neutron/doc/source/devref/linuxbridge_agent.rst

L2 Networking with Linux Bridge

This Agent uses the Linux Bridge to provide L2 connectivity for VM instances running on the compute node to the public network. A graphical illustration of the deployment can be found in Networking Guide

In most common deployments, there is a compute and a network node. On both the compute and the network node, the Linux Bridge Agent will manage virtual switches, connectivity among them, and interaction via virtual ports with other network components such as namespaces and underlying interfaces. Additionally, on the compute node, the Linux Bridge Agent will manage security groups.

Three use cases and their packet flow are documented as follows:

1. Legacy implementation with Linux Bridge
2. High Availability using L3HA with Linux Bridge
3. Provider networks with Linux Bridge