| Internet-Draft | IANA/IETF and IEEE 802 Parameters | April 2023 |
| Eastlake, et al. | Expires 16 October 2023 | [Page] |
Some IETF protocols make use of Ethernet frame formats and IEEE 802 parameters. This document discusses several aspects of such parameters and their use in IETF protocols, specifies IANA considerations for assignment of points under the IANA OUI (Organizationally Unique Identifier), and provides some values for use in documentation. This document obsoletes RFC 7042.¶
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Some IETF protocols use Ethernet or other IEEE 802-related communication frame formats and parameters [IEEE802]. These include MAC (Media Access Control) addresses and protocol identifiers. The IEEE Registration Authority [IEEE-RA] manages the assignment of identifiers used in IEEE 802 networks, in some cases assigning blocks of such identifiers whose sub-assignment is managed by the entity to which the block is assigned. The IEEE RA also provides a number of tutorials concerning these parameters [IEEEtutorials].¶
Descriptions herein of [IANA] policies and procedures are authoritative but descriptions of IEEE registration policies, procedures, and standards are only informative; for authoritative IEEE information, consult the IEEE sources.¶
IANA has been assigned an Organizationally Unique Identifier (OUI) by the IEEE RA and an associated set of MAC addresses and other organanizationally unique code points based on that OUI. This document specifies IANA considerations for the assignment of code points under that IANA OUI, including MAC addresses and protocol identifiers, and provides some values for use in documentation. As noted in [RFC2606] and [RFC5737], the use of designated code values reserved for documentation and examples reduces the likelihood of conflicts and confusion arising from such code points conflicting with code points assigned for some deployed use. This document also discusses several other uses by the IETF of IEEE 802 code points, including IEEE 802 Connectivity Fault Management (CFM) code points [RFC7319] and IEEE 802 Link Local Discovery Protocol (LLDP [IEEE802.1AB]) Organizationally-Specific TLV Sub-Types [RFC8520]. It also specifies CBOR tags for MAC addresses and OUI/CIDs.¶
[RFC8126] is incorporated herein except where there are contrary provisions in this document. In this document, "IESG Ratification" is used in some cases. "IESG Ratification" is specified in Section 5.1. It is NOT the same as "IESG Approval" in [RFC8126].¶
This document uses hexadecimal notation. Each octet (that is, 8-bit byte) is represented by two hexadecimal digits giving the value of the octet as an unsigned integer. Successive octets are separated by a hyphen. This document consistently uses IETF ("network") bit ordering although the physical order of bit transmission within an octet on an IEEE [IEEE802.3] link is from the lowest order bit to the highest order bit (i.e., the reverse of the IETF's ordering).¶
In this document:¶
This document obsoletes [RFC7042] and makes the changes listed below. However, the completed application template based upon which an IANA OUI-based protocol number value was assigned for document use remains that in Appendix C of RFC 7042.¶
Originally the responsibility of Xerox Corporation, the registration authority for Ethernet parameters since 1986 has been the IEEE Registration Authority, available on the web at [IEEE-RA].¶
The IEEE Registration Authority operates under the direction of the IEEE Standards Association (IEEE-SA) Board of Governors, with oversight by the IEEE Registration Authority Committee (RAC). The IEEE RAC is a committee of the Board of Governors.¶
Anyone may apply to that Authority for parameter assignments. The IEEE Registration Authority may impose fees or other requirements but commonly waives fees for applications from standards development organizations. Lists of assignments and their holders are downloadable from the IEEE Registration Authority site.¶
The Organizationally Unique Identifier (OUI) 00-00-5E has been assigned to IANA by the IEEE Registration Authority.¶
There is no OUI value reserved at this time for documentation, but there are documentation code points under the IANA OUI specified below.¶
IEEE Std 802.1Q [IEEE802.1Q] allocates two blocks of 802 Connectivity Fault Management (CFM) code points to the IETF, one for CFM OpCodes and one for CFM TLV Types. For further information see [RFC7319]. The IANA "Connectivity Fault Management (CFM) OAM IETF Parameters" Registry has subregistries for these code points. This document does not further discuss these blocks of code points.¶
This section includes information summarized from [IEEE802_OandA] that is being provided for context. The definitive information, which prevails in case of any discrepancy, is in [IEEE802_OandA].¶
Section 2.1 discusses 48-bit MAC identifiers, their relationship to OUIs and other prefixes, and assignment under the IANA OUI. Section 2.2 extends this to 64-bit identifiers. Section 2.3 discusses other IETF MAC identifier use not under the IANA OUI. Section 2.4 specifies CBOR tags for MAC addresses and OUI/CIDs.¶
Historical Note: [RAC_OUI] is an expired draft that provides additional historic information on [IEEE802] registries.¶
48-bit MAC "addresses" are the most commonly used Ethernet interface identifiers. Those that are globally unique are also called EUI‑48 identifiers (Extended Unique Identifier 48). An EUI‑48 is structured into an initial prefix assigned by the IEEE Registration Authority and additional bits assigned by the prefix owner. Currently there are three lengths of prefixes assigned, as shown in the table below; however, some prefix bits can have special meaning as shown in Figure 1.¶
| Prefix Length in bits | Name> | Owner Supplied Bits for 48‑bit MAC Addresses |
|---|---|---|
| 24 | MA-L | 24 |
| 28 | MA-M | 20 |
| 36 | MA-S | 12 |
The bottom (least significant) four bits of the first octet of the 3-octet 48-bit MAC have special meaning, as shown in Figure 1, and are referred to below as the M, X, Y, and Z bits.¶
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | . . . . Z Y X M| . . . . . . . .| octets 0+1 +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | . . . . . . . .| . . . . . . . .| octets 2+3 +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | . . . . . . . .| . . . . . . . .| octets 4+5 +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
For global addresses, X=0 and a MAC address begins with 3 octets or a larger initial prefix indicating the assignee of the block of MAC addresses. This prefix is followed by a sequence of additional octets so as to add up to the total MAC address length. For example, the IEEE assigns MA-S (MAC Address Block Small), where the first 4 1/2 octets (36 bits) are assigned, giving the holder of the MA-S 1 1/2 octets (12 bits) they can control in constructing 48-bit MAC addresses; other prefix lengths are also available [RAC_OUI].¶
An AFN, a DNS RRTYPE, and a CBOR tag have been assigned for 48-bit MAC addresses as discussed in Sections 2.4, 5.3 and 5.9.¶
IEEE Std 802 describes assignment procedures and policies for IEEE 802-related identifiers [IEEE802_OandA]. IEEE-RA documentation on EUIs, OUIs, and CIDs is available at [RAC_OUI].¶
Four bits within the initial octet of an IEEE MAC interface identifier, such as an EUI‑48, have special significance [IEEE802_OandA] as follows:¶
| Y bit | Z bit | Quadrant |
|---|---|---|
| 0 | 0 | Administratively Assigned |
| 0 | 1 | Extended Local |
| 1 | 0 | Reserved |
| 1 | 1 | Standard Assigned |
While a local network administrator can assign any addresses with the X bit a one, the optional SLAP characterizes the four quadrants of the "local" address space using the Y and Z bits as follows:¶
NOTE: While the SLAP has MAC addresses assigned through a local protocol in the SAI quadrant and assigned by a protocol specified in an IEEE 802 standard, the SLAP is optional. Local network administrators may use the IETF protocol provisions in [RFC8947] and [RFC8948] which support assignment of a MAC address in the local MAC address space using DHCPv6 [RFC8415] or other protocol methods.¶
MA-L, MA-M, and MA-S MAC prefixes are assigned with the Local bit zero. The assignee of an OUI is exclusively authorized to assign group MAC addresses by extending a modified version of the assigned OUI in which the M bit (see Figure 1) is set to 1 [RAC_OUI].¶
The Local bit is zero for globally unique EUI‑48 identifiers assigned by the owner of a MAC-L or owner of a longer prefix. If the Local bit is a one, the identifier has historically been a local identifier under the control of the local network administrator; however, there are now recommendations on optional management of the local address space as discussed in Section 2.1.1. If the Local bit is a one, the holder of an OUI has no special authority over MAC identifiers whose first 3 octets correspond to their OUI or the beginning of their longer prefix.¶
A CID is a 24-bit Company Identifier. It is assigned for organizations that need such an identifier that can be used in place of an OUI, but do not need to assign subsidiary global MAC addresses. A CID has X and Z bits equal to 1 and its Y bit equal to 0 (see Figure 1).¶
An AFN and a CBOR tag have been assigned for OUI/CIDs as discussed in Sections 2.4, 5.3 and 5.9.¶
The OUI 00‑00‑5E has been assigned to IANA as stated in Section 1.4 above. This includes 2**24 48‑bit multicast identifiers from 01‑00‑5E‑00‑00‑00 to 01‑00‑5E‑FF‑FF‑FF and 2**24 EUI‑48 unicast identifiers from 00‑00‑5E‑00‑00‑00 to 00‑00‑5E‑FF‑FF‑FF.¶
Of these identifiers, the sub-blocks reserved or thus far assigned are as follows:¶
Unicast, all blocks of 2**8 addresses thus far:¶
Multicast:¶
For more detailed and up-to-date information, see the "Ethernet Numbers" registry at [EthernetNum].¶
The following values have been assigned for use in documentation:¶
48-bit assignments under the current or a future IANA OUI (see Section 5.6) must meet the following requirements:¶
In addition, approval must be obtained as follows (see the procedure in Section 5.1):¶
IEEE also defines a system of 64-bit MAC identifiers including EUI‑64s. EUI‑64 identifiers are currently used as follows:¶
Adding a 5-octet (40-bit) extension to a 3-octet (24-bit) assignment, or a shorter extension to longer assigned prefixes [RAC_OUI] so as to total 64 bits, produces an EUI‑64 identifier under that OUI or longer prefix. As with EUI‑48 identifiers, the first octet has the same special low order bits.¶
An AFN, a DNS RRTYPE, and CBOR tag have been assigned for 64-bit MAC addresses as discussed in Sections 2.4, 5.3, and 5.9.¶
The discussion below is almost entirely in terms of the "Modified" form of EUI‑64 identifiers; however, anyone assigned such an identifier can also use the unmodified form as a MAC identifier on any link that uses such 64-bit identifiers for interfaces.¶
EUI‑64 identifiers are used to form the lower 64 bits of some IPv6 addresses (Section 2.5.1 and Appendix A of [RFC4291] and Appendix A of [RFC5214]). When so used, the EUI‑64 is modified by inverting the X (Local/Global) bit to form an IETF "Modified EUI‑64 identifier". Below is an illustration of a Modified EUI‑64 unicast identifier under the IANA OUI, where aa-bb-cc-dd-ee is the extension.¶
02-00-5E-aa-bb-cc-dd-ee¶
The first octet is shown as 02 rather than 00 because, in Modified EUI‑64 identifiers, the sense of the X bit is inverted compared with EUI‑48 identifiers. It is the globally unique values (universal scope) that have the 02 bit on in the first octet, while those with this bit off are typically locally assigned and out of scope for global assignment.¶
The X (Local/Global) bit was inverted to make it easier for network operators to type in local-scope identifiers. Thus, such Modified EUI‑64 identifiers as 1, 2, etc. (ignoring leading zeros) are local. Without the modification, they would have to be 02-00-00-00-00-00-00-01, 02-00-00-00-00-00-00-02, etc. to be local.¶
As with 48-bit MAC identifiers, the M-bit (0x01) on in the first octet indicates a group identifier (multicast or broadcast).¶
When the first two octets of the extension of a Modified EUI‑64 identifier are FF-FE, the remainder of the extension is a 24-bit value as assigned by the OUI owner for an EUI‑48. For example:¶
02-00-5E-FF-FE-yy-yy-yy¶
or¶
03-00-5E-FF-FE-yy-yy-yy¶
where yy-yy-yy is the portion (of an EUI‑48 global unicast or multicast identifier) that is assigned by the OUI owner (IANA in this case). Thus, any holder of one or more EUI‑48 identifiers under the IANA OUI also has an equal number of Modified EUI‑64 identifiers that can be formed by inserting FF-FE in the middle of their EUI‑48 identifiers and inverting the Local/Global bit.¶
In addition, certain Modified EUI‑64 identifiers under the IANA OUI are reserved for holders of IPv4 addresses as follows:¶
02-00-5E-FE-xx-xx-xx-xx¶
where xx-xx-xx-xx is a 32-bit IPv4 address. The owner of an IPv4 address has both a unicast- and multicast-derived EUI‑64 address. Modified EUI‑64 identifiers from¶
02-00-5E-FE-F0-00-00-00 to 02-00-5E-FE-FF-FF-FF-FF¶
are effectively reserved pending the specification of IPv4 "Class E" addresses [RFC1112]. However, for Modified EUI‑64 identifiers based on an IPv4 address, the Local/Global bit should be set to correspond to whether the IPv4 address is local or global. (Keep in mind that the sense of the Modified EUI‑64 identifier Local/Global bit is reversed from that in (unmodified) EUI‑64 identifiers.)¶
The following table shows which Modified EUI‑64 identifiers under the IANA OUI are reserved, assigned, or available as indicated. As noted above, the corresponding MAC addresses can be determined by complementing the 02 bit in the first octet. In all cases, the corresponding multicast 64-bit MAC addresses formed by complementing the 01 bit in the first octet have the same status as the modified 64-bit unicast address blocks listed below.¶
The reserved identifiers above require IESG Ratification (see Section 5.1) for assignment. IANA EUI‑64 identifier assignments under the IANA OUI must meet the following requirements:¶
In addition, approval must be obtained as follows (see the procedure in Section 5.1):¶
The following blocks of unmodified 64-bit MAC addresses are for documentation use. The IPv4-derived addresses are based on the IPv4 documentation addresses [RFC5737], and the MAC-derived addresses are based on the EUI‑48 documentation addresses above.¶
Unicast values for Documentation Use:¶
00‑00‑5E‑EF‑10‑00‑00‑00 to 00‑00‑5E‑EF‑10‑00‑00‑FF general¶
00‑00‑5E‑FE‑C0‑00‑02‑00 to 00‑00‑5E‑FE‑C0‑00‑02‑FF and 00‑00‑5E‑FE‑C6‑33‑64‑00 to 00‑00‑5E‑FE‑C6‑33‑64‑FF and 00‑00‑5E‑FE‑CB‑00‑71‑00 to 00‑00‑5E‑FE‑CB‑00‑71‑FF IPv4 derived¶
00‑00‑5E‑FF‑FE‑00‑53‑00 to 00‑00‑5E‑FF‑FE‑00‑53‑FF EUI‑48 derived¶
00‑00‑5E‑FE‑EA‑C0‑00‑02 and 00‑00‑5E‑FE‑EA‑C6‑33‑64 and 00‑00‑5E‑FE‑EA‑CB‑00‑71 IPv4 multicast derived from IPv4 unicast [RFC6034]¶
Multicast values for Documentation Use:¶
01‑00‑5E‑EF‑10‑00‑00‑00 to 01‑00‑5E‑EF‑10‑00‑00‑FF general¶
01‑00‑5E‑FE‑C0‑00‑02‑00 to 01‑00‑5E‑FE‑C0‑00‑02‑FF and 01‑00‑5E‑FE‑C6‑33‑64‑00 to 01‑00‑5E‑FE‑C6‑33‑64‑FF and 01‑00‑5E‑FE‑CB‑00‑71‑00 to 01‑00‑5E‑FE‑CB‑00‑71‑FF IPv4 derived¶
01‑00‑5E‑FE‑EA‑C0‑00‑02 and 01‑00‑5E‑FE‑EA‑C6‑33‑64 and 01‑00‑5E‑FE‑EA‑CB‑00‑71 IPv4 multicast derived from IPv4 unicast [RFC6034]¶
01‑00‑5E‑FF‑FE‑90‑10‑00 to 01‑00‑5E‑FF‑FE‑90‑10‑FF EUI‑48 derived¶
There are two other blocks of 48-bit MAC identifiers that are used by the IETF as described below.¶
All 48-bit multicast MAC identifiers prefixed "33-33" (that is, the 2**32 multicast MAC identifiers in the range from 33-33-00-00-00-00 to 33-33-FF-FF-FF-FF) are used as specified in [RFC2464] for IPv6 multicast. In all of these identifiers, the Group bit (the bottom bit of the first octet) is on, as is required to work properly with existing hardware as a multicast identifier. They also have the Local bit on but any Ethernet using standard IPv6 multicast should note that these addresses will be used for that purpose. These multicast MAC addresses fall into the Administratively Assigned SLAP quadrant (see Section 2.1.1).¶
Historical notes: It was the custom during IPv6 design to use "3" for unknown or example values and 3333 Coyote Hill Road, Palo Alto, California, is the address of PARC (Palo Alto Research Center, formerly "Xerox PARC"). Ethernet was originally specified by the Digital Equipment Corporation, Intel Corporation, and Xerox Corporation. The pre-IEEE [IEEE802.3] Ethernet protocol has sometimes been known as "DIX" Ethernet from the first letters of the names of these companies.¶
The Informational [RFC2153] declared the 3-octet values from CF-00-00 through CF-FF-FF to be "OUIs" available for assignment by IANA to software vendors for use in PPP [RFC1661] or for other uses where vendors do not otherwise need an IEEE-assigned OUI. When used as 48-bit MAC prefixes, these values have all of the Z, Y, X (Local), and M (Group) special bits at the bottom of the first octet equal to one, while all IEEE-assigned OUIs thus far have the X and M bits zero and all CIDs have bits Y and M zero; thus, there can be no conflict between CF Series "OUI"s and IEEE assigned OUI/CIDs. Multicast MAC addresses constructed with a "CF" series OUI would fall into the Standard Assigned SLAP quadrant (see Section 2.1.1). The Group bit is meaningless in PPP. To quote [RFC2153]: "The 'CF0000' series was arbitrarily chosen to match the PPP NLPID 'CF', as a matter of mnemonic convenience." (For further information on NLPIDs, see [RFC6328].)¶
CF-00-00 is reserved, and IANA lists multicast identifier¶
CF-00-00-00-00-00 is used for Ethernet loopback tests.¶
In over a decade of availability, only a handful of values in the CF Series have been assigned. (See "IANA OUI Ethernet Numbers" [EthernetNum] and "PPP Numbers" [PPPNum] ).¶
The IANA Considerations in [RFC2153] were updated as follows by the approval of RFC 5342 and remain so updated (no technical changes have been made):¶
The Concise Binary Object Representation (CBOR [RFC8949]) is a data format whose design goals include the possibility of very small code size, fairly small message size, and extensibility. In CBOR, a data item can be enclosed by a CBOR tag to give it some additional semantics identified by that tag. CBOR tagged data items (fields) are not used in actual IEEE 802 address fields but may be used in CBOR encoded parts of protocol messages.¶
IANA has assigned TBD1 as the CBOR tag to indicate a MAC address. The enclosed data item is an octet string. The length of the octet string indicates whether a 48-bit (6 octet) or 64-bit (8 octet) MAC address is encoded. Should some other multiple of 8 bits length MAC addresses be used in the future, such as a 128-bit (16 octet) MAC address, the TBD1 tag will be used.¶
IANA has assigned TDB2 as the CBOR tag to indicate an OUI, CID, or "CF" series organizational identifier. The enclosed data item is a octet string of length 3 to hold the 24-bit OUI or CID (see Section 2.1.2).¶
Ethernet protocol parameters provide a means of indicating the contents of a frame -- for example, that its contents are IPv4 or IPv6.¶
There are two types of protocol identifier parameters (See [EthernetNum]) that can occur in Ethernet frames after the initial MAC address destination and source identifiers:¶
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | Source MAC Address /// +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | Destination MAC Address /// +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | EtherType, greater than or equal to 0x0600 | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | Protocol Data /// +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | Source MAC Address /// +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | Destination MAC Address /// +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | Frame length (or 0x8870) | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | DSAP | SSAP | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | CTL = 0x03 | Protocol Data /// +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
The concept has been extended to labeling by Ethernet "tags". An Ethernet tag in this sense is a prefix whose type is identified by an EtherType that is then followed by either another tag, an EtherType, or an LSAP (Link-Layer Service Access Point) protocol indicator for the "main" body of the frame, as described below. Traditionally, in the [IEEE802_OandA] world, tags are a fixed length and do not include any encoding of their own length. Any device that is processing a frame cannot, in general, safely process anything in the frame past an EtherType it does not understand. An example is the C-Tag (formerly the Q-Tag) [IEEE802.1Q]. It provides customer VLAN and priority information for a frame.¶
Neither EtherTypes nor LSAPs are assigned by IANA; they are assigned by the IEEE Registration Authority [IEEE-RA] (see Section 1.3 above and Appendix B). However, both LSAPs and EtherTypes have extension mechanisms so that they can be used with five-octet Ethernet protocol identifiers under an OUI, including those assigned by IANA under the IANA OUI.¶
When using the IEEE 802 Logical Link Control (LLC) format (Subnetwork Access Protocol (SNAP)) [IEEE802_OandA] for a frame, an OUI-based protocol identifier can be expressed as follows:¶
xx‑xx‑AA‑AA‑03‑yy‑yy‑yy‑zz‑zz¶
where xx‑xx is the frame length and, as above, must be small enough not to be confused with an EtherType; "AA" is the LSAP that indicates this use and is sometimes referred to as the SNAP Service Access Point (SNAP SAP); "03" is the LLC control octet indicating datagram service; yy‑yy‑yy is an OUI; and zz‑zz is a protocol number, under that OUI, assigned by the OUI owner. The five-octet length for such OUI-based protocol identifiers results, with the LLC control octet ("0x03"), in the preservation of 16-bit alignment.¶
When using an EtherType to indicate the main type for a frame body, the special "OUI Extended EtherType" 0x88B7 is available. Using this EtherType, a frame body can begin with¶
88‑B7‑yy‑yy‑yy‑zz‑zz¶
where yy‑yy‑yy and zz‑zz have the same meaning as in the SNAP format described above.¶
It is also possible, within the SNAP format, to use an arbitrary EtherType. Putting the EtherType as the zz‑zz field after an all-zeros OUI (00‑00‑00) does this. It looks like¶
xx‑xx‑AA‑AA‑03‑00‑00‑00‑zz‑zz¶
where zz‑zz is the EtherType.¶
As well as labeling frame contents, 802 protocol types appear within NBMA (Non-Broadcast Multi-Access) Next Hop Resolution Protocol [RFC2332] messages. Such messages have provisions for both two-octet EtherTypes and OUI-based protocol types. 16-bit EtherTypes also occur in the Generic Router Encapsulation (GRE [RFC2784]) header.¶
Two-octet protocol numbers under the IANA OUI are available, as in¶
88‑B7‑00‑00‑5E‑qq‑qq¶
or¶
xx‑xx‑AA‑AA‑03‑00‑00‑5E‑qq‑qq¶
where qq‑qq is the protocol number.¶
A number of such assignments have been made out of the 2**16 protocol numbers available from 00‑00‑5E‑00‑00 to 00‑00‑5E‑FF‑FF (see [EthernetNum]). The extreme values of this range, 00‑00‑5E‑00‑00 and 00‑00‑5E‑FF‑FF, are reserved and require IESG Ratification for assignment (see Section 5.1). New assignments of protocol numbers (qq‑qq) under the IANA OUI must meet the following requirements:¶
In addition, the Expert Review (or IESG Ratification for the two reserved values) must be obtained using the procedure specified in Section 5.1.¶
0x0042 is a protocol number under the IANA OUI (that is, 00‑00‑5E‑00‑42) to be used as an example for documentation purposes.¶
Some IEEE 802 and other protocols provide for parameters based on an OUI or CID beyond those discussed above. Such parameters commonly consist of an OUI or CID plus one octet of additional value. They are called Organizationally-Specific parameters (sometimes informally and less accurately referred to as "vendor specific"). They would look like¶
yy‑yy‑yy‑zz¶
where yy‑yy‑yy is the OUI/CID and zz is the additional specifier. An example is the Cipher Suite Selector in [IEEE802.11].¶
Values may be assigned under the IANA OUI for such other OUI-based parameter usage by Expert Review except that, for each use, the additional specifier values consisting of all zero bits and all one bits (0x00 (00‑00‑5E‑00) and 0xFF (00‑00‑5E‑FF) for a one-octet specifier) are reserved and require IESG Ratification (see Section 5.1) for assignment; also, the additional specifier value 0x42 (00‑00‑5E‑42 for a one octet specifier, right justified and filled with zeros on the left if the specifier is more than one octet) is assigned for use as an example in documentation.¶
Assignments of such other IANA OUI-based parameters must be for standards use (either for an IETF Standard or other standard related to IETF work) and be documented in an Internet-Draft or RFC. The first time a value is assigned for a particular parameter of this type, an IANA registry will be created to contain that assignment and any subsequent assignments of values for that parameter under the IANA OUI. The Expert may specify the name of the registry.¶
If different policies from those above are required for such a parameter, a BCP or Standards Track RFC should be adopted to update this BCP and specify the new policy and parameter.¶
An example of such an "other IANA OUI based parameter" is specified in [RFC8520]. This provides for an Organizationally-Specific TLV type for announcing a Manufacturer Usage Description (MUD) Uniform Resource Locator (URL) in the IEEE Link Local Discovery Protocol (LLDP [IEEE802.1AB]). Additional IETF use of code points in this space have been proposed [BGP11dp]. (See also Section 5.8.)¶
This document concerns IANA considerations for the assignment of Ethernet parameters in connection with the IANA OUI and related matters.¶
Note: The "IETF OUI Ethernet Numbers" IANA web page is for registries of numbers assigned under the IANA OUI while the "IEEE 802 Numbers" IANA web page has Informational lists of numbers assigned by the IEEE Registration Authority.¶
This document does not create any new IANA registries.¶
The MAC address values assigned for documentation and the protocol number for documentation were both assigned by [RFC7042].¶
No existing assignment is changed by this document.¶
This section specifies the procedure for Expert Review and IESG Ratification of MAC, protocol, and other IANA OUI-based identifiers. The Expert(s) referred to in this document shall consist of one or more persons appointed by and serving at the pleasure of the IESG.¶
The procedure described for Expert Review assignments in this document is consistent with the IANA Expert Review policy described in [RFC8126].¶
While finite, the universe of MAC code points from which Expert-judged assignments will be made is felt to be large enough that the requirements given in this document and the Experts' good judgment are sufficient guidance. The idea is for the Expert to provide a light sanity check for small assignments of MAC identifiers, with increased scrutiny by the Expert for medium-sized assignments of MAC identifiers and assignments of protocol identifiers and other IANA OUI-based parameters. However, it can make sense to assign very large portions of the MAC identifier code point space. (Note that existing assignments include one for 1/2 of the entire multicast IANA 48‑bit code point space and one for 1/16 of that multicast code point space.) In those cases, and in cases of the assignment of "reserved" values, IESG Ratification of an Expert Review approval recommendation is required as described below. The procedure is as follows:¶
The applicant always completes the appropriate template from Appendix A below and sends it to IANA <iana@iana.org>.¶
IANA always sends the template to an appointed Expert. If the Expert recuses themselves or is non-responsive, IANA may choose an alternative appointed Expert or, if none is available, will contact the IESG.¶
In all cases, if IANA receives a disapproval from an Expert selected to review an application template, the application will be denied. The Expert should provide a reason for refusal which IANA will communicate back to the applicant.¶
If the assignment is based on Expert Review:¶
If IANA receives approval and code points are available, IANA will make the requested assignment.¶
If the assignment is based on IESG Ratification:¶
The procedure starts with the first steps above for Expert Review. If the Expert disapproves the application, they simply inform IANA who in turn informs the applicant that their request is denied; however, if the Expert believes the application should be approved, or is uncertain and believes that the circumstances warrant the attention of the IESG, the Expert will inform IANA about their advice, and IANA will forward the application, together with the reasons provided by the Expert for approval or uncertainty, to the IESG. The IESG must decide whether the assignment will be granted. This can be accomplished by a management item in an IESG telechat as is done for other types of requests. If the IESG decides not to ratify a favorable opinion by the Expert or decides against an application where the Expert is uncertain, the application is denied; otherwise, it is granted. The IESG will communicate its decision to the Expert and to IANA. In case of refusal, the IESG should provide a reason which IANA will communicate to the applicant.¶
For clarity and parallelism with the IANA "IEEE 802 Numbers" web page, the IANA "Ethernet Numbers" web page is re-named the "IANA OUI Ethernet Numbers" web page.¶
As this document replaces [RFC7042], references to [RFC7042] in IANA registries on both the IANA IEEE 802 Numbers web page and the IANA IETF OUI Ethernet Numbers web pages will be replaced by references to [this document]. Other IANA web page references to [RFC7042] are not changed.¶
IANA has assigned Address Family Numbers (AFNs) for MAC addresses as follows:¶
| AFN | Decimal | Hex | Reference |
|---|---|---|---|
| 48-bit MAC | 16389 | 0x4005 | [RFC7042] |
| 64-bit MAC | 16390 | 0x4006 | [RFC7042] |
| 24-bit OUI | 16391 | 0x4007 | [RFC7961] |
| Lower 24 bits of a 48-bit MAC address: | |||
| MAC/24 | 16392 | 0x4008 | [RFC7961] |
| Lower 40 bits of a 64-bit MAC address: | |||
| MAC/40 | 16393 | 0x4009 | [RFC7961] |
IANA has assigned DNS RRTYPEs [RFC6895] for MAC addresses as follows:¶
| RRTYPE Code | ||||
|---|---|---|---|---|
| Data | Mnemonic | Decimal | Hex | Reference |
| 48-bit MAC | EUI48 | 108 | 0x006C | [RFC7043] |
| 64-bit MAC | EUI64 | 109 | 0x006D | [RFC7043] |
IANA maintains an informational listing on its web site concerning EtherTypes, OUIs, and multicast addresses assigned under OUIs other than the IANA OUI. The title of this informational registry is "IEEE 802 Numbers". IANA will update that informational registry when changes are provided by or approved by the Expert(s).¶
Applying to the IEEE Registration Authority for an EtherType needed by an IETF protocol requires IESG approval as stated in Appendix B. To minimize confusion, this process will normally be done by the primary expert for the informational IANA 802 Numbers EtherType registry (see Section 5.2).¶
After IESG approval of the requirement for an EtherType, the IESG should refer the matter to IANA. In any case, IANA will ask the IANA IEEE 802 Numbers EtherType registry expert to execute the IEEE EtherType assignment request process.¶
When the available space for either multicast or unicast EUI‑48 identifiers under OUI 00-00-5E has been 90% or more exhausted, IANA should request an additional OUI from the IEEE Registration Authority for further IANA assignment. The appointed Expert(s) should monitor for this condition and notify IANA.¶
No changes are made by this document to the "IANA Unicast 48-bit MAC Addresses" and "IANA Multicast 48-bit MAC Addresses" tables except for the updates to references as specified in Section 5.2.¶
IANA is requested to move the "IANA Link Layer Discovery Protocol (LLDP) TLV Subtypes" Registry from the IANA IEEE 802 Numbers web page to the IANA OUI Ethernet Numbers web page, since code points within it are assigned by IANA, and to add [this document] as an additional reference for that registry.¶
In addition, IANA is requested to update three entries in that Registry as follows:¶
| Value | Description | Reference |
|---|---|---|
| 0 | Reserved | [this document] |
| 42 | Example for use in documentation | [this document] |
| 255 | Reserved | [this document] |
The entries for 1 (MUD), 2-41 (unassigned), and 43-254 (unassigned) are unchanged.¶
IANA is requested to assign two CBOR Tags as shown below. [The values of 48 and 49 are requested for TBD1 and TBD2 respectively.]¶
| Tag | Data Item | Semantics | Reference |
|---|---|---|---|
| TBD1 | byte string | IEEE MAC Address | [this document] |
| TBD2 | byte string | IEEE OUI/CID | [this document] |
This document is concerned with assignment of IEEE 802 parameters allocated to IANA, particularly those under the IANA OUI, and closely related matters. It is not directly concerned with security except as follows:¶
Confusion and conflict can be caused by the use of MAC addresses or other OUI-derived protocol parameters as examples in documentation. Examples that are "only" to be used in documentation can end up being coded and released or cause conflicts due to later real use and the possible acquisition of intellectual property rights in such addresses or parameters. The reservation herein of MAC addresses and parameters for documentation purposes will minimize such confusion and conflict.¶
See [RFC7043] for security considerations on storing MAC addresses in the DNS.¶
This appendix provides the specific templates for IANA assignments of parameters. Explanatory words in parentheses in the templates below may be deleted in a completed template as submitted to IANA.¶
Applicant Name:¶
Applicant Email:¶
Applicant Telephone: (starting with country code)¶
Use Name: (brief name of Parameter use such as "Foo Protocol" [RFC3092])¶
Document: (ID or RFC specifying use to which the identifier or block of identifiers will be put.)¶
Specify whether this is an application for EUI‑48 or EUI‑64 identifiers:¶
Size of Block requested: (must be a power-of-two-sized block, can be a block of size one (2**0))¶
Specify multicast, unicast, or both:¶
Applicant Name:¶
Applicant Email:¶
Applicant Telephone: (starting with country code)¶
Use Name: (brief name of use of code point such as "Foo Protocol")¶
Document: (ID or RFC specifying use to which the protocol identifier will be put.)¶
Note: (any additional note)¶
Applicant Name:¶
Applicant Email:¶
Applicant Telephone: (starting with country code)¶
Protocol where the OUI/CID-Based Parameter for which a value is being requested appears: (such as: Cipher Suite selection in IEEE 802.11)¶
Use Name: (brief name of use of code point to be assigned, such as "Foo Cipher Suite" [RFC3092])¶
Document: (ID or RFC specifying use to which the other IANA OUI-based parameter value will be put.)¶
Note: (any additional note)¶
This appendix provides a copy of the IESG Statement issued in October 2012 on obtaining new IETF EtherTypes in Section B.1. Note that there is an informational list on the IANA web site of some important EtherTypes specified for IETF protocols or by IEEE 802 available, currently at [IANA]. The IEEE Registration Authority page of EtherTypes, http://standards.ieee.org/regauth/ethertype/eth.txt, may also be useful. See Section 3 above.¶
From: IESG Date: 25 October 2012¶
The IEEE Registration Authority (IEEE RA) assigns Ethertypes with oversight from the IEEE Registration Authority Committee (IEEE RAC).¶
(See http://standards.ieee.org/develop/regauth/ethertype/.) Some IETF protocol specifications make use of Ethertypes. All Ethertype requests are subject to review by a consultant to the IEEE RA followed by IEEE RAC confirmation.¶
Since Ethertypes are a fairly scarce resource, the IEEE RAC has let us know that they will not assign a new Ethertype to a new IETF protocol specification until the IESG has approved the protocol specification for publication as an RFC. In exceptional cases, the IEEE RA is willing to consider "early allocation" of an Ethertype for an IETF protocol that is still under development as long as the request comes from and has been vetted by the IESG.¶
To let the IEEE RAC know that the IESG has approved the request for an Ethernet assignment for an IETF protocol, all future requests for assignment of Ethertypes for IETF protocols will be made by the IESG.¶
Note that playpen Ethertypes have been assigned in IEEE 802 [1] for use during protocol development and experimentation.¶
[1] IEEE Std 802a-2003 (Amendment to IEEE Std 802-2001). IEEE standard for Local and Metropolitan Area Networks: Overview and Architecture -- Amendment 1: Ethertypes for Prototype and Vendor-Specific Protocol Development.¶
The comments and suggestions of the following people persons and organizations are gratefully acknowledged:¶
Comments and suggestions leading to this Document:¶
Carsten Bormann, The IEEE 802.1 Working Group¶
Comments and suggestions leading to RFC 7042 (which is obsoleted by this document):¶
David Black, Adrian Farrel, Bob Grow, Joel Jaeggli, Pearl Liang, Glenn Parsons, Pete Resnick, and Dan Romascanu.¶