# Upgrading Router Software with Unified ISSU

To upgrade your router software by means of unified ISSU, perform the following steps.

1. Disable autosynchronization.
   host1(config)#disable-autosync
2. Copy the new release to the router.

   | Note: Be sure to specify the correct software release (.rel) filename for the router you are using, as described in the section Identifying the Software Release File in the JunosE System Basics Configuration Guide.

   host1#copy /incoming/releases/ftpserver/quebec2.rel R2.rel
3. Save the current configuration.
   host1#copy running-configuration system2.cnf
4. Determine whether the router hardware and the software release meet the criteria required for unified ISSU to operate successfully by using one of the following commands:
   host1#show issu host1#show issu brief host1#show issu detail
5. Arm the primary SRP module with the upgrade release.
   host1#boot system R2.rel

   | Note: You must arm any hotfixes that need to be loaded with the new release after you have armed the new release. The hotfixes are supplied when the modules to which they apply are rebooted.

6. Synchronize the NVS file system of the redundant SRP module with that of the primary SRP module.
   host1#synchronize

   Because the redundant SRP module is running a different release than the armed release, the module automatically reboots and runs the armed (upgrade) release, R2.rel.

   Wait for the redundant SRP module to boot, initialize, and reach the standby state. At this point, the REDUNDANT LED on the module is illuminated and the ONLINE LED is off. The State field in the show version display indicates that the redundant module is in the standby state.

7. Synchronize the file system of the primary module with that of the redundant module.

   The NVS file systems of the two SRP modules are unsynchronized because the redundant SRP module rebooted.

   host1#synchronize
8. Reenable autosynchronization.
   host1(config)#no disable-autosync
9. (ERX1440 only) Configure the ERX1440 license key.
   host(config)#license issu xyz123abc License for ISSU configured.
10. Determine whether unified ISSU is in the Idle state and whether all upgrade requirements have been met.
    host1#show issu

    | Note: If the results indicate that some requirements are not met, you must correct this situation before proceeding.

11. Ensure that stateful SRP switchover is configured on the router.
    host1#show redundancy srp

    If it is not already configured, do so now.

    host1(config)#redundancy host1(config-redundancy)#mode high-availability
12. For each configured protocol on the router and its neighbors, ensure that graceful restart is configured. See the relevant protocol configuration chapters in the JunosE document set for information about configuring graceful restart.
13. Begin the initialization phase of the unified in-service software upgrade.
    host1#issu initialize

    The CLI displays the status of the initialization as it proceeds.

14. (Optional) From a different CLI session, display the progress of the initialization.
    host1#show issu

    Unified ISSU must be in the Initialized state before you proceed to the next step. The time required for initialization varies with the system load and the complexity of the router configuration.

15. Start the upgrade phase.
    host1#issu start

    The router switches to the redundant SRP module running the upgrade release, R2.rel. Significant upgrade milestones are displayed as they occur.

16. When the console indicates that the upgrade is completed, you can verify that the router is back in the idle state and running the upgrade release, R2.rel.
    host1#show issu

    You can also verify the status of the SRP modules and line modules, as well as the running and armed releases.

    host1#show version

#### Related Documentation

- issu initialize
- issu start
- issu stop
- license issu