One of the core functions of OpenStack Networking is to provide end-to-end network connectivity to instances running in the cloud. In chapter 3 Installing Neutron, we installed the Neutron API service and the ML2 plugin across all nodes in the cloud. Beginning with this chapter, you will be introduced to networking concepts and architectures that Neutron relies on to provide connectivity to instances and other virtual devices.

The ML2 plugin for Neutron allows an OpenStack cloud to leverage multiple Layer 2 technologies simultaneously through the use of Mechanism drivers. In the next few chapters, we will look at multiple Mechanism drivers that extend the functionality of the ML2 network plugin, including the Linux bridge and Open vSwitch drivers.

In this chapter, you will do the following:

• Discover how Linux bridges are used to build a virtual network infrastructure
• Visualize traffic flow through virtual bridges
• Deploy the Linux bridge Mechanism driver and agent on hosts