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Increase Shared Buffer Pool by Reducing Dedicated Buffer

Overview

Each device that supports this feature partitions its buffer into dedicated and shared buffers. The dedicated buffer is exclusive to each port, and only that port can use its dedicated buffer. The shared buffer is shared across all ports. When ports have little traffic, their dedicated buffer space is unused. Ports with a lot of traffic cannot use that unused buffer space as long as it is dedicated to other ports. You can effectively increase the global shared buffer space, and therefore the buffer of busy ports, by decreasing the dedicated buffer space from the default value.

You can also define a dedicated buffer profile to increase or decrease the dedicated buffer that is allocated to an individual port. Buffer profiles for individual ports are particularly useful for decreasing dedicated buffer space on unused or down ports, thereby increasing dedicated buffer space available to active ports.

Benefits

  • Allow the device to allocate buffer space more efficiently among ports.

  • Increase the buffer space available to active ports.

  • Busy traffic ports can use more of the buffer space according to their dynamic-threshold value.

Configuration

Note:

Modify the dedicated buffer settings with caution to prevent traffic loss due to buffer misconfiguration.

  1. Configure the dedicated buffer.

    To avoid all ports contending with the shared buffers and to address line-rate traffic, you cannot reduce dedicated buffers below 15 percent of the default value.

    Range of percent: 15 through 100 (percent).

  2. Configure the dedicated buffer profile.

    If the dedicated buffer configured as part of the dedicated-buffer-profile statement exceeds the total available dedicated buffers, the configuration is not effective. The configuration commits but the device logs a system logging error and does not program the configuration in the hardware. ​

    Range of buffer-size: 20 through 50,000 (absolute value in cells).

  3. Configure the dedicated buffer profile on a specific interface.

    You can configure this feature only on physical interfaces. You cannot attach dedicated buffer profiles to aggregated Ethernet parent ports.

  4. Verify the configuration is correct.

Platform Support

See Feature Explorer for platform and release support.