Cisco Technology, Inc.

Nokia Solutions and Networks Oy

3 Leaf Systems, Inc.

Krishnan Subramani

Georges Akis

Vinod Mitulal

Peter Clarke Newman

Mohammadreza Alizadeh Attar

Brian Alleyne

Sha Ma

Mohamed Abdul Malick Mohamed Usman

Mimi Dannhardt

Matias Cavuoti

Li-Chuan Egan

Roxanna Ganji

Stephen Russell

Kinjal Shah

Rong Pan

Bryan Chin

Najeeb Imran Ansari

Chetana Nagendra Keltcher

Parvin Taheri

Isam Akkawi

Janakiramanan Vaidyanathan

Liyuan Quan

Michael Woodacre

The subject technology relates to the management of a shared buffer memory in a network switch. Systems, methods, and machine readable media are provided for receiving a data packet at a first network queue from among a plurality of network queues, determining if a fill level of a queue in a shared buffer of the network switch exceeds a dynamic queue threshold, and in an event that the fill level of the shared buffer exceeds the dynamic queue threshold, determining if a fill level of the first network queue is less than a static queue minimum threshold.

Queue protection using a shared global memory reserve

Systems and methods for protecting external memory resources to prevent bandwidth collapse in a network processor. One embodiment is a network processor including an input port configured to receive packets from a source device, on-chip memory configured to store packets in queues, an external memory interface configured to couple the on-chip memory with an external memory providing a backing store to the on-chip memory, and bandwidth monitor configured to measure a bandwidth utilization of the external memory. The network processor also includes a processor configured to apply the bandwidth utilization of the external memory to a congestion notification profile, to generate one or more congestion notifications based on the bandwidth utilization applied to the congestion notification profile, and to send the one or more congestion notifications to the source device to request decreasing packet rate for decreasing the bandwidth utilization of the external memory.

Network processor with external memory protection

Systems and methods for protecting external memory resources to prevent bandwidth collapse in a network processor. One embodiment is a network processor including an input port configured to receive packets from a source device, on-chip memory configured to store packets in queues, and external memory configured to provide a backing store to the on-chip memory. The network processor also includes a processor configured, in response to determining that the source device is unresponsive to a congestion notification, to reduce a size of one or more queues to prevent packets transferring from the on-chip memory to the external memory.

Systems, methods, and computer-readable storage media for monitoring queue occupancy in a network buffer, detecting microbursts, and analyzing the same. An ASIC device can monitor a queue occupancy value of a network buffer, detect when the queue occupancy value exceeds a first predetermined threshold queue occupancy, create a record with a time that the queue occupancy value exceeds the first predetermined threshold queue occupancy, a queue occupancy value at the time that the queue occupancy value exceeds the first predetermined threshold queue occupancy, detect when the queue occupancy value falls below a second predetermined threshold queue occupancy, and determine a maximum queue occupancy value between the time that the queue occupancy value exceeded the first predetermined threshold queue occupancy and a time that the queue occupancy value falls below the second predetermined threshold queue occupancy, and add to the record the maximum queue occupancy value, a time of the maximum queue occupancy value, the time that the queue that the queue occupancy value falls below the second predetermined threshold queue occupancy and the queue occupancy value at the time that the queue occupancy value falls below the second predetermined threshold queue occupancy.

Detecting and measuring microbursts in a networking device

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

A network device receives a packet at a port from among a number of ports. A queue threshold is randomly adjusted for a queue having an output buffer to which the packet is stored. When a fullness of the queue exceeds the adjusted queue threshold, at a time when the packet is to be enqueued into the queue, an action is performed. The action includes either dropping the received packet, or flow-controlling the port at which the packet is received.

Providing source fairness on congested queues using random noise

A network switch includes a buffer to store network packets linked to queues to feed the packets to output ports of the switch associated with the queues. The buffer is shared dynamically among multiple traffic pools. The network switch determines per-pool dynamic thresholds each based on an amount of unused buffer space, and per-queue dynamic thresholds based on amounts of unused buffer space available in the pools with which the queues are associated. The network switch receives packets, and for each received packet, the network switch admits the packet to the pool with which the packet is associated and the queue for which the packet is destined if (i) occupancy of the associated pool is less than the corresponding per-pool dynamic threshold, and (ii) occupancy of the queue for which the packet is destined is less than the corresponding per-queue dynamic threshold, and otherwise drops the packet.

Dynamic protection of shared memory used by output queues in a network device

A network switch includes a buffer to store network packets and packet descriptors (PDs) used to link the packets into queues for output ports. The buffer and PDs are shared among the multiple traffic pools. The switch receives a multicast packet for queues in a given pool. The switch determines if there is unused buffer space available for packets in the given pool based on a pool dynamic threshold, if there is unused buffer space available for packets in each queue based on a queue dynamic threshold for the queue, if there are unused PDs available to the given pool based on a pool dynamic threshold for PDs, and if there are unused PDs available for each queue based on a queue dynamic threshold for PDs for the queue. The network switch admits the packet only into the queues for which all of the determining operations pass.

Dynamic protection of shared memory and packet descriptors used by output queues in a network device

An example embodiment of the present invention provides processes relating to a cache coherence protocol for distributed shared memory. In one process, a DSM-management chip receives a request to modify a block of memory stored on a node that includes the chip and one or more CPUs, which request is marked for fast invalidation and comes from one of the CPUs. The DSM-management chip sends probes, also marked for fast invalidation, to DSM-management chips on other nodes where the block of memory is cached and responds to the original probe, allowing the requested modification to proceed without waiting for responses from the probes. Then the DSM-management chip delays for a pre-determined time period before incrementing the value of a serial counter which operates in connection with another serial counter to prevent data from leaving the node's CPUs over the network until responses to the probes have been received.

Growing community of inventors

San Jose, CA, United States of America

Krishnan Subramani