RFC 4122 defines a handful of UUIDs to use with "for some potentially interesting name spaces."
| Constant | Description |
|---|---|
| :php:const:`Uuid::NAMESPACE_DNS <Ramsey\\Uuid\\Uuid::NAMESPACE_DNS>` | The name string is a fully-qualified domain name. |
| :php:const:`Uuid::NAMESPACE_URL <Ramsey\\Uuid\\Uuid::NAMESPACE_URL>` | The name string is a URL. |
| :php:const:`Uuid::NAMESPACE_OID <Ramsey\\Uuid\\Uuid::NAMESPACE_OID>` | The name string is an ISO object identifier (OID). |
| :php:const:`Uuid::NAMESPACE_X500 <Ramsey\\Uuid\\Uuid::NAMESPACE_X500>` | The name string is an X.500 DN in DER or a text output format. |