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Applications and Real-Time Area (art) Internet Engineering Task Force YANG-CBOR YANG-CBOR, RFC 9254 defines YANG Schema Item iDentifiers (YANG SID), globally unique 63-bit unsigned integers used to identify YANG items. RFC 9595 defines ways to allocate these SIDs on the basis of IANA registries. The present specification employs these SID allocation mechanisms to allocate ranges with 100 000 63-bit SIDs each for each of the first 1 000 000 holders of IANA-registered Private Enterprise Numbers (PENs), as well as ranges with 10 000 32-bit SIDs each for each of the first 100 000 holders. About This Document Status information for this document may be found at . Discussion of this document takes place on the CoRE Working Group mailing list (), which is archived at . Subscribe at . Source for this draft and an issue tracker can be found at .

Introduction YANG-CBOR defines YANG Schema Item iDentifiers (YANG SID), globally unique 63-bit unsigned integers used to identify YANG items. RFC 9595 defines ways to allocate these SIDs on the basis of IANA registries. The present specification employs these SID allocation mechanisms to allocate ranges with 100 000 63-bit SIDs each for each of the first 1 000 000 holders of IANA-registered Private Enterprise Numbers (PENs), as well as ranges with 10 000 32-bit SIDs each for each of the first 100 000 holders. IANA [is requested to allocate/has allocated] 100 000 mega-ranges, for the SID numbers 300 000 000 000 to 399 999 999 999. IANA also [is requested to allocate/has allocated] 1000 mega-ranges, for the SID numbers 3 000 000 000 to 3 999 999 999. Private Enterprise Numbers (PENs) are registered in in a low-threshold, low-overhead registration process. At the time of writing (~ 37 years after creating this registry), around 65 000 PENs are registered. We speak of the registrant for a PEN as the "PEN holder". The present specification makes the following SID ranges available to certain (current or future) PEN holders for allocation in a scheme defined by the holder:

• The holder of a PEN ppp ppp (< 1 000 000) can use the SID numbers 3pp ppp p00 000 to 3pp ppp p99 999.
• The holder of a PEN pp ppp (< 100 000) can use the SID numbers 3 ppp pp0 000 to 3 ppp pp9 999.

Example The Department for Mathematics and Computer Science of holds PEN 30810. To this PEN holder, the present specification confers control over the SID ranges:

• 303 081 000 000 up to 303 081 099 999, and
• 3 308 100 000 up to 3 308 109 999.

(The plaintext form of this document shows "*" characters around the digits conveying the PEN, which are shown in boldface in the typographic forms.)

Discussion This allocation provides an extremely-low-threshold (zero-interaction) way for PEN holders to get number space for the YANG SIDs used in their YANG modules. If a PEN is not already available to the entity needing such number space, it can be obtained in a very low-threshold process. Employing this number space is, however, not always the approach to recommend to a module author:

• The large space uses 64-bit numbers. While this is of relatively little consequence due to the delta-encoding used for SIDs in YANG-CBOR, a few further bytes can be saved by allocating the SIDs in one of the mega-ranges that are specifically allocated by an organization (which, for the first 2000 or so, will lead to 32-bit outer deltas).
• For the first 100 000 PEN holders, there also is a smaller space that uses 32-bit numbers. This space is likely to run out before or around 2040; the expectation is that by that time there will be enough opportunities to request ranges from a megarange operator that this mechanism is no longer needed.
• This space has no infrastructure to discover the YANG module behind a SID. Of course, each PEN holder can provide such infrastructure, but even then the problem remains how to find that infrastructure for a SID. (Search engines may mitigate this somewhat.) On the other hand, in some cases this relative obscurity may be exactly what a PEN holder wants to achieve by using this mechanism.

Relying on the PEN registry might theoretically trigger a land-grab by prospective writers of YANG modules. However, PENs have been around for decades (see , which continues to be in force with no technical changes as Section of RFC 1155 ), and such a land-grab hasn't occurred for the other allocations implicitly provided by obtaining a PEN.

IANA Considerations This document allocates 100 000 63-bit and 1000 32-bit SID mega-ranges as per . The contact for the allocation is: IETF CORE Working Group (core@ietf.org) or IETF Applications and Real-Time Area (art@ietf.org). The allocation policy inside the mega-range is "private". The URL is that of the present specification. The management of the SID blocks of 100 000 SIDs each, 10 such blocks for each mega-range 3nn nnn 000 000, is delegated to the PEN holder for nnn nnx, where x is the sequence number of the SID block in the mega-range (i.e., the PEN holder for nnn nnx controls SID 3nn nnn x00 000 to 3nn nnn x99 999). Similarly, the management of the SID blocks of 10 000 SIDs each, 100 such blocks for each mega-range 3 nnn 000 000, is delegated to the PEN holder for nn nxx, where x is the sequence number of the SID block in the mega-range (i.e., the PEN holder for nn nxx controls SID 3 nnn xx0 000 to 3 nnn xx9 999). The technical capacity to ensure the sustained operation of the registry for a period of at least 10 years (as required for registries of class "private") is derived from the capacity of IANA to maintain the PEN number registry.

References Normative References YANG (RFC 7950) is a data modeling language used to model configuration data, state data, parameters and results of Remote Procedure Call (RPC) operations or actions, and notifications. This document defines encoding rules for YANG in the Concise Binary Object Representation (CBOR) (RFC 8949). YANG Schema Item iDentifiers (YANG SIDs) are globally unique 63-bit unsigned integers used to identify YANG items. SIDs provide a more compact method for identifying those YANG items that can be used efficiently, notably in constrained environments (RFC 7228). This document defines the semantics, registration processes, and assignment processes for YANG SIDs for IETF-managed YANG modules. To enable the implementation of these processes, this document also defines a file format used to persist and publish assigned YANG SIDs. IANA Informative References This RFC provides the common definitions for the structure and identification of management information for TCP/IP-based internets. In particular, together with its companion memos, which describe the initial management information base along with the initial network management protocol, these documents provide a simple, working architecture and system for managing TCP/IP-based internets and in particular, the Internet. This memo specifies a draft standard for the Internet community. TCP/IP implementation in the Internet which are network manageable are expected to adopt and implement this specification. This RFC is a re-release of RFC 1065, with a changed "Status of this Memo", plus a few minor typographical corrections. The technical content of the document is unchanged from RFC 1065. [STANDARDS-TRACK] This memo describes a straight-forward approach toward producing concise, yet descriptive, MIB modules. This memo defines a format for producing MIB modules. [STANDARDS-TRACK]

Acknowledgments This document was inspired by the discussion of the authors of and how to handle feedback.