In a cross-vCenter NSX deployment, you can create universal logical switches, which can span all vCenters. The transport zone type determines whether the new switch is a logical switch or a universal logical switch. When you add a logical switch to a universal transport zone, the logical switch is universal.
When you create a logical switch, in addition to selecting a transport zone and replication mode, you configure two options: IP discovery, and MAC learning.
IP discovery minimizes ARP traffic flooding within individual VXLAN segments---in other words, between VMs connected to the same logical switch. IP discovery is enabled by default.
You cannot disable IP discovery when you create a universal logical switch. You can disable IP discovery via the API after the universal logical switch is created. This setting is managed separately on each NSX Manager. See the NSX API Guide.
MAC learning builds a VLAN/MAC pair learning table on each vNIC. This table is stored as part of the dvfilter data. During vMotion, dvfilter saves and restores the table at the new location. The switch then issues RARPs for all the VLAN/MAC entries in the table. You might want to enable MAC learning if you are using virtual NICs that are trunking VLANs.
Universal Logical Switch
- Navigate to Home > Networking & Security > Logical Switches.
- Select the primary NSX Manager.
- Click the New Logical Switch () icon.
- Type a name and optional description for the logical switch.
- In the Transport Zone section, click Change to select a Transport Zone. Select the universal transport zone to create a universal logical switch.
If you create a universal logical switch and select hybrid as the replication mode, you must ensure that the multicast address used does not conflict with other multicast addresses assigned on any NSX Manager in the cross-vCenter NSX environment.
- (Optional) Override the replication mode determined by the transport zone.
You can change it to one of the other available modes. The available modes are unicast, hybrid, and multicast.
The case in which you might want to override the inherited transport zone's control plane replication mode for an individual logical switch is when the logical switch you are creating has significantly different characteristics in terms of the amount of BUM traffic it will to carry. In this case, you might create a transport zone that uses as unicast mode, and use hybrid or multicast mode for the individual logical switch.
- (Optional) Click Enable MAC learning
Logical Switch and Universal Logical Switch
App is a logical switch connected to a transport zone. It is available only on the NSX Manager on which it was created.
Universal-App is a universal logical switch connected to a universal transport zone. It is available on any of the NSX Managers in the cross-vCenter NSX environment.
The logical switch and the universal logical switch have segment IDs from different segment ID pools.
What to do next
Add VMs to a universal logical switch.
Optionally, create a universal logical router and attach it to your universal logical switches to enable connectivity between VMs that are connected to different universal logical switches.