Specifications

Upgrading Using Unified ISSU

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.

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 13.3

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.

NOTE: 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:

user@host> request system snapshot

NOTE: 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 for Routing Devices.

Release Notes: Junos OS Release 13.3R6 for the EX Series, M Series, MX Series, PTX Series, and T Series