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Catalyst 2975 Switch Software Configuration Guide
OL-19720-02
Chapter 6 Managing Switch Stacks
Troubleshooting Stacks
Hardware Loop Example: LINK NOT OK Event
Switch#
show platform stack ports buffer
Stack Debug Event Data Trace
==============================================================
Event type LINK: Link status change
Event type RAC: RAC changes to Not OK
Event type SYNC: Sync changes to Not OK
==============================================================
Event Stack Stack PCS Info Ctrl-Status Loopback Cable
Count Port IOS / HW length
========= ===== =================================== =========== ======== ========
Event type: LINK OK Stack Port 2
0000000005 1 FF08FF00 0001FBD3 0801080B EFFFFFFF 0C100CE6 No /No No cable
0000000005 2 FF08FF00 8603E4A9 5555FFFF FFFFFFFF 0C100CE6 No /No 50 cm
Event type: RAC
0000000006 1 FF08FF00 0001FC14 08050204 EFFFFFFF 0C100CE6 No /No No cable
0000000006 2 FF08FF00 8603E4A9 5555FFFF FFFFFFFF 0C100CE6 No /No 50 cm
Event type: LINK NOT OK Stack Port 2
0000000939 1 FF08FF00 00016879 00010000 EFFFFFFF 0C100C14 No /No No cable
0000000939 2 FF08FF00 0001901F 00000000 FFFFFFFF 0C100C14 No /No No cable
Event type: RAC
0000000940 1 FF08FF00 000168BA 00010001 EFFFFFFF 0C100C14 No /No No cable
0000000940 2 FF08FF00 0001905F 00000000 FFFFFFFF 0C100C14 No /No No cable
Event type: LINK OK Stack Port 1
0000000956 1 FF08FF00 86034DAC 5555FFFF FFFFFFFF 1CE61CE6 Yes/Yes No cable
0000000956 2 FF08FF00 86033431 55AAFFFF FFFFFFFF 1CE61CE6 Yes/Yes No cable
Event type: LINK OK Stack Port 2
0000000957 1 FF08FF00 86034DAC 5555FFFF FFFFFFFF 1CE61CE6 Yes/Yes No cable
0000000957 2 FF08FF00 86033431 55AAFFFF FFFFFFFF 1CE61CE6 Yes/Yes No cable
Event type: RAC
0000000958 1 FF08FF00 86034DAC 5555FFFF FFFFFFFF 1CE61CE6 Yes/Yes No cable
0000000958 2 FF08FF00 86033431 55AAFFFF FFFFFFFF 1CE61CE6 Yes/Yes No cable
Finding a Disconnected StackWiseStackCable
Stack cables connect all stack members. Port 2 on Switch 1 connects to Port 1 on Switch 2.
This is the port status for the members:
Switch#
show switch stack-ports summary
Switch#/ Stack Neighbor Cable Link Link Sync # In
Port# Port Length OK Active OK Changes Loopback
Status To LinkOK
-------- ------ -------- -------- ---- ------ ---- --------- --------
1/1 OK 2 50 cm Yes Yes Yes 0 No
1/2 OK 2 50 cm Yes Yes Yes 0 No
2/1 OK 1 50 cm Yes Yes Yes 0 No
2/2 OK 1 50 cm Yes Yes Yes 0 No
If you disconnect the cable from Port 2 on Switch 1, these messages appear:
%STACKMGR-4-STACK_LINK_CHANGE: Stack Port 1 Switch 2 has changed to state DOWN
%STACKMGR-4-STACK_LINK_CHANGE: Stack Port 2 Switch 1 has changed to state DOWN