Roughly described: a network interface device has an interface. The interface is coupled to first network interface device circuitry, host interface circuitry and host offload circuitry. The host interface circuitry is configured to interface to a host device and has a scheduler configured to schedule providing and/or receiving of data to/from the host device. The interface is configured to allow at least one of: data to be provided to said host interface circuitry from at least one of said first network device interface circuitry and said host offload circuitry; and data to be provided from said host interface circuitry to at least one of said first network interface device circuitry and said host offload circuitry.

Roughly described: a network interface device has an interface. The interface is coupled to first network interface device circuitry, host interface circuitry and host offload circuitry. The host interface circuitry is configured to interface to a host device and has a scheduler configured to schedule providing and/or receiving of data to/from the host device. The interface is configured to allow at least one of: data to be provided to said host interface circuitry from at least one of said first network device interface circuitry and said host offload circuitry; and data to be provided from said host interface circuitry to at least one of said first network interface device circuitry and said host offload circuitry.

In some embodiments, an apparatus includes a flow control module configured to receive a first data packet from an output queue of a stage of a multi-stage switch at a first rate when an available capacity of the output queue crosses a first threshold. The flow control module is configured to receive a second data packet from the output queue of the stage of the multi-stage switch at a second rate when the available capacity of the output queue crosses a second threshold. The flow control module configured to send a flow control signal to an edge device of the multi-stage switch from which the first data packet or the second data packet entered the multi-stage switch.

In some embodiments, an apparatus includes a flow control module configured to receive a first data packet from an output queue of a stage of a multi-stage switch at a first rate when an available capacity of the output queue crosses a first threshold. The flow control module is configured to receive a second data packet from the output queue of the stage of the multi-stage switch at a second rate when the available capacity of the output queue crosses a second threshold. The flow control module configured to send a flow control signal to an edge device of the multi-stage switch from which the first data packet or the second data packet entered the multi-stage switch.

In a switching system that comprises a central switching device an at least one port extender device, the central switching device includes at least one port configured to interface with the port extender device, and the port extender device includes a plurality of front ports for interfacing with one or more networks. The central switching device includes a processor that processes packets received from the at least one port extender device, and a plurality of egress queues for storing processed packets that are to be forwarded to the at least one port extender device for transmission via ones of the front ports. The central switching device also includes a flow control processor configured to, responsively to flow control messages received from the at least one port extender device, control transmission of packets to the at least one port extender device to prevent overflow of egress queues of the port extender device.

In a switching system that comprises a central switching device an at least one port extender device, the central switching device includes at least one port configured to interface with the port extender device, and the port extender device includes a plurality of front ports for interfacing with one or more networks. The central switching device includes a processor that processes packets received from the at least one port extender device, and a plurality of egress queues for storing processed packets that are to be forwarded to the at least one port extender device for transmission via ones of the front ports. The central switching device also includes a flow control processor configured to, responsively to flow control messages received from the at least one port extender device, control transmission of packets to the at least one port extender device to prevent overflow of egress queues of the port extender device.

A switching system includes a port extender device coupled to a central switching device. Packets processed by the central switching device are forwarded to the port extender device and enqueued in ones of a plurality of egress queues in the port extender device for transmission of the packets via the front ports of the port extender device. Respective egress queues in the port extender device have a queue depth that is less than a queue depth of corresponding respective egress queues in the central switching device. A flow control message indicative of congestion in a particular egress queue of the port extender device is generated and transmitted to the central switch device to control transmission of packets from the central switching device to the particular egress queue of the port extender device.

The present invention relates to a method of managing congestion in a multi-path network, the network having a plurality of network elements arranged in a plurality of switch stages and a plurality of network links interconnecting the network elements, the method comprising the steps of detecting congestion on a network link, the congested network link interconnecting the output port of a first network element with a first input port of a second network element in a subsequent switch stage; identifying an uncongested network link connected to a second input port of said second network element; and directing future data packets on a route across the multi-path network which includes the identified uncongested network link. Also provided is a multi-path network and an Ethernet bridge or router incorporating such a multi-path network.

Described embodiments process data packets received that include a source address and at least one destination address. If the destination address is stored in a memory of an I/O adapter, the received data packet is processed in accordance with bridging rules associated with each destination address stored in the I/O adapter memory. If the destination address is not stored in the I/O adapter memory, the I/O adapter sends a task message to a processor to determine whether the destination address is stored in an address table stored in a shared memory of the network processor. The I/O adapter memory has lower access latency than the address table. If the destination address is stored in the address table, the received data packet is processed in accordance with bridging rules stored in the address table and the bridging rules stored in the I/O adapter memory are updated.

In some embodiments, an apparatus includes a switch fabric having at least a first switch stage and a second switch stage, an edge device operatively coupled to the switch fabric and a management module. The edge device is configured to send a first portion of a data stream to the switch fabric such that the first portion of the data stream is received at a queue of the second switch stage of the switch fabric via the first switch stage of the switch fabric. The management module is configured to send a flow control signal configured to trigger the edge device to suspend transmission of a second portion of the data stream when a congestion level of the queue of the second switch stage of the switch fabric satisfies a condition in response to the first portion of the data stream being received at the queue.