Identifying Loopback Problems - Cisco Catalyst 3560-X Software Configuration Manual

Chapter 1 Managing Switch Stacks
Table 1-5
Field
Link OK
Link Active
Sync OK
# Changes to LinkOK
In Loopback

Identifying Loopback Problems

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OL-25303-03
show switch stack-ports summary Command Output (continued)
Description
This shows if the link is stable.
The link partner is a stack port on a neighbor switch.
This shows if the stack port is in the same state as its link partner.
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.
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
No—The link partner receives invalid protocol messages from the
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port.
Yes—The link partner receives valid protocol messages from the
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port.
No—The port cannot send traffic to the link partner.
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Yes—The port can send traffic to the link partner.
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No—The link partner does not send valid protocol messages to the
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stack port.
Yes—The link partner sends valid protocol messages to the port.
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No—At least one stack port on the member has an attached stack
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cable.
• Yes—None of the stack ports on the member has an attached stack
cable.
Catalyst 3750-X and 3560-X Switch Software Configuration Guide
Troubleshooting Stacks
1-33