Learning OpenStack Networking - Third Edition

Local

When creating a local network in Neutron, it is not possible to specify a VLAN ID or even a physical interface. The Neutron Linux bridge agent will create a bridge and connect only the tap interface of the instance to the bridge. Instances in the same local network on the same node will be connected to the same bridge and are free to communicate with one another. Because the host does not have a physical or virtual VLAN interface connected to the bridge, traffic between instances is limited to the host on which the instances reside. Traffic between instances in the same local network that reside on different hosts will be unable to communicate with one another.

Figure 4.5 demonstrates the lack of physical or virtual VLAN interfaces ...