Cisco Technology, Inc.

Parvin Taheri

Thomas James Edsall

Rong Pan

Sha Ma

Keerthi Manjunathan Swarnamanjunathan

Dennis Khoa Dang Nguyen

Krishnan Subramani

Tom Edsall

Liyuan Quan

Mohammad Alizadeh Attar

A first node of a packet switched network transmits at least one flow of protocol data units of a network to at least one output context of one of a plurality of second nodes of the network. The first node includes X virtual output queues (VOQs). The first node receives, from at least one of the second nodes, at least one fair rate record. Each fair rate record corresponds to a particular second node output context and describes a recommended rate of flow to the particular output context. The first node allocates up to X of the VOQs among flows corresponding to i) currently allocated VOQs, and ii) the flows corresponding to the received fair rate records. The first node operates each allocated VOQ according to the corresponding recommended rate of flow until a deallocation condition obtains for the each allocated VOQ.

Managing virtual output queues

A network device, including ports that receive/send data packets from/to a network, receives data packets of multiple traffic flows, and populates a queue in memory with the data packets. The network device periodically updates a fair rate for the multiple traffic flows to converge a length of the queue to a reference length. Specifically, the network device determines a length of the queue, a change in the length from a previous length, and a deviation of the length from the reference length. The network device detects an increase in the change in length above a threshold that is based on the reference length. If the increase is not above the threshold, the network device derives the fair rate from a previous fair rate using proportional integral control. The network device identifies elephant flows among the multiple traffic flows, and sends the fair rate to a source of each elephant flow.

Layer 3 fair rate congestion control notification

A network device includes network ports to communicate with source devices and destination devices. The network device receives respective packets from each source device and, for each source device, respectively performs the following operations. The network device stores the respective packets in a shared memory that stores all packets from all of the source devices, and dequeues the respective packets from the shared memory to send the packets to destination devices. Responsive to the storing and the dequeuing, the network device respectively increases and decreases an input packet count for the source device. The network device determines for the source device a packet sending rate based on the input packet count and a flow control threshold common across all of the source devices in accordance with a proportional integral (PI) control equation. The network device transmits to the source device a control message including the packet sending rate.

Proportional integral based shaper for lossless output buffer

A network device is configured to transmit acknowledgement packets according to the length of the egress queue. The network device receives data packets from one or more endpoints and buffers the data packets in an egress buffer before transmitting the data packets. The network device also receives acknowledgement packets that are sent in response to data packets previously transmitted by the network device. The network device buffers the acknowledgement packets in an acknowledgement buffer. The network device transmits the acknowledgement packets at an acknowledgment rate that is based on a queue length of the egress buffer.

Adaptive acknowledgement control

In one embodiment, a method includes measuring a rate of traffic received at a leaf node, marking a plurality of packets in the flow as protected at the leaf node to match the rate of traffic with a configured rate of traffic for the flow at the leaf node, and dropping a plurality of non-protected packets at the leaf node when a queue at the leaf node is congested. A minimum bandwidth is provided for the flow based on the configured rate of traffic at the leaf node. The leaf node comprises an ingress node or an egress node connected to a fabric. An apparatus is also disclosed herein.

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San Jose, CA, United States of America

Parvin Taheri