Network Working Group A. Huang-Feng Internet-Draft P. Francois Intended status: Standards Track INSA-Lyon Expires: 19 June 2026 K. Watsen Watsen Networks 16 December 2025 YANG Groupings for UDP Clients and UDP Servers draft-ietf-netconf-udp-client-server-10 Abstract This document defines two YANG 1.1 modules with reusable groupings for managing UDP clients and UDP servers. Notes to the RFC editor This note is to be removed before publishing as an RFC. Please replace "RFC XXXX" with the assigned RFC number prior to publication. Note that there are also several occurrences of "RFC XXXX" in the YANG modules. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at https://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on 19 June 2026. Copyright Notice Copyright (c) 2025 IETF Trust and the persons identified as the document authors. All rights reserved. Huang-Feng, et al. Expires 19 June 2026 [Page 1] Internet-Draft Groupings for UDP Clients and Servers December 2025 This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/ license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Revised BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Revised BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 2 1.2. Adherence to the NMDA . . . . . . . . . . . . . . . . . . 3 1.3. Conventions . . . . . . . . . . . . . . . . . . . . . . . 3 2. The "ietf-udp-client" Module . . . . . . . . . . . . . . . . 3 2.1. Data Model Overview . . . . . . . . . . . . . . . . . . . 3 2.2. Example Usage . . . . . . . . . . . . . . . . . . . . . . 4 2.3. YANG Module . . . . . . . . . . . . . . . . . . . . . . . 5 3. The "ietf-udp-server" Module . . . . . . . . . . . . . . . . 7 3.1. Data Model Overview . . . . . . . . . . . . . . . . . . . 7 3.2. Example Usage . . . . . . . . . . . . . . . . . . . . . . 8 3.3. YANG Module . . . . . . . . . . . . . . . . . . . . . . . 9 4. Security Considerations . . . . . . . . . . . . . . . . . . . 11 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11 5.1. URI . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 5.2. YANG Module Name . . . . . . . . . . . . . . . . . . . . 12 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 12 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 12 7.1. Normative References . . . . . . . . . . . . . . . . . . 12 7.2. Informative References . . . . . . . . . . . . . . . . . 13 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14 1. Introduction This document defines two YANG 1.1 [RFC7950] modules with reusable groupings for managing UDP clients and UDP servers [RFC768]. These modules may be used directly (e.g., define a specific UDP client or UDP server) or in conjunction with the configuration defined for higher level protocols that depend on UDP. 1.1. Requirements Language 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 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here. Huang-Feng, et al. Expires 19 June 2026 [Page 2] Internet-Draft Groupings for UDP Clients and Servers December 2025 1.2. Adherence to the NMDA This document is compliant with the Network Management Datastore Architecture (NMDA) [RFC8342]. It does not define any protocol accessible nodes that are "config false". 1.3. Conventions Various examples in this document use the XML [W3C.REC-xml-20081126] encoding. Other encodings, such as JSON [RFC8259], could alternatively be used. 2. The "ietf-udp-client" Module This section defines a YANG 1.1 module called "ietf-udp-client". This YANG module defines the "udp-client" grouping for providing UDP clients with remote server information. Section 2.1 provides the overview of the YANG module. An example of usage is illustrated in Section 2.2, while Section 2.3 defines the YANG module itself. 2.1. Data Model Overview This section provides an overview of the features and the grouping defined in the "ietf-udp-client" YANG module. 2.1.1. Features The "ietf-udp-client" module defines the following "feature" statement: Features: +-- local-binding The diagram above uses syntax that is similar to but not defined in [RFC8340]. This feature indicates that the client supports configuring local bindings (i.e., the local address and local port number) for UDP clients. 2.1.2. The "udp-client" Grouping The following tree diagram [RFC8340] illustrates the tree structure of the "udp-client" grouping: Huang-Feng, et al. Expires 19 June 2026 [Page 3] Internet-Draft Groupings for UDP Clients and Servers December 2025 module: ietf-udp-client grouping udp-client: +-- remote-address inet:host +-- remote-port? inet:port-number +-- local-address? inet:ip-address {local-binding}? +-- local-port? inet:port-number {local-binding}? The description of these parameters is provided below: * The "remote-address", which is mandatory, may be configured as an IPv4 address, an IPv6 address, or a hostname. The resolved address should be compatible with the local address family, if also provided. * The "remote-port" is defined with neither a "default" nor a "mandatory" statement. YANG modules using this grouping SHOULD refine the grouping with a "default" statement, when the port number is well-known (e.g., a port number allocated by IANA), or with a "mandatory" statement, if a port number needs to always be configured. This MAY be ignored when the port number is neither well-known nor mandatory to configure, such as might be the case when this grouping is used by another grouping. * The "local-address", which is enabled by the "local-binding" feature, may be configured as an IPv4 address, an IPv6 address, or a wildcard value. In normal operation, the local and configured remote addresses SHOULD be from the same address family. Differences between address families may occur in abnormal or error conditions and are therefore allowed to be reported. * The "local-port", which depends on the "local-binding" feature, is not mandatory. Its default value is "0", indicating that the operating system can select an arbitrary port number. 2.2. Example Usage This section presents an example of usage of the "udp-client" grouping. Huang-Feng, et al. Expires 19 June 2026 [Page 4] Internet-Draft Groupings for UDP Clients and Servers December 2025 www.example.com 10000 192.0.2.2 12345 2.3. YANG Module This module imports types defined in [I-D.ietf-netmod-rfc6991-bis]. file "ietf-udp-client@2025-12-16.yang" module ietf-udp-client { yang-version 1.1; namespace "urn:ietf:params:xml:ns:yang:ietf-udp-client"; prefix udpc; import ietf-inet-types { prefix inet; reference "RFC 9911: Common YANG Data Types"; } organization "IETF NETCONF (Network Configuration) Working Group"; contact "WG Web: WG List: Authors: Alex Huang Feng Pierre Francois "; description "Defines a generic grouping for UDP-based client applications. Copyright (c) 2025 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). Huang-Feng, et al. Expires 19 June 2026 [Page 5] Internet-Draft Groupings for UDP Clients and Servers December 2025 All revisions of IETF and IANA published modules can be found at the YANG Parameters registry group (https://www.iana.org/assignments/yang-parameters). This version of this YANG module is part of RFC XXXX; see the RFC itself for full legal notices. 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 (RFC 2119) (RFC 8174) when, and only when, they appear in all capitals, as shown here."; revision 2025-12-16 { description "Initial revision"; reference "RFC XXXX: YANG Groupings for UDP Clients and UDP Servers"; } feature local-binding { description "Indicates that the UDP client supports configuring local bindings (i.e., the local address and local port number) for UDP clients."; } grouping udp-client { description "A reusable grouping for UDP clients. Note that this grouping uses fairly typical descendant node names such that a stack of 'uses' statements will have name conflicts. It is intended that the consuming data model will resolve the issue (e.g., by wrapping the 'uses' statement in a container called 'udp-client-parameters'). This model purposely does not do this itself so as to provide maximum flexibility to consuming models."; leaf remote-address { type inet:host; mandatory true; description "The IP address or hostname of the remote UDP server."; } leaf remote-port { Huang-Feng, et al. Expires 19 June 2026 [Page 6] Internet-Draft Groupings for UDP Clients and Servers December 2025 type inet:port-number; description "The port number of the remote UDP server."; } leaf local-address { if-feature "local-binding"; type inet:ip-address; description "The local IP address to bind to when sending UDP datagrams to the remote server. INADDR_ANY ('0.0.0.0') or INADDR6_ANY ('0:0:0:0:0:0:0:0' a.k.a. '::') may be used so that the client can bind to any IPv4 or IPv6 address. In normal operation, the local and configured remote addresses SHOULD be from the same address family. Differences between address families may occur in abnormal or error conditions and are therefore allowed to be reported."; } leaf local-port { if-feature "local-binding"; type inet:port-number; default "0"; description "The local port number to bind to when sending UDP datagrams to the remote server. The port number '0', which is the default value, indicates that any available local port number may be used."; } } } 3. The "ietf-udp-server" Module This section defines a YANG 1.1 module called "ietf-udp-server". This YANG module defines the "udp-server" grouping for managing UDP servers. Section 3.1 provides an overview of the "ietf-udp-server" YANG module. An example of usage is illustrated in Section 3.2 while Section 3.3 defines the YANG module itself. 3.1. Data Model Overview This section provides an overview of the grouping defined in the "ietf-udp-server" module. Huang-Feng, et al. Expires 19 June 2026 [Page 7] Internet-Draft Groupings for UDP Clients and Servers December 2025 3.1.1. The "udp-server" Grouping The following tree diagram [RFC8340] illustrates the structure of "udp-server" grouping: module: ietf-udp-server grouping udp-server: +-- local-bind* [local-address] +-- local-address inet:ip-address +-- local-port? inet:port-number The description of these parameters is provided below: * The "local-address", which is mandatory, may be configured as an IPv4 address, an IPv6 address, or a wildcard value. * The "local-port" is defined with neither a "default" nor a "mandatory" statement. YANG modules using this grouping SHOULD refine the grouping with a "default" statement, when the port number is well-known (e.g., a port number allocated by IANA), or with a "mandatory" statement, if a port number needs to always be configured. This MAY be ignored when the port number is neither well-known nor mandatory to configure, such as might be the case when this grouping is used by another grouping. 3.2. Example Usage This section presents two examples of usage of the "udp-server" grouping. This following shows an example of a server configured for listening to an IPv4 address: 192.0.2.2 49152 This following shows an example of a server configured to listen to an IPv4 and IPv6 together: Huang-Feng, et al. Expires 19 June 2026 [Page 8] Internet-Draft Groupings for UDP Clients and Servers December 2025 192.0.2.2 49152 2001:db8::0 49153 3.3. YANG Module The "ietf-udp-server" imports types defined in [I-D.ietf-netmod-rfc6991-bis]. file "ietf-udp-server@2025-12-16.yang" module ietf-udp-server { yang-version 1.1; namespace "urn:ietf:params:xml:ns:yang:ietf-udp-server"; prefix udps; import ietf-inet-types { prefix inet; reference "RFC 9911: Common YANG Data Types"; } organization "IETF NETCONF (Network Configuration) Working Group"; contact "WG Web: WG List: Authors: Alex Huang Feng Pierre Francois "; description "Defines a generic grouping for UDP-based server applications. Copyright (c) 2025 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 Huang-Feng, et al. Expires 19 June 2026 [Page 9] Internet-Draft Groupings for UDP Clients and Servers December 2025 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). All revisions of IETF and IANA published modules can be found at the YANG Parameters registry group (https://www.iana.org/assignments/yang-parameters). This version of this YANG module is part of RFC XXXX; see the RFC itself for full legal notices."; revision 2025-12-16 { description "Initial revision"; reference "RFC XXXX: YANG Groupings for UDP Clients and UDP Servers"; } grouping udp-server { description "Provides a reusable grouping for managing UDP servers. Note that this grouping uses fairly typical descendant node names such that a stack of 'uses' statements will have name conflicts. It is intended that the consuming data model will resolve the issue (e.g., by wrapping the 'uses' statement in a container called 'udp-server-parameters'). This model purposely does not do this itself so as to provide maximum flexibility to consuming models."; list local-bind { key "local-address"; min-elements 1; description "A list of bind (listen) points for this server instance. A server instance may have multiple bind points to support, e.g., the same port number in different address families or different port numbers in the same address family."; leaf local-address { type inet:ip-address; mandatory true; description "The local IP address to listen on for incoming UDP datagrams. INADDR_ANY ('0.0.0.0') or INADDR6_ANY ('0:0:0:0:0:0:0:0' a.k.a. '::') may be used so that the server can listen to any IPv4 or IPv6 address."; Huang-Feng, et al. Expires 19 June 2026 [Page 10] Internet-Draft Groupings for UDP Clients and Servers December 2025 } leaf local-port { type inet:port-number; description "The local port number to listen on for incoming UDP datagrams."; } } } } 4. Security Considerations This section uses the template described in Section 3.7 of [I-D.ietf-netmod-rfc8407bis]. The "ietf-udp-client" and "ietf-udp-server" YANG modules defines a data model that is designed to be accessed via YANG-based management protocols, such as NETCONF [RFC6241] and RESTCONF [RFC8040]. These YANG-based management protocols (1) have to use a secure transport layer (e.g., SSH [RFC6242], TLS [RFC8446], and QUIC [RFC9000]) and (2) have to use mutual authentication. The Network Configuration Access Control Model (NACM) [RFC8341] 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. These YANG modules define a set of identities, types, and groupings. These nodes are intended to be reused by other YANG modules. The modules by themselves do not expose any data nodes that are writable, data nodes that contain read-only state, or RPCs. As such, there are no additional security issues related to the YANG module that need to be considered. Modules that use the groupings that are defined in this document should identify the corresponding security considerations. For example, reusing some of these groupings will expose privacy-related information (e.g., 'remote-address', 'remote-port', 'local-address', or 'local-port'). 5. IANA Considerations This document describes the URIs from IETF XML Registry and the registration of a two new YANG module names Huang-Feng, et al. Expires 19 June 2026 [Page 11] Internet-Draft Groupings for UDP Clients and Servers December 2025 5.1. URI IANA is requested to assign two new URIs from the IETF XML Registry [RFC3688]: URI: urn:ietf:params:xml:ns:yang:ietf-udp-client Registrant Contact: The IESG. XML: N/A; the requested URI is an XML namespace. URI: urn:ietf:params:xml:ns:yang:ietf-udp-server Registrant Contact: The IESG. XML: N/A; the requested URI is an XML namespace. 5.2. YANG Module Name This document also requests IANA to register the following YANG modules in the YANG Module Names registry [RFC6020] within the "YANG Parameters" registry group: name: ietf-udp-client namespace: urn:ietf:params:xml:ns:yang:ietf-udp-client prefix: udpc maintained by IANA? N reference: RFC XXXX name: ietf-udp-server namespace: urn:ietf:params:xml:ns:yang:ietf-udp-server prefix: udps maintained by IANA? N reference: RFC XXXX 6. Acknowledgements The authors would like to thank Mohamed Boucadair, Ran Chen, Benoit Claise, Mahesh Jethanandani, Qiufang Ma, Jürgen Schönwälder, Ketan Talaulikar, Eric Vyncke, Paul Wouters and Qin Wu for their review and valuable comments. 7. References 7.1. Normative References [I-D.ietf-netmod-rfc6991-bis] Schönwälder, J., "Common YANG Data Types", Work in Progress, Internet-Draft, draft-ietf-netmod-rfc6991-bis- 18, 23 June 2025, . Huang-Feng, et al. Expires 19 June 2026 [Page 12] Internet-Draft Groupings for UDP Clients and Servers December 2025 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, DOI 10.17487/RFC3688, January 2004, . [RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)", RFC 6020, DOI 10.17487/RFC6020, October 2010, . [RFC768] Postel, J., "User Datagram Protocol", STD 6, RFC 768, DOI 10.17487/RFC0768, August 1980, . [RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language", RFC 7950, DOI 10.17487/RFC7950, August 2016, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . [RFC8341] Bierman, A. and M. Bjorklund, "Network Configuration Access Control Model", STD 91, RFC 8341, DOI 10.17487/RFC8341, March 2018, . 7.2. Informative References [I-D.ietf-netmod-rfc8407bis] Bierman, A., Boucadair, M., and Q. Wu, "Guidelines for Authors and Reviewers of Documents Containing YANG Data Models", Work in Progress, Internet-Draft, draft-ietf- netmod-rfc8407bis-28, 5 June 2025, . [RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed., and A. Bierman, Ed., "Network Configuration Protocol (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011, . Huang-Feng, et al. Expires 19 June 2026 [Page 13] Internet-Draft Groupings for UDP Clients and Servers December 2025 [RFC6242] Wasserman, M., "Using the NETCONF Protocol over Secure Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, June 2011, . [RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017, . [RFC8259] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data Interchange Format", STD 90, RFC 8259, DOI 10.17487/RFC8259, December 2017, . [RFC8340] Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams", BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018, . [RFC8342] Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K., and R. Wilton, "Network Management Datastore Architecture (NMDA)", RFC 8342, DOI 10.17487/RFC8342, March 2018, . [RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018, . [RFC9000] Iyengar, J., Ed. and M. Thomson, Ed., "QUIC: A UDP-Based Multiplexed and Secure Transport", RFC 9000, DOI 10.17487/RFC9000, May 2021, . [W3C.REC-xml-20081126] Bray, T., Paoli, J., Sperberg-McQueen, C.M., Maler, E., and F. Yergeau, "Extensible Markup Language (XML) 1.0 (Fifth Edition)", World Wide Web Consortium Recommendation REC-xml-20081126, November 2008, . Authors' Addresses Alex Huang Feng INSA-Lyon Lyon France Email: alex.huang-feng@insa-lyon.fr Huang-Feng, et al. Expires 19 June 2026 [Page 14] Internet-Draft Groupings for UDP Clients and Servers December 2025 Pierre Francois INSA-Lyon Lyon France Email: pierre.francois@insa-lyon.fr Kent Watsen Watsen Networks Email: kent+ietf@watsen.net Huang-Feng, et al. Expires 19 June 2026 [Page 15]