In Neutron, there are two categories used to describe networks that provide connectivity to instances:
Provider networks are networks, created by the OpenStack administrator, that map directly to a physical network in the data center. Useful network types in this category include flat (untagged) and VLAN (802.1q tagged). Other network types, such as local and GRE, are configurable options but are rarely implemented as provider networks.
Tenant networks are networks created by users to provide connectivity between instances within a tenant. By default, tenant networks are fully isolated from each other, including other networks within the same tenant.
Neutron supports a range of networking ...