Visualizing traffic flow through Linux bridges

For an Ethernet frame to travel from a virtual machine instance to a device on the physical network, it will pass through three or four devices inside the host:

    
     
          
Network type           Interface type           Interface name
        
          
all           tap           tapN
        
          
all           bridge           brqXXXX
        
          
vxlan           vxlan           vxlan-z (where Z is the VNI)
        
          
vlan           vlan           ethX.Y (where X is the physical interface and Y is the VLAN ID)
        
          
flat, vlan           physical           ethX (where X is the interface)
        
  

 

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