If you create a OVF file descriptor with the following information about a network card:

      <Item>
        <rasd:AutomaticAllocation>true</rasd:AutomaticAllocation>
        <rasd:Connection>Bridged</rasd:Connection>
        <rasd:Description>E1000 ethernet adapter on "Bridged"</rasd:Description>
        <rasd:ElementName>unknown device</rasd:ElementName>
        <rasd:InstanceID>6</rasd:InstanceID>
        <rasd:ResourceSubType>E1000</rasd:ResourceSubType>
        <rasd:ResourceType>10</rasd:ResourceType>
      </Item>

In VirtualBox, this information is not applied in the configuration of the Virtual Machine.

For all the hypervisor, it should be created a Network Card according to the information provided by the OVF, and no assumption about the Network Card Controller should be done.

At this moment, it seems that the virtual machines created for each hypervisor uses the default network card and this is not correct. It should use the NIC provided in the OVF.

If no information about the NIC is provided. then it should be assigned the 'E1000' card by default, because it's the one that guarantees that will work in all the hypervisors.