Learning OpenStack Networking (Neutron) - Second Edition

Visualizing traffic flow when using LinuxBridge

While an Ethernet frame travels from the virtual machine instance to a remote physical network, it passes through three or four of the following devices depending on the network type:

• The tap interface: tapN
• The Linux bridge: brqXXXX
• The VXLAN interface: vxlan-Z (where z is the VNI)
• The VLAN interface: ethX.Y (where X is the interface and Y is the VLAN ID)
• The physical interface: ethX (where X is the interface)

To help conceptualize how Neutron uses Linux bridges, a few examples of LinuxBridge architectures are provided in the following sections.

VLAN

Imagine a basic OpenStack cloud that consists of a single network on VLAN 100 for use with instances. The network architecture within the compute node resembles ...