Communication between NSX logical switches: When VMs connected to different NSX logical switches need to communicate with each other, the traffic can be routed through the Shared Transit Uplink VLAN.
Communication with physical network: When NSX logical switches need to communicate with devices on the physical network (outside the NSX environment), the traffic can be routed through the Shared Transit Uplink VLAN.
Use cases for Point to Point Transit Uplink VLANs:
Isolated connectivity for critical VMs: When certain VMs require dedicated and isolated connectivity to specific physical network interfaces, Point to Point Transit Uplink VLANs can be used to ensure a direct and private connection.
Specialized network requirements: In some cases, certain applications or workloads might have specific network requirements that necessitate direct communication with the physical network without any shared resources.