OpenStack Networking provides "network connectivity as a service" between interface devices managed by other OpenStack services (most likely Compute). The service works by allowing users to create their own networks and then attach interfaces to them. Like many of the OpenStack services, OpenStack Networking is highly configurable due to its plug-in architecture. These plug-ins accommodate different networking equipment and software. As such, the architecture and deployment can vary dramatically. In the above architecture, a simple Linux networking plug-in is shown.
quantum-serveraccepts API requests and then routes them to the appropriate OpenStack Networking plugin for action.OpenStack Networking plugins and agents perform the actual actions such as plugging and unplugging ports, creating networks or subnets and IP addressing. These plugins and agents differ depending on the vendor and technologies used in the particular cloud. OpenStack Networking ships with plugins and agents for: Cisco virtual and physical switches, Nicira NVP product, NEC OpenFlow products, Open vSwitch, Linux bridging and the Ryu Network Operating System.
The common agents are L3 (layer 3), DHCP (dynamic host IP addressing) and the specific plug-in agent.
Most OpenStack Networking installations also make use of a messaging queue to route information between the quantum-server and various agents as well as a database to store networking state for particular plugins.
OpenStack Networking interacts mainly with OpenStack Compute, where it provides networks and connectivity for its instances.
