Hello, The sub-interface you are referring to is just an alias for adding a secondary IP to the same interface. In networking terms, it is the same network with multiple subnets (some can even overlap) and there is no separation between them. oVirt networks are considered layer 2, as such, only sub-interfaces that reflect that are supported: VLAN/s. I am not sure if an interface named em1:1 collide is some way with the root interface em1, we have never tested such a scenario in oVirt. But assuming it does not, and em1:1 is just another interface that the oVirt host ignores, you can attach the VM/s to the em1 interface and do whatever you will like with em1:1. Another path to go with this is composing your own handling of the scenario you need using the oVirt hooks. See: http://www.ovirt.org/develop/developer-guide/vdsm/hooks Here is one specific for defining secondary addresses: https://github.com/oVirt/vdsm/tree/master/vdsm_hooks/extra_ipv4_addrs Thanks, Edy. On Sat, Jun 17, 2017 at 12:14 AM, Adam Mills <amills(a)riotgames.com&gt; wrote: