vmnic Link Down Status with LACP Port State DEF in vSphere ESXi

Products

• VMware vSphere ESXi

Issue/Introduction

When reviewing host networking performance or troubleshooting a loss of connectivity, the following symptoms may be observed:

    • The vmnic interfaces on an ESXi host report a 'Down' status within the vSphere Client, ESXi host client, and when executing the network command line interface:

# esxcfg-nics -l

    • The following trace logs are repeatedly generated inside /var/log/vmkernel.log on the affected ESXi host:

===============================================================================================================
yyyy-mm-ddThh-mm-ss.zzz cpu7:2097549)i40en: indrv_DeviceReset:3003: Device Resetting vmnic4
yyyy-mm-ddThh-mm-ss.zzz cpu7:2097549)i40en: indrv_Stop:2275: stopping vmnic4
yyyy-mm-ddThh-mm-ss.zzz cpu21:2097893)NetPort: 1890: disabled port 0xXXXXXXXX
yyyy-mm-ddThh-mm-ss.zzz cpu21:2097893)netschedHClk: NetSchedHClkNotify:5067: vmnic4: link down notification
yyyy-mm-ddThh-mm-ss.zzz cpu21:2097893)Team.cswitch: TeamVSLACPLAGEventCB:9117: [nsx@6876 comp="nsx-esx" subcomp="vswitch"]Received event UPLINK ADD, LAG lag1/-XXXXXXXXXX, link UNKNOWN, uplink vmnic4/0xXXXXXXXX, link UNKNOWN
yyyy-mm-ddThh-mm-ss.zzz cpu42:2098461)Net: 2238: connected Shadow of vmnic4  to null config, portID 0x400001e
yyyy-mm-ddThh-mm-ss.zzz cpu42:2098461)cswitch: VSwitchPortEthFRPUpdateInt:5829: [nsx@6876 comp="nsx-esx" subcomp="vswitch"]Unblock Port 67108894
yyyy-mm-ddThh-mm-ss.zzz cpu42:2098461)Mirror.cswitch: VSwitchMirrorPortEnable:4006: [nsx@6876 comp="nsx-esx" subcomp="vswitch"]Failed to get port 0x400001e linkup flag
yyyy-mm-ddThh-mm-ss.zzz cpu42:2098461)NetPort: 1621: enabled port 0xXXXXXXXX with mac 00:50:56:xx:xx:xx
yyyy-mm-ddThh-mm-ss.zzz cpu7:2097549)netschedHClk: NetSchedHClkPortQuiesce:7601: vmnic4: received a force quiesce for port 0xXXXXXXXX

=================================================================================================================

    • The physical network interface card (vmnic) is actively bound to an LACP Link Aggregation Group (LAG).

    • Checking the Link Aggregation Control Protocol state shows an isolated interface stuck in a Default (DEF) condition while adjacent peer interfaces function as expected:

      # esxcli network vswitch dvs vmware lacp status get

       LAG ID: XXXXXXXXXX
       Mode: Passive
   
       Nic List:
            Local Information:
                  Admin Key: 0
                  Flags: SP
                  Oper Key: 0
                  Port Number: 4
                  Port Priority: 255
                  Port State: DEF,      <--- Default State
            Nic: vmnic4
            Partner Information:
                  Age: 00:00:00
                  Device ID:
                  Flags:
                  Oper Key: 0
                  Port Number: 0
                  Port Priority: 0
                  Port State:
            State: Down
           

             Local Information:
                  Admin Key: 15
                  Flags: SP
                  Oper Key: 15
                  Port Number: 3
                  Port Priority: 255
                  Port State: AGG,SYN,COL,DIST,
            Nic: vmnic8
            Partner Information:
                  Age: 00:00:19
                  Device ID: 00:23:04:ee:be:01
                  Flags: SA
                  Oper Key: 33009
                  Port Number: 8973
                  Port Priority: 32768
                  Port State: ACT,AGG,SYN,COL,DIST,
            State: Bundled

    • Temporarily removing the port channel/LAG mapping on the adjacent upstream physical access switch and reverting the target interface to an unaggregated, standalone access/trunk switchport transitions the vmnic back to an functional Link Up status inside ESXi.

Environment

vSphere ESXi

Cause

The LACP port state DEF (Default) indicates that the ESXi virtual switch layer is completely decoupled from LACP protocol exchanges with the upstream network infrastructure. While the lower physical signaling layer may detect link availability, the protocol engine transitions to a fallback default state because no Link Aggregation Control Protocol Data Units (LACPDUs) are successfully negotiated or received from the physical hardware vendor switch.

This scenario is typically driven by an upstream network switch policy configuration mismatch, out-of-sync port channel negotiation modes, or invalid transceiver hardware speed initialization parameters.

Resolution

Isolate and correct the configuration state on the physical fabric layers using the following validation workflow:

    1. Verify out-of-band server hardware management state: Log in to the hardware out-of-band controller interface (e.g., HPE iLO, Dell iDRAC) to confirm that the physical network adapter status reports as healthy and functional at the underlying PCIe/PHY bus layer.

    2. Audit upstream physical network switchports: Validate that the exact upstream port mapping assigned to the affected vmnic interface shows an operational state from the physical network infrastructure console.

    3. Validate firmware and driver compliance boundaries: Cross-reference the network card's driver module version and firmware image string against the official hardware compatibility matrix. Ensure the installed software layers conform strictly to the supported runtime configurations.

    4. Synchronize LACP channel configuration parameters: Verify that the LACP negotiation parameters on the host's virtual distributed switch match the physical switchport aggregation policies (e.g., ensuring active vs. passive mode parameters, timers, and EtherChannel hashing algorithms align without conflicting flags). If inconsistencies are isolated, rebuild the target port channel bundle across the physical infrastructure side.

    5. Engage physical platform and vendor support ecosystems: If the layer-2 protocol negotiation patterns remain unestablished after re-aligning configuration parameters, engage the hardware system or network fabric switch vendor to trace downstream LACPDU packet delivery failures.

 

Additional Information

An LACP interface entering the DEF (Default) operational state generally points to the following underlying architectural or fabric layer anomalies:

• The host layer detects valid media attachment parameters (physical link state shows up), but the LACP control layer fails to form a protocol-compliant adjacency path.
  
  
• An structural configuration mismatch exists across the logical boundaries (e.g., mismatching passive/passive LACP mode selection rules).
  
  
• Upstream switch access policies or security features are actively dropping or filtering outbound LACPDUs traversing the physical port layer.
  
  
• Hardware synchronization failures or layer-1 auto-negotiation protocol speed mismatches impairing high-level framing operations.