Both the LinuxBridge and Open vSwitch drivers and agents for Neutron provide unique solutions to the same problem of connecting virtual machine instances to the network. The use of Open vSwitch relies on flow rules to determine how traffic in and out of the environment should be processed and requires both user-space utilities and kernel modules to perform such actions. On the other hand, the use of Linux bridges requires the 8021q and bridge kernel modules and relies on the use of VLAN and VXLAN interfaces on the host to bridge instances to the physical network. For most environments, I recommend using the ML2 plugin and LinuxBridge driver and agent unless integration with OpenFlow controllers or the use of a third-party solution or plugin is required.
In the next chapter, you will be guided through the process of creating different types of networks to provide connectivity to instances. The process of creating networks is the same for both LinuxBridge- and Open vSwitch-based environments...