Currently during BMH provisioning user can provide network data either 

• In the node section of nodeset for interfaces to be configured for a node
• In `preProvisioningNetworkDataName` either in the BMH spec or node section of nodeset spec.

If `preProvisioningNetworkDataName` is provided without node section network data, it would be used as in BMO. 

If none of these are provided, we create network data from a generic template[1] using ctlplane ip from IPAM and use it.

When providing network data for individual nodes in nodeset node section or using `preProvisioningNetworkDataName` user has to ensure that they use the same ips as cofigured for IPAM (fixedIP) in the nework secion of nodes.

However, when provisioning nodes using virtual-media and the "external" network (DCN or non-IPI installed OCP) with multiple interfaces on ocp nodes,  there would be asymmetric routing issues. The current workarounds to avoid this is to:

• Use both `preProvisioningNetworkDataName` and `networkData` in section.
• Use a VRF on the OCP nodes via NNCP, i.e separate routing table for OSP internal networks. (POC here: https://github.com/openstack-k8s-operators/architecture/pull/406 - Needs more testing.)

We probably need a better way to handle this either by

• Always overiding `preProvisioningNetworkDataName` with node section `networkData` or generated `networkData` which would be different from how BMO falls back to `preProvisioningNetworkDataName`[2] and can be confusing for existing BMO users. Also, it would require users to configure port groups with fallback at the switch when using bonds etc. 
• Provide a better way of templating `networkData` from IPAM to provide different options to the users. However, there is could be little value in it as we would anyway configure the interfaces during edpm deployment with `os-net-config` before any workload has been deployed.

 [1]https://github.com/openstack-k8s-operators/openstack-baremetal-operator/blob/main/templates/openstackbaremetalset/cloudinit/networkdata

[2] https://github.com/metal3-io/baremetal-operator/blob/main/controllers/metal3.io/host_config_data.go#L71-L76