There's a new parameter for localnet topologies - `physicalNetworkName`, which was introduced in 4.18. You can read more about it in the [upstream documentation](https://github.com/ovn-kubernetes/ovn-kubernetes/blob/master/docs/features/multiple-networks/multi-homing.md#network-configuration-reference-2). The document I'm pointing at is in chapter [16.3.1.1.2. OVN-Kubernetes network plugin JSON configuration table](https://docs.redhat.com/en/documentation/openshift_container_platform/4.18/html/networking/multiple-networks#configuration-ovnk-network-plugin-json-object_configuring-additional-network-ovnk)