DMM Working Group J. Kaippallimalil Internet-Draft Futurewei Intended status: Standards Track L.M. Contreras Expires: 7 June 2026 Telefonica U. Chunduri Intel Corporation 4 December 2025 A YANG Data Model for Attachment Circuit as a Service with UDP Tunnel Support draft-jlu-dmm-udp-tunnel-acaas-02 Abstract Delivery of network services over a Layer 3 tunnel assumes that the appropriate setup is provisioned over links that connect the customer termination points and provider network. The required setup to allow successful data exchange over these links is referred to as an attachment circuit (AC) while the underlying link for carrying network services is referred to as "bearer", in this case a Layer 3 UDP tunnel. This document specifies an extension for UDP tunnel as Layer 3 bearer to the YANG service data model for AC. 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 7 June 2026. Copyright Notice Copyright (c) 2025 IETF Trust and the persons identified as the document authors. All rights reserved. Kaippallimalil, et al. Expires 7 June 2026 [Page 1] Internet-Draft A YANG Data Model for Attachment Circuit 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 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Attachment Circuit for UDP Tunnel . . . . . . . . . . . . . . 3 4. ietf-ac-udp-tunnel YANG Module . . . . . . . . . . . . . . . 4 5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 6 6. Security Considerations . . . . . . . . . . . . . . . . . . . 6 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 8 8.1. Normative References . . . . . . . . . . . . . . . . . . 8 8.2. Informative References . . . . . . . . . . . . . . . . . 8 Appendix A. Example . . . . . . . . . . . . . . . . . . . . . . 10 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 16 1. Introduction Connectivity services provided by networks to customers ensure the transfer of data between termination points via a provider network. The objectives of the connectivity service can be negotiated and agreed between customers and network providers. To facilitate data transfer within the provider network, it is assumed that the appropriate setup is provisioned over links that connect customer termination points and provider network (usually via Provider Edges (PEs)). This is referred to as attachment circuit (AC) and the underlying link defined in this document is a UDP tunnel as Layer 3 bearer. In general, a bearer can be described as a physical or logical link that connects a customer node (or site) to a provider network. [RFC9834] describes further details of bearers and 'Attachment Circuits'-as-a-service. [RFC9834] specifies YANG data models for bearers and 'Attachment circuits'-as-a-service ACaaS. Layer 3 UDP tunnel as bearer is not defined in the ACaaS specification and is an extension defined in this document. An example of Layer 3 UDP tunnel as a bearer is in 5G networks where a GTP-U (UDP) bearer [TS.29.281-3GPP] is used to transport datagrams of a mobile end-user between 3GPP user plane functions. Section 3 describes the "ietf-ac-udpt" YANG module for Layer 3 UDP tunnel service. Section 4 describes the UDP tunnel YANG Kaippallimalil, et al. Expires 7 June 2026 [Page 2] Internet-Draft A YANG Data Model for Attachment Circuit December 2025 data model. An example of UDP Tunnel with source port number to identify bearers at the transport network Provider Edge (PE) is provided in Appendix A. 2. Terminology AC – Attachment Circuit CE – Customer Edge GTP-U – General Packet Radio Service (GPRS) Tunneling Protocol - User plane (3GPP) GW – Gateway NSC – Network Slice Controller PE – Service Function SF – Provider Edge SMO – Service Management and Orchestration TN – Transport Network UDP – User Datagram Protocol 3. Attachment Circuit for UDP Tunnel [RFC9834] defines a YANG service model for AC based on underlying bearers. A bearer is a logical link with the appropriate level of resources, QoS and priority for the data traffic it carries. This document extends the YANG service model for AC in [RFC9834] to support UDP tunnel as the underlying bearer. The 'l3-service' and 'l3-tunnel-service' in the AC structure in [RFC9834] is used to configure the relevant layer 3 tunnel properties of a UDP tunnel AC. IPv4 and IPv6 properties of the UDP tunnel AC are provided in the "ip-connection" container (Section 5.2.5.2 of [RFC9834]). The extension below adds source port number and range for the UDP tunnel. The meanings of the symbols in the YANG tree diagram are defined in "YANG Tree Diagrams" [RFC8340]. Kaippallimalil, et al. Expires 7 June 2026 [Page 3] Internet-Draft A YANG Data Model for Attachment Circuit December 2025 module: ietf-ac-udpt augment /ac-svc:attachment-circuits/ac-svc:ac/ac-svc:ip-connection /ac-svc:l3-service/ac-svc:l3-tunnel-service /ac-svc:l3-tunnel-service: +--rw (udp-port)? +--:(port-range-or-operator) +--rw source-port-range-or-operator +--rw (port-range-or-operator)? +--:(range) | +--rw lower-port inet:port-number | +--rw upper-port inet:port-number +--:(operator) +--rw operator? operator +--rw port inet:port-number Figure 1: UDP Tunnel Yang Module 'l3-tunnel-service' in Section 5.2.5.2 of [RFC9834] is extended in this document to specify UDP source port number or a range port numbers. Also, this document defines a new identity (called 'udp') based on the base identity 'l3-tunnel-type' defined in Section 4.2 of [RFC9833]. 4. ietf-ac-udp-tunnel YANG Module The "ietf-ac-udp-tunnel" module uses types and groupings defined in [RFC9833], [RFC9834], and [RFC8519]. file "ietf-ac-udp-tunnel@2025-09-18.yang" module ietf-ac-udp-tunnel { yang-version 1.1; namespace "urn:ietf:params:xml:ns:yang:ietf-ac-udp-tunnel"; prefix ac-udpt; import ietf-ac-common { prefix ac-common; reference "RFC 9833: A Common YANG Data Model for Attachment Circuits"; } import ietf-ac-svc { prefix ac-svc; reference "RFC 9834: YANG Data Models for Bearers and 'Attachment Kaippallimalil, et al. Expires 7 June 2026 [Page 4] Internet-Draft A YANG Data Model for Attachment Circuit December 2025 Circuits'-as-a-Service (ACaaS)"; } import ietf-packet-fields { prefix packet-fields; reference "RFC 8519: YANG Data Model for Network Access Control Lists (ACLs), Section 4.2"; } organization "IETF DMM (Distributed Mobility Management)"; contact "WG Web: WG List: Author: John Kaippallimalil "; description "This YANG module defines a YANG model for augmenting the ACaaS service model with UDP Encapsulation as Layer 3 tunnel service. 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). 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 2025-09-18 { description "Initial revision."; reference "RFC XXXX: A YANG Data Model for Attachment Circuit as a Service with UDP Tunnel Support"; } identity udp { Kaippallimalil, et al. Expires 7 June 2026 [Page 5] Internet-Draft A YANG Data Model for Attachment Circuit December 2025 base ac-common:l3-tunnel-type; description "UDP Encapsulation."; reference "RFC 8085: UDP Usage Guidelines, Section 3.1.11"; } augment "/ac-svc:attachment-circuits/ac-svc:ac" + "/ac-svc:ip-connection/ac-svc:l3-service" + "/ac-svc:l3-tunnel-service/ac-svc:l3-tunnel-service" { when "derived-from-or-self(./ac-svc:type, 'ac-udpt:udp')" { description "Only applicable if l3 service type is UDP encapsulation."; } description "Augments Layer 3 AC service with required data nodes for UDP encapsulation support."; choice udp-port { description "Choice of specifying the source port number or referring to a group of port numbers."; container source-port-range-or-operator { description "Indicates a set of source ports numbers."; uses packet-fields:port-range-or-operator; } } } } Figure 2: UDP Tunnel YANG Module Note to RFC Editor: Replace "RFC XXXX" with the RFC number to be assigned to this document. 5. Acknowledgements Thanks to Mohamed Boucadair for the review and comments. 6. Security Considerations This section is modeled after the template described in Section 3.7 of [I-D.ietf-netmod-rfc8407bis]. Kaippallimalil, et al. Expires 7 June 2026 [Page 6] Internet-Draft A YANG Data Model for Attachment Circuit December 2025 The "ietf-ac-udp-tunnel" 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 YANG-based management protocols (1) have to use a secure transport layer (e.g., SSH [RFC4252], TLS [RFC8446], and QUIC [RFC9000]) and (2) have to use mutual authentication. Servers MUST verify that requesting clients are entitled to access and manipulate a given bearer or AC. For example, a given customer must not have access to bearers (attachment circuits) of other customers. 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. The data nodes in the YANG model in this document inherits from [RFC9834], and the security constraints to the data structures there apply. Data nodes defined in the ietf-ac-udp-tunnel YANG module are writable/creatable/deletable (i.e., config true, which is the default). These data nodes may be considered sensitive or vulnerable in some network environments. Write operations (e.g., edit-config) and delete operations to these data nodes without proper protection or authentication can have a negative effect on network operations. The 'udp-port' information may be used to track a customer of the slice service and may be considered a violation of the customer- provider trust relationship. 7. IANA Considerations IANA is requested to register the following URI in the "ns" subregistry within the "IETF XML Registry" [RFC3688]: URI: urn:ietf:params:xml:ns:yang:ietf-ac-udp-tunnel Registrant Contact: The IESG. XML: N/A; the requested URI is an XML namespace. IANA is requested to register the following YANG module in the "YANG Module Names" subregistry [RFC6020] within the "YANG parameters" registry. Name: ietf-ac-udp-tunnel Maintained by IANA? N Namespace: urn:ietf:params:xml:ns:yang:ietf-ac-udp-tunnel Kaippallimalil, et al. Expires 7 June 2026 [Page 7] Internet-Draft A YANG Data Model for Attachment Circuit December 2025 Prefix: ac-udp-tunnel Reference: RFC XXXX 8. References 8.1. Normative References [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, . [RFC8341] Bierman, A. and M. Bjorklund, "Network Configuration Access Control Model", STD 91, RFC 8341, DOI 10.17487/RFC8341, March 2018, . [RFC8519] Jethanandani, M., Agarwal, S., Huang, L., and D. Blair, "YANG Data Model for Network Access Control Lists (ACLs)", RFC 8519, DOI 10.17487/RFC8519, March 2019, . [RFC9833] Boucadair, M., Ed., Roberts, R., Ed., Gonzalez de Dios, O., Barguil, S., and B. Wu, "A Common YANG Data Model for Attachment Circuits", RFC 9833, DOI 10.17487/RFC9833, September 2025, . [RFC9834] Boucadair, M., Ed., Roberts, R., Ed., Gonzalez de Dios, O., Barguil, S., and B. Wu, "YANG Data Models for Bearers and Attachment Circuits as a Service (ACaaS)", RFC 9834, DOI 10.17487/RFC9834, September 2025, . 8.2. 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, . Kaippallimalil, et al. Expires 7 June 2026 [Page 8] Internet-Draft A YANG Data Model for Attachment Circuit December 2025 [RFC4252] Ylonen, T. and C. Lonvick, Ed., "The Secure Shell (SSH) Authentication Protocol", RFC 4252, DOI 10.17487/RFC4252, January 2006, . [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, . [RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017, . [RFC8085] Eggert, L., Fairhurst, G., and G. Shepherd, "UDP Usage Guidelines", BCP 145, RFC 8085, DOI 10.17487/RFC8085, March 2017, . [RFC8340] Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams", BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018, . [RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018, . [RFC8792] Watsen, K., Auerswald, E., Farrel, A., and Q. Wu, "Handling Long Lines in Content of Internet-Drafts and RFCs", RFC 8792, DOI 10.17487/RFC8792, June 2020, . [RFC9000] Iyengar, J., Ed. and M. Thomson, Ed., "QUIC: A UDP-Based Multiplexed and Secure Transport", RFC 9000, DOI 10.17487/RFC9000, May 2021, . [RFC9543] Farrel, A., Ed., Drake, J., Ed., Rokui, R., Homma, S., Makhijani, K., Contreras, L., and J. Tantsura, "A Framework for Network Slices in Networks Built from IETF Technologies", RFC 9543, DOI 10.17487/RFC9543, March 2024, . [TS.29.281-3GPP] 3rd Generation Partnership Project (3GPP), "GPRS Tunneling Protocol User Plane (GTPv1-U), 3GPP TS 29.281 v19.2.0", September 2025. Kaippallimalil, et al. Expires 7 June 2026 [Page 9] Internet-Draft A YANG Data Model for Attachment Circuit December 2025 Appendix A. Example This example is adapted from Appendix A.7 of [RFC9834] where details of the topology and service are described. Figure 3 describes the end-to-end network topology as well as orchestration scope: * The topology is made up of two sites ("site1" and "site2"), interconnected via a Transport Network (e.g., IP/MPLS network). An SF is deployed within each site in a dedicated IP subnet. * A 5G Service Management and Orchestration (SMO) is responsible for the deployment of SFs and the indirect management of a local Gateway (i.e., CE). * An IETF Network Slice Controller (NSC) [RFC9543] is responsible for the deployment of IETF Network Slices across the Transport Network. 5G SMO IETF NSC 5G SMO | (TN Orchestrator) | | | | <-----+-----> <---------+--------> <----+----> Site1 Transport Network Site2 .--------------. | | .---. .---. .---. .---. | | | | .---. .---. |SF1+----------------+PE1| |PE2+---------------|SF2| '---' |GW1| ^ | | | | ^ |GW2| '---' '---' | '-+-' '-+-' | '---' | | | | | '--------------' | | | | | UDP Tunnel Bearer: UDP Tunnel Bearer: bearerX@site1 bearerX@site2 Figure 3: An example of a Network Topology to Deploy Slices with UDP Tunnel Bearer Figure 4 describes the logical connectivity enforced with IETF Network slice and ACaaS models with UDP tunnel bearer identified by the UDP source port number. Kaippallimalil, et al. Expires 7 June 2026 [Page 10] Internet-Draft A YANG Data Model for Attachment Circuit December 2025 AS 65536 <----BGP--> AS 65550 .---. .--------. .---. |SF1| 192.0.2.0/30 | | 192.0.2.4/30 |SF2| '-+-' .---. .-+-. .-+-. .---. '-+-' | | |.1 .2| | | |.6 .5| | | --+-----+GW1+-----------+PE1| |PE2+-----------+GW2+-----+-- | |udp-src-prt| | | |udp-src-prt| | '---' 5678 '-+-' '-+-' 7890 '---' 198.51.100.0/24 | | 203.0.113.0/24 '--------' sdp1 sdp2 <--------------------> <-----------> <------------------> Attachment Network Slice Attachment * "ac1" properties: - bearer-reference: bearerX@site1 - udp-src-prt: 5678 - CE address (SF1): 198.51.100.0/24 - PE address: 192.0.2.2/30 - Routing: static 198.51.100.0/24 via 192.0.2.1 tag primary_UP_slice * "ac2" properties: - bearer-reference: bearerY@site2 - udp-src-prt: 7890 - CE address (SF2): 203.0.113.0/24 - PE address: 192.0.2.6/30 - Routing: BGP local-as: 65536 (Provider ASN) peer-as: 65550 (customer ASN) remote-address: 192.0.2.5 (Customer address) Figure 4: Logical Overview Figure 5 is an adaptation of A.7, Figure 41 in [RFC9834] with a UDP Tunnel bearer identified by the source port number. =============== NOTE: '\' line wrapping per RFC 8792 ================ { "ietf-ac-svc:attachment-circuits": { "ac": [ { "name": "ac1", "description": "Connection to site1 on vlan 100", "requested-start": "2023-12-12T05:00:00.00Z", Kaippallimalil, et al. Expires 7 June 2026 [Page 11] Internet-Draft A YANG Data Model for Attachment Circuit December 2025 "l2-connection": { "bearer-reference": "bearerX@site1" }, "ip-connection": { "ipv4": { "address-allocation-type": "ietf-ac-common:static-\ address" }, "l3-service" { "l3-tunnel-service": "ietf-ac-udpt:udp" } }, "routing-protocols": { "routing-protocol": [ { "id": "1", "type": "ietf-vpn-common:static-routing", "static": { "cascaded-lan-prefixes": { "ipv4-lan-prefix": [ { "lan": "198.51.100.0/24", "next-hop": "192.0.2.1", "lan-tag": "primary_UP_slice" } ] } } } ] } }, { "name": "ac2", "description": "Connection to site2 on vlan 200", "requested-start": "2023-12-12T05:00:00.00Z", "l2-connection": { "bearer-reference": "bearerY@site2" }, "ip-connection": { "ipv4": { "address-allocation-type": "ietf-ac-common:static-\ address" }, "l3-service" { "l3-tunnel-service": "ietf-ac-udpt:udp" } Kaippallimalil, et al. Expires 7 June 2026 [Page 12] Internet-Draft A YANG Data Model for Attachment Circuit December 2025 }, "routing-protocols": { "routing-protocol": [ { "id": "1", "type": "ietf-vpn-common:bgp-routing", "bgp": { "neighbor": [ { "id": "1", "peer-as": 65550 } ] } } ] } } ] } } Figure 5: Message Body of a Request to Create AC with UDP Tunnel Figure 6 is an adaptation of A.7, Figure 42 in [RFC9834] that shows the message body of that response to a GET request received from the controller. { "ietf-ac-svc:attachment-circuits": { "ac": [ { "name": "ac1", "description": "Connection to site1 on vlan 100", "actual-start": "2023-12-12T05:00:00.00Z", "l2-connection": { "bearer-reference": "bearerX@site1" }, "ip-connection": { "ipv4": { "local-address": "192.0.2.2", "prefix-length": 30, "address": [ { "address-id": "1", "customer-address": "192.0.2.1" Kaippallimalil, et al. Expires 7 June 2026 [Page 13] Internet-Draft A YANG Data Model for Attachment Circuit December 2025 } ] }, "l3-service" { "l3-tunnel-service": "ietf-udpt:udp", "ietf-ac-udpt:source-port-range-or-operator" { "port": 5678 } } } }, "routing-protocols": { "routing-protocol": [ { "id": "1", "type": "ietf-vpn-common:static-routing", "static": { "cascaded-lan-prefixes": { "ipv4-lan-prefix": [ { "lan": "198.51.100.0/24", "next-hop": "192.0.2.1", "lan-tag": "primary_UP_slice" } ] } } } ] } }, { "name": "ac2", "description": "Connection to site2 on vlan 200", "actual-start": "2023-12-12T05:00:00.00Z", "l2-connection": { "bearer-reference": "bearerY@site2" }, "ip-connection": { "ipv4": { "local-address": "192.0.2.6", "prefix-length": 30, "address": [ { "address-id": "1", "customer-address": "192.0.2.5" } ] Kaippallimalil, et al. Expires 7 June 2026 [Page 14] Internet-Draft A YANG Data Model for Attachment Circuit December 2025 }, "l3-service" { "l3-tunnel-service": "ietf-udpt:udp", "ietf-ac-udpt:source-port-range-or-operator" { "port": 7890 } } } }, "routing-protocols": { "routing-protocol": [ { "id": "1", "type": "ietf-vpn-common:bgp-routing", "bgp": { "neighbor": [ { "id": "1", "peer-as": 65550, "local-as": 65536 } ] } } ] } } ] } Figure 6: Example of a Message Body of a Response Indicating Creation of the ACs Figure 7 is derived from A.7, Figure 43 in [RFC9834]. Figure 7 shows the message body of the request to create a Slice Service bound to the ACs created using Figure 5. Only references to these ACs are included in the Slice Service request. Kaippallimalil, et al. Expires 7 June 2026 [Page 15] Internet-Draft A YANG Data Model for Attachment Circuit December 2025 { "ietf-network-slice-service:network-slice-services": { "slo-sle-templates": { "slo-sle-template": [ { "id": "low-latency-template", "description": "Lowest latency forwarding behavior" } ] }, "slice-service": [ { "id": "Slice URLLC_UP", "description": "Dedicated TN Slice for URLLC-UP", "slo-sle-template": "low-latency-template", "status": {}, "sdps": { "sdp": [ { "id": "sdp1", "ac-svc-name": [ "ac1" ] }, { "id": "sdp2", "ac-svc-name": [ "ac2" ] } ] } } ] } } Figure 7: Example of a Message Body of a Response Indicating Creation of the ACs Authors' Addresses John Kaippallimalil Futurewei United States of America Email: john.kaippallimalil@futurewei.com Kaippallimalil, et al. Expires 7 June 2026 [Page 16] Internet-Draft A YANG Data Model for Attachment Circuit December 2025 Luis M. Contreras Telefonica Telefonica Sur-3 building, 3rd floor 28050 Madrid Spain Email: luismiguel.contrerasmurillo@telefonica.com Uma Chunduri Intel Corporation 2191 Laurelwood Rd Santa Clara, CA 95054 United States of America Email: umac.ietf@gmail.com Kaippallimalil, et al. Expires 7 June 2026 [Page 17]