UUIDVariants Category

The global constants for specifying the layout of a generated Universally Unique Identifier (UUID) are listed in the following table.

Global Constant	Integer Value	Description
VariantDce	2	Distributed Computing Environment, a Version 2 UUID based on date‑ time and MAC address.
VariantMicrosoft	3	Generates a UUID using CoCreateGuid, which .NET Guid.NewGuid() also uses. Currently this is a Version 4 UUID and is the most unique UUID you can have. This is the recommended variant.
VariantNcs	1	Reserved for NCS (Network Computing System) backward compatibility.