Alcatel Internetworking, (pe), Inc.

Cisco Technology, Inc.

Other

Cisco Systems Inc.

Alcatel Internetworking, Inc.

Bernard N Daines

Greg W Davis

Timothy Scott Michels

James E Cathey

Brian Arnold Petersen

Richard J Hausman

Stewart Findlater

David H Yen

David Talaski

Lazar Birenbaum

James P Rivers

James R Rivers

David K Couch

Christopher A Schalick

Frank S Lawrence

Thomas J Hammond

A switching device for forwarding network traffic to a desired destination on a network, such as a telephone or computer network. The switching device includes multiple ports and uses a lookup table to determine which port to forward network traffic over. The lookup table includes network addresses that are maintained in ascending or descending order. The switching device includes multiple binary search engines coupled in series including one or more precursor binary search engines and a final stage binary search engine. Together, the binary search engines perform an N iteration binary search. Additionally, a single search engine can perform multiple concurrent searches so that source and destination addresses can be obtained simultaneously and without wasted memory cycles.

Network switching device with pipelined search engines

Provided is a 10Base-T MAC to PHY interface requiring only two wires (pins) per port, with two additional global wires: a clock wire (pin), and a synchronization wire (pin). This reduction in the number of pins associated with each port is achieved by time-division multiplexing wherein each time-division multiplexed wire combines a plurality of definitions from the conventional seven-wire interface. As a result, each port has its own pair of associated time-division multiplexed wires (pins) and the addition of each port simply requires two additional wires. According to a preferred embodiment of the present invention, information normally transferred on nine wires in a conventional seven-wire interface at 10 MHz is time-division multiplexed onto two wires (corresponding to two pins) that transfer data at 40 MHz, four times the speed of conventional interfaces. Importantly, this multiplexing is done on a port by port basis. Therefore, the number of pins required for a MAC to transceiver interface is two times the number of ports plus two instead of nine times the number of ports, and the addition of each additional port requires only two more wires (pins).

Reduced pin-count 10Base-T MAC to transceiver interface

A packet switch includes a multiple of bidirectional ports that are each connected by dedicated signal paths to a multiple of memory subsystems that in turn are connected to shared memory within the switch. The signal path from each port carries a fragment of a data stream between the port and each memory subsystem. The ports send and receive data stream fragments in parallel from the memory subsystems. This parallel action reduces the bandwidth required of a memory subsystem by dividing the port's data stream among the multiple memory subsystems. In storing data for forwarding to another port, each memory subsystem selects on a time division basis in parallel the data stream fragments from the same port and stores them in memory. In retrieving data from memory for a port, each memory subsystem selects on a time division basis in parallel the same port to receive the data stream fragments read from memory. The bit width of the signal paths between the ports and memory subsystems is reduced by sending smaller, individual data stream fragments between ports and memory subsystems and sending larger, aggregate data stream fragments between memory subsystems and memory. Within each memory subsystem are modules that combine individual data stream fragments into aggregate data stream fragments for storage in memory and modules that split aggregate data stream fragments read from memory into individual data stream fragments for transmission to ports.

Computer network switch with parallel access shared memory architecture

Network switching device with concurrent key lookups

A full duplex repeater for collision-free transmission of data packets between node of a local area network. The repeater includes a multiple of ports, a signal path for communicating data between the ports, and an arbitration mechanism. Each of the ports has an input and output buffer. The mechanism routes data through the repeater by activating each of the ports one port at a time, such as with a round robin algorithm, to transmit stored data from the input buffer of an activated port through the signal path to the other ports. The repeater has a congestion control mechanism that includes level indicators and preset high and low threshold levels for the input buffers and a flow control device. The flow control device monitors the level indicators to determine if the amount of data in a buffer exceeds the high threshold level. If that occurs, the flow control device alerts the transmitting node to stop transmitting by inserting a congestion indication frame into the port's output buffer for transmission to the node. Once the amount of data in the input buffer then drops below the low threshold level, the flow control device alerts the transmitting node to resume transmitting by inserting a clear indication frame in the port's output buffer.

Repeater with flow control device transmitting congestion indication data from output port buffer to associated network node upon port input buffer crossing threshold level

A variable latency cut through bridge (210) for selectively forwarding data packets (10) within a network (310) of computers (312), the variable latency cut through bridge (210) employing a variable latency bridging method wherein the latency factor of the variable latency cut through bridge (210) is set according to the position of a variable threshold point (428). The variable threshold point (428) is optionally set to within a rapid drop off portion (520) of a probability line (514) describing the probability that the data packet (10) is bad as a function of the amount of the packet (10) which has been examined within the variable latency cut through bridge (210).

Variable latency cut through bridge having variable latency threshold

Variable latency cut through bridge for forwarding packets in response

Growing community of inventors

Spokane, WA, United States of America

Bernard N Daines