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Configure Global Load Balancing for your AI Fabric

Apstra version 6.0 comes with a default Dynamic Load Balancing (DLB) policy that you can assign to devices in the blueprint. The image below shows the default DLB policy settings. Note that Global Load Balancing (GLB) is disabled by default.


To create and assign a DLB policy with GLB enabled.

  1. From within your blueprint, navigate to Staged > Fabric Settings > Load Balancing.
  2. Select Load Balancing Policies on the right > Create Load Balancing Policy.
  3. Enter a name for your policy, and select DLB as the Load Balancing Mode.
  4. Select Flowlet or Per Packet mode for DLB Mode.
  5. (Optional) Set the following Flowlet Options:

    • Inactivity Interval: Configurable value for the flowlet inactivity timer. When the timer expires, the flowlet traffic tuple is removed from hardware and software caches and freed from allocations. The default value is 256 microseconds.

    • Flowset Table Size: Number of flowset (macro-flow) entries in DLB hash bucket. The default bucket size is 256 entries.

    • Quality Delta: The difference in quality between the current stream member and the member available for reassignment. Set to 0 to disable reassignment of flows.

    • Probability Threshold: The probability threshold that reactive path rebalancing uses to reassign the existing flow to a better member.

  6. (Optional) Set the Sampling Rate. If left blank, no configuration is applied to the device.
    The Sampling Rate is the rate at which ECMP members update link quality based on egress port load.
  7. For GLB Mode, select Helper Only or Load Balancer Only, depending on the type of device being configured.
  8. (Optional) Define the following GLB Options:

    • Message TX Interval: The interval (in microseconds) at which the GLB app transmits messages about link quality, regardless of any change in quality state. The default value is 10ms.

    • Monitor Interval: The interval (in microseconds) at which the GLB app transmits messages about link quality, if quality has changed from the previous state. This is independent of msg_tx_interval. The default value is 20ms.

    • Update Interval: The interval (in microseconds) that the GLB app updates the remote quality in hardware. The default value is 20ms.

  9. (Optional) Define the following Egress Quantization settings:

    • Quantization Min: The minimum percentage of link utilization at which a flowset packet entry is either discarded, or considered an elephant flow. The default is 20% in flowlet mode and 80% in per-packet mode.

    • Quantization Max: The maximum percentage of link utilization at which a flowset packet entry is either discarded, or considered an elephant flow. The default is 50% in flowlet mode and 99% in packet mode.

    • Rate Weightage:

  10. Click Create.
    Your policy displays in the list.

After configuring GLB, you can bulk-assign your load balancing policy to your managed devices. For more information, see Bulk-Assign a Load Balancing Policy.

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