Barefoot Networks, Inc.

Yi Li

Anurag Agrawal

Michael Feng

Remy Chang

Changhoon Kim

Jeongkeun Lee

Srivathsa Dhruvanarayan

Yan Wang

Some embodiments provide a method for an ingress packet processing pipeline of a network forwarding integrated circuit (IC). The ingress packet processing pipeline is for receiving packets from a port of the network forwarding IC and processing the packets to assign different packets to different queues of a traffic management unit of the network forwarding IC. The method receives state data from the traffic management unit. The method stores the state data in a stateful table. The method assigns a particular packet to a particular queue based on the state data received from the traffic management unit and stored in the stateful table.

Using stateful traffic management data to perform packet processing

Some embodiments provide a method for a traffic management circuit of a data plane forwarding circuit. The traffic management circuit receives data messages from a set of ingress pipelines and provides the data messages to a set of egress pipelines. The method identifies a flow control event. The method provides metadata regarding the flow control event to a message generation circuit of the data plane forwarding circuit via a bus between the traffic management circuit and the message generation circuit.

Flow control visibility

Some embodiments provide a method for a hardware forwarding element that includes multiple queues. The method receives a packet at a multi-stage processing pipeline of the hardware forwarding element. The method determines, at one of the stages of the processing pipeline, to modify a setting of a particular one of the queues. The method stores an identifier for the particular queue and instructions to modify the queue setting with data passed through the processing pipeline for the packet. The stored information is subsequently used by the hardware forwarding element to modify the queue setting.

Queue scheduler control via packet data

Some embodiments provide a method for a hardware forwarding element. The method receives a packet to add to a buffer. The packet is assigned a packet class. The method determines an amount of buffer space available for the assigned packet class. Different packet classes have different amounts of buffer space available in the buffer. When the available buffer space for the assigned packet class is large enough for the received packet, the method adds the packet to the buffer.

Buffer space availability for different packet classes

Some embodiments provide a method for a hardware forwarding element. The method adds a received packet to a buffer. The method determines whether adding the packet to the buffer causes the buffer to pass one of multiple flow control thresholds, each of which corresponds to a different packet priority. When adding the packet to the buffer causes the buffer to pass a particular flow control threshold corresponding to a particular priority, the method generates a flow control message for the particular priority.

Priority-based flow control

Some embodiments provide a method for a traffic management unit of a network forwarding integrated circuit (IC). The traffic management unit includes multiple queues for storing packets. Each stored packet is (i) received by the traffic management unit from one of multiple ingress packet processing pipelines and (ii) for processing by an egress packet processing pipeline after being released from the queue storing the packet. The method determines that a particular one of the queues has crossed a threshold amount of stored packet data. The method provides queue state data including an identifier of the particular queue and a current amount of data stored in the particular queue to at least a subset of the multiple ingress pipelines. The ingress pipelines use the provided data to process subsequent packets.

Transmission of traffic management data to processing pipeline

Some embodiments provide a network forwarding integrated circuit (IC) including multiple configurable ingress pipelines, multiple configurable egress pipelines, a traffic management unit, and a statistics bus. The configurable ingress pipelines are for processing packets received from ports of the network forwarding IC. The configurable egress pipelines are for processing packets to be transmitted out the ports of the network forwarding IC. The traffic management unit includes multiple queues, each of which corresponds to one of the egress pipelines, and is for receiving a packet from an ingress pipeline and enqueuing the packet into one of the queues. The statistics bus connects the traffic management unit to at least a subset of the ingress pipelines, and is for providing the ingress pipelines with state information regarding the queues.

Bus for providing traffic management statistics to processing pipeline

Some embodiments provide a method for scheduling a packet to be dequeued to a processing pipeline of a hardware forwarding element. The method selects a node representing one of multiple ports associated with the processing pipeline. For each of one or more layers of logical queues, the method (i) identifies a set of logical queue nodes associated with a previously selected node based on a configuration that maps multiple physical queues to the multiple ports via the one or more layers of logical queues and (ii) selects one of the identified logical queue nodes based on properties of the identified logical queue nodes. The method selects one of a set of physical queues associated with a selected logical queue node of the last layer of logical queues. The method dequeues a next packet from the selected physical queue for processing by the processing pipeline.

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Fremont, CA, United States of America

Yi Li