Tandem Computers Incorporated

Hewlett-packard Development Company, L.p.

Compaq Computer Corporation, Inc.

International Business Machines Corporation

Hewlett-packard Company

Adaptec, Inc.

Siemens Business Communication Systems, Inc.

John C Krause

William P Bunton

William J Watson

David P Sonnier

David Allen Brown

David J Garcia

Linda Ellen Zalzala

Robert W Horst

Patricia L Whiteside

William Edward Baker

Richard W Cutts, Jr

John D Coddington

Susan S Meredith

Charles Edward Peet

Geoffrey I Iswandhi

Stephen G Low

Daniel L Fowler

Scott Stuart Smith

James Stevens Klecka

Curtis Willard Jones, Jr

Renato John Recio

Melvin K Benedict

Patricia Ann Thaler

Michael R Krause

John Michael Brown

William F Bruckert

Douglas E Jewett

Steven C Meyers

Larry A Stell

Joel Q Adams

Frank A Williams

Randall G Banton

Paul N Hintikka

David C Black

Charles E Peet, Jr

Norman Endick

Gary F Campbell

David T Heron

William F Dunn, Jr

Michael K Kounnas

Wiliam P Bunton

James B Koehler

Diep N Le

Kenneth H Porter

Barry Lee Drexler

Harry Frank Elrod

Michael P Simpson

Patracia L Whiteside

An adapter that buffers received symbols and automatically determines and corrects for skew between lanes is disclosed. In one embodiment, the adapter is a part of a network that includes a first and second devices coupled together by a communications link having multiple independent serial lanes. The first device initiates communication by repeatedly transmitting a training sequence that includes a start symbol for each lane. An adapter in the second device includes a set of buffers each configured to receive the symbols conveyed by a corresponding serial lane. The buffers are coupled to a reconstruction circuit that removes one 'symbol group' at a time from the buffers. A symbol group is made up of one symbol from each buffer. The reconstruction circuit removes symbol groups until a start symbol is detected. If the start symbol is not detected in all buffers, output from the buffers having start symbols is temporarily suspended.

High-speed interconnection adapter having automated lane de-skew

A distributed computer system includes links and routing devices coupled between the links and routing frames between the links. Each of the routing devices includes a congestion control mechanism for detecting congestion at the routing device and responding to detected congestion by gradually reducing an injection rate of frames routed from the routing device.

Congestion management in a distributed computer system multiplying current variable injection rate with a constant to set new variable injection rate at source node

A multi-lane link that automatically detects if the lanes in the link have been reordered and corrects the order of the lanes. In one embodiment, the link includes a transmitter and a receiver. The receiver is configured to receive a plurality of lanes and includes a receiver logic circuit configured to receive signals from each of the plurality of lanes. Lane misordering is corrected during a training sequence in which a first training sequence and a second training sequence are bilaterally transmitted between the transmitter and receiver. The receiver monitors the training sequence for symbols that are unique to each lane and if an unexpected symbol is detected in the lane, the receiver logic circuit will correct the order of the lanes. The link further comprises a transmitter logic circuit configured to transmit signals to the lanes. The transmitter logic circuit is configured to reorder the sequence of the signals transmitted to the lanes if the transmitter does not detect a response from the receiver. The transmitter logic circuit may consist of a bank of multiplexers configured to transmit a selected one of two input signals to be transmitted through a lane. Similarly, the receiver logic circuit may comprises a bank of multiplexers configured to transmit a selected one of two input signals received from a lane. The unique lane identifiers symbols are preferably insensitive to binary inversion and are preferably 10-bit symbols compatible with an 8B/10B encoding scheme.

High-speed interconnection link having automated lane reordering

A speculative transmit function, utilizing a configurable logical buffer, is implemented in a network. When a transmission is started the logical buffer is configured as a FIFO to reduce transmit latency. If a data under-run lasts for more than a fixed time interval the transmission is abandoned and the logical buffer is reconfigured as a STORE-AND-FORWARD buffer. The transmission is restarted after all transmit data is buffered.

Speculative transmit for system area network latency reduction

A link extender node is used to extend links between end nodes and/or routing nodes in a system area network. A connection includes a first link, coupling an end or routing node to a local port of a first link extender, a second link coupling the remote ports of first and second link extenders, and a third link coupling the local port of the second link extender to an end or routing node. The link extender includes link exception detection logic and transmits a this link bad command on the link generating the exception and transmits an other link bad command on the link not generating the exception.

Link extenders with error propagation and reporting

An adapter configured to automatically detect and compensate for differential signal inversion is herein disclosed. In one embodiment, the adapter is part of a computer network having differential conductor pairs conveying differential signals between network devices. The network devices include adapters coupled to transmit and receive signals via the differential conductor pairs. The adapter preferably includes a lane receiver, a decoder, and a synchronization circuit. The lane receiver is configured to receive a single differential signal and to convert the differential signal into a sequence of code symbols. The decoder decodes the code symbols to produce a sequence of received symbols. The synchronization circuit examines the sequence of received symbols to determine if it is incorrect due to inversion of the differential signal, and if so, it causes the lane receiver to correct for the differential signal inversion. It is expected that the received symbol sequence will include a training symbol sequence which will have a start symbol whose decoded value is unaffected by differential signal inversion, and a training symbol whose decoded value is indicative of the presence or absence of invasion. The synchronization circuit, upon identifying the training sequence, will thus be able to determine whether inversion exists and be able to automatically correct for it.

High-speed interconnection adapter having automated crossed differential pair correction

A multiprocessor or clustered system with processing elements communicatively interconnected transmits and receives data in the form of message packets. Certain of the message packets are either responding to earlier requests with the data, or are requests that the data of the packet be written at the destination. Each message packet has an initial portion that includes information about the packet, including what the data is carrying (i.e., data in response to an earlier request, or data to be written), the source and ultimate destination of the message packet. This information prevents errant data being written at the destination by determining if the source has &ldquo;permission&rdquo; to send such data to the destination. When a message packet carrying data is received, processing of the packet is started in parallel with continued reception of the data it carries by using the information contained in the initial portion to check the permissions.

Data communication with speculative reception of data in a data processing system

An adapter that buffers received symbols and automatically determines and corrects for skew between lanes is disclosed. In one embodiment, the adapter is a part of a network that includes a first and second devices coupled together by a communications link having multiple independent serial lanes. The first device Initiates communication by repeatedly transmitting a training sequence that includes a start symbol for each lane. An adapter in the second device includes a set of buffers each configured to receive the symbols conveyed by a corresponding serial lane. The buffers are coupled to a reconstruction circuit that removes one &ldquo;symbol groups&rdquo; at a time from the buffers. A symbol group is made up of one symbol from each buffer. The reconstruction circuit removes symbol groups until a start symbol is detected. If the start symbol is not detected in all buffers, output from buffers having start symbols is temporarily suspended.

An improved hybrid flow control protocol for providing FIFO capacity to prevent overflow due to bytes arriving after the FIFO indicates it is not ready to receive any more bytes utilizes a combination of a high/low watermark and credit based system. In one embodiment, when the byte count exceed the high watermark fixed credits are sent when N bytes are pulled from the FIFO. In a second embodiment, variable credits are sent depending on the difference between the number of bytes received in and pulled from the FIFO.

Hybrid flow control

A system and technique of auto-configuring a first module to be in the same mode as a second module includes testing the frequency of a clock signal received from the second module to determine its mode of operation. The first module then auto-configures its ports to be in the same state as the second module. Additional test include the number of clock signals and symbol size to detect additional modes of operation. The first module is auto-configured as a result of the tests.

Network system for a first module port auto configuring same mode as a second module port

A multiprocessor system includes a number of sub-processor systems, each substantially identically constructed, and each comprising a central processing unit (CPU), and at least one I/O device, interconnected by routing apparatus that also interconnects the sub-processor systems. A CPU of any one of the sub-processor systems may communicate, through the routing elements, with any I/O device of the system, or with any CPU of the system. Communications between I/O devices and CPUs is by packetized messages. Interrupts from I/O devices are communicated from the I/O devices to the CPUs (or from one CPU to another CPU) as message packets. CPUs and I/O devices may write to, or read from, memory of a CPU of the system. Memory protection is provided by an access validation method maintained by each CPU in which CPUs and/or I/O devices are provided with a validation to read/write memory of that CPU, without which memory access is denied.

Method of data communication flow control in a data processing system

Detecting and isolating errors occurring in data communication in a

A processing system includes multiple processor units and multiple input/output elements communicatively interconnected by a system area network having a plurality of multi-ported router elements. Communication between the system elements uses message packets that contain, among other things, destination information that identifies the intended recipient of the message packet. That destination information is used, at least in part, for routing message packets from a its source to its intended destination. Deadlocks are eliminated by providing each router with information as to which ports cannot be used for re-transmission of a message packet, depending upon which port is receiving that message packet.

Network message routing using routing table information and supplemental

A method of encoding data and commands as N-bit words includes using a first portion of the word to identify whether the word carries data or a command. In the case of a command, the command is in a second portion of the word. In the case of data, a part of the data is contained in the second portion of the word, while the remaining part of the data is encoded in the first portion of the word.

Encoding for communicating data and commands

Growing community of inventors

Georgetown, TX, United States of America

John C Krause