Cisco Catalyst 4500 Series Configuration Manual page 209

Configuring the Cisco IOS In-Service Software
Upgrade Process
Starting with Cisco IOS 12.2(31)SGA, ISSU is supported on the Catalyst 4500. All line cards are
Note
supported.
Operating on redundant systems, 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. This 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.
This section includes these topics:
Prerequisites to Performing ISSU, page 5-2
•
About ISSU, page 5-3
•
Performing the ISSU Process, page 5-15
•
Related Documents, page 5-39
•
Note For complete syntax and usage information for the switch commands used in this chapter, first look at
the Cisco Catalyst 4500 Series Switch Command Reference and related publications at this location:
http://www.cisco.com/en/US/products//hw/switches/ps4324/index.html
If the command is not found in the Catalyst 4500 Series Switch Command Reference, it will be found in
the larger Cisco IOS library. Refer to the Cisco IOS Command Reference and related publications at this
location:
http://www.cisco.com/en/US/products/ps6350/index.html
OL-25340-01
C H A P T E R
Software Configuration Guide—Release IOS XE 3.3.0SG and IOS 15.1(1)SG
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