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Catalyst 3750-X and 3560-X Switch Software Configuration Guide
OL-21521-01
Chapter 5 Managing Switch Stacks Troubleshooting Stacks
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 1 No
1/2 Absent None No cable No No No 2 No
2/1 Down None 50 cm No No No 2 No
2/2 OK 1 50 cm Yes Yes Yes 1 No
Only one end of the cable connects to a stack port, Port 1 on Switch 2.
The Stack Port Status value for Port 2 on Switch 1 is Absent, and the value for Port 1 on Switch 2 is
Down.
The Cable Length value is No cable.
Diagnosing the problem:
Verify the cable connection for Port 2 on Switch 1.
Port 2 on Switch 1 has a port or cable problem if
The In Loopback value is Yes.
or
The Link OK, Link Active, or Sync OK value is No.
Fixing a Bad Connection Between Stack Ports
Stack cables connect all members. Port 2 on Switch 1 connects to Port 1 on Switch 2.
This is the port status:
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 1 No
1/2 Down None 50 cm No No No 2 No
2/1 Down None 50 cm No No No 2 No
2/2 OK 1 50 cm Yes Yes Yes 1 No
Diagnosing the problem:
The Stack Port Status value is Down.
Link OK, Link Active, and Sync OK values are No.
The Cable Length value is 50 cm. The switch detects and correctly identifies the cable.
The connection between Port 2 on Switch 1 and Port 1 on Switch 2 is unreliable on at least one of the
connector pins.