On 08/29/2016 03:37 AM, Marina Danial wrote: Aside from the part about disabling multicast, this is all handled (including creation of the tap device, and destroying it when the guest is terminated) by libvirt's <interface type='bridge'> with a <virtualport type='openvswitch'> subelement. This page has more details and an example: http://www.libvirt.org/formatdomain.html#elementsNICSBridge As far as turning off multicast, this is the first time I've seen anyone request that. Unfortunately the network hooks (https://www.libvirt.org/hooks.html ) that are run for each interface happen prior to the creation of the tap devices, so you can't just add a network hook script to do it. If you *really* need multicast disabled, with current libvirt you would need to add a *qemu* hook script that looked for the tap device name in the guest's xml and set -multicast, or you would need to use "<interface type='ethernet'> (which just creates a tap device, then calls a script to "connect it to the network") with a "<script path='some script that sets -multicast *and* adds the tap to the ovs bridge'/>". type='ethernet' and its script are also described a bit further down in the same link I posted above.