[libvirt-users] how to restart the network connection of kvm guest OS ?

When a vm move from one VLAN(e.g. VLAN 1) to another VLAN (e.g. VLAN 2), it is needed to restart the network connection of guest OS, so that it can begin a dhcp discover and get a new ip again. But i can't find the way to restart the guest os's network connection by libvirt (neither python API nor virsh command). Is any other ways? PS: i found that the VirtualBox can detach the cable of VMs and re-attach so that the guest OS will recognize and restart a dhcp discover when the cable re-attach. I guess the KVM will have some feature like that , is anybody know something about that? thanks and looking forward to your answers.