Comment 17 for bug 1414559

We are hitting the same issue with the neutron ml2 linuxbridge driver. As pointed out by Andreas Scheuring in https://review.openstack.org/#/c/246910/ nova just creates the bridge but does not plug the physical interface to it. If the VM migration succeeds in a short time, then the RARP packets are sent out before the neutron-linuxbridge-agent loop to detect new interfaces had a chance to detect the new interface and correctly set up the bridge's physical interface.