A switching device comprises at least two base racks, each base rack including a switch card in communication with a line card across a backplane, the line card having at least an external port. The at least two base racks are coupled such that the switch cards of each are linked. A method for switching...http://www.google.de/patents/US7110394?utm_source=gb-gplus-sharePatent US7110394 - Packet switching apparatus including cascade ports and method for switching packets
