LLDP discovery failure and MAC address learning issues in Cisco ACI VMM integration due to vmnic mapping
Article ID: 448567
Updated On:
Products
Issue/Introduction
- Virtual Machine (VM) MAC addresses are not learned in the Cisco APIC (ACI fabric).
- The ESXi host does not appear in the APIC endpoint list for the associated VMM domain.
- Network connectivity fails (e.g., ping, telnet) for VMs residing on the affected host.
Environment
VMware vSphere ESXi 7.x / 8.x
Cause
In a Cisco ACI VMM integration, the APIC relies on LLDP or CDP to map the hypervisor's physical uplinks (vmnics) to specific leaf ports, triggering dynamic EPG VLAN deployment. This connectivity issue can occur when the hypervisor's vDS uplinks are connected to ACI leaf ports that lack the necessary LLDP configuration. Because the APIC cannot form an LLDP adjacency to verify the host's location on these misaligned ports, it will not dynamically deploy the required VLANs, preventing MAC learning and inherently breaking VM connectivity
Resolution
To resolve this, reassign the correct physical adapters to the vSphere Distributed Switch (vDS):
Identify LLDP-Enabled Uplinks:
- Identify which physical adapters (vmnics) on the ESXi host are connected to the Cisco Leaf ports where LLDP is enabled.
Reassign Adapters in vCenter:
- Navigate to the Networking view in vCenter and select the affected Distributed Switch.
- Manage the host's physical adapters and remove the incorrectly mapped vmnics from the vDS uplinks.
- Add and assign the correct, LLDP-enabled vmnics to the vDS uplinks.
Configure vDS Discovery Protocol:
- Select the Distributed Switch > Configure > Settings > Properties > Edit.
- Under Advanced, ensure Discovery Protocol is set to Link Layer Discovery Protocol (LLDP) and the Operation is set to Both.
Verification:
- Verify that LLDP neighbor information now populates under the Physical adapters tab for the host.
- Confirm the host and its resident VMs are correctly discovered and learned within the Cisco APIC UI.
Additional Information
- Broadcom Support Portal:
- Broadcom Downloads:
- Contact Broadcom Support:
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