Introduction A long time ago, I wrote an article all about OpenStack Neutron (which at that time was called Quantum). That served as an excellent reference for a number of years, but if you’ve deployed a recent version of OpenStack you may have noticed that the network architecture looks completely different. The network namespaces previously used to implement routers and dhcp servers are gone (along with iptables rules and other features), and have been replaced by OVN (“Open Virtual Network”).