https://codingpackets.com/blog/cisco-csr-1000v-vagrant-libvirt-box-install

NOTES:
Be sure you have 'virtio' as interface type and you use the mac generation algo:

node.vm.provider :libvirt do |domain|
  domain.nic_model_type = "virtio"
node.vm.network :private_network,
  :mac => "#{get_mac_cisco()}",