#NSX #Concept
L2 broadcast domain, shows up as a port group on a VDS in vCenter.
Similar to the 2 types of [[NSX - Transport Zone.md|Transport zones]]|[[NSX - Transport Zone]] we also have 2 types of segments in NSX, Overlay and Vlan-backed.
## VLAN-backed Segment
backed by a traditional VLAN based in the physical network, Gateway is also in the physical environment. Is used to connect networks which are already created in the old network. This type of network is not being able to be stretched/tunneled through NSX.
## Overlay segment
Uses [[NSX - Distributed Router.md|[NSX - GENEVE]]|[[NSX - Distributed Router]]. The distributed Router is residing directly on the ESXi host itself. Can be connected to a single [[NSX - T0 Router.md|T0]]|[[NSX - T0 Router]] or [[NSX - T1 Router.md|T1 Gateway]]|[[NSX - T1 Router]]