Cisco Technology, Inc.

Carnegie Mellon University

Jeffrey Wayne Kidd

Kenneth Harvey Potter, Jr

Herman Henry Schmit

David A Carroll

Kara J Adams

Carson Stuart

Christopher Maverick Petersen

Brian Christopher Van Essen

William E Jennings

Claude Alan Cartee

Randall Graham Campbell

Wayne Garavaglia

Kevin R Lingle

Eric Decker

The present invention relates to a secure method of distributing configuration data for a programmable logic device (PLD). The configuration data is encrypted to generate encrypted configuration data. A decryption key is encrypted using a silicon key. The encrypted configuration data and the encrypted decryption key are transferred to a PLD. Within the PLD, the encrypted decryption key is decrypted using the silicon key. Then, also within the PLD, the encrypted configuration data is decrypted using the decryption key to recover the configuration data. The PLD is then configured using the configuration data. The silicon key may be communicated to the PLD by tying predetermined input pins to an active high voltage level or signal ground, to form a binary code.

Method of securing programmable logic configuration data

A technique efficiently transports token ring (TR) frames over trunks interconnecting switches of a distributed TR bridge. The TR bridge is characterized by a logical switch fabric that is distributed among the interconnected switches by the trunks, which are preferably interswitch link (ISL) trunks. Each switch includes a Bridge Relay Function (BRF) coupled to a plurality of Concentrator Relay Functions (CRFs) having a plurality of ports for receiving TR frames over TR segments. The BRF and CRF of the distributed TR bridge operate according to a 2-tier switching model wherein each CRF and BRF is assigned an individual virtual local area network identifier. The technique encapsulates the TR frames in a TR-ISL protocol format that accomodates differences in formats of various TR frames and that comports with the 2-tier switching model of the distributed TR bridge.

Switched token ring over ISL (TR-ISL) network

A distributed token ring (TR) bridge has a logical switch fabric that is distributed over a TR switching network of switches interconnected by trunk links. The distributed TR bridge includes a plurality of TR switches, each having a Bridge Relay Function (BRF) logically coupled to at least one Concentrator Relay Function (CRF). Distribution of the switch fabric essentially comprises logically distributing the BRF function among the network of switches.

Token ring bridge distributed in a switched fabric

A system and method are provided that permit an accurate checksum to be generated of a block of data being transmitted via a prefetched bus, despite repeated transmissions of identical portions of the block and presentation of those identical to checksum logic simultaneously with their transmission by the bus, by ensuring that only those portions of the data block that have yet to be checksummed are checksummed.

Ensuring accurate data checksum

Growing community of inventors

Hillsborough, NC, United States of America

Jeffrey Wayne Kidd