Dell Networking: S4100 Series Switches Using Port Monitoring Drop Traffic
Summary: Traffic impact occurs due to a split-brain scenario. The issue arises when using an S4100 switch plus virtual link trunk (VLT) configuration and a monitoring session (port-mirroring).
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Instructions
Issue Description
The issue typically arises when the VLTi link is declared down on one VLT peer, while it remains "up" on the other VLT peer. The physical links between switches never go down, and the VLT member ports remain up.
A log review may elicit no obvious logs to tell us what failed. Logs may show:
(bo1000) entered disabled state
orMultiple bit ECC error
followed by (bo1000) entered disabled state
within 60 s.
Temporary Solutions
Customers have found that rebooting the switch temporarily resolves the issue, although it may recur at any time. Documented cases show the issue recurring between one day and six months later. Customers can disable port-monitoring as a workaround. Customers can also use an S5200 model switch instead of the S4100 model.
Permanent Solution
Dell engineering is working on this issue, but there is no current ETA on a permanent resolution.
Affected Products
PowerSwitch S4112F-ON/S4112T-ON, PowerSwitch S4128F-ON/S4128T-ON, PowerSwitch S4148F-ON/S4148T-ON/S4148FE-ON, PowerSwitch S4148U-ONArticle Properties
Article Number: 000228204
Article Type: How To
Last Modified: 03 Feb 2026
Version: 5
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