Hi all,
I have a stack of 4 3750 Switches.
1. WS-C3750G-12S
2. WS-C3750G-12S
3. WS-C3750X-48P
4. WS-C3750X-48P
The stack cable connected to Switch 1 Port 1 and Switch 4 Port 2 will not come back online. The logs show that there was a Stack line change.
Here is the Log:
.May 18 05:45:52: %STACKMGR-4-STACK_LINK_CHANGE: Stack Port 2 Switch 4 has changed to state DOWN
.May 18 05:45:53: %STACKMGR-4-STACK_LINK_CHANGE: Stack Port 1 Switch 1 has changed to state UP
.May 18 05:45:52: %STACKMGR-4-STACK_LINK_CHANGE: Stack Port 2 Switch 4 has changed to state DOWN
.May 18 05:45:53: %STACKMGR-4-STACK_LINK_CHANGE: Stack Port 1 Switch 1 has changed to state UP
I have replaced the 1 meter Stack cable from Switch 1 to Switch 4 three times and it still does not come back online.
This is the part that is interesting.. I have disconnected Port 1 Switch 4 and connected it to Port 2 Switch 4 and then Switch 4 came back online. This made me think Port 2 on Switch 4 was working correctly.
Then I disconnected Port 2 Switch 1 and connected it to Port 1 Switch 1 and then Switch 1 came back online..
Output from "Show switch stack-port Summary"
Any help would be great.
Hi,
You have done all necessary testing and swapping. It maybe that you have a bad stack port on one of the switches.
Problem: StackWise Port is Flapping
These conditions might cause StackWise port flapping:
•
An unreliable or intermittent (bad) connection between a StackWise cable connector and the switch stack port connector
•A defective StackWise cable
•A defective StackWise interface on a switch
When one or more StackWise ports are flapping, the source of the problem is probably an unreliable connection between a StackWise cable and a StackWise switch port.
If you suspect StackWise port flapping, first verify that the retainer screws are adequately tightened and fully seated against the connector shell. Make sure both retainer screws are tightened the same amount. In some cases you need to disconnect and reconnect the cable while you are troubleshooting, but do not test the connection unless the retainer screws are firmly holding the connector.
An unreliable StackWise connection might produce a similar error message:
#
STACKMGR-4-STACK_LINK_CHANGE: Stack Port 1 Switch 1 has changed to state UP
STACKMGR-4-STACK_LINK_CHANGE: Stack Port 1 Switch 1 has changed to state DOWN
STACKMGR-4-STACK_LINK_CHANGE: Stack Port 1 Switch 1 has changed to state UP
STACKMGR-4-STACK_LINK_CHANGE: Stack Port 1 Switch 1 has changed to state DOWN
STACKMGR-4-STACK_LINK_CHANGE: Stack Port 1 Switch 1 has changed to state UP
STACKMGR-4-STACK_LINK_CHANGE: Stack Port 1 Switch 1 has changed to state DOWN
HTH
