Prior to Neutron, setting up a network for virtual machines in OpenStack was quite seamless. As was described in Chapter 1, Designing OpenStack Cloud Architecture, nova-compute uses the nova-network service to connect instances to an existing network defined by the cloud administrator, where users do not have to bother with the network setup. Also, there was no possibility to do more. With Neutron, new horizons are explored to provide more topologies and advanced network setups that might enrich the user experience and provide more freedom. But first, a slight learning curve might be needed.
By virtue of the plugins concept in Neutron, more additional networking features have been introduced in OpenStack, which differ depending on hardware requirements, vendor specs lock-in, scale, or performance. Some of the plugins might use the Linux IP tables and VLANs. Many other plugins are created by third-party vendors that interact with their network devices...