Universal logical switches allow layer 2 networks to span multiple sites.
When you create a logical switch in a universal transport zone, you create a universal logical switch. This switch is available on all clusters in the universal transport zone. The universal transport zone can include clusters in any vCenter in the cross-vCenter NSX environment.
The segment ID pool is used to assign VNIs to logical switches, and the universal segment ID pool is used to assign VNIs to universal logical switches. These pools must not overlap.
You must use a universal logical router to route between universal logical switches. If you need to route between a universal logical switch and a logical switch, you must use an Edge Services Gateway.