[libvirt] oVirt considers using macTableManager='libvirt'

Hi guys, We, at oVirt, are considring using the automatic bridge management feature of libvirt for our hosts (macTableManager='libvirt'). I could find any discussion in the mailing list archives about the motivation for this feature. (was there?). If there wasn't I would like to start a new one, about the possible trade offs it would have in oVirt. Specifically I have a few questions: 1) The obvious performance motivation is clear: considering N hosts with M vms each connected to the same LAN, the first packet to any unknown yet host will flood all the vms in all N bridges. -- was there any other motivation that I do not understand (apart from slightly better security? 2) oVirt uses TC for port mirroring, in case this is requested by users, to mirror traffic from a chosen bridge to a chosen NIC in the host. I could not understand if macTableManager will interfere with it, or not. 3) Are there any drawbacks to enabling this feature? 4) We aim for rhel7.2. Will the feature be supported (or partially supported) for kernels older then 3.17? And if so, in what way? 5) oVirt currently builds its own bridges and tell libvirt about them. Does that have any affect on the functionality of that feature? 6) are there any plans to support OVS for this feature in the future? -- Thanks, Ido Barkan