VMware NSX VNIs (segment IDs) are between 5,000-167,772,15. As per vSphere maximum configurations, the maximum static/dynamic port groups per vCenter is 10,000; therefore, up to 10,000 VNIs per NSX Manager will be sufficient; for example 10,000–19,999. If you are planning to use the hybrid or multicast replication mode, a multicast address range must be specified and you can start from 239.0.1.0/24.