GUIDELINES FOR
64-BIT GLOBAL IDENTIFIER (EUI-64)
REGISTRATION AUTHORITY
General
The IEEE defined 64-bit global identifier (EUI-64) is assigned by a manufacturer that has been assigned a company_id value by the IEEE Registration Authority. The 64-bit identifier is a concatenation of the 24-bit company_id value assigned by the IEEE Registration Authority and a 40-bit extension identifier assigned by the organization with that company_id assignment.
The IEEE defined 64-bit extended unique identifier (EUI-64) is a concatenation of the 24-bit company_id value by the IEEE Registration Authority and a 40-bit extension identifier assigned by the organization with that company_id assignment.
The IEEE administers the assignment of 24-bit company_id values. The assignments of these values are public, so that a user of an EUI-64 value can identify the manufacturer that provided any value[1]. The IEEE/RAC has no control over the assignments of 40-bit extension identifiers and assumes no liability for assignments of duplicate EUI-64 identifiers assigned by manufacturers.
Application restrictions
Given the minimal probability of consuming all the EUI-64 identifiers, the IEEE/RAC places minimal restrictions on their use within standards. However, if used within the context of an IEEE standard, the documentation shall be reviewed by the IEEE/RAC for correctness and clarity. The IEEE/RAC shall not otherwise restrict the use of EUI-64 identifiers within standards. If the EUI-64 is referenced within non-IEEE standards, there shall not be any reference to IEEE unless approved by the IEEE/RAC.
Distribution restrictions
Given the minimal probability of consuming all the EUI-64 identifiers, the IEEE/RAC places minimal restrictions on their redistribution through third parties, as follows:
- Allocation. The EUI-64 values shall be sold within electronically-readable parts; no more than one EUI-64 value shall be contained within each component that is manufactured.
- Packaging. A component containing the EUI-64 value shall have a distinguishing characteristic (such as color or shape) to distinguish it from other commonly-used identifier components.
- Documentation. Readily available documentation (see following page).
- Legal indemnification. Any organization producing EUI-64 values shall indemnify the IEEE for damages arising from duplicate number assignments.
The term EUI-64 is trademarked by the IEEE. Companies are allowed to use this term for commercial purposes, but only if their use of this term has been reviewed by the IEEE/RAC and the proposed products using the EUI-64 conform to these restrictions.
Application documentation
As a condition for receiving a company_id assignment, a manufacturer of EUI-64 values accepts the following responsibilities:
- This documentation shall be readily available (at no cost) to any purchaser of EUI-64 values.
- The manufacturer's part specification should include an unambiguous description of how the EUI-64 value is accessed (pin and/or address descriptions).
Manufacturer-assigned identifiers
The manufacturer identifier assignment allows the assignee to generate approximately 1 trillion (1012) unique EUI-64 values, by varying the last 40 bits. The IEEE intends not to assign another OUI/company_id value to a manufacturer of EUI-64 values until the manufacturer has consumed, in product, the preponderance (more than 90%) of this block of potential unique words. It is incumbent upon the manufacturer to ensure that large portions of the unique word block are not left unused in manufacturing.
64-BIT GLOBAL IDENTIFIER FORMAT TUTORIAL
General
The IEEE defined 64-bit global identifier (EUI-64) is assigned by a manufacturer who has been assigned a company_id value by the IEEE Registration Authority. The 64-bit identifier is a concatenation of the 24-bit company_id value assigned by the IEEE Registration Authority and a 40 bit extension identifier assigned by the organization with that company_id assignment.
The IEEE administers the assignments of 24-bit company_id values. The assignments of these values are public, so that a user of a EUI-64 value can identify the manufacturer that provided any value. The IEEE/RAC has no control over the assignments of 40-bit extension identifiers and assumes no liability for assignments of duplicate EUI-64 identifiers.
Format
You may have a 64-bit global identifier (EUI-64) provided by an authorized manufacturer of these values (in the form of electronically-readable chips). The most-significant 24 bits of this value are the company_id value assigned to the manufacturer by the IEEE Registration Authority. The least-significant 40-bit extension identifier is assigned by the manufacturer.
For example, assume that a manufacturer's IEEE-assigned company_id value is ACDE4816 and the manufacturer-selected extension identifier for a given component is 234567ABCD16. The EUI-64 value generated from these two numbers is ACDE48234567ABCD16, whose byte and bit representations are illustrated below:
| company_id | extension identifier | field
|addr+0 | addr+1 | addr+2 | addr+3 | addr+4 | addr+5 | addr+6 | addr+7| order
| AC | DE | 48 | 23 | 45 | 67 | AB | CD | hex
10101100 11011110 01001000 00100011 01000101 01100111 10101011 11001101 bits
| | | |
| most significant byte least significant byte |
most-significant bit least-significant bit
If provided in byte-addressable media, the original byte-address order of the manufacturer is specified: the most through least significant bytes of the EUI-64 value are contained within the lowest through highest byte addresses, as illustrated above.
When transferred to other electronically-readable locations (within a disk file or network packet, for example) the relative ordering of the bytes may be changed, as specified within the applicable standard.
Restricted encapsulated values
To support encapsulation of EUI-48 and MAC-48 values within small subsets of the EUI-64 values, the first four digits of the manufacturer's extension identifier shall not be FFFF16 or FFFE16. Thus, the 64-bit values of the following form are never-assigned EUI-64 values:
ccccccFFFEeeeeee16 (an EUI-48 extension)
ccccccFFFFeeeeee16 (a MAC-48 extension)
The letters 'c' and 'e' represent hexadecimal digits and show how the EUI-48 value can be unambiguously encapsulated within the EUI-64 value; the 'c' and 'e' digits represent the company_id and extension-identifier portions of the EUI-48/MAC-48 values.
This allows MAC-48 and EUI-48 identifiers to be encapsulated and transported as (otherwise unassigned) EUI-64 identifiers. The intent is to enable migration to a single form of OUI/company_id based globally unique 64-bit identifiers.
Encapsulated EUI-48 values
For example, assume that a manufacturer's IEEE-assigned company_id value is ACDE4816 and the manufacturer-selected extension identifier for a given item is 23456716. The EUI-48 value generated from these two numbers is ACDE4823456716, whose byte and bit representations are illustrated below:
| company_id | extension identifier | field
| AC | DE | 48 | 23 | 45 | 67 | hex
10101100 11011110 01001000 00100011 01000101 01100111 bits
| | | |
| most significant byte least significant byte |
most-significant bit least-significant bit
A unique EUI-64 value is generated by concatenating the company_id, an FFFE16 valued label, and the extension identifier values. The (EUI-48 like) significance-ordered representation for this encapsulated EUI-48 identifier is listed below:
The byte and bit representations for this EUI-64 value are illustrated below:
| company_id | EUI label | extension identifier | field
| AC | DE | 48 | FF | FE | 23 | 45 | 67 | hex
10101100 11011110 01001000 11111111 11111110 00100011 01000101 01100111 bits
| | | |
| most significant byte least significant byte |
most-significant bit least-significant bit
Encapsulated MAC-48 values
A MAC-48 identifier can be encapsulated and placed within an EUI-64 container. The intent is to allow nonconflicting representation of existing MAC-48 identifiers within the standard EUI-64 format. For example, assume a manufacturer's IEEE-assigned OUI is AC-DE-48 and was used to generate the MAC-48 address:
AC-DE-48-23-45-67
which has the binary transmission-ordered representation:
| OUI | extension identifier | field
| 1st | 2nd | 3rd | 4th | 5th | 6th | octet
| C A | E D | 8 4 | 3 2 | 5 4 | 7 6 | hex
0011 0101 0111 1011 0001 0010 1100 0100 1010 0100 1110 0110 bits
| | | | | | | | | | | |
lsb msb lsb msb msb lsb msb lsb msb lsb msb lsb
A unique EUI-64 value is generated by concatenating the OUI, an FF-FF valued label, and the extension identifier values. The (MAC-48 like) transmission-ordered binary representations for this encapsulated MAC-48 identifier is listed below:
| OUI | MAC label | extension identifier | field
| 1st | 2nd | 3rd | 4th | 5th | 6th | 7th | 8th | order
| C A | E D | 8 4 | F F | F F | 3 2 | 5 4 | 7 6 | hex
00110101 01111011 00010010 11111111 11111111 11000100 10100100 11100110 bits
| | | | | | | | | | | | | | | |
lsb msb lsb msb msb lsb msb lsb msb lsb msb lsb msb lsb msb lsb
The (EUI-48 like) significance-ordered representation for this encapsulated MAC-48 identifier is listed below:
| OUI | MAC label | extension identifier | field
| AC | DE | 48 | FF | FF | 23 | 45 | 67 | hex
10101100 11011110 01001000 11111111 11111111 00100011 01000101 01100111 bits
| | | |
| most significant byte least significant byte |
most-significant bit least-significant bit
[1]Except for private company_id values, where the owner of the company_id value is confidential. These shall remain private.
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