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Installing Software on an EX Series devices with a Single Routing Engine


You can use this procedure to upgrade Junos OS on switch with a single Routing Engine.


Junos OS is delivered in signed packages that contain digital signatures to ensure the Juniper Networks software is running. When installing the software packages, Junos OS validates the signatures and the public key certificates used to digitally sign the software packages. If the signature or certificate is found to be invalid (for example, when the certificate validity period has expired or cannot be verified against the root CA stored in the Junos OS internal store), the installation process fails.

To install software upgrades on a switch with a single Routing Engine:

  1. Download the software package as described in Downloading Software Packages from Juniper Networks .
  2. If you have not already done so, connect to the console port on the switch from your management device, and log in to the Junos OS CLI. (For instructions, see Connecting and Configuring an EX Series Switch (CLI Procedure) for EX4300 Series devices.
  3. (Optional) Back up the current software configuration to a second storage option. See the Junos OS Installation and Upgrade Guide for instructions on performing this task.
  4. (Optional) Copy the software package to the switch. We recommend that you use FTP to copy the file to the /var/tmp/ directory.

    This step is optional because Junos OS can also be upgraded when the software image is stored at a remote location. These instructions describe the software upgrade process for both scenarios.

  5. Install the new package on the switch:

    Replace package with one of the following paths:

    • For a software package in a local directory on the switch, use /var/tmp/package.tgz.

    • For a software package on a remote server, use one of the following paths, replacing package with the software package name—for example, jinstall-ex-4300-18.1R3-S2-signed.tgz .

      • ftp://hostname/pathname/package.tgz

      • http://hostname/pathname/package.tgz


    If you need to terminate the installation, do not reboot your switch; instead, finish the installation and then issue the request system software delete package.tgz command, where package.tgz is, for example, jinstall-ex-4300-18.1R3-S2-signed.tgz. This is your last chance to stop the installation.

  6. Reboot the switch to load the installation and start the new software: