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Use of EUI-64 for New Designs

Please note that the RAC is currently considering a specific change to
ensure the integrity of the 48-bit address space. I would be interested in
any comments for this change. Does this effect any coordination issues with
the IETF? I assume these have been handled already, since 1394 uses a 64-bit
address space. I also am not aware of whether 802.3, because of its increase
use of addresses, may also have to consider migration proposals to 64-bit
space.

Please send any comments to Geoff Thompson (chair of RAC) and I.

++++++++++++++++
The IEEE Registration Authority Committee (RAC) has been dealing with the
issue of the possible over-load of the unique 48-bit address space (EUI-48)
for the various standards and products being considered for design today.
The goal is to maintain the integrity of a world-wide unique address for all
product instantiations. Because of the high potential use rate, the RAC
believes that all new designs which use a specific world-wide unique address
SHALL use the 64-bit address space (EUI-64) and those applications which are
currently on a path to use up all the address space currently using the
48-bit address SHALL migrate to the 64-bit space.

We would appreciate feedback and your consideration of this proposal before
a final decision is made to disallow use of EUI48 for new designs. Attached
is the actual guidelines being considered for approval, and your attention
is called to the following section:

"Given the possibility of consuming all the EUI-48 identifiers, the IEEE/RAC
places restrictions on their use. For new standards, EUI-48 identifiers are
restricted to use in low volume applications, such as the identification of
software interface standards or hardware model numbers.

Other new applications (including those that identify distinct hardware
instances) shall not use an EUI-48 identifier; they should use the extended
EUI-64 or other identifiers."

Please provide comments to me by 15Feb2000.

Jim Carlo(jcarlo@ti.com) Cellular:1-214-693-1776 Voice&Fax:1-214-853-5274
TI Fellow, Networking Standards at Texas Instruments
Chair, IEEE802 LAN/MAN Standards Committee
Chair, IEEE-SA NesCom

GUIDELINES FOR USE OF AN
48-BIT GLOBAL IDENTIFIER (EUI-48)

General

The IEEE defined 48-bit global identifier (EUI-48) is assigned by a manufacturer that has been assigned a company_id value by the IEEE Registration Authority. The 48-bit identifier is a concatenation of the 24-bit company_id value assigned by the IEEE Registration Authority and a 24-bit extension identifier assigned by the organization with that company_id assignment.

The IEEE defined 48-bit extended unique identifier (EUI-48) is a concatenation of the 24-bit company_id value by the IEEE Registration Authority and a 24-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-48 value can identify the manufacturer that provided any value[1]. The IEEE/RAC has no control over the assignments of 24-bit extension identifiers and assumes no liability for assignments of duplicate EUI-48 identifiers assigned by manufacturers.

Application restrictions

Given the possibility of consuming all the EUI-48 identifiers, the IEEE/RAC places restrictions on their use within new standards. With the exception of existing applications, EUI-48 identifiers are restricted to use in volume applications, such as the identification of software interface standards or hardware model numbers.

Given the possibility of consuming all the EUI-48 identifiers, the IEEE/RAC places restrictions on their use. For new standards, EUI-48 identifiers are restricted to use in low volume applications, such as the identification of software interface standards or hardware model numbers.

New high-volume applications (such as the identification of distinct hardware instances) shall not use an EUI-48 identifier; they should use the extended EUI-64.

Other new applications (including those that identify distinct hardware instances) shall not use an EUI-48 identifier; they should use the extended EUI-64 or other identifiers.

The term EUI-48 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-48 conform to these restrictions.

Manufacturer-assigned identifiers

The manufacturer identifier assignment allows the assignee to generate approximately 16 million unique EUI-48 values, by varying the last 24 bits. The IEEE intends not to assign another OUI/company_id value to a manufacturer of EUI-48 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.

48-BIT GLOBAL IDENTIFIER FORMAT TUTORIAL

General

The IEEE defined 48-bit global identifier (EUI-48) is assigned by a manufacturer who has been assigned a company_id value by the IEEE Registration Authority. The 48-bit identifier is a concatenation of the 24-bit company_id value assigned by the IEEE Registration Authority and a 24 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-48 value can identify the manufacturer that provided any value. The IEEE/RAC has no control over the assignments of 24-bit extension identifiers and assumes no liability for assignments of duplicate EUI-48 identifiers.

Distribution restrictions

The IEEE has no established policies on the redistribution of EUI-48 values or range of values through third parties.

Format

You may have use for a 48-bit global identifier (EUI-48) in new low-volume applications or for implementations of an existing standard that specifies an EUI-48 or equivalent. 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 24-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 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 
|addr+0 | addr+1 | addr+2 | addr+3 | addr+4 | addr+5| order
|  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

 

The byte-address values (addr+0, addr+2, …) in this illustation correspond to the data-transmission order of existing network applications and the memory-addressing order of ISO/IEC 13213 defined memory-mapped identifiers. However, the mapping of the EUI-48 value to sequential data-byte locations is application dependent and could (in theory) be different in new applications.

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:

  1. 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.
  2. 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.
  3. Documentation. Readily available documentation (see following page).
  4. 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:

  1. This documentation shall be readily available (at no cost) to any purchaser of EUI-64 values.
  2. 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.

GUIDELINES FOR USE OF
24-BIT OUI/company_id IDENTIFIERS WITHIN
48-BIT GLOBAL IDENTIFIER (EUI-48) AND
64-BIT GLOBAL IDENTIFIER (EUI-64)
WHEN DEFINED BY NEW APPLICATIONS

Extended unique identifiers

The IEEE defined 48-bit and 64-bit global identifiers (EUI-48 and EUI-64) are assigned by a manufacturer that has been assigned a company_id value by the IEEE Registration Authority.

The IEEE administers the assignment of 24-bit identifiers. The identifier is formally known as an "Organizationally Unique Identifier" (OUI) or "company_id" when refering to octet-string or binary-number formats respectively. The phrase "OUI/company_id" refers to an identifier in either of these two formats.

The MAC-48 is a concatenation of the 24-bit OUI assigned assigned by the IEEE Registration Authority and a 24-bit extension identifier assigned by the organization with that OUI assignment.

The EUI-48 is a concatenation of the 24-bit company_id value assigned by the IEEE Registration Authority and a 24-bit extension identifier assigned by the organization with that company_id assignment.

The EUI-64 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 EUI-48 and EUI-64 values are intended to be used within applications that require fixed size universal identifiers. Other applications may elect to use variable length identifiers (such as those defined in ASN.1, which support a more flexible and extensible hierarchy of organizational identifiers.

IEEE administered identifiers

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-48 or EUI-64 value can identify the manufacturer that provided any value[1]. The IEEE/RAC has no control over the assignments of the extension identifiers and assumes no liability for assignments of duplicate EUI-48/EUI-64 identifiers assigned by manufacturers.

The 24-bit OUI/company_id value is intended to identify the organization that administers the remaining bits in EUI-48 and EUI-64 values, and should not be used (in isolation) to identify a vendor or the format of vendor-dependent information. A large organization could assign distinct EUI-48 identifiers, so that each division is viewed as a distinct "vendor". Alternatively, small groups within an SDO (standards development organization) could be identified by distinct EUI-48 identifiers administered by their sponsoring body.

Identifier applications

In new applications, the OUI/company_id values shall only be used to generate extended unique identifiers of the following forms:

  • MAC-48. A 48-bit identifier used to address hardware interfaces within 802 based networking applications.
  • EUI-48. A 48-bit identifier used to identify a design instance, as opposed to an hardware instance. Examples include software interface standards (such as VGA) or the model number for a product.
  • EUI-64. A 64-bit identifier used to identify each hardware instance of a product, regardless of application, such as wireless devices and computerized toasters.

The EUI-64 value was originally conceived as a mechanism to avoid excess consumption of OUI/company_id values within high-volume non-networking applications. Given the minimal probability of consuming all the EUI-64 identifiers, the IEEE/RAC places minimal restrictions on their use within standards.

The terms EUI-48 and EUI-64 are 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-48 or EUI-64 conform to these restrictions.

Nonoverlapping assignments

The organization that purchases an OUI/company_id is encouraged to assign only one form of MAC-48/EUI-48 identifier, regardless of application. Manufacturing entities within each organization can generate their EUI-64 assignments by appending an entity-dependent 16-bit sequence number to that code.

The IEEE/RAC recognizes that companies may have assigned distinct groups to administer MAC-48 and EUI-48 identifiers, and these groups (acting independently) may have generated matching MAC-48 and EUI-48 identifiers. This limited form of number-space overlap is discouraged but forbidden.

However, duplication within each of these spaces is forbidden. For example, the EUI-48 values that specify I/O driver software interfaces, language codes, and hardware model numbers shall never overlap. This no-overlap strategy is expected to reduce unintentional duplication of EUI-48 values, by elimination of subjective application-class judgments, although a few more EUI-48 values may be consumed.

Identifier consumption

The manufacturer identifier assignment allows the assignee to generate approximately 1 trillion (1012) unique EUI-64 values, by varying the last 40 bits. Alternatively, the assignee can generate approximately 16 million (106) unique MAC-48/EUI-48 values, by varying the last 24 bits. The IEEE intends not to assign another OUI/company_id value to a manufacturer until the manufacturer has consumed, in product, the preponderance (more than 90%) of the block of potential MAC-48 or EUI-64 words. It is incumbent upon the manufacturer to ensure that large portions of the unique word block are not left unused in manufacturing.

Questions of use

Question: My company has consumed ½ of the MAC-48 address space to distinctively identify networking cards in desktop computers. Another division is planning to produce laptop computers. Should that division apply for a different OUI/company_id identifier?
Answer: No. The organization is responsible for consuming a preponderance of its MAC-48 address space before requesting an additional OUI/company_id identifier. To avoid duplicate address assignments, a central authority should assign blocks of MAC-48 address space to each division, on a demand basis, until all blocks have been consumed.

Question: In my company, division A has consumed ½ of the MAC-48 address space to distinctively identify networking cards. Now division B plans to produce IEEE Std 1394-1995 nodes, which have distinctive EUI-64 identifiers. Can we use the existing OUI/company_id identifier to generate these EUI-64 node identifiers?
Answer: Yes. The same OUI/company_id identifier can be used to generate these EUI-64 identifiers.
Question: Do the previously assigned MAC-48 addresses affect the assignment of future EUI-64 identifiers?
Answer: Previously consumed MAC-48 addresses have no effect on the assignment of future EUI-64 identifiers.

Question: My group is designing an IEEE Std 1394-1995 networking node, which has MAC-48 and EUI-64 identifiers in the 1394 and network interfaces respectively. Since both identifier effectively identify the same node, could the MAC-48 identifier be extended to form the EUI-64?
Answer: Yes. A valid (known to be unique) EUI-64 can be generated by encapsulating the MAC-48 identifier, as described in: GUIDELINES FOR 64-BIT GLOBAL IDENTIFIER (EUI-64) REGISTRATION AUTHORITY
subclause Restricted and encapsulated values.

[1]Except for private company_id values, where the owner of the company_id value is confidential. These shall remain private.