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Migration, Upgrade, and Downgrade Instructions


This section contains the procedure to upgrade Junos OS, and the upgrade and downgrade policies for Junos OS for the PTX Series. Upgrading or downgrading Junos OS can take several hours, depending on the size and configuration of the network.

Upgrading Using Unified ISSU


Unified ISSU is not supported in Junos OS Release 16.2R1.

Unified in-service software upgrade (ISSU) enables you to upgrade between two different Junos OS releases with no disruption on the control plane and with minimal disruption of traffic. Unified in-service software upgrade is only supported by dual Routing Engine platforms. In addition, graceful Routing Engine switchover (GRES) and nonstop active routing (NSR) must be enabled. For additional information about using unified in-service software upgrade, see the High Availability Feature Guide for Routing Devices.

For information on ISSU support across platforms and Junos OS releases, see the In-Service Software Upgrade (ISSU) Web application.

Upgrading a Router with Redundant Routing Engines

If the router has two Routing Engines, perform a Junos OS installation on each Routing Engine separately to avoid disrupting network operation as follows:

  1. Disable graceful Routing Engine switchover (GRES) on the master Routing Engine and save the configuration change to both Routing Engines.

  2. Install the new Junos OS release on the backup Routing Engine while keeping the currently running software version on the master Routing Engine.

  3. After making sure that the new software version is running correctly on the backup Routing Engine, switch over to the backup Routing Engine to activate the new software.

  4. Install the new software on the original master Routing Engine that is now active as the backup Routing Engine.

For the detailed procedure, see the Installation and Upgrade Guide.

Basic Procedure for Upgrading to Release 16.2

When upgrading or downgrading Junos OS, use the jinstall package. For information about the contents of the jinstall package and details of the installation process, see the Installation and Upgrade Guide. Use other packages, such as the jbundle package, only when so instructed by a Juniper Networks support representative.


Back up the file system and the currently active Junos OS configuration before upgrading Junos OS. This allows you to recover to a known, stable environment if the upgrade is unsuccessful. Issue the following command:


The installation process rebuilds the file system and completely reinstalls Junos OS. Configuration information from the previous software installation is retained, but the contents of log files might be erased. Stored files on the router, such as configuration templates and shell scripts (the only exceptions are the juniper.conf and ssh files), might be removed. To preserve the stored files, copy them to another system before upgrading or downgrading the routing platform. For more information, see the Junos OS Administration Library.


We recommend that you upgrade all software packages out of band using the console because in-band connections are lost during the upgrade process.

To download and install Junos OS Release 16.2R2:

  1. Using a Web browser, navigate to the All Junos Platforms software download URL on the Juniper Networks webpage:

  2. Select the name of the Junos OS platform for the software that you want to download.
  3. Select the release number (the number of the software version that you want to download) from the Release drop-down list to the right of the Download Software page.
  4. Select the Software tab.
  5. In the Install Package section of the Software tab, select the software package for the release.
  6. Log in to the Juniper Networks authentication system using the username (generally your e-mail address) and password supplied by Juniper Networks representatives.
  7. Review and accept the End User License Agreement.
  8. Download the software to a local host.
  9. Copy the software to the routing platform or to your internal software distribution site.
  10. Install the new jinstall package on the router.Note

    We recommend that you upgrade all software packages out of band using the console because in-band connections are lost during the upgrade process.

    All customers except the customers in the Eurasian Customs Union (currently composed of Armenia, Belarus, Kazakhstan, Kyrgyzstan, and Russia) can use the following package:

    user@host> request system software add validate reboot source/junos-install-ptx-x86-64-16.2R2.9.tgz

    Customers in the Eurasian Customs Union (currently composed of Armenia, Belarus, Kazakhstan, Kyrgyzstan, and Russia) can use the following package (limited encryption Junos OS package):

    user@host> request system software add validate reboot source/junos-install-ptx-x86-64-16.2R2.9-limited.tgz

    Replace the source with one of the following values:

    • /pathname—For a software package that is installed from a local directory on the router.

    • For software packages that are downloaded and installed from a remote location:

      • ftp://hostname/pathname

      • http://hostname/pathname

      • scp://hostname/pathname (available only for Canada and U.S. version)

    The validate option validates the software package against the current configuration as a prerequisite to adding the software package to ensure that the router reboots successfully. This is the default behavior when the software package being added is a different release.

    Adding the reboot command reboots the router after the upgrade is validated and installed. When the reboot is complete, the router displays the login prompt. The loading process might take 5 to 10 minutes.

    Rebooting occurs only if the upgrade is successful.


You need to install the Junos OS software package and host software package on the routers with the RE-PTX-X8 Routing Engine. For upgrading the host OS on this router with VM Host support, use the junos-vmhost-install-x.tgz image and specify the name of the regular package in the request vmhost software add command. For more information, see the VM Host Installation topic in the Installation and Upgrade Guide.


After you install a Junos OS Release 16.2 jinstall package, you cannot return to the previously installed software by issuing the request system software rollback command. Instead, you must issue the request system software add validate command and specify the jinstall package that corresponds to the previously installed software.


Most of the existing request system commands are not supported on routers with RE-PTX-X8 Routing Engines. See the VM Host Software Administrative Commands in the Installation and Upgrade Guide.

Changes Planned For Future Releases

  • Change in default behavior of traffic engineering shortcuts in labeled IS-IS segment routing (MX and PTX Series)—In Junos OS Releases 15.1F6, 15.1F7, 16.2R1, and 17.1R1, traffic engineering shortcuts are enabled for labeled IS-IS segment routes, when you configure shortcuts at the following hierarchy levels.

    • [edit protocols is-is traffic-engineering family inet] for IPv4 traffic.

    • [edit protocols is-is traffic-engineering family inet6] for IPv6 traffic.

    Starting with Junos OS Release 17.2R1 onwards, explicit configuration of traffic engineering shortcuts for labeled IS-IS segment routes is planned to be introduced by configuring shortcuts at the following hierarchy levels:

    • [edit protocols is-is traffic-engineering family inet-mpls] for IPv4 traffic.

    • [edit protocols is-is traffic-engineering family inet6-mpls] for IPv6 traffic.