[c-nsp] c3570 stack flapping

[Wyatt Mattias Ishmael Jovial Gyllenvarg]

Hi All

I have a new stack of 2x 3750-12s that was recently stacked.

We just noticed packet loss there and as part of the troubleshooting
we powered of the second switch as the below was flooding the log. (no
connections in it yet)

*Nov 21 20:57:52.834: %STACKMGR-6-STACK_LINK_CHANGE: Stack Port 1
Switch 2 has changed to state DOWN
*Nov 21 20:57:53.589: %STACKMGR-6-STACK_LINK_CHANGE: Stack Port 2
Switch 1 has changed to state DOWN
*Nov 21 20:57:54.587: %STACKMGR-6-STACK_LINK_CHANGE: Stack Port 2
Switch 1 has changed to state UP
*Nov 21 20:57:54.587: %STACKMGR-6-STACK_LINK_CHANGE: Stack Port 2
Switch 1 has changed to state DOWN
*Nov 21 20:57:58.622: %STACKMGR-6-STACK_LINK_CHANGE: Stack Port 2
Switch 1 has changed to state UP
*Nov 21 20:57:59.629: %STACKMGR-6-STACK_LINK_CHANGE: Stack Port 2
Switch 1 has changed to state DOWN
*Nov 21 20:58:01.642: %STACKMGR-6-STACK_LINK_CHANGE: Stack Port 2
Switch 1 has changed to state UP
*Nov 21 20:58:02.900: %STACKMGR-6-STACK_LINK_CHANGE: Stack Port 1
Switch 2 has changed to state UP
*Nov 21 20:58:03.655: %STACKMGR-6-STACK_LINK_CHANGE: Stack Port 2
Switch 1 has changed to state DOWN
*Nov 21 20:58:03.907: %STACKMGR-6-STACK_LINK_CHANGE: Stack Port 1
Switch 2 has changed to state DOWN

This stopped the packet loss.

As this is in production we are not able too perform and more
troubleshooting at the time.

Has anyone seen this before?

Do I have a bad stack cable or a bad stack interface?
Or perhaps a missmatch in ios version (cant double check that they are
the same now) or firmware or hardware?

Best regards
Mattias Gyllenvarg
Skycom AB