What is the difference between tenant_network_types and tunnel_type?
Initially I thought the ML2 tenant_network_type variable defines the type of internal segregation (VLAN, GRE, VXLAN) for networks belonging to different tenants using the same compute node (i.e., the network between the VMs and br-int). Similarly, I thought that tunnel_type specifies the type of tunnel (if any) between the compute node and the network node that carries traffic between VM instances running on different compute nodes. This would be the network between two br-int devices located on separate nodes, where the tunnel ID provides external segregation.
However, in most examples I've seen tenant_network_types and tunnel_type are set to the same value which leads me to believe I am perhaps misunderstanding how they should be used.
a) Can something else than VLAN be used for internal segregation on a compute node (on the integration bridge) and what are the configuration variables controlling that?
b) Can external segregation (i..e, tunnel type between compute node and network node) be defined independent of internal segregation and what are the configuration variables controlling that?