The universal segment ID pool specifies a range for use when building logical network segments. Cross-vCenter NSX deployments use a unique universal segment ID Pool to ensure that the universal logical switches VXLAN network identifiers (VNIs) are consistent across all secondary NSX Managers.
The universal segment ID is defined once on the primary NSX Manager and then synced to all of the secondary NSX Managers. The universal segment ID range controls the number of universal logical switches that can be created. Note that the segment ID range must be unique across any NSX Manager that you plan use in a cross-vCenter NSX deployment. This example uses a high range to provide future scalability.
1. In vCenter, navigate to Home > Networking & Security > Installation and select the Logical Network Preparation tab.
2. Click Segment ID > Edit.
3. Enter a range for universal segment IDs, such as 900000-909999.