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Internet-Draft This memo provides for an extension to RFC 8520 (Manufacturer Usage Description Specification, MUD) that allows MUD file authors to specify ownership and licensing of MUD files themselves. This memo updates RFC 8520. However, it can also be used for purposes outside of MUD, and the grouping is structured as such.

Introduction Manufacturer Usage Descriptions (MUD) can be used to describe devices and their requirements to the network infrastructure. The original version of the specification does not provide for a means to specify ownership and licensing of the MUD file itself. This can hinder those wishing to use, modify, or adapt MUD files for the purpose of offering them, when the manufacturer is not involved. To avoid any confusion, we define an extension that allows for specifying of owners and licensing terms for MUD files. Those generating MUD files SHOULD use this extension, and thus this extension updates RFC 8520. There are two ways to specify a license: a URL pointing to the license itself or an SPDX tag . These alternatives are expressed as distinct cases of a YANG choice, so each license entry unambiguously carries either one or more SPDX tags or one or more license URLs. If an SPDX tag is supplied consumers MUST interpret that tag through its meaning as specified by . This grouping may be used for other YANG models that reside as static objects. The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 when, and only when, they appear in all capitals, as shown here.

The owner-license extension and model Because the model is primarily motivated by MUD, and based on the way that YANG trees are formed, the model appears as an augmentation for MUD. The tree diagram below uses the notation defined in .

Each license list entry is keyed by owner-name, so different owners can declare different licenses. The license-type choice is mandatory, so every entry carries either one or more SPDX tags or one or more license URLs (but not a mix of both kinds under a single owner; multi-licensing across kinds is expressed by adding additional entries with distinct owner names).

The YANG schema for ownership and licensing The following grouping and augmentation are proposed. The module imports ietf-inet-types for the inet:uri type used to carry license URLs, and ietf-mud for the augmentation point.

WG List: Editor: Eliot Lear Editor: Carsten Bormann "; description "This YANG module defines a grouping for expressing ownership and licensing information for YANG-described static objects, and augments the MUD model (RFC 8520) with that grouping. Copyright (c) 2026 IETF Trust and the persons identified as authors of the code. All rights reserved. Redistribution and use in source and binary forms, with or without modification, is permitted pursuant to, and subject to the license terms contained in, the Revised BSD License set forth in Section 4.c of the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info). This version of this YANG module is part of RFC XXXX (https://www.rfc-editor.org/info/rfcXXXX); see the RFC itself for full legal notices."; revision 2026-06-28 { description "Initial revision."; reference "RFC XXXX: Ownership and Licensing Statements in YANG"; } grouping owner-license { description "A grouping expressing ownership and license information."; container owner-license { description "Container relating to ownership and licensing."; list license { key "owner-name"; description "List of licenses that may be applied."; leaf owner-name { type string { length "1..128"; } description "Name of the owner."; } choice license-type { mandatory true; description "Either choose a standard license type or point to one of your own."; case spdx { leaf-list spdx-tag { type string; min-elements 1; description "SPDX License Identifier."; reference "https://spdx.org/licenses/: SPDX License List"; } } case url { leaf-list license-info { type inet:uri; min-elements 1; description "A URL pointing to licensing information."; } } } } } } augment "/ietf-mud:mud" { description "Add extension for ownership and licensing."; uses owner-license; } } ]]>

Extension for MUD MUD files using this extension MUST include the string "ol" in the extensions array, as specified by . Note that "ol" is the MUD extension token registered with IANA (see ); it is distinct from the YANG container name owner-license and from the YANG module name ietf-owner-license.

Example In this example, the Frobmaster company is using the 0BSD SPDX tag to indicate a relatively open license. The "ol" extension and the owner-license container are present. There is a single owner listed.

Security Considerations The YANG module specified in this document defines a schema for data that is designed to be accessed via network management protocols such as NETCONF or RESTCONF . The lowest NETCONF layer is the secure transport layer, and the mandatory-to-implement secure transport is Secure Shell (SSH) . The lowest RESTCONF layer is HTTPS, and the mandatory-to-implement secure transport is TLS . The Network Configuration Access Control Model (NACM) provides the means to restrict access for particular NETCONF or RESTCONF users to a preconfigured subset of all available NETCONF or RESTCONF protocol operations and content. In practice, instance data conforming to this module is most often carried inside a MUD file rather than served from a NETCONF/RESTCONF server; the considerations of for obtaining and validating MUD files therefore apply. There are a number of data nodes defined in this YANG module that are writeable/creatable/deletable (i.e., config true, which is the default). All data nodes under the augmented container /ietf-mud:mud/ol:owner-license fall in this category. Unauthorized modification of these data nodes can falsify the asserted ownership or licensing terms of a MUD file. This is not expected to directly influence the behavior of protective network infrastructure, but it may be used by an aggregator as input for deciding the legal basis that enables providing aggregated information; depending on the juridical environment, false information in the MUD file may thus expose the aggregator to additional legal risk. The data nodes defined in this YANG module are not considered sensitive or vulnerable from a disclosure (read) standpoint: ownership and licensing statements are intended to be publicly readable. This YANG module does not define any RPC or action operations.

IANA Considerations

MUD Extension The IANA is requested to add "ol" to the of as follows:

Extension Name:

ol

Standard reference:

This document

XML Name Space Entry This document requests IANA to register the following URI in the "ns" subregistry within the "IETF XML Registry" in accordance with :

URI:

urn:ietf:params:xml:ns:yang:ietf-owner-license

Registrant Contact:

The IESG.

XML: N/A; the requested URI is an XML namespace.

YANG Module Names This document requests IANA to register the following YANG module in the "YANG Module Names" subregistry in accordance with within the "YANG Parameters" registry.

name:

ietf-owner-license

namespace:

urn:ietf:params:xml:ns:yang:ietf-owner-license

maintained by IANA:

N

prefix:

ol

reference:

RFC XXXX

This memo specifies a component-based architecture for Manufacturer Usage Descriptions (MUDs). The goal of MUD is to provide a means for end devices to signal to the network what sort of access and network functionality they require to properly function. The initial focus is on access control. Later work can delve into other aspects. This memo specifies two YANG modules, IPv4 and IPv6 DHCP options, a Link Layer Discovery Protocol (LLDP) TLV, a URL, an X.509 certificate extension, and a means to sign and verify the descriptions. IANA The Linux Foundation In many standards track documents several words are used to signify the requirements in the specification. These words are often capitalized. This document defines these words as they should be interpreted in IETF documents. This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements. RFC 2119 specifies common key words that may be used in protocol specifications. This document aims to reduce the ambiguity by clarifying that only UPPERCASE usage of the key words have the defined special meanings. This document captures the current syntax used in YANG module tree diagrams. The purpose of this document is to provide a single location for this definition. This syntax may be updated from time to time based on the evolution of the YANG language. This document defines a collection of common data types to be used with the YANG data modeling language. It includes several new type definitions and obsoletes RFC 6991. This document describes an IANA maintained registry for IETF standards which use Extensible Markup Language (XML) related items such as Namespaces, Document Type Declarations (DTDs), Schemas, and Resource Description Framework (RDF) Schemas. YANG is a data modeling language used to model configuration and state data manipulated by the Network Configuration Protocol (NETCONF), NETCONF remote procedure calls, and NETCONF notifications. [STANDARDS-TRACK] The Network Configuration Protocol (NETCONF) defined in this document provides mechanisms to install, manipulate, and delete the configuration of network devices. It uses an Extensible Markup Language (XML)-based data encoding for the configuration data as well as the protocol messages. The NETCONF protocol operations are realized as remote procedure calls (RPCs). This document obsoletes RFC 4741. [STANDARDS-TRACK] This document describes an HTTP-based protocol that provides a programmatic interface for accessing data defined in YANG, using the datastore concepts defined in the Network Configuration Protocol (NETCONF). This document describes a method for invoking and running the Network Configuration Protocol (NETCONF) within a Secure Shell (SSH) session as an SSH subsystem. This document obsoletes RFC 4742. [STANDARDS-TRACK] This document specifies version 1.3 of the Transport Layer Security (TLS) protocol. TLS allows client/server applications to communicate over the Internet in a way that is designed to prevent eavesdropping, tampering, and message forgery. This document updates RFCs 5705 and 6066, and obsoletes RFCs 5077, 5246, and 6961. This document also specifies new requirements for TLS 1.2 implementations. The standardization of network configuration interfaces for use with the Network Configuration Protocol (NETCONF) or the RESTCONF protocol requires a structured and secure operating environment that promotes human usability and multi-vendor interoperability. There is a need for standard mechanisms to restrict NETCONF or RESTCONF protocol access for particular users to a preconfigured subset of all available NETCONF or RESTCONF protocol operations and content. This document defines such an access control model. This document obsoletes RFC 6536.

Changes from Earlier Versions Draft -04: Address RFC 8407 review: Rename the module to ietf-owner-license (namespace urn:ietf:params:xml:ns:yang:ietf-owner-license); the ol prefix is preserved. Update the example, the IANA registrations, and the file name accordingly. Improve the module description. Move the SPDX URL out of the leaf-list description into a reference substatement. Update the copyright year in the module to 2026. Expand "IOTOPS" as "IoT Operations" in the organization statement. Rewrite the Security Considerations to follow the YANG Security Considerations template (NETCONF/RESTCONF transports, NACM, writable subtree analysis, readability statement, RPC/action statement). Add a normative reference to RFC 9911 (imported by the module). Add a normative reference to RFC 8340 (for the tree diagram). Note in the prose that the MUD extension token "ol" is distinct from the YANG module name and container name. Normalise heading style in the IANA Considerations section. Resolve the outstanding Issue and Task markers. Draft -03: Address YANG doctors review: Reformat the YANG contact statement per RFC 8407bis. Rename the container from ol to owner-license. Rename the SPDX case from spdx-lt to spdx. Drop the -grouping suffix from the grouping name. Make the license-type choice mandatory so that every license entry carries either an SPDX tag or a URL. Correct the example to use the singular leaf-list name spdx-tag and the renamed container. Draft -02: Small updates to the example Draft -01: Format IANA considerations Discuss security considerations Draft -00: Resubmit unchanged Individual Draft -01: Add some issues correct spacing Individual Draft -00: Initial revision