Cisco Cisco IOS Software Releases 12.2 MC
Corporate Headquarters:
Copyright © 2006 Cisco Systems, Inc. All rights reserved.
Cisco Systems, Inc., 170 West Tasman Drive, San Jose, CA 95134-1706 USA
Cisco IOS In Service Software Upgrade Process
The In Service Software Upgrade (ISSU) process allows Cisco IOS software to be updated or otherwise
modified while packet forwarding continues. In most networks, planned software upgrades are a
significant cause of downtime. ISSU allows Cisco IOS software to be modified while packet forwarding
continues, which increases network availability and reduces downtime caused by planned software
upgrades. This document provides information about ISSU concepts and describes the steps taken to
perform ISSU in a system.
modified while packet forwarding continues. In most networks, planned software upgrades are a
significant cause of downtime. ISSU allows Cisco IOS software to be modified while packet forwarding
continues, which increases network availability and reduces downtime caused by planned software
upgrades. This document provides information about ISSU concepts and describes the steps taken to
perform ISSU in a system.
Feature History for ISSU
Release
Modification
12.2(28)SB This
feature was introduced.