Host network disconnected after LACP configuration on Cisco Nexus switches

Products

• VMware vSphere ESXi

Issue/Introduction

You may encounter the following symptoms when configuring LACP:

• The ESXi host management network and others configured on the DVS goes down immediately after the LACP configuration is applied.
• Physical Cisco Nexus switch ports remain in a suspended state.

Environment

• VMware vSphere ESXi

Cause

By default, Cisco Nexus switches use the suspend-individual feature. If a physical port in a Link Aggregation Group (LAG) does not receive LACP Protocol Data Units (PDUs) from the host, the switch suspends the port to prevent loops. During the transition to LACP, the host may not yet be sending PDUs, causing the switch to disable the ports.

Resolution

To restore connectivity, you must synchronize the physical port activation with the host-side configuration.

1. Administratively shut down the physical Cisco Nexus switch ports connected to the ESXi host uplinks:

   shutdown

2. In the vSphere Client, add the VDS uplinks of the host to the configured Link Aggregation Group (LAG).
3. Configure the Cisco physical ports to be members of the respective port-channel.
4. Perform a no shutdown on the physical switch ports only after the host-side configuration is verified and active:

   no shutdown

Alternative Resolution Path

Consult with a Cisco network engineer to evaluate disabling the port suspension behavior. This allows the ports to remain active as standalone links until LACP negotiation completes, preventing the initial disconnect.

If approved by your network team, apply the following to the affected port-channel depending on the version:

1. Enter configuration mode for the port-channel interface:

   interface port-channel ####

2. Disable the LACP suspension behavior:

   no lacp suspend-individual

    

Note: The 'no-lacp suspend' configuration on physical switches can cause network disruptions if an administrative link-down command is executed from the host. Please review the attached document and fully understand the implications before executing this command.
Reference: Total Network Outage After Administrative Uplink Shutdown Due to Switch LACP Standalone Configuration

Additional Information

Cisco Nexus LAG supportability with "no suspend-individual"