Alarm of Uplink redundancy degraded on virtual switch

Hi all,

I have the received from different NICs the error below (this is just from one out of 3 NIC). server is already in production and it was running smoothly. Cables were checked, no issues.

VMware vCenter - Alarm alarm.NetworkRedundancyDegradedAlarm] Uplink redundancy degraded on virtual switch "vSwitch0". Physical NIC vmnic3 is down. Affected portgroups: "xxxxx".

Have someone experienced some similar?

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2 Replies

Hi Marcelo,

I've seen this multiple times and it could be a number of issues that you need to work through by process of elimination.

The first things to check are firmware and drivers, ensuring you have the correct levels for the specific hardware and ESXi build version. If these are onboard ports, collect logs and send them to your hardware vendor for analysis.

Next check the switch ports for CRC errors, caused by faulty SFP, bad port or even a damaged cable (sometimes not visible). Replace the ethernet cable to rule it out.

Review the release notes for the ESXi build number to identify any known issues. Simpler to check with Skyline if you have it implemented.

You'll probably find that the port stays up for a while if you manually bring it up but then goes down again. This behaviour will continue to occur until you're identified and resolved the root cause.



vExpert 2014 - 2022 | VCP6-DCV | | @JonMunday77
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Are you aggregating links? As in making a channel of multiple physical nic's? In that case make sure the settings on the host side match the settings on the switch side for type and settings.


Link aggregation group: lag1

Name lag1
Number of ports 2
Mode Active
Timeout Slow
Load balancing mode Source and destination IP address, TCP/UDP port and VLAN
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