A YANG Data Model for Augmenting VPN Service and Network Models with Attachment Circuits

A YANG Data Model for Augmenting VPN Service and Network Models with Attachment Circuits Orange

mohamed.boucadair@orange.com

Juniper

rroberts@juniper.net

Nokia

samier.barguil_giraldo@nokia.com

Telefonica

oscar.gonzalezdedios@telefonica.com

OPS opsawg Slice Service L3VPN L2VPN Automation Network Automation Orchestration service delivery Service provisioning service segmentation service flexibility service simplification Network Service 3GPP Network Slicing This document defines a YANG data model, referred to as the "AC Glue" model, to augment the LxVPN Service Model (LxSM) and LxVPN Network Model (LxNM) with references to attachment circuits (ACs). The AC Glue model enables a provider to associate Layer 2/3 VPN (LxVPN) services with the underlying AC infrastructure, thereby facilitating consistent provisioning and management of new or existing ACs in conjunction with LxVPN services. Specifically, by introducing an integrated approach to AC and LxVPN management, this model supports Attachment Circuit as a Service (ACaaS) and provides a standardized mechanism for aligning AC/VPN requests with the network configurations required to deliver them.

Status of This Memo This is an Internet Standards Track document. This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 7841. Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at .

Copyright Notice Copyright (c) 2025 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 () 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

. Introduction
. Conventions and Definitions
. Relationship to Other AC Data Models
. Sample Uses of the Data Models
- . ACs Terminated by One or Multiple Customer Edges (CEs)
- . Separate AC Provisioning from Actual VPN Service Provisioning
. Module Tree Structure
. The AC Glue ("ietf-ac-glue") YANG Module
. Security Considerations
. IANA Considerations
. References
- . Normative References
- . Informative References
. Examples
- . A Service AC Reference Within the VPN Network Access
- . Network and Service AC References
Acknowledgments
Authors' Addresses

Introduction To facilitate data transfer within the provider network, it is assumed that the appropriate setup is provisioned over the links that connect customer termination points and a provider network (usually via a Provider Edge (PE)), allowing data to be successfully exchanged over these links. The required setup is referred to in this document as an attachment circuit (AC), while the underlying link is referred to as "bearer". The document specifies a YANG module ("ietf-ac-glue", ) that updates existing service and network Virtual Private Network (VPN) modules with the required information to bind specific services to ACs that are created using the AC service model . Specifically, the following modules are augmented:

The L2VPN Service Model (L2SM)
The L3VPN Service Model (L3SM)
The L2VPN Network Model (L2NM)
The L3VPN Network Model (L3NM)

Likewise, the document augments the L2NM and L3NM with references to the ACs that are managed using the AC network model . This approach allows operators to separate AC provisioning from actual VPN service provisioning. Refer to for more discussion. The YANG data model in this document conforms to the Network Management Datastore Architecture (NMDA) defined in . Examples to illustrate the use of the "ietf-ac-glue" module are provided in .

Conventions and Definitions The meanings of the symbols in the YANG tree diagrams are defined in . This document uses terms defined in . LxSM refers to both the L2SM and the L3SM. LxNM refers to both the L2NM and the L3NM. The following terms are used in the module's prefixes:

ac:: Attachment circuit
ntw:: Network
ref:: Reference
svc:: Service

The names of data nodes are prefixed using the prefix associated with the corresponding imported YANG module as shown in : Modules and Their Associated Prefixes

Prefix	Module	Reference
ac-svc	ietf-ac-svc
ac-ntw	ietf-ac-ntw
l2nm	ietf-l2vpn-ntw
l2vpn-svc	ietf-l2vpn-svc
l3nm	ietf-l3vpn-ntw
l3vpn-svc	ietf-l3vpn-svc

Relationship to Other AC Data Models depicts the relationship between the various AC data models:

"ietf-ac-common"
"ietf-bearer-svc" ()
"ietf-ac-svc" ()
"ietf-ac-ntw"
"ietf-ac-glue" ()

AC Data Models ietf-ac-common ^ ^ ^ | | | .----------' | '----------. | | | | | | ietf-ac-svc <--- ietf-bearer-svc | ^ ^ | | | | | '------------------------ ietf-ac-ntw | ^ | | | | '------------ ietf-ac-glue ----------' X --> Y: X imports Y The "ietf-ac-common" module is imported by the "ietf-bearer-svc", "ietf-ac-svc", and "ietf-ac-ntw" modules. Bearers managed using the "ietf-bearer-svc" module may be referenced by service ACs managed using the "ietf-ac-svc" module. Similarly, a bearer managed using the "ietf-bearer-svc" module may list the set of ACs that use that bearer. To facilitate correlation between an AC service request and the actual AC provisioned in the network, "ietf-ac-ntw" leverages the AC references exposed by the "ietf-ac-svc" module. Furthermore, to bind Layer 2 VPN (L2VPN) or Layer 3 VPN (L3VPN) services with ACs, the "ietf-ac-glue" module augments the LxSM and LxNM with AC service references exposed by the "ietf-ac-svc" module and AC network references exposed by the "ietf-ac-ntw" module.

Sample Uses of the Data Models

ACs Terminated by One or Multiple Customer Edges (CEs) depicts two target topology flavors that involve ACs. These topologies have the following characteristics:

A Customer Edge (CE) can be either a physical device or a logical entity. Such logical entity is typically a software component (e.g., a virtual service function that is hosted within the provider's network or a third-party infrastructure). A CE is seen by the network as a peer Service Attachment Point (SAP) .
CEs may be either dedicated to one single connectivity service or host multiple connectivity services (e.g., CEs with roles of service functions ).
A network provider may bind a single AC to one or multiple peer SAPs (e.g., CE1 and CE2 are tagged as peer SAPs for the same AC). For example, and as discussed in , multiple CEs can be attached to a PE over the same AC. This scenario is typically implemented when the Layer 2 infrastructure between the CE and the network is a multipoint service.
A single CE may terminate multiple ACs, which can be associated with the same bearer or distinct bearers (e.g., CE4).
Customers may request protection schemes in which the ACs associated with their endpoints are terminated by the same PE (e.g., CE3), distinct PEs (e.g., CE4), etc. The network provider uses this request to decide where to terminate the AC in the service provider network and also whether to enable specific capabilities (e.g., Virtual Router Redundancy Protocol (VRRP)).

Examples of ACs .--------------------. | | .------. | .--. (b1) .-----. | +----. | | +---AC---+ | | CE1 | | | |PE+---AC---+ CE3 | '------' | .--. '--' (b2) '-----' +---AC--+PE| Network | .------. | '--' .--. (b3) .-----. | | | | | +---AC---+ | | CE2 +----' | |PE+---AC---+ CE4 | '------' | '--' (b3) '---+-' | .--. | | '----------+PE+------' | '--' | | | '-----------AC----------' (bx) = bearer Id x These ACs can be referenced when creating VPN services. Refer to the examples provided in to illustrate how VPN services can be bound to ACs.

Separate AC Provisioning from Actual VPN Service Provisioning The procedure to provision a service in a service provider network may depend on the practices adopted by a service provider. This includes the flow put in place for the provisioning of advanced network services and how they are bound to an AC. For example, a single AC may be used to host multiple connectivity services (e.g., L2VPN ("ietf-l2vpn-svc"), L3VPN ("ietf-l3vpn-svc"), Network Slice Service ("ietf-network-slice-service")). In order to avoid service interference and redundant information in various locations, a service provider may expose an interface to manage ACs network-wide using the modules in . Customers can request for an AC ("ietf-ac-svc") to be put in place and then refer to that AC when requesting VPN services that are bound to the AC ("ietf-ac-glue"). Also, internal references ("ietf-ac-ntw") used within a service provider network to implement ACs can be used by network controllers to glue the L2NM ("ietf-l2vpn-ntw") or the L3NM ("ietf-l3vpn-ntw") services with relevant ACs. shows the positioning of the AC models in the overall service delivery process.

Module Tree Structure specifies that a 'site-network-access' attachment is achieved through a 'bearer' with an 'ip-connection' on top. From that standpoint, a 'site-network-access' is mapped to an AC with both Layer 2 and Layer 3 properties per . specifies that a 'site-network-access' represents a logical Layer 2 connection to a site. A 'site-network-access' can thus be mapped to an AC with Layer 2 properties . Similarly, 'vpn-network-access' defined in both and is mapped to an AC per or . As such, ACs created using the "ietf-ac-svc" module can be referenced in other VPN-related modules (e.g., LxSM and LxNM). Also, ACs managed using the "ietf-ac-ntw" module can be referenced in VPN-related network modules (mainly, the LxNM). The required augmentations to that aim are shown in .

AC Glue Tree Structure module: ietf-ac-glue augment /l2vpn-svc:l2vpn-svc/l2vpn-svc:sites/l2vpn-svc:site /l2vpn-svc:site-network-accesses: +--rw ac-svc-ref* ac-svc:attachment-circuit-reference augment /l2vpn-svc:l2vpn-svc/l2vpn-svc:sites/l2vpn-svc:site /l2vpn-svc:site-network-accesses /l2vpn-svc:site-network-access: +--rw ac-svc-ref? ac-svc:attachment-circuit-reference {ac-glue}? augment /l3vpn-svc:l3vpn-svc/l3vpn-svc:sites/l3vpn-svc:site /l3vpn-svc:site-network-accesses: +--rw ac-svc-ref* ac-svc:attachment-circuit-reference augment /l3vpn-svc:l3vpn-svc/l3vpn-svc:sites/l3vpn-svc:site /l3vpn-svc:site-network-accesses /l3vpn-svc:site-network-access: +--rw ac-svc-ref? ac-svc:attachment-circuit-reference {ac-glue}? augment /l2nm:l2vpn-ntw/l2nm:vpn-services/l2nm:vpn-service /l2nm:vpn-nodes/l2nm:vpn-node/l2nm:vpn-network-accesses: +--rw ac-svc-ref* ac-svc:attachment-circuit-reference +--rw ac-ntw-ref* [ac-ref] +--rw ac-ref leafref +--rw node-ref? leafref +--rw network-ref? -> /nw:networks/network/network-id augment /l2nm:l2vpn-ntw/l2nm:vpn-services/l2nm:vpn-service /l2nm:vpn-nodes/l2nm:vpn-node/l2nm:vpn-network-accesses /l2nm:vpn-network-access: +--rw ac-svc-ref? ac-svc:attachment-circuit-reference {ac-glue}? +--rw ac-ntw-ref {ac-glue}? +--rw ac-ref? leafref +--rw node-ref? leafref +--rw network-ref? -> /nw:networks/network/network-id augment /l3nm:l3vpn-ntw/l3nm:vpn-services/l3nm:vpn-service /l3nm:vpn-nodes/l3nm:vpn-node/l3nm:vpn-network-accesses: +--rw ac-svc-ref* ac-svc:attachment-circuit-reference +--rw ac-ntw-ref* [ac-ref] +--rw ac-ref leafref +--rw node-ref? leafref +--rw network-ref? -> /nw:networks/network/network-id augment /l3nm:l3vpn-ntw/l3nm:vpn-services/l3nm:vpn-service /l3nm:vpn-nodes/l3nm:vpn-node/l3nm:vpn-network-accesses /l3nm:vpn-network-access: +--rw ac-svc-ref? ac-svc:attachment-circuit-reference {ac-glue}? +--rw ac-ntw-ref {ac-glue}? +--rw ac-ref? leafref +--rw node-ref? leafref +--rw network-ref? -> /nw:networks/network/network-id When an AC is referenced within a specific network access, that AC information takes precedence over any overlapping information that is also enclosed for this network access. The "ietf-ac-glue" module includes provisions to reference ACs within or outside a VPN network access to accommodate deployment contexts where an AC reference may be created before or after a VPN instance is created. illustrates how an AC reference can be included as part of a specific VPN network access, while shows how AC references can be indicated outside individual VPN network access entries.

The AC Glue ("ietf-ac-glue") YANG Module This modules augments the L2SM , the L3SM , the L2NM , and the L3NM . This module uses references defined in and . module ietf-ac-glue { yang-version 1.1; namespace "urn:ietf:params:xml:ns:yang:ietf-ac-glue"; prefix ac-glue; import ietf-l3vpn-svc { prefix l3vpn-svc; reference "RFC 8299: YANG Data Model for L3VPN Service Delivery"; } import ietf-l2vpn-svc { prefix l2vpn-svc; reference "RFC 8466: A YANG Data Model for Layer 2 Virtual Private Network (L2VPN) Service Delivery"; } import ietf-l3vpn-ntw { prefix l3nm; reference "RFC 9182: A YANG Network Data Model for Layer 3 VPNs"; } import ietf-l2vpn-ntw { prefix l2nm; reference "RFC 9291: A YANG Network Data Model for Layer 2 VPNs"; } import ietf-ac-svc { prefix ac-svc; reference "RFC 9834: YANG Data Models for Bearers and Attachment Circuits as a Service (ACaaS)"; } import ietf-ac-ntw { prefix ac-ntw; reference "RFC 9835: A Network YANG Data Model for Attachment Circuits"; } organization "IETF OPSAWG (Operations and Management Area Working Group)"; contact "WG Web: <https://datatracker.ietf.org/wg/opsawg/> WG List: <mailto:opsawg@ietf.org> Editor: Mohamed Boucadair <mailto:mohamed.boucadair@orange.com> Author: Richard Roberts <mailto:rroberts@juniper.net> Author: Samier Barguil <mailto:ssamier.barguil_giraldo@nokia.com> Author: Oscar Gonzalez de Dios <mailto:oscar.gonzalezdedios@telefonica.com>"; description "This YANG module defines a YANG data model for augmenting the LxSM and the LxNM with AC references. 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). This version of this YANG module is part of RFC 9836; see the RFC itself for full legal notices."; revision 2025-09-29 { description "Initial revision."; reference "RFC 9836: A YANG Data Model for Augmenting VPN Service and Network Models with Attachment Circuits"; } feature ac-glue { description "The VPN implementation supports binding a specific VPN network access or site access to an AC."; } grouping single-ac-svc-ref { description "A grouping with a single reference to a service AC."; leaf ac-svc-ref { type ac-svc:attachment-circuit-reference; description "A reference to the AC as exposed at the service that was provisioned using the ACaaS module."; } } grouping single-ac-svc-ntw-ref { description "A grouping with single AC references."; leaf ac-svc-ref { type ac-svc:attachment-circuit-reference; description "A reference to the AC as exposed at the service that was provisioned using the ACaaS module."; } container ac-ntw-ref { description "A reference to the AC that was provisioned using the AC network module."; uses ac-ntw:attachment-circuit-reference; } } grouping ac-svc-ref { description "A set of service-specific AC-related data."; leaf-list ac-svc-ref { type ac-svc:attachment-circuit-reference; description "A reference to the AC as exposed at the service that was provisioned using the ACaaS module."; } } grouping ac-svc-ntw-ref { description "A set of AC-related data."; leaf-list ac-svc-ref { type ac-svc:attachment-circuit-reference; description "A reference to the AC as exposed at the service that was provisioned using the ACaaS module."; } list ac-ntw-ref { key "ac-ref"; description "A reference to the AC that was provisioned using the AC network module."; uses ac-ntw:attachment-circuit-reference; } } augment "/l2vpn-svc:l2vpn-svc" + "/l2vpn-svc:sites/l2vpn-svc:site" + "/l2vpn-svc:site-network-accesses" { description "Augments VPN site network accesses with AC provisioning details. Concretely, it binds a site to a set of ACs with Layer 2 properties that were created using the ACaaS module."; uses ac-svc-ref; } augment "/l2vpn-svc:l2vpn-svc" + "/l2vpn-svc:sites/l2vpn-svc:site" + "/l2vpn-svc:site-network-accesses" + "/l2vpn-svc:site-network-access" { if-feature "ac-glue"; description "Augments VPN site network access with AC provisioning details. Concretely, it glues a 'site-network-access' to an AC with Layer 2 properties that was created using the ACaaS module. The ACaaS information takes precedence over any overlapping information that is also provided for a site network access."; uses single-ac-svc-ref; } augment "/l3vpn-svc:l3vpn-svc" + "/l3vpn-svc:sites/l3vpn-svc:site" + "/l3vpn-svc:site-network-accesses" { description "Augments VPN site network accesses with AC provisioning details. Concretely, it binds a site to a set of ACs with both Layer 2 and Layer 3 properties that were created using the ACaaS module."; uses ac-svc-ref; } augment "/l3vpn-svc:l3vpn-svc" + "/l3vpn-svc:sites/l3vpn-svc:site" + "/l3vpn-svc:site-network-accesses" + "/l3vpn-svc:site-network-access" { if-feature "ac-glue"; description "Augments VPN site network access with AC provisioning details. Concretely, it glues a 'site-network-access' to an AC with both Layer 2 and Layer 3 properties that was created using the ACaaS module. The ACaaS information takes precedence over any overlapping information that is also provided for a site network access."; uses single-ac-svc-ref; } augment "/l2nm:l2vpn-ntw/l2nm:vpn-services/l2nm:vpn-service" + "/l2nm:vpn-nodes/l2nm:vpn-node" + "/l2nm:vpn-network-accesses" { description "Augments VPN network accesses with both service and network AC provisioning details. Concretely, it binds a site to (1) a set of ACs with Layer 2 properties that were created using the ACaaS module and (2) a set of ACs with Layer 2 properties that were provisioned using the AC network model."; uses ac-svc-ntw-ref; } augment "/l2nm:l2vpn-ntw/l2nm:vpn-services/l2nm:vpn-service" + "/l2nm:vpn-nodes/l2nm:vpn-node" + "/l2nm:vpn-network-accesses" + "/l2nm:vpn-network-access" { if-feature "ac-glue"; description "Augments VPN network access with service and network references to an AC. Concretely, it glues a VPN network access to (1) an AC with Layer 2 properties that was created using the ACaaS module and (2) an AC with Layer 2 properties that was created using the AC network module. The AC service and network information takes precedence over any overlapping information that is also provided for a VPN network access."; uses single-ac-svc-ntw-ref; } augment "/l3nm:l3vpn-ntw/l3nm:vpn-services/l3nm:vpn-service" + "/l3nm:vpn-nodes/l3nm:vpn-node" + "/l3nm:vpn-network-accesses" { description "Augments VPN network accesses with both service and network AC provisioning details. Concretely, it binds a site to (1) a set of ACs with both Layer 2 and Layer 3 properties that were created using the ACaaS module and (2) a set of ACs with both Layer 2 and Layer 3 properties that were provisioned using the AC network model."; uses ac-svc-ntw-ref; } augment "/l3nm:l3vpn-ntw/l3nm:vpn-services/l3nm:vpn-service" + "/l3nm:vpn-nodes/l3nm:vpn-node" + "/l3nm:vpn-network-accesses" + "/l3nm:vpn-network-access" { if-feature "ac-glue"; description "Augments VPN network access with service and network references to an AC. Concretely, it glues a VPN network access to (1) an AC with both Layer 2 and Layer 3 properties that was created using the ACaaS module and (2) an AC with both Layer 2 and Layer 3 properties that was created using the AC network module. The AC service and network information takes precedence over any overlapping information that is also provided for a VPN network access."; uses single-ac-svc-ntw-ref; } }

Security Considerations This section is modeled after the template described in . The "ietf-ac-common" YANG module defines a data model that is designed to be accessed via YANG-based management protocols, such as NETCONF and RESTCONF . These protocols have to use a secure transport layer (e.g., SSH , TLS , and QUIC ) and have to use mutual authentication. 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. There are a number of data nodes defined in this YANG module that are writable/creatable/deletable (i.e., "config true", which is the default). All writable data nodes are likely to be reasonably 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 following subtrees and data nodes have particular sensitivities/vulnerabilities:

'ac-svc-ref' and 'ac-ntw-ref':: An attacker who is able to access network nodes can undertake various attacks, such as deleting a running VPN service, interrupting all the traffic of a client. Specifically, an attacker may modify (including delete) the ACs that are bound to a running service, leading to malfunctioning of the service and therefore to Service Level Agreement (SLA) violations. Such activity can be detected by adequately monitoring and tracking network configuration changes.

Some of the readable data nodes in this YANG module may be considered sensitive or vulnerable in some network environments. It is thus important to control read access (e.g., via get, get-config, or notification) to these data nodes. Specifically, the following subtrees and data nodes have particular sensitivities/vulnerabilities:

'ac-svc-ref' and 'ac-ntw-ref':: These references do not expose privacy-related information per se; however, 'ac-svc-ref' may be used to track the set of VPN instances in which a given customer is involved. Note that, unlike 'ac-svc-ref', 'ac-ntw-ref' is unique within the scope of a node and may multiplex many peer CEs.

IANA Considerations IANA has registered the following URI in the "ns" subregistry within the "IETF XML Registry" :

URI:: urn:ietf:params:xml:ns:yang:ietf-ac-glue
Registrant Contact:: The IESG.
XML:: N/A; the requested URI is an XML namespace.

IANA has registered the following YANG module in the "YANG Module Names" registry within the "YANG Parameters" registry group:

Name:: ietf-ac-glue
Maintained by IANA?: N
Namespace:: urn:ietf:params:xml:ns:yang:ietf-ac-glue
Prefix:: ac-glue
Reference:: RFC 9836

References Normative References The IETF XML Registry 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 - A Data Modeling Language for the Network Configuration Protocol (NETCONF) 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] YANG Data Model for L3VPN Service Delivery This document defines a YANG data model that can be used for communication between customers and network operators and to deliver a Layer 3 provider-provisioned VPN service. This document is limited to BGP PE-based VPNs as described in RFCs 4026, 4110, and 4364. This model is intended to be instantiated at the management system to deliver the overall service. It is not a configuration model to be used directly on network elements. This model provides an abstracted view of the Layer 3 IP VPN service configuration components. It will be up to the management system to take this model as input and use specific configuration models to configure the different network elements to deliver the service. How the configuration of network elements is done is out of scope for this document. This document obsoletes RFC 8049; it replaces the unimplementable module in that RFC with a new module with the same name that is not backward compatible. The changes are a series of small fixes to the YANG module and some clarifications to the text. Network Configuration Access Control Model 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. Network Management Datastore Architecture (NMDA) Datastores are a fundamental concept binding the data models written in the YANG data modeling language to network management protocols such as the Network Configuration Protocol (NETCONF) and RESTCONF. This document defines an architectural framework for datastores based on the experience gained with the initial simpler model, addressing requirements that were not well supported in the initial model. This document updates RFC 7950. A YANG Data Model for Layer 2 Virtual Private Network (L2VPN) Service Delivery This document defines a YANG data model that can be used to configure a Layer 2 provider-provisioned VPN service. It is up to a management system to take this as an input and generate specific configuration models to configure the different network elements to deliver the service. How this configuration of network elements is done is out of scope for this document. The YANG data model defined in this document includes support for point-to-point Virtual Private Wire Services (VPWSs) and multipoint Virtual Private LAN Services (VPLSs) that use Pseudowires signaled using the Label Distribution Protocol (LDP) and the Border Gateway Protocol (BGP) as described in RFCs 4761 and 6624. The YANG data model defined in this document conforms to the Network Management Datastore Architecture defined in RFC 8342. A YANG Network Data Model for Layer 3 VPNs As a complement to the Layer 3 Virtual Private Network Service Model (L3SM), which is used for communication between customers and service providers, this document defines an L3VPN Network Model (L3NM) that can be used for the provisioning of Layer 3 Virtual Private Network (L3VPN) services within a service provider network. The model provides a network-centric view of L3VPN services. The L3NM is meant to be used by a network controller to derive the configuration information that will be sent to relevant network devices. The model can also facilitate communication between a service orchestrator and a network controller/orchestrator. A YANG Network Data Model for Layer 2 VPNs This document defines an L2VPN Network Model (L2NM) that can be used to manage the provisioning of Layer 2 Virtual Private Network (L2VPN) services within a network (e.g., a service provider network). The L2NM complements the L2VPN Service Model (L2SM) by providing a network-centric view of the service that is internal to a service provider. The L2NM is particularly meant to be used by a network controller to derive the configuration information that will be sent to relevant network devices. Also, this document defines a YANG module to manage Ethernet segments and the initial versions of two IANA-maintained modules that include a set of identities of BGP Layer 2 encapsulation types and pseudowire types. YANG Data Models for Bearers and Attachment Circuits as a Service (ACaaS) Orange Juniper Telefonica Nokia Huawei Technologies A Network YANG Data Model for Attachment Circuits Orange Juniper Telefonica Nokia Huawei Technologies Informative References The Secure Shell (SSH) Authentication Protocol The Secure Shell Protocol (SSH) is a protocol for secure remote login and other secure network services over an insecure network. This document describes the SSH authentication protocol framework and public key, password, and host-based client authentication methods. Additional authentication methods are described in separate documents. The SSH authentication protocol runs on top of the SSH transport layer protocol and provides a single authenticated tunnel for the SSH connection protocol. [STANDARDS-TRACK] BGP/MPLS IP Virtual Private Networks (VPNs) This document describes a method by which a Service Provider may use an IP backbone to provide IP Virtual Private Networks (VPNs) for its customers. This method uses a "peer model", in which the customers' edge routers (CE routers) send their routes to the Service Provider's edge routers (PE routers); there is no "overlay" visible to the customer's routing algorithm, and CE routers at different sites do not peer with each other. Data packets are tunneled through the backbone, so that the core routers do not need to know the VPN routes. [STANDARDS-TRACK] Framework for Layer 2 Virtual Private Networks (L2VPNs) This document provides a framework for Layer 2 Provider Provisioned Virtual Private Networks (L2VPNs). This framework is intended to aid in standardizing protocols and mechanisms to support interoperable L2VPNs. This memo provides information for the Internet community. Network Configuration Protocol (NETCONF) 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] Service Function Chaining (SFC) Architecture This document describes an architecture for the specification, creation, and ongoing maintenance of Service Function Chains (SFCs) in a network. It includes architectural concepts, principles, and components used in the construction of composite services through deployment of SFCs, with a focus on those to be standardized in the IETF. This document does not propose solutions, protocols, or extensions to existing protocols. RESTCONF Protocol 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). YANG Tree Diagrams 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. The Transport Layer Security (TLS) Protocol Version 1.3 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. QUIC: A UDP-Based Multiplexed and Secure Transport This document defines the core of the QUIC transport protocol. QUIC provides applications with flow-controlled streams for structured communication, low-latency connection establishment, and network path migration. QUIC includes security measures that ensure confidentiality, integrity, and availability in a range of deployment circumstances. Accompanying documents describe the integration of TLS for key negotiation, loss detection, and an exemplary congestion control algorithm. A YANG Network Data Model for Service Attachment Points (SAPs) This document defines a YANG data model for representing an abstract view of the provider network topology that contains the points from which its services can be attached (e.g., basic connectivity, VPN, network slices). Also, the model can be used to retrieve the points where the services are actually being delivered to customers (including peer networks). This document augments the 'ietf-network' data model defined in RFC 8345 by adding the concept of Service Attachment Points (SAPs). The SAPs are the network reference points to which network services, such as Layer 3 Virtual Private Network (L3VPN) or Layer 2 Virtual Private Network (L2VPN), can be attached. One or multiple services can be bound to the same SAP. Both User-to-Network Interface (UNI) and Network-to-Network Interface (NNI) are supported in the SAP data model. A Common YANG Data Model for Attachment Circuits Orange Juniper Telefonica Nokia Huawei Technologies Guidelines for Authors and Reviewers of Documents Containing YANG Data Models YumaWorks Orange Huawei Work in Progress A YANG Data Model for the RFC 9543 Network Slice Service Huawei Technologies Huawei Technologies Ciena Cisco Systems, Inc Cisco Systems, Inc This document defines a YANG data model for RFC 9543 Network Slice Service. The model can be used in the Network Slice Service interface between a customer and a provider that offers RFC 9543 Network Slice Services. Work in Progress

Examples

A Service AC Reference Within the VPN Network Access Let us consider the example depicted in , which is inspired from . Each PE is servicing two CEs. Let us also assume that the service references to identify ACs with these CEs are shown in .

VPWS Topology Example .----. .----. | | AC1 AC2 | | | CE1 |--+ 2001:db8:100::1 2001:db8:200::1 +--| CE2 | | | | .-----. .-----. .-----. | | | '----' +----|---- | | P | | ----+----+ '----' |VPWS\----|-----|-----|/VPWS| | PE1 |===|=====|=====| PE2 | | /|---|-----|-----|\\ | .----. +----|---- | | | | ----|----+ .----. | | | '-----' '-----' '-----' | | | | CE3 |--+ +--| CE4 | | | AC3 AC4 | | '----' '----' As shown in , the service AC references can be explicitly indicated in the L2NM query for the realization of the Virtual Private Wire Service (VPWS) ().

Example of VPWS Creation with AC Service References =============== NOTE: '\' line wrapping per RFC 8792 ================ { "ietf-l2vpn-ntw:l2vpn-ntw":{ "vpn-services":{ "vpn-service":[ { "vpn-id":"vpws12345", "vpn-description":"Sample VPWS with AC service \ references", "customer-name":"customer-12345", "vpn-type":"ietf-vpn-common:vpws", "bgp-ad-enabled":true, "signaling-type":"ietf-vpn-common:ldp-signaling", "global-parameters-profiles":{ "global-parameters-profile":[ { "profile-id":"simple-profile", "local-autonomous-system":65550, "rd-auto":{ "auto":[ null ] }, "vpn-target":[ { "id":1, "route-targets":[ { "route-target":"0:65535:1" } ], "route-target-type":"both" } ] } ] }, "vpn-nodes":{ "vpn-node":[ { "vpn-node-id":"pe1", "ne-id":"2001:db8:100::1", "active-global-parameters-profiles":{ "global-parameters-profile":[ { "profile-id":"simple-profile" } ] }, "bgp-auto-discovery":{ "vpn-id":"587" }, "signaling-option":{ "advertise-mtu":true, "ldp-or-l2tp":{ "saii":1, "remote-targets":[ { "taii":2 } ], "t-ldp-pw-type":"ethernet" } }, "vpn-network-accesses":{ "vpn-network-access":[ { "id":"1/1/1.1", "interface-id":"1/1/1", "description":"Interface to CE1", "active-vpn-node-profile":"simple-\ profile", "status":{ "admin-status":{ "status":"ietf-vpn-common:\ admin-up" }, "ietf-ac-glue:ac-svc-ref":"AC1" } }, { "id":"1/1/3.1", "interface-id":"1/1/3", "description":"Interface to CE3", "active-vpn-node-profile":"simple-\ profile", "status":{ "admin-status":{ "status":"ietf-vpn-common:\ admin-up" }, "ietf-ac-glue:ac-svc-ref":"AC3" } } ] } }, { "vpn-node-id":"pe2", "ne-id":"2001:db8:200::1", "active-global-parameters-profiles":{ "global-parameters-profile":[ { "profile-id":"simple-profile" } ] }, "bgp-auto-discovery":{ "vpn-id":"587" }, "signaling-option":{ "advertise-mtu":true, "ldp-or-l2tp":{ "saii":2, "remote-targets":[ { "taii":1 } ], "t-ldp-pw-type":"ethernet" } }, "vpn-network-accesses":{ "vpn-network-access":[ { "id":"2/1/2.1", "interface-id":"2/1/2", "description":"Interface to CE2", "active-vpn-node-profile":"simple-\ profile", "status":{ "admin-status":{ "status":"ietf-vpn-common:\ admin-up" }, "ietf-ac-glue:ac-svc-ref":"AC2" } }, { "id":"2/1/4.1", "interface-id":"2/1/4", "description":"Interface to CE4", "active-vpn-node-profile":"simple-\ profile", "status":{ "admin-status":{ "status":"ietf-vpn-common:\ admin-up" }, "ietf-ac-glue:ac-svc-ref":"AC4" } } ] } } ] } } ] } } }

Network and Service AC References Let us consider the example depicted in with two customer termination points (CE1 and CE2). Let us also assume that the bearers to attach these CEs to the service provider network are already in place. References to identify these bearers are shown in .

Topology Example .-----. .--------------. .-----. .---. | PE1 +===+ +===+ PE2 | .---. | CE1+------+"450"| | MPLS | |"451"+------+ CE2| '---' ^ '-----' | | '-----' ^ '---' | | Core | | Bearer:1234 '--------------' Bearer:5678 The AC service model can be used by the provider to manage and expose the ACs over existing bearers as shown in .

ACs Created Using ACaaS { "ietf-ac-svc:attachment-circuits": { "ac-group-profile": [ { "name": "an-ac-profile", "l2-connection": { "encapsulation": { "type": "ietf-vpn-common:dot1q", "dot1q": { "tag-type": "ietf-vpn-common:c-vlan", "cvlan-id": 550 } } }, "service": { "mtu": 1550, "svc-pe-to-ce-bandwidth": { "bandwidth": [ { "bw-type": "ietf-vpn-common:bw-per-port", "cir": "20480000" } ] }, "svc-ce-to-pe-bandwidth": { "bandwidth": [ { "bw-type": "ietf-vpn-common:bw-per-port", "cir": "20480000" } ] }, "qos": { "qos-profiles": { "qos-profile": [ { "profile": "QoS_Profile_A", "direction": "ietf-vpn-common:both" } ] } } } } ], "ac": [ { "name": "ac-1", "description": "First attachment", "ac-group-profile": [ "an-ac-profile" ], "l2-connection": { "bearer-reference": "1234" } }, { "name": "ac-2", "description": "Second attachment", "ac-group-profile": [ "an-ac-profile" ], "l2-connection": { "bearer-reference": "5678" } } ] } } Let us now consider that the customer wants to request a Virtual Private LAN Service (VPLS) instance between the sites as shown in .

Example of VPLS |---------- VPLS "1543" ----------| .-----. .--------------. .-----. .---. AC1 | PE1 +===+ +===+ PE2 | AC2 .---. | CE1+------+"450"| | MPLS | |"451"+------+ CE2| '---' ^ '-----' | | '-----' ^ '---' | | Core | | Bearer:1234 '--------------' Bearer:5678 To that aim, existing ACs are referenced during the creation of the VPLS instance using the L2NM and the "ietf-ac-glue" module as shown in .

Example of a VPLS Request Using L2NM and AC Glue (Message Body) { "ietf-l2vpn-ntw:l2vpn-ntw": { "vpn-services": { "vpn-service": [ { "vpn-id": "1543", "vpn-name": "CORPO-EXAMPLE", "customer-name": "EXAMPLE", "vpn-type": "ietf-vpn-common:vpls", "vpn-service-topology": "ietf-vpn-common:hub-spoke", "bgp-ad-enabled": false, "signaling-type": "ietf-vpn-common:ldp-signaling", "global-parameters-profiles": { "global-parameters-profile": [ { "profile-id": "simple-profile", "ce-vlan-preservation": true, "ce-vlan-cos-preservation": true } ] }, "vpn-nodes": { "vpn-node": [ { "vpn-node-id": "450", "ne-id": "2001:db8:5::1", "role": "ietf-vpn-common:hub-role", "status": { "admin-status": { "status": "ietf-vpn-common:admin-up" } }, "active-global-parameters-profiles": { "global-parameters-profile": [ { "profile-id": "simple-profile" } ] }, "signaling-option": { "ldp-or-l2tp": { "t-ldp-pw-type": "vpls-type", "pw-peer-list": [ { "peer-addr": "2001:db8:50::1", "vc-id": "1543" } ] } }, "vpn-network-accesses": { "ietf-ac-glue:ac-svc-ref": ["ac-1"] } }, { "vpn-node-id": "451", "ne-id": "2001:db8:50::1", "role": "ietf-vpn-common:spoke-role", "status": { "admin-status": { "status": "ietf-vpn-common:admin-up" } }, "active-global-parameters-profiles": { "global-parameters-profile": [ { "profile-id": "simple-profile" } ] }, "signaling-option": { "ldp-or-l2tp": { "t-ldp-pw-type": "vpls-type", "pw-peer-list": [ { "peer-addr": "2001:db8:5::1", "vc-id": "1543" } ] } }, "vpn-network-accesses": { "ietf-ac-glue:ac-svc-ref": ["ac-2"] } } ] } } ] } } } Note that before implementing the VPLS instance creation request, the provider service orchestrator may first check if the VPLS service can be provided to the customer using the target delivery locations. The orchestrator uses the SAP model as exemplified in . This example assumes that the query concerns only PE1. A similar query can be issued for PE2.

Example of SAP Response (Message Body) { "ietf-sap-ntw:service":[ { "service-type":"ietf-vpn-common:vpls", "sap":[ { "sap-id":"sap#1", "peer-sap-id":[ "ce-1" ], "description":"A parent SAP", "attachment-interface":"GE0/6/1", "interface-type":"ietf-sap-ntw:phy", "role":"ietf-sap-ntw:uni", "allows-child-saps":true, "sap-status":{ "status":"ietf-vpn-common:op-up" } } ] } ] } The response in indicates that the VPLS service can be delivered to CE1. The "ietf-ac-ntw" module can be also used to access AC-related details that are bound to the target SAP ().

Example of AC Network Response with SAP (Message Body) { "ietf-sap-ntw:service":[ { "service-type":"ietf-vpn-common:vpls", "sap":[ { "sap-id":"sap#1", "peer-sap-id":[ "ce-1" ], "description":"A parent SAP", "attachment-interface":"GE0/6/1", "interface-type":"ietf-sap-ntw:phy", "role":"ietf-sap-ntw:uni", "allows-child-saps":true, "sap-status":{ "status":"ietf-vpn-common:op-up" } }, { "sap-id":"sap#11", "description":"A child SAP", "parent-termination-point":"GE0/6/4", "attachment-interface":"GE0/6/4.2", "interface-type":"ietf-sap-ntw:logical", "encapsulation-type":"ietf-vpn-common:vlan-type", "sap-status":{ "status":"ietf-vpn-common:op-up" }, "ietf-ac-ntw:ac":[ { "ac-ref":"ac-1", "node-ref":"example:pe2", "network-ref":"example:an-id" } ] } ] } ] } The provisioned AC at PE1 can be retrieved using the AC network model as depicted in .

Example of AC Network Response (Message Body) { "ietf-ac-ntw:ac":[ { "name":"ac-11", "svc-ref":"ac-1", "peer-sap-id":[ "ce-1" ], "status":{ "admin-status":{ "status":"ietf-vpn-common:admin-up" }, "oper-status":{ "status":"ietf-vpn-common:op-up" } }, "l2-connection":{ "encapsulation":{ "encap-type":"ietf-vpn-common:dot1q", "dot1q":{ "tag-type":"ietf-vpn-common:c-vlan", "cvlan-id":550 } }, "bearer-reference":"1234" }, "service":{ "mtu":1550, "svc-pe-to-ce-bandwidth":{ "bandwidth":[ { "bw-type": "ietf-vpn-common:bw-per-port", "cir":"20480000" } ] }, "svc-ce-to-pe-bandwidth":{ "bandwidth":[ { "bw-type": "ietf-vpn-common:bw-per-port", "cir":"20480000" } ] }, "qos":{ "qos-profiles":{ "qos-profile":[ { "qos-profile-ref":"QoS_Profile_A", "network-ref":"example:an-id", "direction":"ietf-vpn-common:both" } ] } } } } ] }

Acknowledgments Thanks to and for the review and comments. Thanks to for the YANG Doctors review, for the RTGDIR review, for the OPSDIR review, for the GENART review, and for the SECDIR review. Thanks to for the AD review. Thanks to for the IESG review.

Authors' Addresses Orange