Intel Corporation

National Semiconductor Corporation

Tele Digital Development, Inc.

Xlnt Designs, Inc.

Robert M Grow

Ronald S Perloff

Fazil Ismet Osman

Perry S Stultz

Vitek Zaba

John S Bell

Roger S Moyers

Sally Cordes

Robert J Peyser

Lawrence J Pollack

Randall F Wetzel

A system and method of transmitting data frames between a plurality of input ports to a plurality of output ports is described. The input ports segment portions of the received data frames to provide smaller data cells which are individually transmitted to an output port associated with a destination of the segmented data frame. Based upon information provided in the data cells received at the output port, the output port determines the ordinal positions of the received data cells within the segmented data frame and reassembles the data frame which was segmented at the input port. The output port then forwards the reassembled frame toward the associated destination.

Segmentation and reassembly of data frames

A method of communicating frames of management information includes loading a frame of management information from one of a plurality of stations into a respective one of a plurality of buffers. Whether the frame contains more than a predetermined number of bytes is determined. If an end of the frame is loaded into the respective one of the buffers, then a frame presence flag associated with said one of the plurality of stations is set. A request signal is transmitted to a station management module if the frame contains more than the predetermined number of bytes or if the buffer already contains management information associated with a previously loaded frame. The plurality of stations is polled to determine whether respective frame presence flags have been set. A buffer reading process is performed in a manner dependent upon whether the buffer reading process was triggered by one of the frame presence flags or by the request signal, to provide the station management module with the management information in the frame.

Communication system and method for communicating frames of management information in a multi-station network

A switching fabric for transmitting digital data from a plurality of sources to a plurality of destinations is described. The switching fabric includes a plurality of input ports, a plurality of output ports and a plurality of switching sections. Each of the input ports receives data frames and partitions the received data payload of at least some of the frames into a plurality of associated data cells. Each of the output ports are coupled to at least one destination associated with the headers of the data frames. Each of the switching sections may be coupled to each of the input ports and each of the output ports for transmitting each of selected ones of the data cells from the at least one input port to one or more of the coupled output ports.

Switching fabric including a plurality of crossbar sections

A method and apparatus for coupling a signal from one node to another node prepares a signal for transmission, performs error checking on such signal while simultaneously transferring such signal within a transmitting node, transmits the signal from the transmitting node, receives and formats the signal at a receiving node, including an identifying portion and a data portion, and directly stores the data portion in memory that is directly accessible by a user process executing in the receiving node while simultaneously performing error checking.

Method and apparatus for assisting data bus transfer protocol

Systems and methods for providing graceful insertion of a station or tree into a ring type network. According to one aspect of the invention, graceful insertion is achieved after coupling a tree to a tree link of a master port by switching the tree into a local ring, holding the local ring, and awaiting a token on the network ring. After a token is received on the network ring, the tree is switched from the local ring to the network ring. Monitoring ring status in hardware provides the responsiveness necessary which software graceful insertion typically cannot provide.

Graceful insertion of a tree into a ring network

A ring latency timer provides a station attached to a token ring network with the capability of obtaining an accurate latency measurement of the ring to which it is attached. An internal hardware register, which may be read via the processor control bus interface, contains the latest ring latency measurement. A latency interrupt bit, when cleared, enables the latency measurement function. A subsequent interrupt which causes the latency interrupt bit to be set by the chip signals the completion of the latency measurement and the function is once again disabled. The latency register holds the latency information until the interrupt bit is cleared by the processor.

Ring latency timer

The present invention provides asynchronous priority select logic for allowinig an individual station on a token ring network to hold a token for asynchronous transmission only for a specified maximum time period. The asynchronous priority select logic comprises a token rotation timer for timing token rotations on the ring from arrival to arrival. A token holding timer limits the amount of ring bandwidth used by the station for asynchronous transmission after the token is captured by the station. Select circuitry responsive to the value of the token rotation timer determines if the captured token is still usable for transmission by determining if the token rotation timer value is less than a preselected asynchronous threshold value. The select logic includes means for generating a selected asynchronous threshold value having a first bit length. The selected asynchronous threshold value is then expanded to a second bit length corresponding to the bit length of the token holding timer value. The expanded asynchronous threshold value and the token holding timer value are then compared and an output signal is asserted if the expanded selected asynchronous threshold value is greater than the token holding timer value.

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Poway, CA, United States of America

Robert M Grow