In this blog, we will finally attach our Overlay segments ( DB, Web, App ) to mimic a layer 2 domain within NSX-T.
Logic Behind Segments
App, Web & DB are segments in this diagram. Any segment we create here is similar to how an access port is created on the physical switch. So we have an App segment with a default gateway inside NSX rather than creating the interface in the physical router. All VM’s in the App segment will point to the default gateway defined in the App Segment.
Segments can be of two types;
VLAN Baked Segments: In this type, you will define a VLAN ID for the segments, however, you also have to make sure that the same vlan exists on your physical infrastructure too.
Overlay Backed Segments: This segment can be configured without any configuration on the physical infrastructure. It gets attached to Overlay Transport Zone and traffic is carried by a tunnel between the hosts.
Create Overlay Backed Segments
Log into NSX-T Manager VIP and navigate to Networking >Segments >Segments > Add Segment
Name: Web
Connectivity: Connect it to the Tier-1 Gateway we created in the earlier step.
Transport Zone: Select Overlay Transport Zone as ‘Prod-Overlay-TZ’
Subnet: ’192.168.200.1/24’ Rest all parameters to be on default for now.
Click Save.
The IP here will be used as a gateway for our Web Servers
Similarly, we can create our App and DB subnets as well
Create VLAN Backed Segments
If we wish to create VLAN backed segments, the only change
Name: vCD
Connectivity: None
Transport Zone: Select VLAN Transport Zone as ‘Prod-VLAN-TZ’
VLAN : 30
We can now verify our topology map
