Juniper Networks, Inc.

Sun Microsystems, Inc.

International Business Machines Corporation

Xerox Corporation

Bjorn O Liencres

Pradeep S Sindhu

Nalini Agarwal

Dennis C Ferguson

Rasoul Mirzazadeh Oskouy

Raymond Marcelino Manese Lim

Hann-Hwan Ju

Sreeram Veeragandham

Kireeti Kompella

Ashok Singhal

Erik E Hagersten

David J Broniarczyk

Jeff Price

Frederick M Cerauskis

Douglas B Lee

Gerald Cheung

Matthew J Kalos

Thomas Anthony Gregg

John R Flanagan

Daniel Francis Casper

Jean-Marc Frailong

Ramalingam Krishnamurthi Anand

Jung-Herng Chang

Kang S Lim

Jorge Cruz-Rios

Tung Pham

A method and apparatus for switching a data packet between a source and destination in a network. The data packet includes a header portion and a data portion. The header portion includes routing information for the data packet. The method includes defining a data path in the router comprising a path through the router along which the data portion of the data packet travels and defining a control path comprising a path through the router along which routing information from the header portion travels. The method includes separating the data path and control path in the router such that the routing information can be separated from the data portion allowing for the separate processing of each in the router. The data portion can be stored in a global memory while routing decisions are made on the routing information in the control path.

Separation of data and control in a switching device

A router for switching data packets from a source to a destination in a network in which the router includes a distributed memory. The distributed memory includes two or more memory banks. Each memory bank is used for storing uniform portions of a data packet received from a source and linking information for each data packet to allow for the extraction of the uniform portions of a data packet from distributed locations in memory in proper order after a routing determination has been made by the router.

Memory organization in a network device

Memory organization in a switching device

A network device switches variable length data units from a source to a destination in a network. An input port receives the variable length data unit and a divider divides the variable length data unit into uniform length data units for temporary storage in the network device. A distributed memory includes a plurality of physically separated memory banks addressable using a single virtual address space and an input switch streams the uniform length data units across the memory banks based on the virtual address space. The network device further includes an output switch for extracting the uniform length data units from the distributed memory by using addresses of the uniform length data units within the virtual address space. The output switch reassembles the uniform length data units to reconstruct the variable length data unit. An output port receives the variable length data unit and transfers the variable length data unit to the destination.

A method and apparatus for synchronizing components operating isochronously that are coupled by independent links. The apparatus includes a synchronization circuit having a first and second buffer, each including an input port coupled to an external link, an output port, a read pointer and a write pointer. The read pointer indicates a next location in a respective buffer to be read in transferring data out on the output port. The write pointer indicates a next location in the respective buffer to be written when receiving data on the input port and is configured to automatically increment upon receipt of a first data bit on a respective external link. A trigger circuit is coupled to each link for receiving external trigger signals. Each external trigger signal is included along with data transmitted on the link and indicates when data is present on a respective link. A counter is coupled to the trigger circuit. The counter includes a trigger input and a predefined delay period. After receipt of a first of the external trigger signals on the trigger input, the counter is operable to output a read enable signal to each of the read pointers after the delay period has expired.

Synchronizing source-synchronous links in a switching device

Snooping is implemented on a split transaction snooping bus for a computer system having one or many such buses. Circuit boards including CPU or other devices and/or distributed memory, data input/output buffers, queues including request tag queues, coherent input queues ('CIQ'), and address controller implementing address bus arbitration plug-into one or more split transaction snooping bus systems. All devices snoop on the address bus to learn whether an identified line is owned or shared, and an appropriate owned/shared signal is issued. Receipt of an ignore signal blocks CIQ loading of a transaction until the transaction is reloaded and ignore is deasserted. Ownership of a requested memory line transfers immediately at time of request. Asserted requests are queued such that state transactions on the address bus occur atomically logically without dependence upon the request. Subsequent requests for the same data are tagged to become the responsibility of the owner-requestor. A subsequent requestor's activities are not halted awaiting grant and completion of an earlier request transaction. Processor-level cache changes state upon receipt of transaction data. A single multiplexed arbitration bus carries address bus and data bus request transactions, which transactions are each two-cycles in length.

Implementing snooping on a split-transaction computer system bus

A split transaction snooping bus protocol and architecture is provided for use in a system having one or many such buses. Circuit boards including CPU or other devices and/or distributed memory, data input/output buffers, queues including request tag queues, coherent input queues ('CIQ'), and address controller implementing address bus arbitration plug-into one or more split transaction snooping bus systems. All devices snoop on the address bus to learn whether an identified line is owned or shared, and an appropriate owned/shared signal is issued. Receipt of an ignore signal blocks CIQ loading of a transaction until the transaction is reloaded and ignore is deasserted. Ownership of a requested memory line transfers immediately at time of request. Asserted requests are queued such that state transactions on the address bus occur atomically logically without dependence upon the request. Subsequent requests for the same data are tagged to become the responsibility of the owner-requestor. A subsequent requestor's activities are not halted awaiting grant and completion of an earlier request transaction. Processor-level cache changes state upon receipt of transaction data. A single multiplexed arbitration bus carries address bus and data bus request transactions, which transactions are each two-cycles in length.

Split transaction snooping bus protocol

A router for switching a data packet between a source and destination in a network including a plurality of input ports each including a data handler. The data handler divides a data packet into one or more fixed length cells. The router includes a plurality of output ports at least one of which is for routing the data packet to the destination and a memory divided into a plurality of memory banks. A input switch receives fixed length cells from the input ports and writes a single cell in a cell slot time span to each memory bank. An output switch routes cells received from the memory to an appropriate output port.

High speed switching device

Growing community of inventors

Palo Alto, CA, United States of America

Bjorn O Liencres