Cisco Technology, Inc.

Chien Fang

Hiroshi Suzuki

Norman William Finn

Flavio Giovanni Bonomi

Rong Pan

Sharat C Prasad

Paul S Chang

Stefano Binetti

Shreeram Bhide

Pagalavan Krishnamoorthy

Sitaram Dontu

Chiara Piglione

An example method includes sending a virtual output queue (VOQ) length of a VOQ to an egress chip. The VOQ relates to a flow routed through an egress port associated with the egress chip. The method also includes receiving fair share information for the VOQ from the egress chip, and enforcing a control action on the incoming packets based on the fair share information. An ingress chip and the egress chip can be provided in a VOQ switch. The control action is a selected one of a group of actions, the group consisting of: (a) dropping packets, (b) pausing packets, and (c) marking packets. The method can further include receiving VOQ lengths of corresponding VOQs from respective ingress chips, where the VOQs relate to the flow. The method can also include calculating respective fair share information for each VOQ, and sending the fair share information to the respective ingress chips.

System and method for distributed resource control of switches in a network environment

Various systems and methods that allow multiple aggregation protocol sessions to be established in a daisy chain network are disclosed. One method involves sending a first aggregation protocol packet and a first session identifier associated therewith to a first network device via a first interface and sending a second aggregation protocol packet and a second session identifier associated therewith to a second network device via the first interface.

Multiple aggregation protocol sessions in a daisy chain network

A switching fabric sets a congestion indicator bit (EFCI bit) in an ATM cell if any queue through which the ATM cell passes is filled above a lower threshold. A Traffic Manager monitors the field of the EFCI bit as cells arrive at an output port of the switching fabric. The traffic manager periodically calculates the ratio of ATM cells having the EFCI congestion bit set to all ATM cells routed to a particular output port. The periodically calculated ratio is used as an input parameter to a Random Early Detection (RED) algorithm. The RED algorithm selects a cell for the switch fabric to drop, by use of a random selection method. The destination computer then does not receive the packet since cells forming part of the packet have been discarded.

Random early detection algorithm using an indicator bit to detect congestion in a computer network

An ATM switch, and method for operating such a switch, are disclosed. In one embodiment, the switch detects ABR VCs that are likely bottlenecked elsewhere in their network path, allowing it to calculate a fair share of available bandwidth for those VCs that are bottlenecked locally. In another embodiment, the switch combines this fair share value with a per-VC queue congestion prediction to arrive at an explicit rate for that VC. The congestion prediction is based on a VC's queue occupancy and upon the VC's rate and rate trend, allowing fast response times and aggressive explicit rate values. The present invention allows switches to maximize throughput while maintaining small queue sizes.

Bandwidth allocation for ATM available bit rate service

The invention is to use the ability of a switching fabric to set a congestion indicator bit in a segment if any queue through which the segment passes is filled above a lower threshold. The output linecard monitors the field of the congestion indicator bit as it receives segments from the switching fabric. The output linecard periodically calculates the ratio of segments having the congestion bit set to all segments routed to a particular port. The periodically calculated ratio is used as an input parameter to a Random Early Detection (RED) algorithm. The RED algorithm selects a packet for the output linecard to drop, by use of a random selection method. The destination computer then does not receive the packet. The random selection of packets to drop has the effect of helping to prevent undesirable network synchronization of transmission of replacement packets. With adaptive source computers, the network device then does not reach a congested state, thereby maintaining optimum throughput for the computer network. When an ATM switching fabric is used with ATM cells for the segments, then the Explicit Forward Congestion Indication Field (EFCI bit) of a data cell is used to mark a data cell which has passed through a queue which is filled above a lower threshold level. Data cells arriving at the output line card with the EFCI bit set are then counted, and this count is used in the periodic calculation of the ratio used as input to the RED algorithm.

Random early detection (RED) algorithm using marked segments to detect congestion in a computer network

A network switch and a method for data switching using a crossbar switch fabric with output port groups operating concurrently and independently that increases throughput and reduces scheduling complexity. The network switch includes a crossbar switch fabric, plurality of output port groups, and a plurality of input ports. The crossbar switch fabric includes a plurality of inputs and outputs. The plurality of output port groups operate concurrently and independently, and each output port group includes one or more output ports and is configured to receive a packet from one of the outputs of the crossbar switch and to send the packet to an output port. The plurality of input ports are coupled to an input of the crossbar switch fabric and configured to send packets to the crossbar switch fabric through the input of the crossbar switch fabric. Each input port includes a plurality of input buffer groups, and each input buffer group is assigned to send a packet for one of the output port groups such that there is a one-to-one correspondence between each of the input buffer groups and output port groups.

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Danville, CA, United States of America

Chien Fang