Whole Stack Neighbor problem

Unanswered Question
Jan 6th, 2010

Hi,

I have 7 numbers of 3750 Cisco Switch, they all are part of single stack. I found, there was flapping in the stack ports of Sw-3 (port-2) and Sw-4(port-1) which are directly connected with stack cable.

I have replaced the stack cable with new one, but now whole stack is flapping. Please help, I have attached the log below.

3730741: Jan  6 00:21:34.368: %STACKMGR-4-STACK_LINK_CHANGE: Stack Port 2 Switch3 has changed to state UP
3730742: Jan  6 00:21:35.291: %STACKMGR-4-STACK_LINK_CHANGE: Stack Port 1 Switch 4 has changed to state UP
3730743: Jan  6 00:21:36.382: %STACKMGR-4-STACK_LINK_CHANGE: Stack Port 2 Switch 3 has changed to state DOWN
3730744: Jan  6 00:21:37.304: %STACKMGR-4-STACK_LINK_CHANGE: Stack Port 1 Switch4 has changed to state DOWN
3730745: Jan  6 00:21:38.319: %STACKMGR-4-STACK_LINK_CHANGE: Stack Port 1 Switch 4 has changed to state UP

STACK#sh switch neighbor
  Switch #    Port 1       Port 2
  --------    ------       ------
      1        None          None
      2         1             3
      3         2            None
      4        None          None
      5         4             6
      6        None          None
      7        None           1


STACK#sh switch
Switch/Stack Mac Address : 0011.bbf1.4780
                                           H/W   Current
Switch#  Role   Mac Address     Priority Version  State
----------------------------------------------------------
*1       Master 0011.bbf1.4780     15     0       Ready
2       Member 0017.9409.4600     13     0       Ready
3       Member 0012.4347.0800     11     0       Ready
4       Member 0017.5ac4.2c00     9      0       Ready
5       Member 0017.95a9.5600     7      0       Ready
6       Member 000f.f749.5580     5      0       Ready
7       Member 0017.957f.5c00     3      0       Ready

STACK#sh swit stack-ring sp

Stack Ring Speed        : 16G
Stack Ring Configuration: Half
Stack Ring Protocol     : StackWise

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batsoton2006 Wed, 01/06/2010 - 07:30

I have had this problem many times.(Installed 25 stacks recently)

These 3750 Stack cables can be iffy. Do not tighten the screws too much. Finger tight is usually enough.

Leo Laohoo Wed, 01/06/2010 - 13:28

Recently I've noticed a number of faulty stack cables or faulty switch stack controllers.  Try the following diagnostic commands: diagnostic start switch


Warning:  The command is very disruptive!

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