Cisco Catalyst 3560-X

1-33
Catalyst 3750-X and 3560-X Switch Software Configuration Guide
OL-25303-03
Chapter 1 Managing Switch Stacks
Troubleshooting Stacks
Identifying Loopback Problems
• Software Loopback, page 1-34
• Software Loopback Example: No Connected Stack Cable, page 1-35
• Software Loopback Examples: Connected Stack Cables, page 1-35
• Hardware Loopback, page 1-36
• Hardware Loopback Example: LINK OK event, page 1-36
• Hardware Loop Example: LINK NOT OK Event, page 1-37
Link OK This shows if the link is stable.
The link partner is a stack port on a neighbor switch.
• No—The link partner receives invalid protocol messages from the
port.
• Yes—The link partner receives valid protocol messages from the
port.
Link Active This shows if the stack port is in the same state as its link partner.
• No—The port cannot send traffic to the link partner.
• Yes—The port can send traffic to the link partner.
Sync OK
• No—The link partner does not send valid protocol messages to the
stack port.
• Yes—The link partner sends valid protocol messages to the port.
# Changes to LinkOK This shows the relative stability of the link.
If a large number of changes occur in a short period of time, link flapping
can occur.
In Loopback
• No—At least one stack port on the member has an attached stack
cable.
• Yes—None of the stack ports on the member has an attached stack
cable.
Table 1-5 show switch stack-ports summary Command Output (continued)
Field Description