International Business Machines Corporation

Nikolaos Chrysos

Cyriel Johan Minkenberg

Mircea R Gusat

Fredy Daniel Neeser

Kenneth Michael Valk

Brian Thomas Vanderpool

Casimer M DeCusatis

Claude Basso

Rolf Clauberg

Daniel Crisan

Anil Pothireddy

Girish Gopala Kurup

Vibhor K Srivastava

Keshav G Kamble

David Alan Shedivy

Mark L Rudquist

Florian Alexander Auernhammer

Patricia Maria Sagmeister

Ronald Pete Luijten

Andreas Christian Doering

Yiyu L Chen

In one embodiment, a method includes receiving a plurality of flows, each flow comprising packets of data and assigning a service credit to each of the plurality of flows. In addition, the method includes assigning a weight parameter to each of the plurality of flows, and selecting a flow from a head of a first control queue unless the first control queue is empty or there is indication that the first control queue should be avoided. A flow is selected from a head of a second control queue in response to a determination that the first control queue is empty or there is indication that the first control queue should be avoided. Additionally, the method includes providing a number of units of service to the selected flow. Moreover, the method includes decreasing the selected flow's service credit by an amount corresponding to the number of units of service provided thereto.

Arbitration of multiple-thousands of flows for convergence enhanced ethernet

Embodiments relate to controlling workload flow on converged Ethernet links. An aspect includes coupling, by a processing device, a first control loop to a second control loop. The second control loop monitors the operation of the first control loop. An equilibrium set point is initialized for the second control loop prior to commencing operation of the first control loop. Accordingly, the equilibrium set point value is adjusted in the second control loop continuously based on a rate of operation of the first control loop.

Adaptive setting of the quantized congestion notification equilibrium setpoint in converged enhanced ethernet networks

Adaptive setting of the quantized congestion notification equilibrium setpoint in converged enhanced Ethernet networks

In one embodiment, a method includes selecting a flow from a head of a first control queue or a second control queue. The method also includes providing service to the selected flow. Moreover, the method includes decreasing a service credit of the selected flow by an amount corresponding to an amount of service provided to the selected flow. In another embodiment, a computer program product includes a computer readable storage medium having program code embodied therewith. The embodied program code is readable/executable by a device to select, by the device, a flow from a head of a first control queue or a second control queue. The embodied program code is also readable/executable to provide, by the device, service to the selected flow, and decrease, by the device, a service credit of the selected flow by an amount corresponding to an amount of service provided to the selected flow.

An approach is described for routing data to a plurality of output terminals via a integrated switch router including a crossbar switch having both a crossbar and a plurality of crossbar bypass lines. Whereas the crossbar may connect each input of the crossbar switch to each output of the crossbar switch, each of the plurality of crossbar bypass lines may connect a single input of the crossbar switch to a corresponding single output of the crossbar switch. According to such approach, a replicated copy of a multicast packet may be forwarded to an output terminal via a crossbar bypass line in parallel with other data forwarded via the crossbar, thus increasing integrated switch router bandwidth.

Multicast packet routing via crossbar bypass paths

A method for synchronizing multicast message subflows in a switched network includes associating, with a processing device, a first destination identifier corresponding to a multicast message with a first queue that corresponds to a first output port of a switching device, associating, with a processing device, a second destination identifier corresponding to the multicast message with a second queue that corresponds to a second output port of the switching device, pausing the first queue in response to a message counter corresponding to the first queue crossing a first predetermined threshold, and unpausing the first queue in response to the message counter crossing a second predetermined threshold, wherein the message counter indicates a quantity of data that has been forwarded by the first queue but remains to be forwarded by the second queue.

Computer-based flow synchronization for efficient multicast forwarding for products and services

A method for scheduling a crossbar using distributed request-grant-accept arbitration between input group arbiters and output group arbiters in a switch unit is provided. Each input group arbiter and output group arbiter maintains an ordered queue of links in an input group or an output group. The ordered queue prioritizes links in the output group or output group that was least recently selected. To satisfy an arbitration slot won on the group-level, the input group arbiter or output group arbiter starts a search from the oldest link that was selected and maintains fairness among links in the group.

Oldest link first arbitration between links grouped as single arbitration elements

A method and system are provided for implementing a hierarchical high radix switch with a time-sliced crossbar. The hierarchical high radix switch includes a plurality of inputs and a plurality of outputs. Each input belongs to one input group; each input group sends consolidated requests to each output, by ORing the requests from the local input ports in that input group. Each output port belongs to one output group; each output port grants one of the requesting input groups using a rotating priority defined by a next-to-serve pointer. Each output group consolidates the output port grants and allows one grant to pass back to an input group. Each input port in an input group evaluates all incoming grants in an oldest packet first manner to form an accept. Each input group consolidates the input port accepts and selects one accept to send to the output port.

Implementing hierarchical high radix switch with timesliced crossbar

A method for scheduling a crossbar using distributed request-grant-accept arbitration between input group arbiters and output group arbiters in a switch unit is provided. The switch unit may be a hierarchical high radix switch with a timesliced crossbar that is configured to transfer packets between a plurality of input ports and a plurality of output ports, organized into groups, using wide words. The timesliced crossbar transfers data for a given packet once per supercycle, in a designated timeslice of that supercycle. Multiple buffered packets from one input port to multiple output ports are transferred by utilizing different timeslices of the supercycle.

Simultaneous transfers from a single input link to multiple output links with a timesliced crossbar

Embodiments relate to bypassing congestion points in a network. An aspect includes sampling queues of a plurality of switches in a network. When packet congestion is detected at a congestion point of a first switch, the packet flow contributing to the packet congestion is identified. A congestion notification message indicating the identified packet flow is then propagated to upstream switches, which are upstream from the first switch in the network. The congestion notification message is then snooped by the upstream switches. Virtual queues within the upstream switches are associated with the identified packet flow to hold packets associated with the identified packet flow. The packets associated with the identified packet flow are then re-routed to bypass the packet congestion in the first switch.

Bypassing congestion points in a converged enhanced ethernet fabric

In one embodiment, a system includes a processor and logic integrated with and/or executable by the processor, the logic being adapted to: receive a plurality of flows, each flow comprising packets of data, assign a service credit to each of the plurality of flows, assign a weight parameter to each of the plurality of flows, select a flow from a head of a first control queue unless the first control queue is empty or there is indication that the first control queue should be avoided, wherein a flow is selected from a head of a second control queue when the first control queue is empty or there is indication that the first control queue should be avoided, provide a number of units of service to the selected flow, and decrease the selected flow's service credit by an amount corresponding to the number of units of service provided thereto.

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Thalwil, Switzerland

Nikolaos Chrysos