthrough thereconfigured switch matrix. The first and second tables can thus bealternately updatedand coupled to the switch matrix to appropriately reconfigure the switchwithout affectingexisting connections established through the switch. "Hitless switchover" isthereforeachieved.