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High Availability

  • Unified ISSU support on QFX5120-48Y—Starting in Junos OS Release 21.4R1, QFX5120-48Y switches support unified in-service software upgrade (ISSU). The unified ISSU feature enables you to upgrade between two different Junos OS releases with minimal disruption on the control plane and with minimal disruption of traffic.

    Use the request system software in-service-upgrade package-name.tgz command to use unified ISSU. Use the request system software validate in-service-upgrade package-name.tgz command to verify that your device and target release are compatible.


    QFX5120-48Y switches provide unified ISSU support only if the Cancun versions of the chipset SDK are the same for the current version and the version you are upgrading to. See, High Availability.

    [See Getting Started with Unified In-Service Software Upgrade and Understanding In-Service Software Upgrade (ISSU).]