Understanding Nonstop Software Upgrade On Ex Series Switches; How An Nssu Works - Juniper JUNOS OS 10.4 - FOR EX REV 1 Manual

Complete Software Guide for Junos

Understanding Nonstop Software Upgrade on EX Series Switches

How an NSSU Works

1176
®
OS for EX Series Ethernet Switches, Release 10.4
Nonstop software upgrade (NSSU) enables you to upgrade the software running on a
Juniper Networks EX8200 Ethernet Switch using a single command and with minimal
disruption to network traffic. NSSU is supported on standalone EX8200 switches with
redundant Routing Engines that are running Junos OS Release 10.4 or later.
Performing an NSSU provides these benefits:
No disruption to the control plane—An NSSU takes advantage of graceful Routing
Engine switchover (GRES) and nonstop active routing (NSR) to ensure no disruption
to the control plane. During the upgrade process, interface, kernel, and routing protocol
information is preserved.
Minimal traffic disruption—By default, an NSSU upgrades each line card 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. You can 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 upgrading each line card one at a time can increase the amount of time it
takes to perform an upgrade, you can optionally configure line-card upgrade groups.
The line cards in an upgrade group are upgraded simultaneously, reducing the amount
of time it takes to complete an upgrade.
Reduction of operator effort—You execute an NSSU with a single CLI command,
eliminating the need to manually upgrade each Routing Engine separately.
This topic covers:
How an NSSU Works on page 1176
NSSU and Junos OS Release Support on page 1177
Overview of NSSU Configuration and Operation on page 1177
When you request an NSSU:
The switch verifies that:
1.
Both Routing Engines are online and running the same software version.
Both Routing Engines have sufficient storage space for the new software image.
Graceful Routing Engine switchover and nonstop active routing are enabled.
The switch installs the new software image on the backup Routing Engine and reboots
2.
it.
The switch resynchronizes the backup Routing Engine to the master Routing Engine.
3.
Copyright © 2010, Juniper Networks, Inc.