Organizationally unique identifier

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The organization's unique identifier ( OUI ) is a 24-bit number that uniquely identifies a vendor, manufacturer, or other organization.

These are purchased from the Institute of Electrical and Electronics Engineers, Incorporated (IEEE) Authority Registration by "assignee" (IEEE terms for vendors, manufacturers, or other organizations). They are used as the first part of a derivative identifier to uniquely identify a particular piece of equipment such as a MAC address, an Access Protocol Subnetwork protocol identifier, World Wide Names for Fiber Channel devices.

In the MAC address, the OUI is combined with a 24-bit number (given by the owner or 'assignee' OUI) to establish the address. The first three octets of the address are OUI.

Video Organizationally unique identifier

Conventions and Standards Representatives and Formats (IEEE 802-2001)

The following terms are defined (either implicit or explicit) in IEEE Standard 802-2001 for use in reference to the various representations and OUI formats and identifiers that can be made using them.

Hexadecimal Representation

"The representation of the sequence of octet values ​​in which the values ​​of the individual octets are displayed in sequence from left to right, with each octet value represented as a two-digit hexadecimal number, and with a pair generated from hexadecimal digits separated by a dash. hexadecimal in each pair, and mapping between hexadecimal digits and octet bit values, obtained by interpreting octet bit values ​​as binary numbers using normal mathematical rules for digit significance. "(See hexadecimal).

Canonical Format

"The format of the MAC data frame in which the octets of any MAC address passed in the MAC user data field have the same bit sequence as the Hexadecimal Declaration." (See MAC frame data, MAC address)

Order Significance

This arises from the context of the IEEE 802-2001 Standard being another term for 'Hexadecimal Representation' - that is, "by interpreting the octet bit value as a binary number using normal mathematical rules for digit significance."

Bit-Reversed Representation

"The representation of the sequence of octet values ​​in which the values ​​of the individual octets are displayed in sequence from left to right, with each octet value represented as a two-digit hexadecimal number, and with the pair generated from the hexadecimal digits separated by a colon. hexadecimal in each pair, and mapping between hexadecimal digits and octet bit values, obtained by reversing the bit sequence in the octet value and interpreting the resulting bit sequence as binary numbers using normal mathematical rules for digit significance. "

Inverted-bit representation corresponds to the most significant bit-transmission convention of each of the first bytes in serial data communications.

Non-iconic Representation

"The format of the MAC data frame in which the octet of the MAC address delivered in the MAC user data field has the same bit sequence as in the Inverted-Bit representation."

Transmission Sequence

The order in which octets or octet sequences are transmitted through transmission media - this sequence usually corresponds to an inverted bit representation.

Contoh:

OUI consisting of hexadecimal digits ACDE48 ₁₆ will be represented as follows:

 Hexadecimal/Canonical Formats:    AC-DE-48  | OUI |  | Octet 0 | Octet 1 | Octet 2 |  | A C | D E | 4 8 |  | 1010 1100 | 1101 1110 | 0100 1000 |    Bit-reversed/Noncanonical Format:    35: 7B: 12  | OUI |  | Octet 0 | Octet 1 | Octet 2 |  | 3 5 | 7 B | 1 2 |  | 0011 0101 | 0111 1011 | 0001 0010 | 

Potential Confusion in Token Ring Settings

Ethernet users are used to view canonical forms, as in the output of the ifconfig command. The canonical form is the standard in question.

However, since 802.3 (Ethernet) and 802.4 (Token Bus) send bits via cables with the first most significant bits, while 802.5 (Token Ring) and 802.6 (FDDI) send bits over the cable with the most significant first bits, confusion may appear in where OUI in the latter scenario is represented with an inverse bit of canonical representation. So for example, OUI whose canonical form is ACDE48 can be viewed as 357B12 if the translation is done incorrectly or inconsistently. The last form (Bit-Reversed or Non-Canonic representation), can also be referred to in the literature as "MSB format", "IBM format", or "Token Ring format" for this reason. RFC2469 explains the problem in more detail.

Maps Organizationally unique identifier

Format

OUI is usually discussed and represented as a set of octets in hexadecimal notation separated by hyphens (ie, FF-FF-FF) or as an octet set separated by a colon in inverted bit notation (ie, FF: FF: FF).

The two most significant bits of the second octet bite of the hexadecimal representation (ie, the two most significant bits of the first octet) of the OUI are reserved as flag bits for some protocols (eg, 'M' bits and 'X' bits), flags to indicate whether the address is part of an individual (unicast) or group (multicast) address block (eg Individual/Group I/G or Unicast/Multicast [U/M] bit bits), a flag to indicate whether an address is universally managed or local (eg, Universal/Local [U/L] bits) etc., and should not contain values ​​of 1,2,3,5,6,7,9, a, b, d, e, or f except the value -this value reflects the true meaning of these flag bits - if the organization that owns the OUI does not assign one of these bits when creating the identifier, then the second nibble value of the first octet changes accordingly in the representation of the OUI (for example, if the hexadecimal value from the second bite of the first octet is 'C' and bit most significantly regulated, t hen its value being 'D').

Note: "The three-octet value occupying the same field as OUI can be occupied, but with the LSB on the left of the first octet set to 1, locally set and has no relation to the IEEE- set... ".

Contoh:

The following figure shows the position of these bits in the order of significance:

Note: The OUI AC-DE-48 is used only for illustration and this information applies regardless of the true value of the OUI.

Note:

1. The IEEE also refers to the OUI as a 'company_id' when the OUI is written as a base number 16 (ie, as a hexadecimal number without a dash or a colon separating the OUI octets).
2. Here, 'F' and 'h' represent any hexadecimal number.
3. In the following, 'c' represents the digits of 'company_id', and 'e' represents the extension identifier number provided by the organization to whom the OUI is registered.

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Identifier Type

Contrain Contrast 32-bit Contrast (CDI-32)

CDI-32 is an identifier formed by combining a 24-bit OUI with an 8-bit extension identifier defined by the organization that buys OUI - the generated identifier is generally represented as an octet set separated by a dash (hexadecimal notation) or colon (bit notation (FF: FF: FF, as a 4 byte string like in {FF, FF, FF, FF}, or as base 16 as FFFFFFFF ₁₆ .

40-bit Context Dependent Identifier (CDI-40)

IEEE now considers the MAC-48 label as a deprecated term previously used to refer to the specific type of EUI-48 identifier used to handle hardware interfaces (eg, Network Interface Controllers and other network hardware) in existing IEEE 802 based on network applications and should not be used in the future. In contrast, the term EUI-48 should be used by manufacturers and others in the field for this purpose - that is, this identifier is identical to the EUI-48 identifier and is an obsolete label for identical identifiers, though some differences are still made when encapsulating MAC-48 and EUI -48 identifiers in EUI-64 identifier.

48-bit_Extended_Unique_Identifier_.28EUI-48.29 "> 48-bit Extended Unique Identifier (EUI-48)

EUI-48 is an identifier formed by combining a 24-bit OUI with a 24-bit extension identifier defined by the organization that buys OUI - the generated identifier is generally represented as a set of octets separated by dashes (hexadecimal notation) or colon (bit notation (FF: FF: FF: FF: FF, as a string of 6 bytes as in {FF, FF, FF, FF, FF, FF}, FF, FF, FF, FF, FF, FF, or as a basic 16 number as in FFFFFFFFFFFF ₁₆ .

60-bit_Extended_Unique_Identifier_ (EUI-60) "> 60-bit Extended Unique Identifier (EUI-60) /span>

The EUI-60 is an identifier formed by combining a 24-bit OUI with a 36-bit extension identifier defined by the organization that buys OUI - the generated identifier is generally represented by a string of 15 nibbles, as the base 16 number as in FFFFFFFFFFFFFFF ₁₆ , or as FF-FF-FF: FFFFFFFFF as EUI-64 value.

Note: This identifier was previously used as a worldwide worldwide name (WWN) identifier in some storage systems. Its use is now considered to be no longer used by the IEEE and the EUI-64 identifier should be used in the future for this and all other purposes used by the previous EUI-60. Some storage systems where OUI-based variants are used are Fiber Channel, and Serial Attached SCSI (SAS).

64-bit Extended Unique Identifier (EUI-64)

EUI-64 is an identifier formed by combining a 24-bit OUI with a 40-bit extension identifier defined by the organization that buys OUI - the resulting identifier is generally represented as a set of octets separated by dashes (hexadecimal notation) or colon (bit notation -FF: FF: FF: FF: FF: FF: FF: FF, as an 8-byte string as in {FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF}, or as basic 16 as FFFFFFFFFFFFFF ₁₆ .

Note: According to the IEEE guidelines, the first four digits assigned by the organization (that is, the first four digits of the extension identifier) ​​part of the EUI-64 "should not be FFFE ₁₆ or FFFF ₁₆ "(eg, EUI-64 identifiers in the form ccccccFFFEeeeeee and ccccccFFFFeeeeee are not allowed) - this is to support the encapsulation of EUI-48 and MAC-48 values ​​into EUI-64 values.

Other Identifiers

IPv6 uses a 64-bit Modified Extended Unique Identifier (Modified EUI-64) at the bottom of multiple IPv6 addresses. Modified EUI-64 is EUI-64 with inverted U/L bit.

There are other identifiers that can be established using OUI but the ones listed above are the most commonly used.

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Encapsulating

Other identifiers, such as MAC-48 and EUI-48 values, may be contained in larger identifiers or 'containers', such as EUI-64, by creating larger identifiers through the process of combining smaller identifiers with the specified value placed in position bit bits in the larger identifier - this process is known as 'encapsulation' and is provided for the purpose of facilitating the transition from MAC-48 and EUI-48 to EUI-64 and provides mechanisms for conversion of MAC- 48 and EUI-48 identifiers for EUI-64 in such a way that duplication or contradictory values ​​are avoided.

Encapsulation Example

MAC-48 Encapsulation in EUI-64 Example:

Assuming that the organization has registered the OUI AC-DE-48 and that the organization has created the value of MAC-48 AC-DE-48-23-45-67 by combining the extension identifier 23-45-67, this MAC -48 identifier has a transmission sequence binary as follows:

The same MAC-48 identifier after encapsulation in the EUI-64 has the following transmission sequence:

The same MAC-48 identifier after encapsulation in EUI-64 has the following order of significance:

EUI-48 Encapsulation in EUI-64 Example:

Assuming that the organization has registered the OUI AC-DE-48 and that the organization has created the value of EUI-48 AC-DE-48-23-45-67 by combining the extension identifier 23-45-67, this EUI -48 identifier has the following format in order of significance:

The identical EUI-48 identifier after encapsulation in the EUI-64 has the following format in the order of significance:

MAC-48 or EUI-48 Encapsulation in Modified EUI-64 Example:

In encapsulation in Modified EUI-64, MAC-48 is treated as EUI-48 and the U/L bit is reversed. Assuming that the organization has registered the OUI AC-DE-48 and that the organization has created a MAC-48 or EUI-48 value of AC-DE-48-23-45-67 by combining the extension identifier 23-45-67, MAC-48 or The EUI-48 identifier has the following format in the order of significance:

The identification of the same MAC-48 or EUI-48 after encapsulation in Modified EUI-64 has the following format in the order of significance:

NAA Name_Identifier

Network Address Authority (NAA) Format Name_Identifier specifies the first nibble (4 bits) to determine the format of the identifier:

This encapsulation is used in Fiber Channel and SAS, and is also supported on iSCSI on RFC 3980. This addition requires either a shorter vendor-specific field identifier, or some OUI bit assumed 0, such as when using EUI-64 Mapped format.

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Block Individual Address

Individual Address Block (IAB) is an identifier block formed by combining a 24-bit Unique Organizational Identifier (OUI) owned by the IEEE Registration Authority with additional additional 12-bit identifiers assigned by the IEEE Enrollment Authority and then order an additional 12 bits for use by the assignee. The generated 48-bit identifier uniquely identifies the IAB receiver and assigns 4096 unique EUI-48 numbers for use by organizations that purchase IAB. The assignee can create a unique identifier by combining the 12-bit extension identifiers set by the organization that purchased IAB in bit positions occupied by the aforementioned 12-bit additions. The purpose of the IAB is to allow organizations to purchase smaller identification blocks.

The IEEE Registration Authority differentiates between IAB and OUI-36 scores. Both are 36-bit values ​​that can be used to generate EUI-48 values, but IAB can not be used to generate EUI-64 values.

EUI-48 example created in the IAB: The EUI-48 identifier is formed by combining a 36-bit IEEE that provides an IAB base value with a 12-bit extension identifier defined by the organization - for example, if the IAB given the IEEE is FF-FF-FF-FF-F0-00 and 12-bit extension identifiers are hhh ₁₆ , then the resulting EUI-48 by combining these two numbers is FF -FF-FF- FF-Fh-hh.

Note: There is an IAB sequence based on CDI-40 formed by combining a 36-bit IEEE that provides an IAB base value with a 4-bit extension identifier defined by the organization - for example, if the IEEE assigned IAB base value is FF-FF- FF-FF-F0-00 and the 4-bit extension identifier is 0h ₁₆ , then the resulting CDI-40 value by combining these two numbers is FF-FF-FF-FF-Fh.

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Compare with

• Unique Global Identifier (GUID)
• Object identifier (OID)
• Personal Company Number (PEN)

src: cf.ppt-online.org

See also

• MAC Address
• Block Individual Address

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References

src: cf.ppt-online.org

External links

• IEEE Registration Authority Tutorial
• IEEE Registration Authority - Frequently Asked Questions
• IEEE Public OUI and Company_id Assignment lookup
• IEEE Public OUI List
• List of IEEE Public IAB
• IEEE IAB and OUI MAC Address Lookup Database and API
• IANA Considerations and Use of the IETF Protocol for IEEE 802 Parameters
• IANA List of Ethernet Numbers
• Wireshark's OUI Search tool and MAC address list
• Mac address vendor search (OUI Lookup)

Source of the article : Wikipedia