Patent ID: 7388875

Claim:
A method of upgrading a redundant multi-stage network comprising a plurality of rows, having a first row and a last row, each row comprising a plurality of routers, each router comprising a plurality of ports, said plurality of ports comprises top ports and bottom ports, wherein the top ports of the first row and the bottom ports of the last row are connected to external sources, said method comprising: adding a new top port and a new bottom port to each router in each row; providing a topology where the topology specifies for each port including the new top port and the new bottom port of each router of each row a corresponding port of a corresponding router to be connected, if said corresponding port exists; rewiring a selected port to be connected to the corresponding port of the corresponding router for said selected port, wherein the selected port is any port having a corresponding port of a corresponding router and is not connected to said corresponding port; repeating the rewiring until all the ports that have a corresponding port of a corresponding router are connected to said corresponding port; for each router in the first row, connecting the new top port to an external source; for each router in the last row, connecting the new bottom port to an external source; for each router in the first row, activating the new top port; and for each router in the last row, activating the new bottom port.