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:
tapNThe Linux bridge:
brqXXXXThe VXLAN interface:
vxlan-Z(wherezis the VNI)The VLAN interface:
ethX.Y(whereXis the interface andYis the VLAN ID)The physical interface:
ethX(whereXis 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 the following:
Figure 4.6
In Figure 4.6, three virtual machine instances are connected to a Linux bridge named brqXXXX via their respective tap interfaces. When an instance was launched in the network mapped to VLAN 100, a virtual interface named...
