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GUIDELINES FOR
64-BIT GLOBAL IDENTIFIER (EUI-64™)
REGISTRATION AUTHORITY
General
The IEEE defined 64-bit extended unique identifier (EUI-64) is a concatenation of the 24-bit OUI value by the IEEE Registration Authority and a 40-bit extension identifier assigned by the organization with that OUI assignment.
The IEEE administers the assignment of 24-bit OUI 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 Registration Authority Committee (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. They may be used to identify protocols or options defined within a standard, or to distinctively identify hardware instances of devices. However, they may not be use to identify objects generated by a hardware instance, including the following:
- Transactions or other software generated identifiers.
- Sequence numbers use to distinctively identify power or reboot cycle instances.
- Extensions of hardware functionality to multiple virtual instances.
Note that EUI-64 identifiers, when concatenated with a disk/system managed 64-bit identifier, may be used to create distinct 128-bit (or larger) unique object and/or file identifiers, and such use is not discouraged.
If used within the context of an IEEE standard, the documentation shall must
be
reviewed by the IEEE/RAC for correctness and clarity. The
IEEE/RAC does not restrict the use of EUI-64 identifiers within standards,
based on the perceived value of the application, if the standard conforms to the
aforementioned restrictions. 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
shallcan only be sold within electronically readable parts; no more than one EUI-64 valueshallcan be contained within each component sold for the purpose of redistributing EUI values. (Inclusive products, such as network and/or I/O cards, have no number-of-EUIs restriction and may utilize multiple EUI-64 values to identify each of multiple supported protocols, formats, or features.) - Packaging. A component
containing the EUI-64 value
shallmust 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
shallmust 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 an OUI assignment, a manufacturer of EUI-64 values accepts the following responsibilities:
- This documentation
shallmust 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 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 an OUI value by the IEEE Registration Authority. The 64-bit identifier is a concatenation of the 24-bit OUI value assigned by the IEEE Registration Authority and a 40 bit extension identifier assigned by the organization with that OUI assignment.
The IEEE administers the assignments of 24-bit OUI 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. 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). A 24-bit first portion of this value is the OUI
value assigned to the manufacturer by the IEEE Registration Authority. A 40-bit
second portion of this identifier is assigned by the manufacturer.
For example, assume that a manufacturer's IEEE-assigned
OUI value is AC-DE-48 and the manufacturer-selected extension identifier for a
given component is 23-45-67-AB-CD. The EUI-64 value generated from these two
numbers is AC-DE-48-23-45-67-AB-CD.
Some standards specify an EUI-64 by a string of
eight bytes, labeled as eui[0] through eui[7]. For those
standards, the format of the EUI-64 is illustrated below. Although different
physical standards disagree on the ordering of bit transmissions within bytes,
the bytes are normally transmitted in an ascending index-value order.
| OUI | extension identifier | field | | || eui[0] | eui[1] | eui[2] | eui[3] | eui[4] | eui[5] | eui[6] | eui[7] | order| | | | | | | | || AC | DE | 48 | 23 | 45 | 67 | AB | CD | hex 10101100 11011110 01001000 00100011 01000101 01100111 10101011 11001101 bits
Other standards specify an EUI-64 to be a numerical
value, upon which computations (such as base/bounds or bit selections) can be
performed. For those standards, the format of the EUI-64 is illustrated below:
| OUI | extension identifier | field | | || 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 data bytes eui[0]
through eui[7] should correspond to the lowest through highest byte
addresses.
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 two bytes of the manufacturer's
extension identifier shall must not be FF-FF or FF-FE. Thus, the 64-bit values of
the following form are never assigned EUI-64 values:
XX-XX-XX-FF-FE-YY-YY-YY (an
EUI-48 extension)
XX-XX-XX-FF-FF-YY-YY-YY (a
MAC-48 extension)
The letters 'X' and 'Y' represent hexadecimal digits and show
how the EUI-48 value can be unambiguously encapsulated within the EUI-64 value;
the 'X' and 'Y' digits represent the OUI and extension-identifier portions of
the EUI-48/MAC-48 values, respectively.
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 based globally unique 64-bit
identifiers.
Encapsulated
EUI-48 values
An EUI-48 identifier can be encapsulated and placed within an
EUI-64 container. For example, assume that a manufacturer's IEEE-assigned OUI
value is AC-DE-48 and the manufacturer-selected extension identifier
for a given item is 23-45-67. The EUI-48 value generated from these two numbers
is AC-DE-48-23-45-67, whose byte and bit representations are illustrated below:
| OUI | extension identifier | field | | || AC | DE | 48 | 23 | 45 | 67 | hex 10101100 11011110 01001000 00100011 01000101 01100111 bits
An EUI-64 value is generated by concatenating OUI, FF-FE, and
extension-identifier values. The byte and bit representations for this EUI-64
value are illustrated below:
| OUI | EUI label | extension identifier | field | | | || AC | DE | 48 | FF | FE | 23 | 45 | 67 | hex 10101100 11011110 01001000 11111111 11111110 00100011 01000101 01100111 bits
Encapsulated
MAC-48 values
A MAC-48 identifier can be encapsulated and placed within an
EUI-64 container. For example, assume that a manufacturer's IEEE-assigned OUI value
is AC-DE-48 and the manufacturer-selected extension identifier for a
given item is 01-23-45. The EUI-48 value generated from these two numbers is AC-DE-48-01-23-45,
whose byte and bit representations are illustrated below:
| OUI | extension identifier | field | | || AC | DE | 48 | 01 | 23 | 45 | hex 10101100 11011110 01001000 00000001 00100011 01000101 bits
An EUI-64 value is generated by concatenating OUI, FF-FE, and
extension-identifier values. The byte and bit representations for this EUI-64
value are illustrated below:
| OUI | EUI label | extension identifier | field | | | || AC | DE | 48 | FF | FF | 01 | 23 | 45 | hex 10101100 11011110 01001000 11111111 1111111F 00000001 00100011 01000101 bits
Unassigned
EUI-64 values
The all-zeros and all-ones EUI-64 values will never be
assigned and may be used to represent NULL EUI-64 address values. As an example,
either of these values could represent an uninitialized value, before that location
is accessible or properly initialized by hardware/firmware. Similarly, either
value could represent invalid, when an optional EUI-64 value not supplied.
[1]Except for private company_id OUI
values, where the owner of the
company_id OUI value is confidential. These
shall remain private.
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