C H A P T E R 6 Configuring The Cisco Ios Xe In Service Software Upgrade Process - Cisco Catalyst 4500 Series Configuration Manual

Prerequisites to Performing ISSU
Related Documents
Related Topic
Performing ISSU
Information about Cisco Nonstop Forwarding
Information about Stateful Switchover
Prerequisites to Performing ISSU
Before performing ISSU, you must meet these prerequisites:
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Software Configuration Guide—Release IOS XE 3.3.0SG and IOS 15.1(1)SG
6-2
The type of the existing and target image must match. You cannot upgrade from a Universal Lite
image to a Universal image (and vice versa) without experiencing several minutes of traffic loss. The
same restriction applies between crypto and non-crypto images.
The active and the standby supervisor engines must have the same supervisor engine hardware (same
model, same memory, and so on).
The new and old Cisco IOS XE software images must be loaded into the file systems (bootflash, SD
card, or USB) of both the active and the standby supervisor engines before you begin the ISSU
process.
The old software image should be available either in bootflash, SD card, or USB and the system
should have been booted from one of these locations because the boot variable must be changed
before the ISSU process starts.
auto-boot must be enabled for ISSU to succeed.
Stateful Switchover (SSO) must be configured and the standby supervisor engine should be in
STANDBY HOT state.
These commands indicate whether SSO is enabled: show module, show running-config,
show redundancy state.
If you do not have SSO enabled, see the Stateful Switchover document for further information on
how to enable and configure SSO.
Nonstop Forwarding (NSF) must be configured and working properly. If you do not have NSF
enabled, see the Cisco Nonstop Forwarding document for further information on how to enable and
configure NSF.
Before you perform ISSU, ensure that the file system for both the active and the standby supervisor
engines contains the new ISSU-compatible IOS XE software. The current Cisco IOS XE version
running in the system must also support ISSU.
You can enter various commands on the Catalyst 4500 series switch to determine supervisor engine
versioning and Cisco IOS XE software compatibility. Alternatively, you can use the ISSU
application on Cisco Feature Navigator to determine this.
Chapter 6 Configuring the Cisco IOS XE In Service Software Upgrade Process
Document Title
Cisco IOS Software: Guide to Performing In Service Software
Upgrades
Cisco Nonstop Forwarding
http://www.cisco.com/en/US/docs/ios/12_2s/feature/guide/fsnsf20s.
html
Stateful Switchover
http://www.cisco.com/en/US/docs/ios/12_0s/feature/guide/sso120s.
html
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