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Example: Configuring Line-Card Upgrade Groups for Nonstop Software Upgrade on EX Series Switches

Nonstop software upgrade (NSSU) enables you to upgrade the software running on an EX Series switch with redundant Routing Engines or on most EX Series Virtual Chassis by using a single command and with minimal disruption to network traffic. By default, NSSU upgrades the software running on line cards one line card at a time.

To reduce the time an NSSU takes, you can configure line-card upgrade groups on an EX6200 or EX8200 switch with redundant Routing Engines or on an EX8200 Virtual Chassis.

This example shows how to configure NSSU to use line-card upgrade groups:


This example uses the following hardware and software components:

  • An EX8200 switch with redundant Routing Engines

  • Junos OS Release 10.4 or later for EX Series switches

Before you begin to configure line-card upgrade groups, ensure that you have configured the link aggregation groups (LAGs) as described in Configuring Aggregated Ethernet Links (CLI Procedure). See Overview and Topology for details about the LAG configurations for this example.

Overview and Topology

In its default configuration, NSSU upgrades each line card in a switch or Virtual Chassis one at a time. Traffic continues to flow through the other line cards while a line card is being restarted as part of the upgrade. This behavior allows you minimize disruption to traffic by configuring link aggregation groups (LAGs) such that the member links of each LAG reside on different line cards. When one member link of a LAG is down, the remaining links are up, and traffic continues to flow through the LAG.

Because the default configuration upgrades each line card one at a time, the upgrade can take some time to complete. You can reduce the time it takes to perform an NSSU by configuring line-card upgrade groups. Instead of being upgraded sequentially, the line cards in an upgrade group are upgraded simultaneously. To achieve minimal traffic disruption, you must define the line-card upgrade groups such that the member links of the LAGs reside on line cards that are in different upgrade groups.


NSSU upgrades the groups in the order that they appear in the configuration (in other words, in the order you configure them).


This example uses an EX8200 switch that has five line cards installed in slots 0 through 4. Two LAGs have been configured:

  • ae0—Has two member links, one on the line card in slot 0 and one on the line card in slot 1.

  • ae1—Has two member links, one on the line card in slot 2 and one on the line card in slot 3.

The interfaces on the line card in slot 4 are not part of either LAG.

To minimize the time an upgrade takes and to ensure that the member links of each LAG are in different upgrade groups, this example configures the following two line-card upgrade groups:

  • group1—Contains the line cards in slots 0, 2, and 4.

  • group2—Contains the line cards in slots 1 and 3.

The line card in slot 4 could be put in either group. It could also be left out of an upgrade group entirely, and it would be upgraded separately after the line cards in the upgrade groups have been upgraded. However, it is more efficient to include it in an upgrade group.

Figure 1 illustrates the topology.

Figure 1: Example Line-Card Upgrade Group TopologyExample Line-Card Upgrade Group Topology


To create line-card upgrade groups, perform these tasks:

CLI Quick Configuration

To quickly create the line-card upgrade groups, copy the following commands and paste them into the switch terminal window:


Step-by-Step Procedure

To create the line-card upgrade groups for an NSSU:

  1. Create the first line-card upgrade group:

  2. Create the second line-card upgrade group:


Display the results of the configuration: