Cisco Catalyst 2960 Software Configuration Manual page 193

Chapter 7 Managing Switch Stacks
Understanding Auto-Upgrade and Auto-Advise
When the software detects mismatched software and tries to upgrade the switch in version-mismatch
mode, two software processes are involved: automatic upgrade and automatic advise.
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The automatic upgrade (auto-upgrade) process includes an auto-copy process and an auto-extract
process. By default, auto-upgrade is enabled (the boot auto-copy-sw global configuration command
is enabled). You can disable auto-upgrade by using the no boot auto-copy-sw global configuration
command on the master. You can check the status of auto-upgrade by using the show boot privileged
EXEC command and by checking the Auto upgrade line in the display.
Auto-copy automatically copies the software image running on any member to the switch in
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version-mismatch mode to upgrade (auto-upgrade) it. Auto-copy occurs if auto-upgrade is
enabled, if there is enough flash memory in the switch in version-mismatch mode, and if the
software image running on the stack is suitable for the switch in version-mismatch mode.
A switch in version-mismatch mode might not run all released software. For example, new
Note
switch hardware is not recognized in earlier versions of software.
Automatic extraction (auto-extract) occurs when the auto-upgrade process cannot find the
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appropriate software in the stack to copy to the switch in version-mismatch mode. In that case,
the auto-extract process searches all switches in the stack, whether they are in version-mismatch
mode or not, for the tar file needed to upgrade the switch stack or the switch in
version-mismatch mode. The tar file can be in any flash file system in the stack (including the
switch in version-mismatch mode). If a tar file suitable for the switch in version-mismatch mode
is found, the process extracts the file and automatically upgrades that switch.
The auto-upgrade (auto-copy and auto-extract) processes start a few minutes after the mismatched
software is detected.
When the auto-upgrade process is complete, the switch that was in version-mismatch mode reloads
and joins the stack as a fully functioning member. If you have both stack cables connected during
the reload, network downtime does not occur because the stack operates on two rings.
Automatic advise (auto-advise)—when the auto-upgrade process cannot find appropriate
version-mismatch member software to copy to the switch in version-mismatch mode, the
auto-advise process tells you the command (archive copy-sw or archive download-sw privileged
EXEC command) and the image name (tar filename) needed to manually upgrade the switch stack
or the switch in version-mismatch mode. The recommended image can be the running stack image
or a tar file in any flash file system in the stack (including the switch in version-mismatch mode). If
an appropriate image is not found in the stack flash file systems, the auto-advise process tells you
to install new software on the stack. Auto-advise cannot be disabled, and there is no command to
check its status.
The auto-advise software does not give suggestions when the stack software and the software of the
switch in version-mismatch mode do not contain the same feature sets.The same events occur when
cryptographic and noncryptographic images are running.
You can use the archive-download-sw /allow-feature-upgrade privileged EXEC command to
allow installing an image with a different feature set.
Catalyst 2960 and 2960-S Switches Software Configuration Guide, Release 15.0(1)SE
Understanding Stacks
7-11