NETCONF Working Group Q. Wu Internet-Draft Q. Ma Intended status: Standards Track Huawei Expires: 20 April 2025 A. Huang Feng INSA-Lyon T. Graf Swisscom 17 October 2024 YANG Notification Transport Capabilities draft-netana-netconf-yp-transport-capabilities-00 Abstract This document proposes a YANG module for YANG notifications transport capabilities which augments "ietf-system-capabilities" YANG module defined in [RFC9196] and provides transport, encoding and encryption system capabilities for transport specific notification. This YANG module can be used by the client to learn capability information from the server at runtime or at implementation time, by making use of the YANG instance data file format. 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 20 April 2025. Copyright Notice Copyright (c) 2024 IETF Trust and the persons identified as the document authors. All rights reserved. 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. Wu, et al. Expires 20 April 2025 [Page 1] Internet-Draft YANG Notification Transport Capabilities October 2024 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. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3 2. Capabilities for Systems and Datastore Update Notifications . . . . . . . . . . . . . . . . . . . . . . 3 2.1. Tree Diagram . . . . . . . . . . . . . . . . . . . . . . 4 3. YANG Module . . . . . . . . . . . . . . . . . . . . . . . . . 4 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7 4.1. Updates to the IETF XML Registry . . . . . . . . . . . . 7 4.2. Updates to the YANG Module Names Registry . . . . . . . . 7 5. Security Considerations . . . . . . . . . . . . . . . . . . . 7 6. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 8 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 8 7.1. Normative References . . . . . . . . . . . . . . . . . . 8 7.2. Informative References . . . . . . . . . . . . . . . . . 9 Appendix A. Usage Example of interaction with UDP-Notif and HTTPS-Notif for Configured Subscription . . . . . . . . . 11 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12 1. Introduction Notification capabilities model defined in [RFC9196] allows a client to discover a set of capabilities supported by the server (e.g., basic system capabilities and YANG-Push related capabilities) both at implementation time and at runtime. These capabilities allow the client to adjust its behavior to take advantage of the features exposed by the server. However the client and the server may still support various different transport specific parameters (e.g., transport protocol, encoding format, encryption). As described in Section 3.1 of [RFC8641], a simple negotiation (i.e., inserting hints into error responses to a failed RPC request) between subscribers and publishers for subscription parameters increases the likelihood of success for subsequent RPC requests, but not guaranteed, which may cause unexpected failure or additional message exchange between client and server. This document defines a corresponding solution by proposing a YANG module for YANG notifications transport capabilities that is built on top of [RFC9196]. The module can be used by the client to discover Wu, et al. Expires 20 April 2025 [Page 2] Internet-Draft YANG Notification Transport Capabilities October 2024 capability information from the server at runtime or at implementation time, by making use of the YANG instance data file format. 1.1. Terminology 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. 2. Capabilities for Systems and Datastore Update Notifications The YANG module "ietf-notification-capabilities" defined in [RFC9196] specifies the following server capabilities related to YANG Push: * Supported (reporting) periods for "periodic" subscriptions * Maximum number of objects that can be sent in an update * The set of datastores or data nodes for which "periodic" or "on- change" notification is supported * Supported dampening periods for "on-change" subscriptions These server capabilities are transport independent, session level capabilities. They can be provided either at the implementation time or reported at runtime. This document augments System Capabilities model and provides additional transport related attributes associated with system capabilities: * Specification of transport protocols the client can request to establish a HTTPS-based [I-D.ietf-netconf-https-notif] or UDP- based [I-D.ietf-netconf-udp-notif] configured transport connection; * Specification of transport encoding, such as JSON or XML as defined in [RFC8040] or CBOR as defined in [RFC9254] the client can request to encode YANG notifications; * Specification of secure transport mechanisms that are needed by the client to communicate with the server such as DTLS as defined in [RFC9147] TLS as defined in [RFC8446] or SSH as defined in [RFC4254]; Wu, et al. Expires 20 April 2025 [Page 3] Internet-Draft YANG Notification Transport Capabilities October 2024 2.1. Tree Diagram The following tree diagram [RFC8340] provides an overview of the data model. module: ietf-notification-transport-capabilities augment /sysc:system-capabilities/notc:subscription-capabilities: +--ro transport-capabilities +--ro transport-capability* [transport-protocol] +--ro transport-protocol identityref +--ro security-protocol? identityref +--ro encoding-format* identityref 3. YANG Module file "ietf-notification-transport-capabilities@2024-10-14.yang" module ietf-notification-transport-capabilities { yang-version 1.1; namespace "urn:ietf:params:xml:ns:yang:ietf-notification-transport-capabilities"; prefix ntc; import ietf-subscribed-notifications { prefix sn; reference "RFC 8639: Subscription to YANG Notifications"; } import ietf-system-capabilities { prefix sysc; reference "RFC 9196: YANG Modules Describing Capabilities for Systems and Datastore Update Notifications"; } import ietf-notification-capabilities { prefix notc; reference "RFC 9196: YANG Modules Describing Capabilities for Systems and Datastore Update Notifications"; } organization "IETF NETCONF (Network Configuration) Working Group"; contact "WG Web: WG List: Authors: Qin Wu Wu, et al. Expires 20 April 2025 [Page 4] Internet-Draft YANG Notification Transport Capabilities October 2024 Qiufang Ma Alex Huang Feng Thomas Graf "; description "This module defines an extension to System Capability and YANG Push Notification Capabilities model and provides additional transport specific capabilities for YANG notifications. Copyright (c) 2024 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 Simplified BSD License set forth in Section 4.c of the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info). This version of this YANG module is part of RFC XXXX; see the RFC itself for full legal notices."; revision 2024-10-14 { description "Initial revision."; reference "RFC XXXX: YANG Notifications Transport Capabilities"; } identity security-protocol { description "Identity for security protocols."; } identity tls { base security-protocol; description "Identity for TLS security protocol."; } identity dtls12 { base security-protocol; description "Identity for DTLS 1.2 security protocol."; } Wu, et al. Expires 20 April 2025 [Page 5] Internet-Draft YANG Notification Transport Capabilities October 2024 identity dtls13 { base security-protocol; description "Identity for DTLS 1.3 security protocol."; } identity ssh { base security-protocol; description "Identity for ssh transport protocol."; } augment "/sysc:system-capabilities/notc:subscription-capabilities" { description "Add system level capability."; container transport-capabilities { description "Capabilities related to YANG-Push transports."; list transport-capability { key "transport-protocol"; description "Capability list related to notification transport capabilities."; leaf transport-protocol { type identityref { base sn:transport; } description "Supported transport protocol for YANG-Push."; } leaf security-protocol { type identityref { base security-protocol; } description "Type of secure transport."; } leaf-list encoding-format { type identityref { base sn:encoding; } description "Supported encoding formats."; } } } } } Wu, et al. Expires 20 April 2025 [Page 6] Internet-Draft YANG Notification Transport Capabilities October 2024 4. IANA Considerations 4.1. Updates to the IETF XML Registry This document registers a URI in the "IETF XML Registry" [RFC3688]. Following the format in [RFC3688], the following registration has been made: URI: urn:ietf:params:xml:ns:yang:ietf-notification-transport-capabilities Registrant Contact: The IESG. XML: N/A; the requested URI is an XML namespace. 4.2. Updates to the YANG Module Names Registry This document registers one YANG module in the "YANG Module Names" registry [RFC6020]. Following the format in [RFC6020], the following registration has been made: name: ietf-notification-transport-capabilities namespace: urn:ietf:params:xml:ns:yang:ietf-notification-transport-capabilities prefix: ntc reference: RFC XXXX (RFC Ed.: replace XXX with actual RFC number and remove this note.) 5. Security Considerations This section is modeled after the template described in Section 3.7 of [I-D.ietf-netmod-rfc8407bis] The "ietf-notification-transport-capabilities" YANG module defines a data model that is designed to be accessed via YANG-based management protocols, such as NETCONF [RFC6241] and RESTCONF [RFC8040]. These protocols have to use a secure transport layer (e.g., SSH [RFC4252], TLS [RFC8446], and QUIC [RFC9000]) and 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. Wu, et al. Expires 20 April 2025 [Page 7] Internet-Draft YANG Notification Transport Capabilities October 2024 All protocol-accessible data nodes are read-only and cannot be modified. The data in the module is not security sensitive. It inherits all the security considerations of [RFC9196]. 6. Contributors Ran Tao Huawei 101 Software Avenue, Yuhua District Nanjing, Jiangsu 210012 China Email: taoran20@huawei.com Liang Geng China Mobile 32 Xuanwumen West St, Xicheng District Beijing 10053 China Email: gengliang@chinamobile.com Peng Liu China Mobile Beiqijia Town, Changping District Beijing 10053 China Email: liupengyjy@chinamobile.com Wei Wang China Telecom 32 Xuanwumen West St, Xicheng District Beijing 102209 China Email: wangw36@chinatelecom.cn 7. References 7.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC4254] Ylonen, T. and C. Lonvick, Ed., "The Secure Shell (SSH) Connection Protocol", RFC 4254, DOI 10.17487/RFC4254, January 2006, . Wu, et al. Expires 20 April 2025 [Page 8] Internet-Draft YANG Notification Transport Capabilities October 2024 [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, . [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, . [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, . [RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018, . [RFC8641] Clemm, A. and E. Voit, "Subscription to YANG Notifications for Datastore Updates", RFC 8641, DOI 10.17487/RFC8641, September 2019, . [RFC9147] Rescorla, E., Tschofenig, H., and N. Modadugu, "The Datagram Transport Layer Security (DTLS) Protocol Version 1.3", RFC 9147, DOI 10.17487/RFC9147, April 2022, . [RFC9196] Lengyel, B., Clemm, A., and B. Claise, "YANG Modules Describing Capabilities for Systems and Datastore Update Notifications", RFC 9196, DOI 10.17487/RFC9196, February 2022, . [RFC9254] Veillette, M., Ed., Petrov, I., Ed., Pelov, A., Bormann, C., and M. Richardson, "Encoding of Data Modeled with YANG in the Concise Binary Object Representation (CBOR)", RFC 9254, DOI 10.17487/RFC9254, July 2022, . 7.2. Informative References Wu, et al. Expires 20 April 2025 [Page 9] Internet-Draft YANG Notification Transport Capabilities October 2024 [I-D.ietf-netconf-https-notif] Jethanandani, M. and K. Watsen, "An HTTPS-based Transport for YANG Notifications", Work in Progress, Internet-Draft, draft-ietf-netconf-https-notif-15, 1 February 2024, . [I-D.ietf-netconf-udp-notif] Zheng, G., Zhou, T., Graf, T., Francois, P., Feng, A. H., and P. Lucente, "UDP-based Transport for Configured Subscriptions", Work in Progress, Internet-Draft, draft- ietf-netconf-udp-notif-14, 4 July 2024, . [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-18, 11 October 2024, . [RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, DOI 10.17487/RFC3688, January 2004, . [RFC4252] Ylonen, T. and C. Lonvick, Ed., "The Secure Shell (SSH) Authentication Protocol", RFC 4252, DOI 10.17487/RFC4252, January 2006, . [RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)", RFC 6020, DOI 10.17487/RFC6020, October 2010, . [RFC8340] Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams", BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 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, . Wu, et al. Expires 20 April 2025 [Page 10] Internet-Draft YANG Notification Transport Capabilities October 2024 Appendix A. Usage Example of interaction with UDP-Notif and HTTPS-Notif for Configured Subscription The following instance-data example describes the notification transport capabilities of a hypothetical "acme-router". acme-router-notification-capabilities ietf-system-capabilities@2020-03-23 ietf-notification-capabilities@2020-03-23 ietf-notification-transport-capabilities@2024-10-14 Server Capability Discovery hnt:https sn:encode-xml sn:encode-json unt:udp-notif unt:encode-cbor In addition, the client could also query notification transport capabilities from the server. For example, the client sends request message to the the server to query from the server. Wu, et al. Expires 20 April 2025 [Page 11] Internet-Draft YANG Notification Transport Capabilities October 2024 The server returns server data export capability using as follows: hnt:https sn:encode-xml sn:encode-json unt:udp-notif unt:encode-cbor Authors' Addresses Wu, et al. Expires 20 April 2025 [Page 12] Internet-Draft YANG Notification Transport Capabilities October 2024 Qin Wu Huawei 101 Software Avenue, Yuhua District Nanjing Jiangsu, 210012 China Email: bill.wu@huawei.com Qiufang Ma Huawei 101 Software Avenue, Yuhua District Nanjing Jiangsu, 210012 China Email: maqiufang1@huawei.com Alex Huang Feng INSA-Lyon Lyon France Email: alex.huang-feng@insa-lyon.fr Thomas Graf Swisscom Binzring 17 CH-8045 Zurich Switzerland Email: thomas.graf@swisscom.com Wu, et al. Expires 20 April 2025 [Page 13]