Cisco stack auto-upgrade

[binoy.baby]

HI,

Can some one help be to clear the doubt regarding Stack 3750 Switch , I have an existing Switch with the IOS (

c3750e-universalk9-mz.122-55.SE3.bin )  ,  going to add a new 3750 swith to the Existing one this has the IOS  (

c3750e-universalk9-mz.122-55.SE5.bin)  which is higher , both the switches are in Auto upgrade ,  Existing Switch is master , Suppose if the connect the New switch and power it on which switch will get upgraded Existing Switch or  new switch will get downgraded to the OS of Existing ?

Existing-Core #sh switch        flash:

   2 -rwx       3853 Oct 11 2013 13:15:45 +00:00 private-config.text

   3 -rwx         676 Oct 10 2013 15:37:22 +00:00 vlan.dat

453 -rwx       3096 Oct 11 2013 13:15:45 +00:00 multiple-fs

   5 -rwx       14205 Oct 11 2013 13:15:45 +00:00 config.text

   6 drwx         512   Mar 1 1993 00:09:47 +00:00 c3750e-universalk9-mz.122-55.SE3

57671680 bytes total (22457856 bytes free)

===========================================NEW SWITCH=============================

New-Switch#sh flash:

512 -rwx       1048   Mar 1 1993 00:01:21 +00:00 multiple-fs

   3 drwx         512   Mar 1 1993 00:08:25 +00:00 c3750e-universalk9-mz.122-55.SE5

57671680 bytes total (22032384 bytes free)

c3750e-universalk9-mz.122-55.SE5/c3750e-universalk9-mz.122-55.SE5.bin

[daniel.dib · Accepted solution]

According to http://www.cisco.com/en/US/docs/switches/lan/catalyst3750/software/troubleshooting/switch_stacks.html#wp66281

The new member would be downgraded:

"If the stack master detects that the software on a new switch does not match, it upgrades (or downgrades) the new switch with the active image that is running on the switch stack by using the automatic upgrade (auto-upgrade) and the automatic advise (auto-advise) features."

You could always prepare the new switch with the same version as master though or upgrade the existing switches in the stack to the same version.

Daniel Dib
CCIE #37149

[binoy.baby]

Thank you.