Network Uplink Redundancy Lost Alarm on VMware ESXi Host

A vSphere standard or a distributed switch for a host has lost uplink redundancy, according to a warning – Network Uplink Redundancy Lost

The following alarm appears when a host’s redundant physical NICs are not linked to a specific standard or distributed switch:

Host name or IP Network uplink redundancy lost
Network uplink redundancy lost
Network uplink redundancy lost

Cause of Network Uplink Redundancy Lost alarm, On the host only one physical NIC is linked to a standard or a distributed switch. The redundant physical NICs are either not assigned to the switch or are offline.

Consider the following scenario: A host in your environment has physical NICs vmnic0 and vmnic1 connected to vSwitch0, and vmnic1 goes offline, leaving only vmnic0 connected to vSwitch0. As a result, vSwitch0’s uplink redundancy is lost on the host.

In possible Solution for Network uplink redundancy lost, Check which switch on the host has lost uplink redundancy. Reset the alert to green by connecting at least one more physical NIC on the host to this switch. The vSphere Web Client or the ESXi Shell are also options.

If a physical NIC is down, use the ESXi Shell on the host to try to bring it back up.

The Network Adapter (vmnic) is Unavailable or has failed (2014553) – Network Uplink Redundancy Lost

Symptoms –

The “network redundancy lost” or “network redundancy deteriorated” alarm on the ESXi host may appear.

Currently, the ESXi host may show some vmnics as “DOWN.”

There could be NIC flapping if no vmnics go down unexpectedly yet you observe redundancy loss messages.

You could see an error similar to:

Lost network connectivity on virtual switch “vSwitch1”. Physical NIC vmnic1 is down. Affected portgroups: “VM Network”.

The vobd log may show an error like this because the NIC Teaming network adapter fails with a failed criteria code:

Dec 22 23:25:19 10.2.0.109 Dec 25 03:25:19 vobd: Dec 25 03:25:19.927: 8596737035540us: [vob.net.dvport.uplink.transition.down] Uplink: vmnic1 is down. Affected dvPort: 132/2d 0d 3c 50 4a 71 82 e5-54 c7 69 cd b2 01 6f bc. 1 uplinks up.(Failed criteria: 130)

Resolution:

To investigate the source of the failure or to resolve common NIC issues, need to follow the steps given:

From the VMware vSphere Client or the ESXi service console, you may check the current status of the vmnic: Using the vSphere Client, check the status:

  • Click the Configuration tab and select the ESX host.
  • Select Networking (from the menu options)
  • The diagrams show which vmnics are currently assigned to which virtual switches. The link is temporarily down if a vmnic displays a red X.

Using the ESXi service console, perform the following command to check the status:

esxcli network nic list

Check that the vmnic mentioned in the event message is still connected to the switch and properly configured:

  • Check that the network wire is connected to both the switch and the host.
  • Check to see if the system’s connected switch is still operational and hasn’t been misconfigured. Details can be found in the switch documentation.
  • Examine the hardware switch and the vmnic for activity. A network trace or activity LEDs may be used to demonstrate this.
  • Make sure your NIC driver is up to date: In ESXi, determining the network/storage firmware and driver version.

In the vobd log file, search for the word “vmnic.”

  • The NIC may be flapping if you notice “vmnic down” or “vmnic up” signals. Note that some NICs only report the up state of the NIC link, not the down state. If the NIC is “up” but the host does not reboot, the NIC is flapping and not transmitting the down state to ESXi.
  • With the vmnic messages, look for a failed criteria code. If a failed criteria code appears, proceed to step 4 below.
  • Call the hardware vendor about the flapping if there is no failed criteria code and everything was tested in step 2 above.

The vmnic failure in this log may be classified with a Failed criteria code in the vobd file. The cause for the vmnic failure is addressed in this code.

2021-12-17T15:31:02.330Z: [netCorrelator] 4836107200803us: [vob.net.dvport.uplink.transition.down] Uplink: vmnic2 is down. Affected dvPort: 28/50 24 e2 d9 41 d2 48 52-7d da b4 fd 4a ba 37 92. 3 uplinks up. (Failed criteria: 128)

Note: Active Uplinks Left is a failover indicator that shows how many active uplinks are left in the virtual switch’s teaming policy.

The failed criteria codes are listed here

1 – Link speed reported by the driver (exact match for compliance)
2 – Link speed reported by the driver (equal or greater for compliance)
4 – Link duplex reported by the driver

8 – Link LACP state down
32 – Beacon probing
64 – Errors reported by the driver or hardware
128 – Link state reported by the driver

256 – The port is blocked
512 – The driver has registered the device.

VMware vSphere Discussion Community

How do I fix my uplink redundancy lost?

Check which switch on the host has lost uplink redundancy. Reset the alert to green by connecting at least one more physical NIC on the host to this switch. The vSphere Web Client or the ESXi Shell are also options. If a physical NIC is down, use the ESXi Shell on the host to try to bring it back up.

What is uplink redundancy?

With VMware ESXi hosts, the error of network uplink redundancy loss is a fairly prevalent problem. It occurs when the secondary network interface to the ESXi host is not connected or is in a degraded state. Your host is left alone.

How do I check my ESXi NIC status?

Current status of the vmnic can be check from either the VMware vSphere Client or the ESXi service console:
Check status from vSphere Client: Select the ESX host and click the Configuration tab. Click Networking. …
Check status from ESXi service console, run this command: esxcli network nic list.

What is Vmnic in VMware?

On an ESX host, vmnic is a real physical interface. The VMKernel uses a virtual network interface called vmknic. veth = nothing isn’t a real term, although it’s most likely the same as vswif. The service console uses a virtual ethernet interface called vswif.

What is uplink in VMware?

Connections between virtual and physical networks are provided by physical Ethernet adapters. They’re known as uplinks in VMware Infrastructure, and the virtual ports that connect to them are known as uplink ports. A single host can have a maximum of four uplinks, which can be on a single switch or distributed across several switches.

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