OVS is a direct replacement for [[LinuxBridge]] an L2 switch. Linux bridge was not designed with a fast changing landscape of many VMs that need to communicate with each other from many different hosts. OVS is designed with that in mind..

OVS makes it possible to migrate configuration and live network state between two hypervisors by tracking current network state in OVSDB. The OVSDB supports triggers which make it possible to respond to changes of various aspects of the network.