When VXLAN networks are created, each network is assigned a unique segmentation ID that is used to encapsulate traffic.
The vni_ranges configuration option is a comma-separated list of ID ranges that are available for project network allocation when tunnel_type is set to vxlan.
In the following example, segmentation IDs 1 through 1,000 are reserved for allocation to tenant networks upon creation:
vni_ranges = 1:1000
The vni_ranges option supports non-contiguous IDs using a comma-separated list as follows:
vni_ranges = 1:1000,2000:2500
Update the ML2 configuration file on the controller node and add the following vni_ranges to the [ml2_type_vxlan] section if it doesn't already exist:
[ml2_type_vxlan]
...
vni_ranges = 1:1000
The 24-bit VNI field in the VXLAN header supports up to approximately 16 million unique identifiers.