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Performing an In-Service Software Upgrade (ISSU) in ACX5000 Series Routers

You can use an in-service software upgrade to upgrade the software running on the router with minimal traffic disruption during the upgrade.

Note:

ISSU is supported in Junos OS Release 15.1X54–D60 and later on ACX5000 Series routers.

This topic covers:

Preparing the Router for Software Installation

Before you begin software installation using ISSU:

Note:

Before you perform an in-service software upgrade, if applicable, remove the set system internet-options no-tcp-reset drop-all-tcp command from the configuration, otherwise the upgrade will fail and an error message will be displayed.

  • Ensure that nonstop active routing (NSR) and nonstop bridging (NSB) are enabled. If enabled, disable graceful restart (GR), because NSR and GR cannot be enabled simultaneously. NSB and GR enable NSB-supported Layer 2 protocols to synchronize protocol information between the primary and backup Routing Engines.

  • If NSR is not enabled (Stateful Replication is Disabled), then enable NSR. NSR requires you to configure graceful Routing Engine switchover (GRES). By default, NSR is disabled.

    • To enable graceful Routing Engine switchover, include the graceful-switchover statement at the [edit chassis redundancy] hierarchy level as user@host#set chassis redundancy graceful-switchover.

    • To enable NSR, include the nonstop-routing statement at the [edit routing-options] hierarchy level as user@host#set routing-options nonstop-routing.

  • Enable nonstop bridging (NSB). Nonstop bridging requires you to configure graceful Routing Engine switchover (GRES). By default, NSB is disabled.

    • To enable graceful Routing Engine switchover, include the graceful-switchover statement at the [edit chassis redundancy] hierarchy level as user@host#set chassis redundancy graceful-switchover.

    • To enable NSB, include the nonstop-bridging statement at the [edit protocols layer2-control] hierarchy level as user@host#set protocols layer2-control nonstop-bridging.

  • (Optional) Back up the system software—Junos OS, the active configuration, and log files—on the router to an external storage device with the request system snapshot command.

On ACX5000 line of routers, you need to consider the following feature before performing ISSU:

  • ISSU supports link fault management (LFM) timeout sessions of 1 second interval. During ISSU, you may notice LFM flaps for sessions having timeout interval of less than 1 second.

  • Bidirectional Forwarding Detection (BFD) sessions having timeout interval of less than 1 second need to be reconfigured to 1 second before starting the ISSU process. You can restore the timeout interval to its original value after completing the ISSU process.

  • ISSU supports interval slow (every 30 seconds) for periodic transmission of Link Aggregation Control Protocol (LACP) packets.

  • ISSU supports Virtual Router Redundancy Protocol (VRRP) version 3.

ISSU do not support the following ACX5000 features:.

  • Downgrade to an earlier version of Junos OS software. If you want to install an earlier version of Junos OS software, use the request system software add CLI command.

  • Upgrade of Host OS software.

  • Connectivity fault management (CFM).

  • TWAMP, RPF, RFC2544, and clocksyncd daemon (timing functionality).

  • Mirroring and pseudowire cross connect.

  • IPv6 firewall, IPv6 COS (classification and rewrite), IPv6 VPN, and VPLS mesh group.

  • Virtual Router Redundancy Protocol (VRRP) version 1 and 2.

  • Interval fast (every second) for periodic transmission of Link Aggregation Control Protocol (LACP) packets. If the periodic interval fast is configured, then you may notice traffic drops because of LACP links going down during ISSU. ACX5000 line of routers can support LACP with fast hello by configuring the fast-hello-issu option (user@host# set protocols lacp fast-hello-issu) on the main router and peer routers before starting ISSU.

    Note:

    The peer router must have Junos OS software to support this functionality.

Upgrading the Software Using ISSU

This procedure describes how to upgrade the software running on a standalone router:

Note:

If the Host OS software needs to be updated, you cannot perform an ISSU. Instead, perform a standard software upgrade.

It is recommended to cleanup any unwanted data from the /var directory (/var/log, /var/tmp) before initiating the ISSU process.

To upgrade the router using ISSU:

  1. Download the software package from the Juniper Networks Support website https://www.juniper.net/support/downloads/junos.html .

    Note:

    To access the download site, you must have a service contract with Juniper Networks and an access account. If you need help obtaining an account, complete the registration form at the Juniper Networks website https://www.juniper.net/registration/Register.jsp .

  2. Go to ACX Series section and select the ACX5000 Series platform software you want to download.

  3. Copy the software package or packages to the router. We recommend that you copy the file to the /var/tmp directory.

  4. Log in to the console connection. Using a console connection allows you to monitor the progress of the upgrade.

  5. Start the ISSU:

    • On the router, enter:

      where package-name.tgz is, for example, jinstall-acx5k-15.1X54-D60.9-domestic-signed.tgz.

    Note:

    During the upgrade, you will not be able to access the Junos OS CLI.

    The router displays status messages similar to the following messages as the upgrade executes:

    Note:

    An ISSU might stop instead of terminate if the FPC is at the warm boot stage. Also, any links that go down and up will not be detected during a warm boot of the Packet Forwarding Engine (PFE).

    Note:

    If the ISSU process stops, you can look at the log files to diagnose the problem. The log files are located at /var/log/vjunos-log.tgz.

  6. Log in after the router reboots. To verify that the software has been upgraded, enter the following command:

  7. Disable or delete the configuration done to enable the ISSU. This includes disabling nonstop active routing (NSR), nonstop bridging (NBR) and graceful Routing Engine (GRES).

Verifying a Unified ISSU

Verify the status of FPCs and their corresponding PICs after the most recent unified ISSU.

Issue the show chassis in-service-upgrade command on the primary Routing Engine.

Display the unified ISSU process messages by using the show log messages command.