Verify Which Interface Carries OVN Underlay Traffic

💡 Quick Answer: Find OVN encapsulation IP with ovs-vsctl get Open_vSwitch . external_ids:ovn-encap-ip, map it to an interface using ip addr, then inspect br-ex ports to identify the real underlay device.

When troubleshooting SR-IOV and node networking, confirm the interface actually used for OVN underlay instead of guessing by NIC names.

1) Get OVN Encapsulation IP

ovs-vsctl get Open_vSwitch . external_ids:ovn-encap-ip

2) Map Encapsulation IP to Interface

ip addr | grep -B2 <encap-ip>

3) Check External Bridge Ports

ovs-vsctl list-ports br-ex

4) Validate Routes

ip route

Correlate default route and subnet routes with the bridge and lower devices.

Interpretation Pattern

• ovn-encap-ip on br-ex means overlay tunnel egress is tied to br-ex.
• br-ex lower port (for example VLAN/bond sub-interface) identifies the practical underlay path.
• Use this mapping before concluding whether a specific PF participates in host network paths.