The Uniqueness of UUIDs

Documentation: System Management BIOS (SMBIOS) Reference 6 Specification
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In a managed environment, it is important that all hardware assets have a unique identifier so as to not have naming conflicts. This unique identifier is known as the UUID. UUID stands for: Universally Unique ID.

Everything works out fine as long as all of the systems you are managing actually do have unique UUIDs. However, not every OEM adheres to the UUID specifications and instead they may use the MAC address plus some type of padding. The thought here is that the MAC address is unique - it may or may not be, we don't really know. Ensuring systems have unique UUIDs is very important if an organization is using a technology such as Intel(r) Active Management Technology to discover and manage thousands of systems. If UUIDs are not unique, errors will be encountered that will be difficult to trace.

If the OEM follows the SMBIOS specifications then the systems will (most likely) have unique UUIDs. However, any implementation that has potential for implementation variations could result in duplicate UUIDs.

There are actual 5 different versions of UUIDs in use. See below for more details.

The UUID format as defined in the SMBIOS (System management BIOS) standard is as follows:

From the SMBIOS Spec:"One of the main reasons for using UUIDs is that no centralized authority is required to administer them (although one format uses IEEE 802 node identifiers, others do not.) As a result, generation on demand can be completely automated and used for a variety of purposes. The UUID generation algorithm described here supports very high allocation rates of up to 10 million per second per machine if necesarry (Carl Segan might enjoy this fact) so that they could even be used as transaction IDs. UUIDs are of a fixed size (128 bits) which is reasonably small compared to other alternatives. This lends itself well to sorting, ordering, and hashing of all sorts, storing in databases, simple allocation, and ease of programming in general. Since UUIDs are unique and persistent, they make excellent Uniform Resourse Names. The unique ability to generate a new UUID without a registration process allows for UUIDs to be one of the URNs with the lowest minting cost."