Internet-Draft A YANG Network Model for ACs December 2023
Boucadair, et al. Expires 16 June 2024 [Page]
Workgroup:
Operations and Management Area Working Group
Internet-Draft:
draft-ietf-opsawg-ntw-attachment-circuit-04
Published:
Intended Status:
Standards Track
Expires:
Authors:
M. Boucadair, Ed.
Orange
R. Roberts
Juniper
O. G. D. Dios
Telefonica
S. B. Giraldo
Nokia
B. Wu
Huawei Technologies

A Network YANG Data Model for Attachment Circuits

Abstract

This document specifies a network model for attachment circuits. The model can be used for the provisioning of attachment circuits prior or during service provisioning (e.g., Network Slice Service). A companion service model is specified in I-D.ietf-opsawg-teas-attachment-circuit.

The module augments the Service Attachment Point (SAP) model with the detailed information for the provisioning of attachment circuits in Provider Edges (PEs).

Discussion Venues

This note is to be removed before publishing as an RFC.

Discussion of this document takes place on the Operations and Management Area Working Group Working Group mailing list (opsawg@ietf.org), which is archived at https://mailarchive.ietf.org/arch/browse/opsawg/.

Source for this draft and an issue tracker can be found at https://github.com/boucadair/attachment-circuit-model.

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 16 June 2024.

1. Introduction

Connectivity services are provided by networks to customers via dedicated terminating points, such as Service Functions [RFC7665], customer edges (CEs), peer Autonomous System Border Routers (ASBRs), data centers gateways, or Internet Exchange Points.

The procedure to provision a service in a service provider network may depend on the practices adopted by a service provider, including the flow put in place for the provisioning of advanced network services and how they are bound to an Attachment Circuit (AC). For example, the same attachment circuit may host multiple services (e.g., Layer 2 Virtual Private Network (VPN), Slice Service, or Layer 3 VPN). In order to avoid service interference and redundant information in various locations, a service provider may expose an interface to manage ACs network-wide. Customers can then request a standalone attachment circuit to be put in place, and then refer to that attachment circuit when requesting services to be bound to that AC. [I-D.ietf-opsawg-teas-attachment-circuit] specifies a data model for managing attachment circuits as a service.

Section 5 specifies a network model for attachment circuits ("ietf-ac-ntw"). The model can be used for the provisioning of ACs prior or during service provisioning.

The document leverages [RFC9182] and [RFC9291] by adopting an AC provisioning structure that uses data nodes that are defined in these RFCs. Some refinements were introduced to cover, not only conventional service provider networks, but also specifics of other target deployments (cloud, for example).

The AC network model is designed as an augmnetation to the Service Attachment Point (SAP) model [RFC9408]. An attachment circuit can be bound to a single or multiple SAPs. Likewise, the model is designed to accomdate deployments where a SAP can be bound to one or multiple ACs (e.g., a parent AC and its child ACs).

CE6 ac CE5 CE2 ac sap sap sap CE1 sap PE1 PE2 ac ac PE3 PE4 sap CE5 sap sap sap sap ac ac ac CE3 ac CE4
Figure 1: Attachment Circuits Examples

The AC network model uses the AC common model defined in [I-D.ietf-opsawg-teas-common-ac].

The YANG data model in this document conforms to the Network Management Datastore Architecture (NMDA) defined in [RFC8342].

Sample examples are provided in Appendix A.

2. Conventions and Definitions

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.

The reader should be familiar with the terms defined in Section 2 of [RFC9408].

This document uses the term "network model" as defined in Section 2.1 of [RFC8969].

The meanings of the symbols in the YANG tree diagrams are defined in [RFC8340].

In addition, this document uses the following terms:

Bearer:

A physical or logical link that connects a customer node (or site) to a provider network.

A bearer can be a wireless or wired link. One or multiple technologies can be used to build a bearer. The bearer type can be specified by a customer.

The operator allocates a unique bearer reference to identify a bearer within its network (e.g., customer line identifier). Such a reference can be retrieved by a customer and then used in subsequent service placement requests to unambiguously identify where a service is to be bound.

The concept of bearer can be generalized to refer to the required underlying connection for the provisioning of an attachment circuit.

One or multiple attachment circuits may be hosted over the same bearer (e.g., multiple Virtual Local Area Networks (VLANs) on the same bearer that is provided by a physical link).

Network controller:

Denotes a functional entity responsible for the management of the service provider network. One or multiple network controllers can be deployed in a service provider network.

Service orchestrator:

Refers to a functional entity that interacts with the customer of a network service.

A service orchestrator is typically responsible for the attachment circuits, the Provider Edge (PE) selection, and requesting the activation of the requested services to a network controller.

A service orchestrator may interact with one or more network controllers.

Service provider network:

A network that is able to provide network services (e.g., L2VPN, L3VPN, or Network Slice Services).

Service provider:

A service provider that offers network services (e.g., L2VPN, L3VPN, or Network Slice Services).

3. Sample Uses of the Attachment Circuit Data Models

Figure 2 shows the positioning of the AC network model in the overall service delivery process. The "ietf-ac-ntw" module is a network model which augments the SAP with a comprehensive set of parameters to reflect the attachment circuits that are in place in a network. The model also maintains the mapping with the service references that are used to expose these ACs to customers. Whether the same naming conventions to reference an AC are used in the service and network layers is deployment-specific.

Customer Customer Service Model e.g., slice-svc, ac-svc, and bearer-svc Service Orchestration Network Model e.g., l3vpn-ntw, sap, and ac-ntw Network Orchestration Network Configuration Model Domain Domain Orchestration Orchestration Device Configuration Model Config Manager NETCONF/CLI................ . | Bearer Bearer CE#1 Network CE#2 Site A Site B
Figure 2: An Example of the Network AC Model Usage

Similar to [RFC9408], the "ietf-ac-ntw" module can be used for both User-to-Network Interface (UNI) and Network-to-Network Interface (NNI). For example, all the ACs shown in Figure 3 have a 'role' set to "ietf-sap-ntw:nni". Typically, AS Border Routers (ASBRs) of each network is directly connected to an ASBR of a neighboring network via one or multiple links (bearers). ASBRs of "Network#1" behaves as a PE and treats the other adjacent ASBRs as if it were a CE.

4. Description of the Attachment Circuit YANG Module

The full tree diagram of the module can be generated using the "pyang" tool [PYANG]. That tree is not included here because it is too long (Section 3.3 of [RFC8340]). Instead, subtrees are provided in the following subsections for the reader's convenience.

4.1. Overall Structure of the Module

The overall tree structure of the module is shown in Figure 4.

augment /nw:networks/nw:network:
  +--rw specific-provisioning-profiles
  |  ...
  +--rw ac-profile* [name]
     ...
augment /nw:networks/nw:network/nw:node:
  +--rw ac* [name]
     +--rw name                 string
     +--rw ac-svc-ref?          ac-svc:attachment-circuit-reference
     +--rw ac-profile* [profile-id]
     |  +--rw profile-id    -> /nw:networks/network/ac-profile/name
     +--rw ac-parent-ref?       ac-ntw:attachment-circuit-reference
     +--rw peer-sap-id*         string
     +--rw group* [group-id]
     |  +--rw group-id      string
     |  +--rw precedence?   identityref
     +--rw status
     |  +--rw admin-status
     |  |  +--rw status?        identityref
     |  |  +--rw last-change?   yang:date-and-time
     |  +--ro oper-status
     |     +--ro status?        identityref
     |     +--ro last-change?   yang:date-and-time
     +--rw description?         string
     +--rw l2-connection
     |  ...
     +--rw ip-connection
     |  ...
     +--rw routing-protocols
     |  ...
     +--rw oam
     |  ...
     +--rw security
     |  ...
     +--rw service
        ...
  augment /nw:networks/nw:network/nw:node/sap:service/sap:sap:
    +--rw ac*   ac-ntw:attachment-circuit-reference
Figure 4: Overall Tree Structure

The full tree of the 'ac-ntw' is provided in [AC-Ntw-Tree].

A node can host one or more SAPs. As per [RFC9408], a SAP is an abstraction of the network reference points (the PE side of an AC, in the context of this document) where network services can be delivered and/or are delivered to customers. Each SAP terminates one or multiple ACs. Each AC in turn may be terminated by one or more peer SAPs ('peer-sap'). In order to expose such AC/SAP binding information, the SAP model [RFC9408] is augmented with required AC-related information.

Unlike the AC service model [I-D.ietf-opsawg-teas-attachment-circuit], an AC is uniquely identified by a name within the scope of a node, not a network. A textual description of the AC may be provided ('description').

Also, in order to ease the correlation between the AC exposed at the service layer and the one that is actually provisioned in the network operation, a reference to the AC exposed to the customer ('ac-svc-ref') is stored in the 'ietf-ac-ntw' module.

ACs that are terminated by a SAP are listed in 'ac' under '/nw:networks/nw:network/nw:node/sap:service/sap:sap'. A controller may indicate a filter based on the service type (e.g., Network Slice or L3VPN) to retrieve the list of available SAPs, and thus ACs, for that service.

In order to factorize common data that is provisioned for a group of ACs, a set of profiles (Section 4.2) can be defined at the network level, and then called under the node level. The information contained in a profile is thus inherited, unless the corresponding data node is refined at the AC level. In such a case, the value provided at the AC level takes precedence over the global one.

In contexts where the same AC is terminated by multiple peer SAPs (e.g., an AC with multiple CEs) but a subset of them have specific information, the module allows operators to:

  • Define a parent AC that may list all these CEs as peer SAPs.

  • Create individual ACs that are bound to the parent AC using 'ac-parent-ref'.

  • Indicate for each individual ACs one or a subset of the CEs as peer SAPs. All these individual ACs will inherit the properties of the parent AC.

Whenever a parent AC is deleted, then all child ACs of that AC MUST be deleted.

An AC may belong to one or multiple groups [RFC9181]. For example, the 'group-id' is used to associate redundancy or protection constraints with ACs.

The status of an AC can be tracked using 'status'. Both operational status and administrative status are maintained. A mismatch between the administrative status vs. the operational status can be used as a trigger to detect anomalies.

An AC can be characterized using Layer 2 connectivity (Section 4.3), Layer 3 connectivity (Section 4.4), routing protocols (Section 4.5), OAM (Section 4.6), security (Section 4.7), and service (Section 4.8) considerations.

4.2. Provisioning Profiles

The specific provisioning profiles tree structure is shown in Figure 5.

  augment /nw:networks/nw:network:
    +--rw specific-provisioning-profiles
    |  +--rw valid-provider-identifiers
    |     +--rw encryption-profile-identifier* [id]
    |     |  +--rw id    string
    |     +--rw qos-profile-identifier* [id]
    |     |  +--rw id    string
    |     +--rw bfd-profile-identifier* [id]
    |     |  +--rw id    string
    |     +--rw forwarding-profile-identifier* [id]
    |     |  +--rw id    string
    |     +--rw routing-profile-identifier* [id]
    |        +--rw id    string
    +--rw ac-profile* [name]
       ...
Figure 5: Profiles Tree Structure

The exact definition of these profiles is local to each service provider. The model only includes an identifier for these profiles in order to ease identifying and binding local policies when building an AC. As shown in Figure 5, the following identifiers can be included:

'encryption-profile-identifier':

An encryption profile refers to a set of policies related to the encryption schemes and setup that can be applied on the AC.

'qos-profile-identifier':

A Quality of Service (QoS) profile refers to a set of policies such as classification, marking, and actions (e.g., [RFC3644]).

'bfd-profile-identifier':

A Bidirectional Forwarding Detection (BFD) profile refers to a set of BFD policies [RFC5880] that can be invoked when building an AC.

'forwarding-profile-identifier':

A forwarding profile refers to the policies that apply to the forwarding of packets conveyed over an AC. Such policies may consist of, for example, applying Access Control Lists (ACLs).

'routing-profile-identifier':

A routing profile refers to a set of routing policies that will be invoked (e.g., BGP policies) for an AC.

4.3. L2 Connection

The 'l2-connection' container is used to manage the Layer 2 properties of an AC. The Layer 2 connection tree structure is shown in Figure 6.

  augment /nw:networks/nw:network/nw:node:
    +--rw ac* [name]
       +--rw name                 string
       +--rw ac-svc-ref?          ac-svc:attachment-circuit-reference
       +--rw ac-profile* [profile-id]
       |  +--rw profile-id    ac-profile-reference
       +--rw ac-parent-ref?       ac-ntw:attachment-circuit-reference
       +--rw peer-sap-id*         string
       +--rw group* [group-id]
       |  +--rw group-id      string
       |  +--rw precedence?   identityref
       +--rw status
       |  +--rw admin-status
       |  |  +--rw status?        identityref
       |  |  +--rw last-change?   yang:date-and-time
       |  +--ro oper-status
       |     +--ro status?        identityref
       |     +--ro last-change?   yang:date-and-time
       +--rw description?         string
       +--rw l2-connection
       |  +--rw encapsulation
       |  |  +--rw encap-type?        identityref
       |  |  +--rw dot1q
       |  |  |  +--rw tag-type?         identityref
       |  |  |  +--rw cvlan-id?         uint16
       |  |  |  +--rw tag-operations
       |  |  |     +--rw (op-choice)?
       |  |  |     |  +--:(pop)
       |  |  |     |  |  +--rw pop?         empty
       |  |  |     |  +--:(push)
       |  |  |     |  |  +--rw push?        empty
       |  |  |     |  +--:(translate)
       |  |  |     |     +--rw translate?   empty
       |  |  |     +--rw tag-1?             dot1q-types:vlanid
       |  |  |     +--rw tag-1-type?
       |  |  |     |       dot1q-types:dot1q-tag-type
       |  |  |     +--rw tag-2?             dot1q-types:vlanid
       |  |  |     +--rw tag-2-type?
       |  |  |             dot1q-types:dot1q-tag-type
       |  |  +--rw priority-tagged
       |  |  |  +--rw tag-type?   identityref
       |  |  +--rw qinq
       |  |     +--rw tag-type?         identityref
       |  |     +--rw svlan-id          uint16
       |  |     +--rw cvlan-id          uint16
       |  |     +--rw tag-operations
       |  |        +--rw (op-choice)?
       |  |        |  +--:(pop)
       |  |        |  |  +--rw pop?         uint8
       |  |        |  +--:(push)
       |  |        |  |  +--rw push?        empty
       |  |        |  +--:(translate)
       |  |        |     +--rw translate?   uint8
       |  |        +--rw tag-1?             dot1q-types:vlanid
       |  |        +--rw tag-1-type?
       |  |        |       dot1q-types:dot1q-tag-type
       |  |        +--rw tag-2?             dot1q-types:vlanid
       |  |        +--rw tag-2-type?
       |  |                dot1q-types:dot1q-tag-type
       |  +--rw (l2-service)?
       |  |  +--:(l2-tunnel-service)
       |  |  |  +--rw l2-tunnel-service
       |  |  |     +--rw type?         identityref
       |  |  |     +--rw pseudowire
       |  |  |     |  +--rw vcid?      uint32
       |  |  |     |  +--rw far-end?   union
       |  |  |     +--rw vpls
       |  |  |     |  +--rw vcid?      uint32
       |  |  |     |  +--rw far-end*   union
       |  |  |     +--rw vxlan
       |  |  |        +--rw vni-id             uint32
       |  |  |        +--rw peer-mode?         identityref
       |  |  |        +--rw peer-ip-address*   inet:ip-address
       |  |  +--:(l2vpn)
       |  |     +--rw l2vpn-id?            vpn-common:vpn-id
       |  +--rw l2-termination-point?      string
       |  +--rw local-bridge-reference?    string
       |  +--rw bearer-reference?          string
       |  |       {vpn-common:bearer-reference}?
       |  +--rw lag-interface {vpn-common:lag-interface}?
       |     +--rw lag-interface-id?   string
       |     +--rw member-link-list
       |        +--rw member-link* [name]
       |           +--rw name    string
       +--rw ip-connection
       |  ...
       +--rw routing-protocols
       |  ...
       +--rw oam
       |  ...
       +--rw security
       |  ...
       +--rw service
          ...
Figure 6: Layer 2 Connection Tree Structure

The 'encapsulation' container specifies the Layer 2 encapsulation to use (if any) and allows the configuration of the relevant tags. Also, the model supports tag manipulation operations (e.g., tag rewrite).

The 'l2-tunnel-service' container is used to specify the required parameters to set a Layer tunneling service (e.g., a Virtual Private LAN Service (VPLS), a Virtual eXtensible Local Area Network (VXLAN), or a pseudowire (Section 6.1 of [RFC8077])). 'l2vpn-id' is used to identify a L2VPN service that is associated with an Integrated Routing and Bridging (IRB) interface.

To accommodate implementations that require internal bridging, a local bridge reference can be specified in 'local-bridge-reference'. Such a reference may be a local bridge domain.

A reference to the bearer is maintained using 'bearer-reference'.

4.4. IP Connection

This 'ip-connection' container is used to group Layer 3 connectivity information, particularly the IP addressing information, of an AC.

The Layer 3 connection tree structure is shown in Figure 7.

  augment /nw:networks/nw:network/nw:node:
    +--rw ac* [name]
       +--rw name                 string
       +--rw ac-svc-ref?          ac-svc:attachment-circuit-reference
       +--rw ac-profile* [profile-id]
       |  +--rw profile-id    ac-profile-reference
       +--rw ac-parent-ref?       ac-ntw:attachment-circuit-reference
       +--rw peer-sap-id*         string
       +--rw group* [group-id]
       |  +--rw group-id      string
       |  +--rw precedence?   identityref
       +--rw status
       |  +--rw admin-status
       |  |  +--rw status?        identityref
       |  |  +--rw last-change?   yang:date-and-time
       |  +--ro oper-status
       |     +--ro status?        identityref
       |     +--ro last-change?   yang:date-and-time
       +--rw description?         string
       +--rw l2-connection
       |  ...
       +--rw ip-connection
       |  +--rw l3-termination-point?   string
       |  +--rw ipv4 {vpn-common:ipv4}?
       |  |  +--rw local-address?
       |  |  |       inet:ipv4-address
       |  |  +--rw prefix-length?                           uint8
       |  |  +--rw address-allocation-type?
       |  |  |       identityref
       |  |  +--rw (allocation-type)?
       |  |     +--:(dynamic)
       |  |     |  +--rw (address-assign)?
       |  |     |  |  +--:(number)
       |  |     |  |  |  +--rw number-of-dynamic-address?   uint16
       |  |     |  |  +--:(explicit)
       |  |     |  |     +--rw customer-addresses
       |  |     |  |        +--rw address-pool* [pool-id]
       |  |     |  |           +--rw pool-id          string
       |  |     |  |           +--rw start-address
       |  |     |  |           |       inet:ipv4-address
       |  |     |  |           +--rw end-address?
       |  |     |  |                   inet:ipv4-address
       |  |     |  +--rw (provider-dhcp)?
       |  |     |  |  +--:(dhcp-service-type)
       |  |     |  |  |  +--rw dhcp-service-type?
       |  |     |  |  |          enumeration
       |  |     |  |  +--:(service-type)
       |  |     |  |     +--rw (service-type)?
       |  |     |  |        +--:(relay)
       |  |     |  |           +--rw server-ip-address*
       |  |     |  |                   inet:ipv4-address
       |  |     |  +--rw (dhcp-relay)?
       |  |     |     +--:(customer-dhcp-servers)
       |  |     |        +--rw customer-dhcp-servers
       |  |     |           +--rw server-ip-address*
       |  |     |                   inet:ipv4-address
       |  |     +--:(static-addresses)
       |  |        +--rw address* [address-id]
       |  |           +--rw address-id          string
       |  |           +--rw customer-address?   inet:ipv4-address
       |  +--rw ipv6 {vpn-common:ipv6}?
       |     +--rw local-address?
       |     |       inet:ipv6-address
       |     +--rw prefix-length?                           uint8
       |     +--rw address-allocation-type?
       |     |       identityref
       |     +--rw (allocation-type)?
       |        +--:(dynamic)
       |        |  +--rw (address-assign)?
       |        |  |  +--:(number)
       |        |  |  |  +--rw number-of-dynamic-address?   uint16
       |        |  |  +--:(explicit)
       |        |  |     +--rw customer-addresses
       |        |  |        +--rw address-pool* [pool-id]
       |        |  |           +--rw pool-id          string
       |        |  |           +--rw start-address
       |        |  |           |       inet:ipv6-address
       |        |  |           +--rw end-address?
       |        |  |                   inet:ipv6-address
       |        |  +--rw (provider-dhcp)?
       |        |  |  +--:(dhcp-service-type)
       |        |  |  |  +--rw dhcp-service-type?
       |        |  |  |          enumeration
       |        |  |  +--:(service-type)
       |        |  |     +--rw (service-type)?
       |        |  |        +--:(relay)
       |        |  |           +--rw server-ip-address*
       |        |  |                   inet:ipv6-address
       |        |  +--rw (dhcp-relay)?
       |        |     +--:(customer-dhcp-servers)
       |        |        +--rw customer-dhcp-servers
       |        |           +--rw server-ip-address*
       |        |                   inet:ipv6-address
       |        +--:(static-addresses)
       |           +--rw address* [address-id]
       |              +--rw address-id          string
       |              +--rw customer-address?   inet:ipv6-address
       +--rw routing-protocols
       |  ...
       +--rw oam
       |  ...
       +--rw security
       |  ...
       +--rw service
          ...
Figure 7: IP Connection Tree Structure

A distinct Layer 3 interface other than the interface indicated under the 'l2-connection' container may be needed to terminate the Layer 3 connectivity. The identifier of such an interface is included in 'l3-termination-point'. For example, this data node can be used to carry the identifier of a bridge domain interface.

This container can include IPv4, IPv6, or both if dual-stack is enabled. For both IPv4 and IPv6, the IP connection supports three IP address assignment modes for customer addresses: provider DHCP, DHCP relay, and static addressing. Note that for the IPv6 case, Stateless Address Autoconfiguration (SLAAC) [RFC4862] can be used.

For both IPv4 and IPv6, 'address-allocation-type' is used to indicate the IP address allocation mode to activate for an AC. The allocated address represents the PE interface address configuration. When 'address-allocation-type' is set to 'provider-dhcp', DHCP assignments can be made locally or by an external DHCP server. Such behavior is controlled by setting 'dhcp-service-type'.

For IPv6, if 'address-allocation-type' is set to 'slaac', the Prefix Information option of Router Advertisements that will be issued for SLAAC purposes will carry the IPv6 prefix that is determined by 'local-address' and 'prefix-length'. For example, if 'local-address' is set to '2001:db8:0:1::1' and 'prefix-length' is set to '64', the IPv6 prefix that will be used is '2001:db8:0:1::/64'.

In some deployment contexts (e.g., network merging), multiple IP subnets may be used in a transition period. For such deployments, multiple ACs (typically, two) with overlapping information may be maintained during a transition period. The correlation between these ACs may rely upon the same "ac-svc-ref".

4.5. Routing

The overall routing subtree structure is shown in Figure 8.

module: ietf-ac-ntw
  augment /nw:networks/nw:network:
    +--rw ac-profile* [name]
       +--rw name                 string
       +--rw l2-connection
       +--rw ip-connection
       +--rw routing-protocols
       |  +--rw routing-protocol* [id]
       |     +--rw id      string
       |     +--rw type?   identityref
       |     +--rw bgp
       |     |  ...
       |     +--rw ospf
       |     |  ...
       |     +--rw isis
       |     |  ...
       |     +--rw rip
       |     |  ...
       |     +--rw vrrp
       |        ...
       +--rw oam
          ...
  augment /nw:networks/nw:network/nw:node:
    +--rw ac* [name]
       +--rw name                 string
       ...
       +--rw l2-connection
       |  ...
       +--rw ip-connection
       |  ...
       +--rw routing-protocols
       |  +--rw routing-protocol* [id]
       |     +--rw id                  string
       |     +--rw type?               identityref
       |     +--rw routing-profiles* [id]
       |     |  +--rw id      leafref
       |     |  +--rw type?   identityref
       |     +--rw static
       |     |  ...
       |     +--rw bgp
       |     |  ...
       |     +--rw ospf
       |     |  ...
       |     +--rw isis
       |     |  ...
       |     +--rw rip
       |     |  ...
       |     +--rw vrrp
       |        ...
       +--rw oam
       |  ...
       +--rw security
       |  ...
       +--rw service
          ...
Figure 8: Routing Tree Structure

Multiple routing instances ('routing-protocol') can be defined, each uniquely identified by an 'id'. Specifically, each instance is uniquely identified to accommodate scenarios where multiple instances of the same routing protocol have to be configured on the same AC.

The type of a routing instance is indicated in 'type'. The values of this attribute are those defined in [RFC9181] (the 'routing-protocol-type' identity). Specific data nodes are then provided as a function of the 'type'. See more details in the following subsections.

One or multiple routing profiles ('routing-profiles') can be provided for a given routing instance.

4.5.1. Static Routing

The static routing subtree structure is shown in Figure 9.

module: ietf-ac-ntw
          ...
  augment /nw:networks/nw:network/nw:node:
    +--rw ac* [name]
       +--rw name                 string
       ...
       +--rw l2-connection
       |  ...
       +--rw ip-connection
       |  ...
       +--rw routing-protocols
       |  +--rw routing-protocol* [id]
       |     +--rw id                  string
       |     +--rw type?               identityref
       |     +--rw routing-profiles* [id]
       |     |  +--rw id      leafref
       |     |  +--rw type?   identityref
       |     +--rw static
       |     |  +--rw cascaded-lan-prefixes
       |     |     +--rw ipv4-lan-prefixes* [lan next-hop]
       |     |     |       {vpn-common:ipv4}?
       |     |     |  +--rw lan           inet:ipv4-prefix
       |     |     |  +--rw lan-tag?      string
       |     |     |  +--rw next-hop      union
       |     |     |  +--rw metric?       uint32
       |     |     |  +--rw bfd-enable?   boolean {vpn-common:bfd}?
       |     |     |  +--rw preference?   uint32
       |     |     |  +--rw status
       |     |     |     +--rw admin-status
       |     |     |     |  +--rw status?        identityref
       |     |     |     |  +--rw last-change?   yang:date-and-time
       |     |     |     +--ro oper-status
       |     |     |        +--ro status?        identityref
       |     |     |        +--ro last-change?   yang:date-and-time
       |     |     +--rw ipv6-lan-prefixes* [lan next-hop]
       |     |             {vpn-common:ipv6}?
       |     |        +--rw lan           inet:ipv4-prefix
       |     |        +--rw lan-tag?      string
       |     |        +--rw next-hop      union
       |     |        +--rw metric?       uint32
       |     |        +--rw bfd-enable?   boolean {vpn-common:bfd}?
       |     |        +--rw preference?   uint32
       |     |        +--rw status
       |     |           +--rw admin-status
       |     |           |  +--rw status?        identityref
       |     |           |  +--rw last-change?   yang:date-and-time
       |     |           +--ro oper-status
       |     |              +--ro status?        identityref
       |     |              +--ro last-change?   yang:date-and-time
       |     +--rw bgp
       |     |  ...
       |     +--rw ospf
       |     |  ...
       |     +--rw isis
       |     |  ...
       |     +--rw rip
       |     |  ...
       |     +--rw vrrp
       |        ...
       +--rw oam
       |  ...
       +--rw security
       |  ...
       +--rw service
          ...
Figure 9: Static Routing Tree Structure

The following data nodes can be defined for a given IP prefix:

'lan-tag':

Indicates a local tag (e.g., "myfavorite-lan") that is used to enforce local policies.

'next-hop':

Indicates the next hop to be used for the static route.

It can be identified by an IP address, a predefined next-hop type (e.g., 'discard' or 'local-link'), etc.

'bfd-enable':

Indicates whether BFD is enabled or disabled for this static route entry.

'metric':

Indicates the metric associated with the static route entry. This metric is used when the route is exported into an IGP.

'preference':

Indicates the preference associated with the static route entry.

This preference is used to select a preferred route among routes to the same destination prefix.

'status':

Used to convey the status of a static route entry. This data node can also be used to control the (de)activation of individual static route entries.

4.5.2. BGP

The BGP routing subtree structure is shown in Figure 10.

module: ietf-ac-ntw
  augment /nw:networks/nw:network:
    +--rw ac-profile* [name]
       +--rw name                 string
       +--rw l2-connection
       +--rw ip-connection
       +--rw routing-protocols
       |  +--rw routing-protocol* [id]
       |     +--rw id      string
       |     +--rw type?   identityref
       |     +--rw bgp
       |     |  +--rw description?              string
       |     |  +--rw apply-policy
       |     |  |  +--rw import-policy*           leafref
       |     |  |  +--rw default-import-policy?   default-policy-type
       |     |  |  +--rw export-policy*           leafref
       |     |  |  +--rw default-export-policy?   default-policy-type
       |     |  +--rw local-as?                 inet:as-number
       |     |  +--rw peer-as                   inet:as-number
       |     |  +--rw address-family?           identityref
       |     |  +--rw multihop?                 uint8
       |     |  +--rw as-override?              boolean
       |     |  +--rw allow-own-as?             uint8
       |     |  +--rw prepend-global-as?        boolean
       |     |  +--rw send-default-route?       boolean
       |     |  +--rw site-of-origin?           rt-types:route-origin
       |     |  +--rw ipv6-site-of-origin?
       |     |  |       rt-types:ipv6-route-origin
       |     |  +--rw redistribute-connected* [address-family]
       |     |  |  +--rw address-family    identityref
       |     |  |  +--rw enable?           boolean
       |     |  +--rw bgp-max-prefix
       |     |  |  +--rw max-prefix?          uint32
       |     |  |  +--rw warning-threshold?   decimal64
       |     |  |  +--rw violate-action?      enumeration
       |     |  |  +--rw restart-timer?       uint32
       |     |  +--rw bgp-timers
       |     |     +--rw keepalive?   uint16
       |     |     +--rw hold-time?   uint16
       |     +--rw ospf
       |     |  ...
       |     +--rw isis
       |     |  ...
       |     +--rw rip
       |     |  ...
       |     +--rw vrrp
       |        ...
       +--rw oam
          ...
  augment /nw:networks/nw:network/nw:node:
    +--rw ac* [name]
       +--rw name                 string
       ...
       +--rw l2-connection
       |  ...
       +--rw ip-connection
       |  ...
       +--rw routing-protocols
       |  +--rw routing-protocol* [id]
       |     +--rw id                  string
       |     +--rw type?               identityref
       |     +--rw routing-profiles* [id]
       |     |  +--rw id      leafref
       |     |  +--rw type?   identityref
       |     +--rw static
       |     |  ...
       |     +--rw bgp
       |     |  +--rw peer-groups
       |     |  |  +--rw peer-group* [name]
       |     |  |     +--rw name                      string
       |     |  |     +--rw local-address?            union
       |     |  |     +--rw description?              string
       |     |  |     +--rw apply-policy
       |     |  |     |  +--rw import-policy*           leafref
       |     |  |     |  +--rw default-import-policy?
       |     |  |     |  |       default-policy-type
       |     |  |     |  +--rw export-policy*           leafref
       |     |  |     |  +--rw default-export-policy?
       |     |  |     |          default-policy-type
       |     |  |     +--rw local-as?                 inet:as-number
       |     |  |     +--rw peer-as                   inet:as-number
       |     |  |     +--rw address-family?           identityref
       |     |  |     +--rw multihop?                 uint8
       |     |  |     +--rw as-override?              boolean
       |     |  |     +--rw allow-own-as?             uint8
       |     |  |     +--rw prepend-global-as?        boolean
       |     |  |     +--rw send-default-route?       boolean
       |     |  |     +--rw site-of-origin?
       |     |  |     |       rt-types:route-origin
       |     |  |     +--rw ipv6-site-of-origin?
       |     |  |     |       rt-types:ipv6-route-origin
       |     |  |     +--rw redistribute-connected* [address-family]
       |     |  |     |  +--rw address-family    identityref
       |     |  |     |  +--rw enable?           boolean
       |     |  |     +--rw bgp-max-prefix
       |     |  |     |  +--rw max-prefix?          uint32
       |     |  |     |  +--rw warning-threshold?   decimal64
       |     |  |     |  +--rw violate-action?      enumeration
       |     |  |     |  +--rw restart-timer?       uint32
       |     |  |     +--rw bgp-timers
       |     |  |     |  +--rw keepalive?   uint16
       |     |  |     |  +--rw hold-time?   uint16
       |     |  |     +--rw authentication
       |     |  |        +--rw enable?            boolean
       |     |  |        +--rw keying-material
       |     |  |           +--rw (option)?
       |     |  |              +--:(ao)
       |     |  |              |  +--rw enable-ao?          boolean
       |     |  |              |  +--rw ao-keychain?
       |     |  |              |          key-chain:key-chain-ref
       |     |  |              +--:(md5)
       |     |  |              |  +--rw md5-keychain?
       |     |  |              |          key-chain:key-chain-ref
       |     |  |              +--:(explicit)
       |     |  |                 +--rw key-id?             uint32
       |     |  |                 +--rw key?                string
       |     |  |                 +--rw crypto-algorithm?
       |     |  |                         identityref
       |     |  +--rw neighbor* [remote-address]
       |     |     +--rw remote-address            inet:ip-address
       |     |     +--rw local-address?            union
       |     |     +--rw peer-group?
       |     |     |       -> ../../peer-groups/peer-group/name
       |     |     +--rw description?              string
       |     |     +--rw apply-policy
       |     |     |  +--rw import-policy*           leafref
       |     |     |  +--rw default-import-policy?
       |     |     |  |       default-policy-type
       |     |     |  +--rw export-policy*           leafref
       |     |     |  +--rw default-export-policy?
       |     |     |          default-policy-type
       |     |     +--rw local-as?                 inet:as-number
       |     |     +--rw peer-as                   inet:as-number
       |     |     +--rw address-family?           identityref
       |     |     +--rw multihop?                 uint8
       |     |     +--rw as-override?              boolean
       |     |     +--rw allow-own-as?             uint8
       |     |     +--rw prepend-global-as?        boolean
       |     |     +--rw send-default-route?       boolean
       |     |     +--rw site-of-origin?
       |     |     |       rt-types:route-origin
       |     |     +--rw ipv6-site-of-origin?
       |     |     |       rt-types:ipv6-route-origin
       |     |     +--rw redistribute-connected* [address-family]
       |     |     |  +--rw address-family    identityref
       |     |     |  +--rw enable?           boolean
       |     |     +--rw bgp-max-prefix
       |     |     |  +--rw max-prefix?          uint32
       |     |     |  +--rw warning-threshold?   decimal64
       |     |     |  +--rw violate-action?      enumeration
       |     |     |  +--rw restart-timer?       uint32
       |     |     +--rw bgp-timers
       |     |     |  +--rw keepalive?   uint16
       |     |     |  +--rw hold-time?   uint16
       |     |     +--rw authentication
       |     |     |  +--rw enable?            boolean
       |     |     |  +--rw keying-material
       |     |     |     +--rw (option)?
       |     |     |        +--:(ao)
       |     |     |        |  +--rw enable-ao?          boolean
       |     |     |        |  +--rw ao-keychain?
       |     |     |        |          key-chain:key-chain-ref
       |     |     |        +--:(md5)
       |     |     |        |  +--rw md5-keychain?
       |     |     |        |          key-chain:key-chain-ref
       |     |     |        +--:(explicit)
       |     |     |           +--rw key-id?             uint32
       |     |     |           +--rw key?                string
       |     |     |           +--rw crypto-algorithm?   identityref
       |     |     +--rw status
       |     |        +--rw admin-status
       |     |        |  +--rw status?        identityref
       |     |        |  +--rw last-change?   yang:date-and-time
       |     |        +--ro oper-status
       |     |           +--ro status?        identityref
       |     |           +--ro last-change?   yang:date-and-time
       |     +--rw ospf
       |     |  ...
       |     +--rw isis
       |     |  ...
       |     +--rw rip
       |     |  ...
       |     +--rw vrrp
       |        ...
       +--rw oam
       |  ...
       +--rw security
       |  ...
       +--rw service
          ...
Figure 10: BGP Routing Tree Structure

The following data nodes are supported for each 'peer-group':

'name':

Defines a name for the peer group.

'local-address':

Specifies an address or a reference to an interface to use when establishing the BGP transport session.

'description':

Includes a description of the peer group.

'apply-policy':

Lists a set of import/export policies [RFC9067] to apply for this group.

'local-as':

Indicates a local AS Number (ASN).

'peer-as':

Indicates the peer's ASN.

'address-family':

Indicates the address family of the peer. It can be set to 'ipv4', 'ipv6', or 'dual-stack'.

This address family will be used together with the 'vpn-type' to derive the appropriate Address Family Identifiers (AFIs) / Subsequent Address Family Identifiers (SAFIs) that will be part of the derived device configurations (e.g., unicast IPv4 MPLS L3VPN (AFI,SAFI = 1,128) as defined in Section 4.3.4 of [RFC4364]).

'multihop':

Indicates the number of allowed IP hops to reach a BGP peer.

'as-override':

If set, this parameter indicates whether ASN override is enabled, i.e., replacing the ASN of the customer specified in the AS_PATH BGP attribute with the ASN identified in the 'local- as' attribute.

'allow-own-as':

Used in some topologies (e.g., hub-and-spoke) to allow the provider's ASN to be included in the AS_PATH BGP attribute received from a peer. Loops are prevented by setting 'allow-own-as' to a maximum number of the provider's ASN occurrences. By default, this parameter is set to '0' (that is, reject any AS_PATH attribute that includes the provider's ASN).

'prepend-global-as':

When distinct ASNs are configured at the node and AC levels, this parameter controls whether the ASN provided at the node level is prepended to the AS_PATH attribute.

'send-default-route':

Controls whether default routes can be advertised to the peer.

'site-of-origin':

Meant to uniquely identify the set of routes learned from a site via a particular AC. It is used to prevent routing loops (Section 7 of [RFC4364]). The Site of Origin attribute is encoded as a Route Origin Extended Community.

'ipv6-site-of-origin':

Carries an IPv6 Address Specific BGP Extended Community that is used to indicate the Site of Origin [RFC5701]. It is used to prevent routing loops.

'redistribute-connected':

Controls whether the AC is advertised to other PEs.

'bgp-max-prefix': Controls the behavior when a prefix maximum is reached.

'max-prefix':

Indicates the maximum number of BGP prefixes allowed in a session for this group. If the limit is reached, the action indicated in 'violate-action' will be followed.

'warning-threshold':

A warning notification is triggered when this limit is reached.

'violate-action':

Indicates which action to execute when the maximum number of BGP prefixes is reached. Examples of such actions include sending a warning message, discarding extra paths from the peer, or restarting the session.

'restart-timer':

Indicates, in seconds, the time interval after which the BGP session will be reestablished.

'bgp-timers':

Two timers can be captured in this container: (1) 'hold-time', which is the time interval that will be used for the Hold Timer (Section 4.2 of [RFC4271]) when establishing a BGP session and (2) 'keepalive', which is the time interval for the KeepaliveTimer between a PE and a BGP peer (Section 4.4 of [RFC4271]).

Both timers are expressed in seconds.

'authentication':

The module adheres to the recommendations in Section 13.2 of [RFC4364], as it allows enabling the TCP Authentication Option (TCP-AO) [RFC5925] and accommodates the installed base that makes use of MD5. In addition, the module includes a provision for using IPsec.

This version of the model assumes that parameters specific to the TCP-AO are preconfigured as part of the key chain that is referenced in the model. No assumption is made about how such a key chain is preconfigured. However, the structure of the key chain should cover data nodes beyond those in [RFC8177], mainly SendID and RecvID (Section 3.1 of [RFC5925]).

For each neighbor, the following data nodes are supported in addition to similar parameters that are provided for a peer group:

'remote-address':

Specifies the remote IP address of a BGP neighbor.

'peer-group':

A name of a peer group.

Parameters that are provided at the 'neighbor' level takes precedence over the ones provided in the peer group.

'status':

Indicates the status of the BGP session.

4.5.3. OSPF

The OSPF routing subtree structure is shown in Figure 11.

module: ietf-ac-ntw
  augment /nw:networks/nw:network:
    +--rw ac-profile* [name]
       +--rw name                 string
       +--rw l2-connection
       +--rw ip-connection
       +--rw routing-protocols
       |  +--rw routing-protocol* [id]
       |     +--rw id      string
       |     +--rw type?   identityref
       |     +--rw bgp
       |     |  ...
       |     +--rw ospf
       |     |  +--rw address-family?   identityref
       |     |  +--rw area-id           yang:dotted-quad
       |     |  +--rw metric?           uint16
       |     |  +--rw max-lsa?          uint32
       |     +--rw isis
       |     |  ...
       |     +--rw rip
       |     |  ...
       |     +--rw vrrp
       |        ...
       +--rw oam
          ...
  augment /nw:networks/nw:network/nw:node:
    +--rw ac* [name]
       +--rw name                 string
       ...
       +--rw l2-connection
       |  ...
       +--rw ip-connection
       |  ...
       +--rw routing-protocols
       |  +--rw routing-protocol* [id]
       |     +--rw id                  string
       |     +--rw type?               identityref
       |     +--rw routing-profiles* [id]
       |     |  +--rw id      leafref
       |     |  +--rw type?   identityref
       |     +--rw static
       |     |  ...
       |     +--rw bgp
       |     |  ...
       |     +--rw ospf
       |     |  +--rw address-family?   identityref
       |     |  +--rw area-id           yang:dotted-quad
       |     |  +--rw metric?           uint16
       |     |  +--rw sham-links {vpn-common:rtg-ospf-sham-link}?
       |     |  |  +--rw sham-link* [target-site]
       |     |  |     +--rw target-site    string
       |     |  |     +--rw metric?        uint16
       |     |  +--rw max-lsa?          uint32
       |     |  +--rw authentication
       |     |  |  +--rw enable?            boolean
       |     |  |  +--rw keying-material
       |     |  |     +--rw (option)?
       |     |  |        +--:(auth-key-chain)
       |     |  |        |  +--rw key-chain?
       |     |  |        |          key-chain:key-chain-ref
       |     |  |        +--:(auth-key-explicit)
       |     |  |           +--rw key-id?             uint32
       |     |  |           +--rw key?                string
       |     |  |           +--rw crypto-algorithm?   identityref
       |     |  +--rw status
       |     |     +--rw admin-status
       |     |     |  +--rw status?        identityref
       |     |     |  +--rw last-change?   yang:date-and-time
       |     |     +--ro oper-status
       |     |        +--ro status?        identityref
       |     |        +--ro last-change?   yang:date-and-time
       |     +--rw isis
       |     |  ...
       |     +--rw rip
       |     |  ...
       |     +--rw vrrp
       |        ...
       +--rw oam
       |  ...
       +--rw security
       |  ...
       +--rw service
          ...
Figure 11: OSPF Routing Tree Structure

The following OSPF data nodes are supported:

'address-family':

Indicates whether IPv4, IPv6, or both address families are to be activated.

When the IPv4 or dual-stack address family is requested, it is up to the implementation (e.g., network orchestrator) to decide whether OSPFv2 [RFC4577] or OSPFv3 [RFC6565] is used to announce IPv4 routes.

'area-id':

Indicates the OSPF Area ID.

'metric':

Associates a metric with OSPF routes.

'sham-links':

Used to create OSPF sham links between two ACs sharing the same area and having a backdoor link (Section 4.2.7 of [RFC4577] and Section 5 of [RFC6565]).

'max-lsa':

Sets the maximum number of Link State Advertisements (LSAs) that the OSPF instance will accept.

'authentication':

Controls the authentication schemes to be enabled for the OSPF instance. The following options are supported: IPsec for OSPFv3 authentication [RFC4552], and the Authentication Trailer for OSPFv2 [RFC5709] [RFC7474] and OSPFv3 [RFC7166].

'status':

Indicates the status of the OSPF routing instance.

4.5.4. IS-IS

The IS-IS routing subtree structure is shown in Figure 12.

module: ietf-ac-ntw
  augment /nw:networks/nw:network:
    +--rw ac-profile* [name]
       +--rw name                 string
       +--rw l2-connection
       +--rw ip-connection
       +--rw routing-protocols
       |  +--rw routing-protocol* [id]
       |     +--rw id      string
       |     +--rw type?   identityref
       |     +--rw bgp
       |     |  ...
       |     +--rw ospf
       |     |  ...
       |     +--rw isis
       |     |  +--rw address-family?   identityref
       |     |  +--rw area-address      area-address
       |     |  +--rw level?            identityref
       |     |  +--rw metric?           uint16
       |     |  +--rw mode?             enumeration
       |     +--rw rip
       |     |  ...
       |     +--rw vrrp
       |        ...
       +--rw oam
          ...
  augment /nw:networks/nw:network/nw:node:
    +--rw ac* [name]
       +--rw name                 string
       ...
       +--rw l2-connection
       |  ...
       +--rw ip-connection
       |  ...
       +--rw routing-protocols
       |  +--rw routing-protocol* [id]
       |     +--rw id                  string
       |     +--rw type?               identityref
       |     +--rw routing-profiles* [id]
       |     |  +--rw id      leafref
       |     |  +--rw type?   identityref
       |     +--rw static
       |     |  ...
       |     +--rw bgp
       |     |  ...
       |     +--rw ospf
       |     |  ...
       |     +--rw isis
       |     |  +--rw address-family?   identityref
       |     |  +--rw area-address      area-address
       |     |  +--rw level?            identityref
       |     |  +--rw metric?           uint16
       |     |  +--rw mode?             enumeration
       |     |  +--rw authentication
       |     |  |  +--rw enable?            boolean
       |     |  |  +--rw keying-material
       |     |  |     +--rw (option)?
       |     |  |        +--:(auth-key-chain)
       |     |  |        |  +--rw key-chain?
       |     |  |        |          key-chain:key-chain-ref
       |     |  |        +--:(auth-key-explicit)
       |     |  |           +--rw key-id?             uint32
       |     |  |           +--rw key?                string
       |     |  |           +--rw crypto-algorithm?   identityref
       |     |  +--rw status
       |     |     +--rw admin-status
       |     |     |  +--rw status?        identityref
       |     |     |  +--rw last-change?   yang:date-and-time
       |     |     +--ro oper-status
       |     |        +--ro status?        identityref
       |     |        +--ro last-change?   yang:date-and-time
       |     +--rw rip
       |     |  ...
       |     +--rw vrrp
       |        ...
       +--rw oam
       |  ...
       +--rw security
       |  ...
       +--rw service
          ...
Figure 12: IS-IS Routing Tree Structure

The following IS-IS data nodes are supported:

'address-family':

Indicates whether IPv4, IPv6, or both address families are to be activated.

'area-address':

Indicates the IS-IS area address.

'level':

Indicates the IS-IS level: Level 1, Level 2, or both.

'metric':

Associates a metric with IS-IS routes.

'mode':

Indicates the IS-IS interface mode type. It can be set to 'active' (that is, send or receive IS-IS protocol control packets) or 'passive' (that is, suppress the sending of IS-IS updates through the interface).

'authentication':

Controls the authentication schemes to be enabled for the IS-IS instance. Both the specification of a key chain [RFC8177] and the direct specification of key and authentication algorithms are supported.

'status':

Indicates the status of the IS-IS routing instance.

4.5.5. RIP

The RIP routing subtree structure is shown in Figure 13.

module: ietf-ac-ntw
  augment /nw:networks/nw:network:
    +--rw ac-profile* [name]
       +--rw name                 string
       +--rw l2-connection
       +--rw ip-connection
       +--rw routing-protocols
       |  +--rw routing-protocol* [id]
       |     +--rw id      string
       |     +--rw type?   identityref
       |     +--rw bgp
       |     |  ...
       |     +--rw ospf
       |     |  ...
       |     +--rw isis
       |     |  ...
       |     +--rw rip
       |     |  +--rw address-family?   identityref
       |     |  +--rw timers
       |     |  |  +--rw update-interval?     uint16
       |     |  |  +--rw invalid-interval?    uint16
       |     |  |  +--rw holddown-interval?   uint16
       |     |  |  +--rw flush-interval?      uint16
       |     |  +--rw default-metric?   uint8
       |     +--rw vrrp
       |        ...
       +--rw oam
          ...
  augment /nw:networks/nw:network/nw:node:
    +--rw ac* [name]
       +--rw name                 string
       ...
       +--rw l2-connection
       |  ...
       +--rw ip-connection
       |  ...
       +--rw routing-protocols
       |  +--rw routing-protocol* [id]
       |     +--rw id                  string
       |     +--rw type?               identityref
       |     +--rw routing-profiles* [id]
       |     |  +--rw id      leafref
       |     |  +--rw type?   identityref
       |     +--rw static
       |     |  ...
       |     +--rw bgp
       |     |  ...
       |     +--rw ospf
       |     |  ...
       |     +--rw isis
       |     |  ...
       |     +--rw rip
       |     |  +--rw address-family?   identityref
       |     |  +--rw timers
       |     |  |  +--rw update-interval?     uint16
       |     |  |  +--rw invalid-interval?    uint16
       |     |  |  +--rw holddown-interval?   uint16
       |     |  |  +--rw flush-interval?      uint16
       |     |  +--rw default-metric?   uint8
       |     |  +--rw authentication
       |     |  |  +--rw enable?            boolean
       |     |  |  +--rw keying-material
       |     |  |     +--rw (option)?
       |     |  |        +--:(auth-key-chain)
       |     |  |        |  +--rw key-chain?
       |     |  |        |          key-chain:key-chain-ref
       |     |  |        +--:(auth-key-explicit)
       |     |  |           +--rw key?                string
       |     |  |           +--rw crypto-algorithm?   identityref
       |     |  +--rw status
       |     |     +--rw admin-status
       |     |     |  +--rw status?        identityref
       |     |     |  +--rw last-change?   yang:date-and-time
       |     |     +--ro oper-status
       |     |        +--ro status?        identityref
       |     |        +--ro last-change?   yang:date-and-time
       |     +--rw vrrp
       |        ...
       +--rw oam
       |  ...
       +--rw security
       |  ...
       +--rw service
          ...
Figure 13: RIP Routing Tree Structure

The following RIP data nodes are supported:

'address-family':

Indicates whether IPv4, IPv6, or both address families are to be activated. This parameter is used to determine whether RIPv2 [RFC2453], RIP Next Generation (RIPng), or both are to be enabled [RFC2080].

'timers':

Indicates the following timers (expressed in seconds):

  • 'update-interval':

    The interval at which RIP updates are sent.

  • 'invalid-interval':

    The interval before a RIP route is declared invalid.

  • 'holddown-interval':

    The interval before better RIP routes are released.

  • 'flush-interval':

    The interval before a route is removed from the routing table.

'default-metric':

Sets the default RIP metric.

'authentication':

Controls the authentication schemes to be enabled for the RIP instance.

'status':

Indicates the status of the RIP routing instance.

4.5.6. VRRP

The VRRP subtree structure is shown in Figure 14.

module: ietf-ac-ntw
  augment /nw:networks/nw:network:
    +--rw ac-profile* [name]
       +--rw name                 string
       +--rw l2-connection
       +--rw ip-connection
       +--rw routing-protocols
       |  +--rw routing-protocol* [id]
       |     +--rw id      string
       |     +--rw type?   identityref
       |     +--rw bgp
       |     |  ...
       |     +--rw ospf
       |     |  ...
       |     +--rw isis
       |     |  ...
       |     +--rw rip
       |     |  ...
       |     +--rw vrrp
       |        +--rw address-family?   identityref
       |        +--rw ping-reply?       boolean
       +--rw oam
          ...
  augment /nw:networks/nw:network/nw:node:
    +--rw ac* [name]
       +--rw name                 string
       ...
       +--rw l2-connection
       |  ...
       +--rw ip-connection
       |  ...
       +--rw routing-protocols
       |  +--rw routing-protocol* [id]
       |     +--rw id                  string
       |     +--rw type?               identityref
       |     +--rw routing-profiles* [id]
       |     |  +--rw id      leafref
       |     |  +--rw type?   identityref
       |     +--rw static
       |     |  ...
       |     +--rw bgp
       |     |  ...
       |     +--rw ospf
       |     |  ...
       |     +--rw isis
       |     |  ...
       |     +--rw rip
       |     |  ...
       |     +--rw vrrp
       |        +--rw address-family?       identityref
       |        +--rw vrrp-group?           uint8
       |        +--rw backup-peer?          inet:ip-address
       |        +--rw virtual-ip-address*   inet:ip-address
       |        +--rw priority?             uint8
       |        +--rw ping-reply?           boolean
       |        +--rw status
       |           +--rw admin-status
       |           |  +--rw status?        identityref
       |           |  +--rw last-change?   yang:date-and-time
       |           +--ro oper-status
       |              +--ro status?        identityref
       |              +--ro last-change?   yang:date-and-time
       +--rw oam
       |  ...
       +--rw security
       |  ...
       +--rw service
          ...
Figure 14: VRRP Tree Structure

The following VRRP data nodes are supported:

'address-family':

Indicates whether IPv4, IPv6, or both address families are to be activated. Note that VRRP version 3 [RFC5798] supports both IPv4 and IPv6.

'vrrp-group':

Used to identify the VRRP group.

'backup-peer':

Carries the IP address of the peer.

'virtual-ip-address':

Includes virtual IP addresses for a single VRRP group.

'priority':

Assigns the VRRP election priority for the backup virtual router.

'ping-reply':

Controls whether the VRRP speaker should reply to ping requests.

'status':

Indicates the status of the VRRP instance.

Note that no authentication data node is included for VRRP, as there isn't any type of VRRP authentication at this time (see Section 9 of [RFC5798]).

4.6. OAM

The OAM subtree structure is shown in Figure 15.

  augment /nw:networks/nw:network:
    +--rw ac-profile* [name]
       +--rw name                 string
       +--rw l2-connection
       +--rw ip-connection
       +--rw routing-protocols
       |  ...
       +--rw oam
          +--rw bfd {vpn-common:bfd}?
             +--rw session-type?               identityref
             +--rw desired-min-tx-interval?    uint32
             +--rw required-min-rx-interval?   uint32
             +--rw local-multiplier?           uint8
             +--rw holdtime?                   uint32
  augment /nw:networks/nw:network/nw:node:
    +--rw ac* [name]
       +--rw name                 string
       +--rw ac-svc-ref?          ac-svc:attachment-circuit-reference
       +--rw ac-profile* [profile-id]
       |  +--rw profile-id    ac-profile-reference
       +--rw ac-parent-ref?       ac-ntw:attachment-circuit-reference
       +--rw peer-sap-id*         string
       +--rw group* [group-id]
       |  +--rw group-id      string
       |  +--rw precedence?   identityref
       +--rw status
       |  +--rw admin-status
       |  |  +--rw status?        identityref
       |  |  +--rw last-change?   yang:date-and-time
       |  +--ro oper-status
       |     +--ro status?        identityref
       |     +--ro last-change?   yang:date-and-time
       +--rw description?         string
       +--rw l2-connection
       |  ...
       +--rw ip-connection
       |  ...
       +--rw routing-protocols
       |  ...
       +--rw oam
       |  +--rw bfd
       |     +--rw profile?                    ac-svc:bfd-profile-reference
       |     +--rw session-type?               identityref
       |     +--rw desired-min-tx-interval?    uint32
       |     +--rw required-min-rx-interval?   uint32
       |     +--rw local-multiplier?           uint8
       |     +--rw holdtime?                   uint32
       |     +--rw authentication!
       |     |  +--rw key-chain?    key-chain:key-chain-ref
       |     |  +--rw meticulous?   boolean
       |     +--rw status
       |        +--rw admin-status
       |        |  +--rw status?        identityref
       |        |  +--rw last-change?   yang:date-and-time
       |        +--ro oper-status
       |           +--ro status?        identityref
       |           +--ro last-change?   yang:date-and-time
       +--rw security
       |  ...
       +--rw service
          ...
Figure 15: OAM Tree Structure

The following OAM data nodes can be specified:

'profile':

Refers to a BFD profile (Section 4.2).

'session-type':

Indicates which BFD flavor is used to set up the session (e.g., classic BFD [RFC5880], Seamless BFD [RFC7880]). By default, it is assumed that the BFD session will follow the behavior specified in [RFC5880].

'desired-min-tx-interval':

The minimum interval, in microseconds, to use when transmitting BFD Control packets, less any jitter applied.

'required-min-rx-interval':

The minimum interval, in microseconds, between received BFD Control packets less any jitter applied by the sender.

'local-multiplier':

The negotiated transmit interval, multiplied by this value, provides the detection time for the peer.

'holdtime':

Used to indicate the expected BFD holddown time, in milliseconds.

'authentication':

Includes the required information to enable the BFD authentication modes discussed in Section 6.7 of [RFC5880]. In particular, 'meticulous' controls the activation of meticulous mode as discussed in Sections 6.7.3 and 6.7.4 of [RFC5880].

'status':

Indicates the status of BFD.

4.7. Security

The security subtree structure is shown in Figure 16. The 'security' container specifies the authentication and the encryption to be applied to traffic for a given AC. Tthe model can be used to directly control the encryption to be applied (e.g., Layer 2 or Layer 3 encryption) or invoke a local encryption profile.

  augment /nw:networks/nw:network/nw:node:
    +--rw ac* [name]
       +--rw name                 string
       +--rw ac-svc-ref?          ac-svc:attachment-circuit-reference
       +--rw ac-profile* [profile-id]
       |  +--rw profile-id    ac-profile-reference
       +--rw ac-parent-ref?       ac-ntw:attachment-circuit-reference
       +--rw peer-sap-id*         string
       +--rw group* [group-id]
       |  +--rw group-id      string
       |  +--rw precedence?   identityref
       +--rw status
       |  +--rw admin-status
       |  |  +--rw status?        identityref
       |  |  +--rw last-change?   yang:date-and-time
       |  +--ro oper-status
       |     +--ro status?        identityref
       |     +--ro last-change?   yang:date-and-time
       +--rw description?         string
       +--rw l2-connection
       |  ...
       +--rw ip-connection
       |  ...
       +--rw routing-protocols
       |  ...
       +--rw oam
       |  ...
       +--rw security
       |  +--rw encryption {vpn-common:encryption}?
       |  |  +--rw enabled?   boolean
       |  |  +--rw layer?     enumeration
       |  +--rw encryption-profile
       |     +--rw (profile)?
       |        +--:(provider-profile)
       |        |  +--rw profile-name?
       |        |          encryption-profile-reference
       |        +--:(customer-profile)
       |           +--rw customer-key-chain?   key-chain:key-chain-ref
       +--rw service
          ...
Figure 16: Security Tree Structure

4.8. Service

The service subtree structure is shown in Figure 17.

  augment /nw:networks/nw:network/nw:node:
    +--rw ac* [name]
       +--rw name                 string
       +--rw ac-svc-ref?          ac-svc:attachment-circuit-reference
       +--rw ac-profile* [profile-id]
       |  +--rw profile-id    ac-profile-reference
       +--rw ac-parent-ref?       ac-ntw:attachment-circuit-reference
       +--rw peer-sap-id*         string
       +--rw group* [group-id]
       |  +--rw group-id      string
       |  +--rw precedence?   identityref
       +--rw status
       |  +--rw admin-status
       |  |  +--rw status?        identityref
       |  |  +--rw last-change?   yang:date-and-time
       |  +--ro oper-status
       |     +--ro status?        identityref
       |     +--ro last-change?   yang:date-and-time
       +--rw description?         string
       +--rw l2-connection
       |  ...
       +--rw ip-connection
       |  ...
       +--rw routing-protocols
       |  ...
       +--rw oam
       |  ...
       +--rw security
       |  ...
       +--rw service
          +--rw mtu?                      uint32
          +--rw svc-pe-to-ce-bandwidth {vpn-common:inbound-bw}?
          |  +--rw bandwidth* [bw-type]
          |     +--rw bw-type      identityref
          |     +--rw (type)?
          |        +--:(per-cos)
          |        |  +--rw cos* [cos-id]
          |        |     +--rw cos-id    uint8
          |        |     +--rw cir?      uint64
          |        |     +--rw cbs?      uint64
          |        |     +--rw eir?      uint64
          |        |     +--rw ebs?      uint64
          |        |     +--rw pir?      uint64
          |        |     +--rw pbs?      uint64
          |        +--:(other)
          |           +--rw cir?   uint64
          |           +--rw cbs?   uint64
          |           +--rw eir?   uint64
          |           +--rw ebs?   uint64
          |           +--rw pir?   uint64
          |           +--rw pbs?   uint64
          +--rw svc-ce-to-pe-bandwidth {vpn-common:outbound-bw}?
          |  +--rw bandwidth* [bw-type]
          |     +--rw bw-type      identityref
          |     +--rw (type)?
          |        +--:(per-cos)
          |        |  +--rw cos* [cos-id]
          |        |     +--rw cos-id    uint8
          |        |     +--rw cir?      uint64
          |        |     +--rw cbs?      uint64
          |        |     +--rw eir?      uint64
          |        |     +--rw ebs?      uint64
          |        |     +--rw pir?      uint64
          |        |     +--rw pbs?      uint64
          |        +--:(other)
          |           +--rw cir?   uint64
          |           +--rw cbs?   uint64
          |           +--rw eir?   uint64
          |           +--rw ebs?   uint64
          |           +--rw pir?   uint64
          |           +--rw pbs?   uint64
          +--rw qos {vpn-common:qos}?
          |  +--rw qos-profiles
          |     +--rw qos-profile* [profile]
          |        +--rw profile      qos-profile-reference
          |        +--rw direction?   identityref
          +--rw access-control-list
             +--rw acl-profiles
                +--rw acl-profile* [profile]
                   +--rw profile    forwarding-profile-reference
Figure 17: Service Tree Structure

The description of the service data nodes is as follows:

'mtu':

Specifies the Layer 2 MTU, in bytes, for the VPN network access.

'svc-pe-to-ce-bandwidth' and 'svc-ce-to-pe-bandwidth':

Specify the service bandwidth for the L2VPN service.

'svc-pe-to-ce-bandwidth' indicates the inbound bandwidth of the connection (i.e., download bandwidth from the service provider to the site).

'svc-ce-to-pe-bandwidth' indicates the outbound bandwidth of the connection (i.e., upload bandwidth from the site to the service provider).

'svc-pe-to-ce-bandwidth' and 'svc-ce-to-pe-bandwidth' can be represented using the Committed Information Rate (CIR), the Excess Information Rate (EIR), or the Peak Information Rate (PIR).

The following types, defined in [RFC9181], can be used to indicate the bandwidth type:

'bw-per-cos':

The bandwidth is per CoS.

'bw-per-port':

The bandwidth is per port.

'bw-per-site':

The bandwidth is to all peer SAPs that belong to the same site.

'bw-per-service':

The bandwidth is per service instance that is bound to an AC.

'qos':

Specifies a list of QoS profiles to apply for this AC.

'access-control-list':

Specifies a list of ACL profiles to apply for this AC.

5. YANG Module

This module uses types defined in [RFC6991], [RFC8177], [RFC8294], [RFC8343], [RFC9067], [RFC9181], [I-D.ietf-opsawg-teas-common-ac], and [IEEE802.1Qcp].

<CODE BEGINS> file ietf-ac-ntw@2022-11-30.yang
module ietf-ac-ntw {
  yang-version 1.1;
  namespace "urn:ietf:params:xml:ns:yang:ietf-ac-ntw";
  prefix ac-ntw;

  import ietf-vpn-common {
    prefix vpn-common;
    reference
      "RFC 9181: A Common YANG Data Model for Layer 2 and Layer 3
                 VPNs";
  }
  import ietf-inet-types {
    prefix inet;
    reference
      "RFC 6991: Common YANG Data Types, Section 4";
  }
  import ietf-key-chain {
    prefix key-chain;
    reference
      "RFC 8177: YANG Data Model for Key Chains";
  }
  import ietf-routing-types {
    prefix rt-types;
    reference
      "RFC 8294: Common YANG Data Types for the Routing Area";
  }
  import ietf-routing-policy {
    prefix rt-pol;
    reference
      "RFC 9067: A YANG Data Model for Routing Policy";
  }
  import ietf-interfaces {
    prefix if;
    reference
      "RFC 8343: A YANG Data Model for Interface Management";
  }
  import ieee802-dot1q-types {
    prefix dot1q-types;
    reference
      "IEEE Std 802.1Qcp: Bridges and Bridged Networks--
                          Amendment 30: YANG Data Model";
  }
  import ietf-network {
    prefix nw;
    reference
      "RFC 8345: A YANG Data Model for Network Topologies,
                 Section 6.1";
  }
  import ietf-sap-ntw {
    prefix sap;
    reference
      "RFC SSSS: A YANG Network Model for Service Attachment
                 Points (SAPs)";
  }
  import ietf-ac-common {
    prefix ac-common;
    reference
      "RFC CCCC: A Common YANG Data Model for Attachment Circuits";
  }
  import ietf-ac-svc {
    prefix ac-svc;
    reference
      "RFC SSSS: YANG Service Data Models 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:   Oscar Gonzalez de Dios
               <mailto:oscar.gonzalezdedios@telefonica.com>
     Author:   Samier Barguil
               <mailto:ssamier.barguil_giraldo@nokia.com>
     Author:   Bo Wu
               <mailto:lana.wubo@huawei.com>";
  description
    "This YANG module defines a YANG network model for the management
     of attachment circuits.

     Copyright (c) 2023 IETF Trust and the persons identified as
     authors of the code.  All rights reserved.

     Redistribution and use in source and binary forms, with or
     without modification, is permitted pursuant to, and subject
     to the license terms contained in, the Revised BSD License
     set forth in Section 4.c of the IETF Trust's Legal Provisions
     Relating to IETF Documents
     (https://trustee.ietf.org/license-info).

     This version of this YANG module is part of RFC XXXX; see the
     RFC itself for full legal notices.";

  revision 2023-11-13 {
    description
      "Initial revision.";
    reference
      "RFC XXXX: A YANG Network Data Model for Attachment Circuits";
  }

  // L2 connection groupings

  /* A set of typedefs to ease referencing cross-modules */

  typedef attachment-circuit-reference {
    type leafref {
      path "/nw:networks/nw:network/nw:node/ac-ntw:ac/ac-ntw:name";
    }
    description
      "Defines a reference to an attachment circuit. The reference
       be used also by other modules.";
  }

  typedef ac-profile-reference {
    type leafref {
      path "/nw:networks/nw:network/ac-profile/name";
    }
    description
      "Defines a reference to an attachment circuit profile that
       can be used, including, by other modules.";
  }

  typedef encryption-profile-reference {
    type leafref {
      path
          "/nw:networks/nw:network"
        + "/ac-ntw:specific-provisioning-profiles"
        + "/ac-ntw:valid-provider-identifiers"
        + "/ac-ntw:encryption-profile-identifier/ac-ntw:id";
    }
    description
      "Defines a type to an encryption profile for referencing
       purposes.";
  }

  typedef qos-profile-reference {
    type leafref {
      path
          "/nw:networks/nw:network"
        + "/ac-ntw:specific-provisioning-profiles"
        + "/ac-ntw:valid-provider-identifiers"
        + "/ac-ntw:qos-profile-identifier/ac-ntw:id";
    }
    description
      "Defines a type to a QoS profile for referencing purposes.";
  }

  typedef bfd-profile-reference {
    type leafref {
      path
          "/nw:networks/nw:network"
        + "/ac-ntw:specific-provisioning-profiles"
        + "/ac-ntw:valid-provider-identifiers"
        + "/ac-ntw:bfd-profile-identifier/ac-ntw:id";
    }
    description
      "Defines a type to a BFD profile for referencing purposes.";
  }

  typedef forwarding-profile-reference {
    type leafref {
      path
          "/nw:networks/nw:network"
        + "/ac-ntw:specific-provisioning-profiles"
        + "/ac-ntw:valid-provider-identifiers"
        + "/ac-ntw:forwarding-profile-identifier/ac-ntw:id";
    }
    description
      "Defines a type to a forwarding profile for referencing
       purposes.";
  }

  typedef routing-profile-reference {
    type leafref {
      path
          "/nw:networks/nw:network"
        + "/ac-ntw:specific-provisioning-profiles"
        + "/ac-ntw:valid-provider-identifiers"
        + "/ac-ntw:routing-profile-identifier/ac-ntw:id";
    }
    description
      "Defines a type to a routing profile for referencing
       purposes.";
  }

  // L2 conenction

  grouping l2-connection {
    description
      "Defines Layer 2 protocols and parameters that are required to
       enable AC connectivity.";
    container encapsulation {
      description
        "Container for Layer 2 encapsulation.";
      leaf encap-type {
        type identityref {
          base vpn-common:encapsulation-type;
        }
        description
          "Tagged interface type.";
      }
      container dot1q {
        when "derived-from-or-self(../encap-type, "
           + "'vpn-common:dot1q')" {
          description
            "Only applies when the type of the tagged interface is
             'dot1q'.";
        }
        description
          "Tagged interface.";
        uses ac-common:dot1q;
        container tag-operations {
          description
            "Sets the tag manipulation policy for this AC. It defines
             a set of tag manipulations that allow for the insertion,
             removal, or rewriting of 802.1Q VLAN tags. These
             operations are indicated for the CE-PE direction.
             By default, tag operations are symmetric. As such, the
             reverse tag operation is assumed on the PE-CE
             direction.";
          choice op-choice {
            description
              "Selects the tag rewriting policy for an AC.";
            leaf pop {
              type empty;
              description
                "Pop the outer tag.";
            }
            leaf push {
              type empty;
              description
                "Pushes one or two tags defined by the tag-1 and
                 tag-2 leaves.  It is assumed that, absent any
                 policy, the default value of 0 will be used for
                 the PCP  setting.";
            }
            leaf translate {
              type empty;
              description
                "Translates the outer tag to one or two tags. PCP
                 bits are preserved.";
            }
          }
          leaf tag-1 {
            when 'not(../pop)';
            type dot1q-types:vlanid;
            description
              "A first tag to be used for push or translate
               operations. This tag will be used as the outermost tag
               as a result of the tag operation.";
          }
          leaf tag-1-type {
            type dot1q-types:dot1q-tag-type;
            default "dot1q-types:s-vlan";
            description
              "Specifies a specific 802.1Q tag type of tag-1.";
          }
          leaf tag-2 {
            when '(../translate)';
            type dot1q-types:vlanid;
            description
              "A second tag to be used for translation.";
          }
          leaf tag-2-type {
            type dot1q-types:dot1q-tag-type;
            default "dot1q-types:c-vlan";
            description
              "Specifies a specific 802.1Q tag type of tag-2.";
          }
        }
      }
      container priority-tagged {
        when "derived-from-or-self(../encap-type, "
           + "'vpn-common:priority-tagged')" {
          description
            "Only applies when the type of the tagged interface is
             'priority-tagged'.";
        }
        description
          "Priority tagged container.";
        uses ac-common:priority-tagged;
      }
      container qinq {
        when "derived-from-or-self(../encap-type, "
           + "'vpn-common:qinq')" {
          description
            "Only applies when the type of the tagged interface is
             'QinQ'.";
        }
        description
          "Includes QinQ parameters.";
        uses ac-common:qinq;
        container tag-operations {
          description
            "Sets the tag manipulation policy for this AC. It defines
             a set of tag manipulations that allow for the insertion,
             removal, or rewriting of 802.1Q VLAN tags. These
             operations are indicated for the CE-PE direction.
             By default, tag operations are symmetric. As such, the
             reverse tag operation is assumed on the PE-CE
             direction.";
          choice op-choice {
            description
              "Selects the tag rewriting policy for a AC.";
            leaf pop {
              type uint8 {
                range "1|2";
              }
              description
                "Pops one or two tags as a function of the indicated
                 pop value.";
            }
            leaf push {
              type empty;
              description
                "Pushes one or two tags defined by the tag-1 and
                 tag-2 leaves. It is assumed that, absent any
                 policy, the default value of 0 will be used for
                 PCP setting.";
            }
            leaf translate {
              type uint8 {
                range "1|2";
              }
              description
                "Translates one or two outer tags. PCP bits are
                 preserved. The following operations are supported:

                 - translate 1 with tag-1 leaf is provided: only the
                   outermost tag is translated to the value in tag-1.

                 - translate 2 with both tag-1 and tag-2 leaves are
                   provided: both outer and inner tags are translated
                   to the values in tag-1 and tag-2, respectively.

                 - translate 2 with tag-1 leaf is provided: the
                   outer tag is popped while the inner tag is
                   translated to the value in tag-1.";
            }
          }
          leaf tag-1 {
            when 'not(../pop)';
            type dot1q-types:vlanid;
            description
              "A first tag to be used for push or translate
               operations. This tag will be used as the outermost tag
               as a result of the tag operation.";
          }
          leaf tag-1-type {
            type dot1q-types:dot1q-tag-type;
            default "dot1q-types:s-vlan";
            description
              "Specifies a specific 802.1Q tag type of tag-1.";
          }
          leaf tag-2 {
            when 'not(../pop)';
            type dot1q-types:vlanid;
            description
              "A second tag to be used for push or translate
               operations.";
          }
          leaf tag-2-type {
            type dot1q-types:dot1q-tag-type;
            default "dot1q-types:c-vlan";
            description
              "Specifies a specific 802.1Q tag type of tag-2.";
          }
        }
      }
    }
    choice l2-service {
      description
        "The Layer 2 connectivity service can be provided by
         indicating a pointer to an L2VPN or by specifying a Layer 2
         tunnel service.";
      container l2-tunnel-service {
        description
          "Defines a Layer 2 tunnel termination.";
        uses ac-common:l2-tunnel-service;
      }
      case l2vpn {
        leaf l2vpn-id {
          type vpn-common:vpn-id;
          description
            "Indicates the L2VPN service associated with an
             Integrated Routing and Bridging (IRB) interface.";
        }
      }
    }
  }

  grouping l2-connection-if-ref {
    description
      "Specifies Layer 2 connection paramters with interface
       references.";
    uses l2-connection;
    leaf l2-termination-point {
      type string;
      description
        "Specifies a reference to a local Layer 2 termination point,
         such as a Layer 2 sub-interface.";
    }
    leaf local-bridge-reference {
      type string;
      description
        "Specifies a local bridge reference to accommodate, e.g.,
         implementations that require internal bridging.
         A reference may be a local bridge domain.";
    }
    leaf bearer-reference {
      if-feature "vpn-common:bearer-reference";
      type string;
      description
        "This is an internal reference for the service provider to
         identify the bearer associated with this AC.";
    }
    container lag-interface {
      if-feature "vpn-common:lag-interface";
      description
        "Container for configuration of Link Aggregation Group (LAG)
         interface attributes.";
      leaf lag-interface-id {
        type string;
        description
          "LAG interface identifier.";
      }
      container member-link-list {
        description
          "Container for the member link list.";
        list member-link {
          key "name";
          description
            "Member link.";
          leaf name {
            type string;
            description
              "Member link name.";
          }
        }
      }
    }
  }

  // IPv4 connection groupings

  grouping ipv4-connection {
    description
      "IPv4-specific parameters.";
    leaf local-address {
      type inet:ipv4-address;
      description
        "The IP address used at the provider's interface.";
    }
    uses ac-common:ipv4-allocation-type;
    choice allocation-type {
      description
        "Choice of the IPv4 address allocation.";
      case dynamic {
        description
          "When the addresses are allocated by DHCP or other
           dynamic means local to the infrastructure.";
        choice address-assign {
          description
            "A choice for how IPv4 addresses are assigned.";
          case number {
            leaf number-of-dynamic-address {
              type uint16;
              description
                "Specifies the number of IP addresses to be
                 assigned to the customer on this access.";
            }
          }
          case explicit {
            container customer-addresses {
              description
                "Container for customer addresses to be allocated
                 using DHCP.";
              list address-pool {
                key "pool-id";
                description
                  "Describes IP addresses to be dyncamically
                   allocated.

                   When only 'start-address' is present, it
                   represents a single address.

                   When both 'start-address' and 'end-address' are
                   specified, it implies a range inclusive of both
                   addresses.";
                leaf pool-id {
                  type string;
                  description
                    "A pool identifier for the address range from
                     'start-address' to 'end-address'.";
                }
                leaf start-address {
                  type inet:ipv4-address;
                  mandatory true;
                  description
                    "Indicates the first address in the pool.";
                }
                leaf end-address {
                  type inet:ipv4-address;
                  description
                    "Indicates the last address in the pool.";
                }
              }
            }
          }
        }
        choice provider-dhcp {
          description
            "Parameters related to DHCP-allocated addresses.
             IP addresses are allocated by DHCP, which is provided
             by the operator.";
          leaf dhcp-service-type {
            type enumeration {
              enum server {
                description
                  "Local DHCP server.";
              }
              enum relay {
                description
                  "Local DHCP relay.  DHCP requests are relayed to a
                   provider's server.";
              }
            }
            description
              "Indicates the type of DHCP service to be enabled on
               this access.";
          }
          choice service-type {
            description
              "Choice based on the DHCP service type.";
            case relay {
              description
                "Container for a list of the provider's DHCP servers
                 (i.e., 'dhcp-service-type' is set to 'relay').";
              leaf-list server-ip-address {
                type inet:ipv4-address;
                description
                  "IPv4 addresses of the provider's DHCP server, for
                   use by the local DHCP relay.";
              }
            }
          }
        }
        choice dhcp-relay {
          description
            "The DHCP relay is provided by the operator.";
          container customer-dhcp-servers {
            description
              "Container for a list of the customer's DHCP servers.";
            leaf-list server-ip-address {
              type inet:ipv4-address;
              description
                "IPv4 addresses of the customer's DHCP server.";
            }
          }
        }
      }
      case static-addresses {
        description
          "Lists the IPv4 addresses that are used.";
        list address {
          key "address-id";
          ordered-by user;
          description
            "Lists the IPv4 addresses that are used. The first
             address of the list is the primary address of the
             connection.";
          leaf address-id {
            type string;
            description
              "An identifier of the static IPv4 address.";
          }
          leaf customer-address {
            type inet:ipv4-address;
            description
              "An IPv4 address of the customer side.";
          }
        }
      }
    }
  }

  grouping ipv6-connection {
    description
      "IPv6-specific parameters.";
    leaf local-address {
      type inet:ipv6-address;
      description
        "IPv6 address of the provider side.";
    }
    uses ac-common:ipv6-allocation-type;
    choice allocation-type {
      description
        "Choice of the IPv6 address allocation.";
      case dynamic {
        description
          "When the addresses are allocated by DHCP or other
           dynamic means local to the infrastructure.";
        choice address-assign {
          description
            "A choice for how IPv6 addresses are assigned.";
          case number {
            leaf number-of-dynamic-address {
              type uint16;
              description
                "Specifies the number of IP addresses to be
                 assigned to the customer on this access.";
            }
          }
          case explicit {
            container customer-addresses {
              description
                "Container for customer addresses to be allocated
                 using DHCP.";
              list address-pool {
                key "pool-id";
                description
                  "Describes IP addresses to be dyncamically
                   allocated.

                   When only 'start-address' is present, it
                   represents a single address.

                   When both 'start-address' and 'end-address' are
                   specified, it implies a range inclusive of both
                   addresses.";
                leaf pool-id {
                  type string;
                  description
                    "A pool identifier for the address range from
                     'start-address' to 'end-address'.";
                }
                leaf start-address {
                  type inet:ipv6-address;
                  mandatory true;
                  description
                    "Indicates the first address in the pool.";
                }
                leaf end-address {
                  type inet:ipv6-address;
                  description
                    "Indicates the last address in the pool.";
                }
              }
            }
          }
        }
        choice provider-dhcp {
          description
            "Parameters related to DHCP-allocated addresses.
             IP addresses are allocated by DHCP, which is provided
             by the operator.";
          leaf dhcp-service-type {
            type enumeration {
              enum server {
                description
                  "Local DHCP server.";
              }
              enum relay {
                description
                  "Local DHCP relay. DHCP requests are relayed to
                   a provider's server.";
              }
            }
            description
              "Indicates the type of DHCP service to
               be enabled on this access.";
          }
          choice service-type {
            description
              "Choice based on the DHCP service type.";
            case relay {
              description
                "Container for a list of the provider's DHCP servers
                 (i.e., 'dhcp-service-type' is set to 'relay').";
              leaf-list server-ip-address {
                type inet:ipv6-address;
                description
                  "IPv6 addresses of the provider's DHCP server, for
                   use by the local DHCP relay.";
              }
            }
          }
        }
        choice dhcp-relay {
          description
            "The DHCP relay is provided by the operator.";
          container customer-dhcp-servers {
            description
              "Container for a list of the customer's DHCP servers.";
            leaf-list server-ip-address {
              type inet:ipv6-address;
              description
                "IPv6 addresses of the customer's DHCP server.";
            }
          }
        }
      }
      case static-addresses {
        description
          "Lists the IPv4 addresses that are used.";
        list address {
          key "address-id";
          ordered-by user;
          description
            "Lists the IPv6 addresses that are used. The first
             address of the list is the primary address of
             the connection.";
          leaf address-id {
            type string;
            description
              "An identifier of the static IPv4 address.";
          }
          leaf customer-address {
            type inet:ipv6-address;
            description
              "An IPv6 address of the customer side.";
          }
        }
      }
    }
  }

  grouping ip-connection {
    description
      "Defines IP connection parameters.";
    leaf l3-termination-point {
      type string;
      description
        "Specifies a reference to a local Layer 3 termination point,
         such as a bridge domain interface.";
    }
    container ipv4 {
      if-feature "vpn-common:ipv4";
      description
        "IPv4-specific parameters.";
      uses ipv4-connection;
    }
    container ipv6 {
      if-feature "vpn-common:ipv6";
      description
        "IPv6-specific parameters.";
      uses ipv6-connection;
    }
  }

  /* Routing */
  //BGP base parameters

  grouping bgp-base {
    description
      "Configuration specific to BGP.";
    leaf description {
      type string;
      description
        "Includes a description of the BGP session. This description
         is meant to be used for diagnostic purposes. The semantic
         of the description is local to an implementation.";
    }
    uses rt-pol:apply-policy-group;
    leaf local-as {
      type inet:as-number;
      description
        "Indicates a local AS Number (ASN), if an ASN distinct from
         the ASN configured at the AC level is needed.";
    }
    leaf peer-as {
      type inet:as-number;
      mandatory true;
      description
        "Indicates the customer's ASN when the customer requests BGP
         routing.";
    }
    leaf address-family {
      type identityref {
        base vpn-common:address-family;
      }
      description
        "This node contains the address families to be activated.
         'dual-stack' means that both IPv4 and IPv6 will be
         activated.";
    }
    leaf multihop {
      type uint8;
      description
        "Describes the number of IP hops allowed between a given BGP
         neighbor and the PE.";
    }
    leaf as-override {
      type boolean;
      description
        "Defines whether ASN override is enabled, i.e., replacing the
         ASN of the customer specified in the AS_PATH attribute with
         the local ASN.";
    }
    leaf allow-own-as {
      type uint8;
      description
        "If set, specifies the maximum number of occurrences of the
         provider's ASN that are permitted within the AS_PATH
         before it is rejected.";
    }
    leaf prepend-global-as {
      type boolean;
      description
        "In some situations, the ASN that is provided at the node
         level may be distinct from the ASN configured at the AC.
         When such ASNs are provided, they are both prepended to the
         BGP route updates for this AC. To disable that behavior,
         'prepend-global-as' must be set to 'false'.  In such a
         case, the ASN that is provided at the node level is not
         prepended to the BGP route updates for this access.";
    }
    leaf send-default-route {
      type boolean;
      description
        "Defines whether default routes can be advertised to a peer.
         If set, the default routes are advertised to a peer.";
    }
    leaf site-of-origin {
      when "../address-family = 'vpn-common:ipv4' "
         + "or 'vpn-common:dual-stack'" {
        description
          "Only applies if IPv4 is activated.";
      }
      type rt-types:route-origin;
      description
        "The Site of Origin attribute is encoded as a Route Origin
         Extended Community. It is meant to uniquely identify the
         set of routes learned from a site via a particular AC and
         is used to prevent routing loops.";
      reference
        "RFC 4364: BGP/MPLS IP Virtual Private Networks (VPNs),
                   Section 7";
    }
    leaf ipv6-site-of-origin {
      when "../address-family = 'vpn-common:ipv6' "
         + "or 'vpn-common:dual-stack'" {
        description
          "Only applies if IPv6 is activated.";
      }
      type rt-types:ipv6-route-origin;
      description
        "The IPv6 Site of Origin attribute is encoded as an IPv6
         Route Origin Extended Community.  It is meant to uniquely
         identify the set of routes learned from a site.";
      reference
        "RFC 5701: IPv6 Address Specific BGP Extended Community
                   Attribute";
    }
    list redistribute-connected {
      key "address-family";
      description
        "Indicates, per address family, the policy to follow for
         connected routes.";
      leaf address-family {
        type identityref {
          base vpn-common:address-family;
        }
        description
          "Indicates the address family.";
      }
      leaf enable {
        type boolean;
        description
          "Enables the redistribution of connected routes.";
      }
    }
    container bgp-max-prefix {
      description
        "Controls the behavior when a prefix maximum is reached.";
      leaf max-prefix {
        type uint32;
        description
          "Indicates the maximum number of BGP prefixes allowed in
           the BGP session.

           It allows control of how many prefixes can be received
           from a neighbor.

           If the limit is exceeded, the action indicated in
           'violate-action' will be followed.";
        reference
          "RFC 4271: A Border Gateway Protocol 4 (BGP-4),
                     Section 8.2.2";
      }
      leaf warning-threshold {
        type decimal64 {
          fraction-digits 5;
          range "0..100";
        }
        units "percent";
        description
          "When this value is reached, a warning notification will be
           triggered.";
      }
      leaf violate-action {
        type enumeration {
          enum warning {
            description
              "Only a warning message is sent to the peer when the
               limit is exceeded.";
          }
          enum discard-extra-paths {
            description
              "Discards extra paths when the limit is exceeded.";
          }
          enum restart {
            description
              "The BGP session restarts after the indicated time
               interval.";
          }
        }
        description
          "If the BGP neighbor 'max-prefix' limit is reached, the
           action indicated in 'violate-action' will be followed.";
      }
      leaf restart-timer {
        type uint32;
        units "seconds";
        description
          "Time interval after which the BGP session will be
           reestablished.";
      }
    }
    container bgp-timers {
      description
        "Includes two BGP timers.";
      leaf keepalive {
        type uint16 {
          range "0..21845";
        }
        units "seconds";
        description
          "This timer indicates the KEEPALIVE messages' frequency
           between a PE and a BGP peer.

           If set to '0', it indicates that KEEPALIVE messages are
           disabled.

           It is suggested that the maximum time between KEEPALIVE
           messages be one-third of the Hold Time interval.";
        reference
          "RFC 4271: A Border Gateway Protocol 4 (BGP-4),
                     Section 4.4";
      }
      leaf hold-time {
        type uint16 {
          range "0 | 3..65535";
        }
        units "seconds";
        description
          "Indicates the maximum number of seconds that may elapse
           between the receipt of successive KEEPALIVE and/or UPDATE
           messages from the peer.

           The Hold Time must be either zero or at least three
           seconds.";
        reference
          "RFC 4271: A Border Gateway Protocol 4 (BGP-4),
                     Section 4.2";
      }
    }
  }

  // RIP base parameters

  grouping rip-base {
    description
      "Configuration specific to RIP routing.";
    leaf address-family {
      type identityref {
        base vpn-common:address-family;
      }
      description
        "Indicates whether IPv4, IPv6, or both address families are
         to be activated.";
    }
    container timers {
      description
        "Indicates the RIP timers.";
      reference
        "RFC 2453: RIP Version 2";
      leaf update-interval {
        type uint16 {
          range "1..32767";
        }
        units "seconds";
        description
          "Indicates the RIP update time, i.e., the amount of time
           for which RIP updates are sent.";
      }
      leaf invalid-interval {
        type uint16 {
          range "1..32767";
        }
        units "seconds";
        description
          "The interval before a route is declared invalid after no
           updates are received. This value is at least three times
           the value for the 'update-interval' argument.";
      }
      leaf holddown-interval {
        type uint16 {
          range "1..32767";
        }
        units "seconds";
        description
          "Specifies the interval before better routes are
           released.";
      }
      leaf flush-interval {
        type uint16 {
          range "1..32767";
        }
        units "seconds";
        description
          "Indicates the RIP flush timer, i.e., the amount of time
           that must elapse before a route is removed from the
           routing table.";
      }
    }
    leaf default-metric {
      type uint8 {
        range "0..16";
      }
      description
        "Sets the default metric.";
    }
  }

  // routing profile

  grouping routing-profile {
    description
      "Defines routing protocols.";
    list routing-protocol {
      key "id";
      description
        "List of routing protocols used on the AC.";
      leaf id {
        type string;
        description
          "Unique identifier for the routing protocol.";
      }
      leaf type {
        type identityref {
          base vpn-common:routing-protocol-type;
        }
        description
          "Type of routing protocol.";
      }
      container bgp {
        when "derived-from-or-self(../type, "
           + "'vpn-common:bgp-routing')" {
          description
            "Only applies when the protocol is BGP.";
        }
        description
          "Configuration specific to BGP.";
        uses bgp-base;
      }
      container ospf {
        when "derived-from-or-self(../type, "
           + "'vpn-common:ospf-routing')" {
          description
            "Only applies when the protocol is OSPF.";
        }
        description
          "Configuration specific to OSPF.";
        uses ac-common:ospf-basic;
        leaf max-lsa {
          type uint32 {
            range "1..4294967294";
          }
          description
            "Maximum number of allowed Link State Advertisements
             (LSAs) that the OSPF instance will accept.";
        }
      }
      container isis {
        when "derived-from-or-self(../type, "
           + "'vpn-common:isis-routing')" {
          description
            "Only applies when the protocol is IS-IS.";
        }
        description
          "Configuration specific to IS-IS.";
        uses ac-common:isis-basic;
        leaf level {
          type identityref {
            base vpn-common:isis-level;
          }
          description
            "Can be 'level-1', 'level-2', or 'level-1-2'.";
          reference
            "RFC 9181: A Common YANG Data Model for Layer 2
                       and Layer 3 VPNs";
        }
        leaf metric {
          type uint16;
          description
            "Metric of the AC. It is used in the routing state
             calculation and path selection.";
        }
        leaf mode {
          type enumeration {
            enum active {
              description
                "The interface sends or receives IS-IS protocol
                 control packets.";
            }
            enum passive {
              description
                "Suppresses the sending of IS-IS updates through the
                 specified interface.";
            }
          }
          description
            "IS-IS interface mode type.";
        }
      }
      container rip {
        when "derived-from-or-self(../type, "
           + "'vpn-common:rip-routing')" {
          description
            "Only applies when the protocol is RIP.";
        }
        description
          "Configuration specific to RIP routing.";
        uses rip-base;
      }
      container vrrp {
        when "derived-from-or-self(../type, "
           + "'vpn-common:vrrp-routing')" {
          description
            "Only applies when the protocol is the Virtual Router
             Redundancy Protocol (VRRP).";
        }
        description
          "Configuration specific to VRRP.";
        reference
          "RFC 5798: Virtual Router Redundancy Protocol (VRRP)
                     Version 3 for IPv4 and IPv6";
        leaf address-family {
          type identityref {
            base vpn-common:address-family;
          }
          description
            "Indicates whether IPv4, IPv6, or both address families
             are to be enabled.";
        }
        leaf ping-reply {
          type boolean;
          description
            "Controls whether the VRRP speaker should reply to ping
             requests.";
        }
      }
    }
  }

  grouping routing {
    description
      "Defines routing protocols.";
    list routing-protocol {
      key "id";
      description
        "List of routing protocols used on the AC.";
      leaf id {
        type string;
        description
          "Unique identifier for the routing protocol.";
      }
      leaf type {
        type identityref {
          base vpn-common:routing-protocol-type;
        }
        description
          "Type of routing protocol.";
      }
      list routing-profiles {
        key "id";
        description
          "Routing profiles.";
        leaf id {
          type routing-profile-reference;
          description
            "Routing profile to be used.";
        }
        leaf type {
          type identityref {
            base vpn-common:ie-type;
          }
          description
            "Import, export, or both.";
        }
      }
      container static {
        when "derived-from-or-self(../type, "
           + "'vpn-common:static-routing')" {
          description
            "Only applies when the protocol is a static routing
             protocol.";
        }
        description
          "Configuration specific to static routing.";
        container cascaded-lan-prefixes {
          description
            "LAN prefixes from the customer.";
          list ipv4-lan-prefixes {
            if-feature "vpn-common:ipv4";
            key "lan next-hop";
            description
              "List of LAN prefixes for the site.";
            uses ac-common:ipv4-static-rtg-entry;
            leaf bfd-enable {
              if-feature "vpn-common:bfd";
              type boolean;
              description
                "Enables BFD.";
            }
            leaf preference {
              type uint32;
              description
                "Indicates the preference associated with the static
                 route.";
            }
            uses vpn-common:service-status;
          }
          list ipv6-lan-prefixes {
            if-feature "vpn-common:ipv6";
            key "lan next-hop";
            description
              "List of LAN prefixes for the site.";
            uses ac-common:ipv4-static-rtg-entry;
            leaf bfd-enable {
              if-feature "vpn-common:bfd";
              type boolean;
              description
                "Enables BFD.";
            }
            leaf preference {
              type uint32;
              description
                "Indicates the preference associated with the static
                 route.";
            }
            uses vpn-common:service-status;
          }
        }
      }
      container bgp {
        when "derived-from-or-self(../type, "
           + "'vpn-common:bgp-routing')" {
          description
            "Only applies when the protocol is BGP.";
        }
        description
          "Configuration specific to BGP.";
        container peer-groups {
          description
            "Configuration for BGP peer-groups";
          list peer-group {
            key "name";
            description
              "List of BGP peer-groups configured on the local
               system - uniquely identified by peer-group name";
            leaf name {
              type string;
              description
                "Name of the BGP peer-group";
            }
            leaf local-address {
              type union {
                type inet:ip-address;
                type if:interface-ref;
              }
              description
                "Sets the local IP address to use for the BGP
                 transport session. This may be expressed as either
                 an IP address or a reference to an interface.";
            }
            uses bgp-base;
            uses ac-common:bgp-authentication;
          }
        }
        list neighbor {
          key "remote-address";
          description
            "List of BGP neighbors.";
          leaf remote-address {
            type inet:ip-address;
            description
              "The remote IP address of this entry's BGP peer.";
          }
          leaf local-address {
            type union {
              type inet:ip-address;
              type if:interface-ref;
            }
            description
              "Sets the local IP address to use for
               the BGP transport session.  This may be
               expressed as either an IP address or a
               reference to an interface.";
          }
          leaf peer-group {
            type leafref {
              path "../../peer-groups/peer-group/name";
            }
            description
              "The peer-group with which this neighbor is
               associated.";
          }
          uses bgp-base;
          uses ac-common:bgp-authentication;
          uses vpn-common:service-status;
        }
      }
      container ospf {
        when "derived-from-or-self(../type, "
           + "'vpn-common:ospf-routing')" {
          description
            "Only applies when the protocol is OSPF.";
        }
        description
          "Configuration specific to OSPF.";
        uses ac-common:ospf-basic;
        container sham-links {
          if-feature "vpn-common:rtg-ospf-sham-link";
          description
            "List of sham links.";
          reference
            "RFC 4577: OSPF as the Provider/Customer Edge Protocol
                       for BGP/MPLS IP Virtual Private Networks
                       (VPNs), Section 4.2.7
             RFC 6565: OSPFv3 as a Provider Edge to Customer Edge
                       (PE-CE) Routing Protocol, Section 5";
          list sham-link {
            key "target-site";
            description
              "Creates a sham link with another
               site.";
            leaf target-site {
              type string;
              description
                "Target site for the sham link connection. The site
                 is referred to by its identifier.";
            }
            leaf metric {
              type uint16;
              description
                "Metric of the sham link. It is used in the routing
                 state calculation and path selection.";
              reference
                "RFC 4577: OSPF as the Provider/Customer Edge
                           Protocol for BGP/MPLS IP Virtual Private
                           Networks (VPNs), Section 4.2.7.3
                 RFC 6565: OSPFv3 as a Provider Edge to Customer Edge
                           (PE-CE) Routing Protocol, Section 5.2";
            }
          }
        }
        leaf max-lsa {
          type uint32 {
            range "1..4294967294";
          }
          description
            "Maximum number of allowed Link State Advertisements
             (LSAs) that the OSPF instance will accept.";
        }
        uses ac-common:ospf-authentication;
        uses vpn-common:service-status;
      }
      container isis {
        when "derived-from-or-self(../type, "
           + "'vpn-common:isis-routing')" {
          description
            "Only applies when the protocol is
             IS-IS.";
        }
        description
          "Configuration specific to IS-IS.";
        uses ac-common:isis-basic;
        leaf level {
          type identityref {
            base vpn-common:isis-level;
          }
          description
            "Can be 'level-1', 'level-2', or 'level-1-2'.";
          reference
            "RFC 9181: A Common YANG Data Model for Layer 2 and
                       Layer 3 VPNs";
        }
        leaf metric {
          type uint16;
          description
            "Metric of the PE-CE link. It is used in the routing
             state calculation and path selection.";
        }
        leaf mode {
          type enumeration {
            enum active {
              description
                "The interface sends or receives
                 IS-IS protocol control packets.";
            }
            enum passive {
              description
                "Suppresses the sending of IS-IS
                 updates through the specified
                 interface.";
            }
          }
          description
            "IS-IS interface mode type.";
        }
        uses ac-common:isis-authentication;
        uses vpn-common:service-status;
      }
      container rip {
        when "derived-from-or-self(../type, "
           + "'vpn-common:rip-routing')" {
          description
            "Only applies when the protocol is RIP.
             For IPv4, the model assumes that RIP
             version 2 is used.";
        }
        description
          "Configuration specific to RIP routing.";
        uses rip-base;
        uses ac-common:rip-authentication;
        uses vpn-common:service-status;
      }
      container vrrp {
        when "derived-from-or-self(../type, "
           + "'vpn-common:vrrp-routing')" {
          description
            "Only applies when the protocol is the VRRP.";
        }
        description
          "Configuration specific to VRRP.";
        reference
          "RFC 5798: Virtual Router Redundancy Protocol (VRRP)
                     Version 3 for IPv4 and IPv6";
        leaf address-family {
          type identityref {
            base vpn-common:address-family;
          }
          description
            "Indicates whether IPv4, IPv6, or both address families
             are to be enabled.";
        }
        leaf vrrp-group {
          type uint8 {
            range "1..255";
          }
          description
            "Includes the VRRP group identifier.";
        }
        leaf backup-peer {
          type inet:ip-address;
          description
            "Indicates the IP address of the peer.";
        }
        leaf-list virtual-ip-address {
          type inet:ip-address;
          description
            "Virtual IP addresses for a single VRRP
             group.";
          reference
            "RFC 5798: Virtual Router Redundancy Protocol (VRRP)
                       Version 3 for IPv4 and IPv6, Sections 1.2
                       and 1.3";
        }
        leaf priority {
          type uint8 {
            range "1..254";
          }
          description
            "Sets the local priority of the VRRP speaker.";
        }
        leaf ping-reply {
          type boolean;
          description
            "Controls whether the VRRP speaker should reply to ping
             requests.";
        }
        uses vpn-common:service-status;
      }
    }
  }

  // OAM

  grouping bfd {
    description
      "Grouping for BFD.";
    leaf session-type {
      type identityref {
        base vpn-common:bfd-session-type;
      }
      description
        "Specifies the BFD session type.";
    }
    leaf desired-min-tx-interval {
      type uint32;
      units "microseconds";
      description
        "The minimum interval between transmissions of BFD Control
         packets, as desired by the operator.";
      reference
        "RFC 5880: Bidirectional Forwarding Detection (BFD),
                   Section 6.8.7";
    }
    leaf required-min-rx-interval {
      type uint32;
      units "microseconds";
      description
        "The minimum interval between received BFD Control packets
         that the PE should support.";
      reference
        "RFC 5880: Bidirectional Forwarding Detection (BFD),
                   Section 6.8.7";
    }
    leaf local-multiplier {
      type uint8 {
        range "1..255";
      }
      description
        "Specifies the detection multiplier that is transmitted to a
         BFD peer.

         The detection interval for the receiving BFD peer is
         calculated by multiplying the value of the negotiated
         transmission interval by the received detection multiplier
         value.";
      reference
        "RFC 5880: Bidirectional Forwarding Detection (BFD),
                   Section 6.8.7";
    }
    leaf holdtime {
      type uint32;
      units "milliseconds";
      description
        "Expected BFD holdtime.

         The customer may impose some fixed values for the holdtime
         period if the provider allows the customer to use this
         function.";
      reference
        "RFC 5880: Bidirectional Forwarding Detection (BFD),
                   Section 6.8.18";
    }
  }

  // OAM

  grouping oam {
    description
      "Defines the Operations, Administration, and Maintenance
       (OAM) mechanisms used.";
    container bfd {
      description
        "Container for BFD.";
      leaf profile {
        type bfd-profile-reference;
        description
          "Well-known service provider profile name.";
      }
      uses bfd;
      container authentication {
        presence "Enables BFD authentication";
        description
          "Parameters for BFD authentication.";
        leaf key-chain {
          type key-chain:key-chain-ref;
          description
            "Name of the key chain.";
        }
        leaf meticulous {
          type boolean;
          description
            "Enables meticulous mode.";
          reference
            "RFC 5880: Bidirectional Forwarding Detection (BFD),
                       Section 6.7";
        }
      }
      uses vpn-common:service-status;
    }
  }

  // security

  grouping security {
    description
      "Security parameters for an AC.";
    container encryption {
      if-feature "vpn-common:encryption";
      description
        "Container for AC encryption.";
      leaf enabled {
        type boolean;
        description
          "If set to 'true', traffic encryption on the connection is
           required. Otherwise, it is disabled.";
      }
      leaf layer {
        when "../enabled = 'true'" {
          description
            "Included only when encryption is enabled.";
        }
        type enumeration {
          enum layer2 {
            description
              "Encryption occurs at Layer 2.";
          }
          enum layer3 {
            description
              "Encryption occurs at Layer 3. For example, IPsec
               may be used when a customer requests Layer 3
               encryption.";
          }
        }
        description
          "Indicates the layer on which encryption is applied.";
      }
    }
    container encryption-profile {
      when "../encryption/enabled = 'true'" {
        description
          "Indicates the layer on which encryption is enabled.";
      }
      description
        "Container for the encryption profile.";
      choice profile {
        description
          "Choice for the encryption profile.";
        case provider-profile {
          leaf profile-name {
            type encryption-profile-reference;
            description
              "Name of the provider's profile to be applied.";
          }
        }
        case customer-profile {
          leaf customer-key-chain {
            type key-chain:key-chain-ref;
            description
              "Customer-supplied key chain.";
          }
        }
      }
    }
  }

  // AC profile

  grouping ac-profile {
    description
      "Grouping for attachment circuit profiles.";
    container l2-connection {
      description
        "Defines Layer 2 protocols and parameters that
         are required to enable AC connectivity.";
      //uses l2-connection;
    }
    container ip-connection {
      description
        "Defines IP connection parameters.";
      //uses l3-connection;
    }
    container routing-protocols {
      description
        "Defines routing protocols.";
      uses routing-profile;
    }
    container oam {
      description
        "Defines the OAM mechanisms used for the AC profile.";
      container bfd {
        if-feature "vpn-common:bfd";
        description
          "Container for BFD.";
        uses bfd;
      }
    }
  }

  //AC network provisioning

  grouping ac {
    description
      "Grouping for attachment circuits.";
    leaf description {
      type string;
      description
        "Associates a description with an AC.";
    }
    container l2-connection {
      description
        "Defines Layer 2 protocols and parameters that are required
         to enable AC connectivity.";
      uses l2-connection-if-ref;
    }
    container ip-connection {
      description
        "Defines IP connection parameters.";
      uses ip-connection;
    }
    container routing-protocols {
      description
        "Defines routing protocols.";
      uses routing;
    }
    container oam {
      description
        "Defines the OAM mechanisms used for the AC.";
      uses oam;
    }
    container security {
      description
        "AC-specific security parameters.";
      uses security;
    }
    container service {
      description
        "AC-specific bandwith parameters.";
      leaf mtu {
        type uint32;
        units "bytes";
        description
          "Layer 2 MTU.";
      }
      uses ac-svc:bandwidth;
      container qos {
        if-feature "vpn-common:qos";
        description
          "QoS configuration.";
        container qos-profiles {
          description
            "QoS profile configuration.";
          list qos-profile {
            key "profile";
            description
              "Points to a QoS profile.";
            leaf profile {
              type qos-profile-reference;
              description
                "QoS profile to be used.";
            }
            leaf direction {
              type identityref {
                base vpn-common:qos-profile-direction;
              }
              description
                "The direction to which the QoS profile
                 is applied.";
            }
          }
        }
      }
      container access-control-list {
        description
          "Container for the Access Control List (ACL).";
        container acl-profiles {
          description
            "ACL profile configuration.";
          list acl-profile {
            key "profile";
            description
              "Points to an ACL profile.";
            leaf profile {
              type forwarding-profile-reference;
              description
                "Forwarding profile to be used.";
            }
          }
        }
      }
    }
  }

  augment "/nw:networks/nw:network" {
    description
      "Add a list of profiles.";
    container specific-provisioning-profiles {
      description
        "Contains a set of valid profiles to reference in the AC
         activation.";
      uses ac-common:ac-profile-cfg;
    }
    list ac-profile {
      key "name";
      description
        "Specifies a list of AC profiles.";
      leaf name {
        type string;
        description
          "Name of the AC.";
      }
      uses ac-ntw:ac-profile;
    }
  }

  augment "/nw:networks/nw:network/nw:node" {
    when '../nw:network-types/sap:sap-network' {
      description
        "Augmentation parameters apply only for SAP networks.";
    }
    description
      "Augments nodes with AC provisioning details.";
    list ac {
      key "name";
      description
        "List of ACs.";
      leaf name {
        type string;
        description
          "A name that identifies the AC locally.";
      }
      leaf ac-svc-ref {
        type ac-svc:attachment-circuit-reference;
        description
          "A reference to the AC as exposed at the service level.";
      }
      list ac-profile {
        key "profile-id";
        description
          "List of AC profiles.";
        leaf profile-id {
          type ac-profile-reference;
          description
            "A reference to an AC profile.";
        }
      }
      leaf ac-parent-ref {
        type ac-ntw:attachment-circuit-reference;
        description
          "Specifies the parent AC that is inherited by an AC.
           Parent ACs are used, e.g., in contexts where multiple
           CEs are terminating the same AC, but some specific
           information is required for each peer SAP.";
      }
      leaf-list peer-sap-id {
        type string;
        description
          "One or more peer SAPs can be indicated.";
      }
      list group {
        key "group-id";
        description
          "List of group-ids.";
        leaf group-id {
          type string;
          description
            "Indicates the group-id to which the AC belongs.";
        }
        leaf precedence {
          type identityref {
            base ac-common:precedence-type;
          }
          description
            "Defines redundancy of an AC.";
        }
      }
      uses vpn-common:service-status;
      uses ac-ntw:ac;
    }
  }

  augment "/nw:networks/nw:network/nw:node"
        + "/sap:service/sap:sap" {
    when '../../../nw:network-types/sap:sap-network' {
      description
        "Augmentation parameters apply only for SAP networks.";
    }
    description
      "Augments SAPs with AC provisioning details.";
    leaf-list ac {
      type ac-ntw:attachment-circuit-reference;
      description
        "Specifies the ACs that are terminated by the SAP.";
    }
  }
}
<CODE ENDS>

6. Security Considerations

The YANG module specified in this document defines a schema for data that is designed to be accessed via network management protocols such as NETCONF [RFC6241] or RESTCONF [RFC8040]. The lowest NETCONF layer is the secure transport layer, and the mandatory-to-implement secure transport is Secure Shell (SSH) [RFC6242]. The lowest RESTCONF layer is HTTPS, and the mandatory-to-implement secure transport is TLS [RFC8446].

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.

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). 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. These are the subtrees and data nodes and their sensitivity/ vulnerability in the "ietf-ac-ntw" module:

'specific-provisioning-profiles':

This container includes a set of sensitive data that influence how an AC is delivered. For example, an attacker who has access to these data nodes may be able to manipulate routing policies, QoS policies, or encryption properties. These data nodes are defined with "nacm:default-deny- write" tagging [I-D.ietf-opsawg-teas-common-ac].

'ac':

An attacker who is able to access network nodes can undertake various attacks, such as modify the attributes of an AC (e.g., QoS, bandwidth, routing protocols, keying material), leading to malfunctioning of services that are delivered over that AC and therefore to Service Level Agreement (SLA) violations. In addition, an attacker could attempt to add a new AC. : In addition to using NACM to prevent unauthorized access, 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. These are the subtrees and data nodes and their sensitivity/vulnerability in the "ietf-ac-svc" module:

'ac':

Unauthorized access to this subtree can disclose the identity of a customer 'peer-sap-id'.

'l2-connection' and 'ip-connection':

An attacker can retrieve privacy-related information, which can be used to track a customer. Disclosing such information may be considered a violation of the customer-provider trust relationship.

'keying-material':

An attacker can retrieve the cryptographic keys protecting an AC (routing, in particular). These keys could be used to inject spoofed routing advertisements.

Several data nodes ('bgp', 'ospf', 'isis', and 'rip') rely upon [RFC8177] for authentication purposes. As such, the AC network module inherits the security considerations discussed in Section 5 of [RFC8177]. Also, these data nodes support supplying explicit keys as strings in ASCII format. The use of keys in hexadecimal string format would afford greater key entropy with the same number of key-string octets. However, such a format is not included in this version of the AC network model, because it is not supported by the underlying device modules (e.g., [RFC8695]).

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-ntw
   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-ntw
   Namespace:  urn:ietf:params:xml:ns:yang:ietf-ac-ntw
   Prefix:  ac-ntw
   Maintained by IANA?  N
   Reference:  RFC XXXX

8. References

8.1. Normative References

[I-D.ietf-opsawg-teas-attachment-circuit]
Boucadair, M., Roberts, R., de Dios, O. G., Barguil, S., and B. Wu, "YANG Data Models for 'Attachment Circuits'-as-a-Service (ACaaS)", Work in Progress, Internet-Draft, draft-ietf-opsawg-teas-attachment-circuit-03, , <https://datatracker.ietf.org/doc/html/draft-ietf-opsawg-teas-attachment-circuit-03>.
[I-D.ietf-opsawg-teas-common-ac]
Boucadair, M., Roberts, R., de Dios, O. G., Barguil, S., and B. Wu, "A Common YANG Data Model for Attachment Circuits", Work in Progress, Internet-Draft, draft-ietf-opsawg-teas-common-ac-02, , <https://datatracker.ietf.org/doc/html/draft-ietf-opsawg-teas-common-ac-02>.
[IEEE802.1Qcp]
IEEE, "IEEE Standard for Local and metropolitan area networks--Bridges and Bridged Networks--Amendment 30: YANG Data Model", , <https://doi.org/10.1109/IEEESTD.2018.8467507>.
[RFC2080]
Malkin, G. and R. Minnear, "RIPng for IPv6", RFC 2080, DOI 10.17487/RFC2080, , <https://www.rfc-editor.org/rfc/rfc2080>.
[RFC2119]
Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, , <https://www.rfc-editor.org/rfc/rfc2119>.
[RFC2453]
Malkin, G., "RIP Version 2", STD 56, RFC 2453, DOI 10.17487/RFC2453, , <https://www.rfc-editor.org/rfc/rfc2453>.
[RFC3688]
Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, DOI 10.17487/RFC3688, , <https://www.rfc-editor.org/rfc/rfc3688>.
[RFC4271]
Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A Border Gateway Protocol 4 (BGP-4)", RFC 4271, DOI 10.17487/RFC4271, , <https://www.rfc-editor.org/rfc/rfc4271>.
[RFC4364]
Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private Networks (VPNs)", RFC 4364, DOI 10.17487/RFC4364, , <https://www.rfc-editor.org/rfc/rfc4364>.
[RFC4552]
Gupta, M. and N. Melam, "Authentication/Confidentiality for OSPFv3", RFC 4552, DOI 10.17487/RFC4552, , <https://www.rfc-editor.org/rfc/rfc4552>.
[RFC4577]
Rosen, E., Psenak, P., and P. Pillay-Esnault, "OSPF as the Provider/Customer Edge Protocol for BGP/MPLS IP Virtual Private Networks (VPNs)", RFC 4577, DOI 10.17487/RFC4577, , <https://www.rfc-editor.org/rfc/rfc4577>.
[RFC5701]
Rekhter, Y., "IPv6 Address Specific BGP Extended Community Attribute", RFC 5701, DOI 10.17487/RFC5701, , <https://www.rfc-editor.org/rfc/rfc5701>.
[RFC5709]
Bhatia, M., Manral, V., Fanto, M., White, R., Barnes, M., Li, T., and R. Atkinson, "OSPFv2 HMAC-SHA Cryptographic Authentication", RFC 5709, DOI 10.17487/RFC5709, , <https://www.rfc-editor.org/rfc/rfc5709>.
[RFC5798]
Nadas, S., Ed., "Virtual Router Redundancy Protocol (VRRP) Version 3 for IPv4 and IPv6", RFC 5798, DOI 10.17487/RFC5798, , <https://www.rfc-editor.org/rfc/rfc5798>.
[RFC5880]
Katz, D. and D. Ward, "Bidirectional Forwarding Detection (BFD)", RFC 5880, DOI 10.17487/RFC5880, , <https://www.rfc-editor.org/rfc/rfc5880>.
[RFC5925]
Touch, J., Mankin, A., and R. Bonica, "The TCP Authentication Option", RFC 5925, DOI 10.17487/RFC5925, , <https://www.rfc-editor.org/rfc/rfc5925>.
[RFC6020]
Bjorklund, M., Ed., "YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)", RFC 6020, DOI 10.17487/RFC6020, , <https://www.rfc-editor.org/rfc/rfc6020>.
[RFC6241]
Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed., and A. Bierman, Ed., "Network Configuration Protocol (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, , <https://www.rfc-editor.org/rfc/rfc6241>.
[RFC6242]
Wasserman, M., "Using the NETCONF Protocol over Secure Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, , <https://www.rfc-editor.org/rfc/rfc6242>.
[RFC6565]
Pillay-Esnault, P., Moyer, P., Doyle, J., Ertekin, E., and M. Lundberg, "OSPFv3 as a Provider Edge to Customer Edge (PE-CE) Routing Protocol", RFC 6565, DOI 10.17487/RFC6565, , <https://www.rfc-editor.org/rfc/rfc6565>.
[RFC6991]
Schoenwaelder, J., Ed., "Common YANG Data Types", RFC 6991, DOI 10.17487/RFC6991, , <https://www.rfc-editor.org/rfc/rfc6991>.
[RFC7166]
Bhatia, M., Manral, V., and A. Lindem, "Supporting Authentication Trailer for OSPFv3", RFC 7166, DOI 10.17487/RFC7166, , <https://www.rfc-editor.org/rfc/rfc7166>.
[RFC7474]
Bhatia, M., Hartman, S., Zhang, D., and A. Lindem, Ed., "Security Extension for OSPFv2 When Using Manual Key Management", RFC 7474, DOI 10.17487/RFC7474, , <https://www.rfc-editor.org/rfc/rfc7474>.
[RFC8040]
Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF Protocol", RFC 8040, DOI 10.17487/RFC8040, , <https://www.rfc-editor.org/rfc/rfc8040>.
[RFC8077]
Martini, L., Ed. and G. Heron, Ed., "Pseudowire Setup and Maintenance Using the Label Distribution Protocol (LDP)", STD 84, RFC 8077, DOI 10.17487/RFC8077, , <https://www.rfc-editor.org/rfc/rfc8077>.
[RFC8174]
Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, , <https://www.rfc-editor.org/rfc/rfc8174>.
[RFC8177]
Lindem, A., Ed., Qu, Y., Yeung, D., Chen, I., and J. Zhang, "YANG Data Model for Key Chains", RFC 8177, DOI 10.17487/RFC8177, , <https://www.rfc-editor.org/rfc/rfc8177>.
[RFC8294]
Liu, X., Qu, Y., Lindem, A., Hopps, C., and L. Berger, "Common YANG Data Types for the Routing Area", RFC 8294, DOI 10.17487/RFC8294, , <https://www.rfc-editor.org/rfc/rfc8294>.
[RFC8341]
Bierman, A. and M. Bjorklund, "Network Configuration Access Control Model", STD 91, RFC 8341, DOI 10.17487/RFC8341, , <https://www.rfc-editor.org/rfc/rfc8341>.
[RFC8342]
Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K., and R. Wilton, "Network Management Datastore Architecture (NMDA)", RFC 8342, DOI 10.17487/RFC8342, , <https://www.rfc-editor.org/rfc/rfc8342>.
[RFC8343]
Bjorklund, M., "A YANG Data Model for Interface Management", RFC 8343, DOI 10.17487/RFC8343, , <https://www.rfc-editor.org/rfc/rfc8343>.
[RFC8446]
Rescorla, E., "The Transport Layer Security (TLS) Protocol Version 1.3", RFC 8446, DOI 10.17487/RFC8446, , <https://www.rfc-editor.org/rfc/rfc8446>.
[RFC9067]
Qu, Y., Tantsura, J., Lindem, A., and X. Liu, "A YANG Data Model for Routing Policy", RFC 9067, DOI 10.17487/RFC9067, , <https://www.rfc-editor.org/rfc/rfc9067>.
[RFC9181]
Barguil, S., Gonzalez de Dios, O., Ed., Boucadair, M., Ed., and Q. Wu, "A Common YANG Data Model for Layer 2 and Layer 3 VPNs", RFC 9181, DOI 10.17487/RFC9181, , <https://www.rfc-editor.org/rfc/rfc9181>.
[RFC9182]
Barguil, S., Gonzalez de Dios, O., Ed., Boucadair, M., Ed., Munoz, L., and A. Aguado, "A YANG Network Data Model for Layer 3 VPNs", RFC 9182, DOI 10.17487/RFC9182, , <https://www.rfc-editor.org/rfc/rfc9182>.
[RFC9291]
Boucadair, M., Ed., Gonzalez de Dios, O., Ed., Barguil, S., and L. Munoz, "A YANG Network Data Model for Layer 2 VPNs", RFC 9291, DOI 10.17487/RFC9291, , <https://www.rfc-editor.org/rfc/rfc9291>.
[RFC9408]
Boucadair, M., Ed., Gonzalez de Dios, O., Barguil, S., Wu, Q., and V. Lopez, "A YANG Network Data Model for Service Attachment Points (SAPs)", RFC 9408, DOI 10.17487/RFC9408, , <https://www.rfc-editor.org/rfc/rfc9408>.

8.2. Informative References

[AC-Ntw-Tree]
"Full Network Attachment Circuit Tree Structure", , <https://github.com/boucadair/attachment-circuit-model/blob/main/yang/full-trees/ac-ntw-without-groupings.txt>.
[PYANG]
"pyang", , <https://github.com/mbj4668/pyang>.
[RFC3644]
Snir, Y., Ramberg, Y., Strassner, J., Cohen, R., and B. Moore, "Policy Quality of Service (QoS) Information Model", RFC 3644, DOI 10.17487/RFC3644, , <https://www.rfc-editor.org/rfc/rfc3644>.
[RFC4862]
Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless Address Autoconfiguration", RFC 4862, DOI 10.17487/RFC4862, , <https://www.rfc-editor.org/rfc/rfc4862>.
[RFC7665]
Halpern, J., Ed. and C. Pignataro, Ed., "Service Function Chaining (SFC) Architecture", RFC 7665, DOI 10.17487/RFC7665, , <https://www.rfc-editor.org/rfc/rfc7665>.
[RFC7880]
Pignataro, C., Ward, D., Akiya, N., Bhatia, M., and S. Pallagatti, "Seamless Bidirectional Forwarding Detection (S-BFD)", RFC 7880, DOI 10.17487/RFC7880, , <https://www.rfc-editor.org/rfc/rfc7880>.
[RFC8340]
Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams", BCP 215, RFC 8340, DOI 10.17487/RFC8340, , <https://www.rfc-editor.org/rfc/rfc8340>.
[RFC8695]
Liu, X., Sarda, P., and V. Choudhary, "A YANG Data Model for the Routing Information Protocol (RIP)", RFC 8695, DOI 10.17487/RFC8695, , <https://www.rfc-editor.org/rfc/rfc8695>.
[RFC8969]
Wu, Q., Ed., Boucadair, M., Ed., Lopez, D., Xie, C., and L. Geng, "A Framework for Automating Service and Network Management with YANG", RFC 8969, DOI 10.17487/RFC8969, , <https://www.rfc-editor.org/rfc/rfc8969>.

Appendix A. Examples

A.1. VPLS

Let's consider the example depicted in Figure 18 with two customer terminating points (CE1 and CE2). Let's also assume that the bearers to attach these CEs to the provider network are already in place. References to the identify these bearers are shown in the figure.

            .-----.   .--------------.   .-----.
.----.      | PE1 +===+              +===+ PE2 |      .----.
| CE1+------+"450"|   |     MPLS     |   |"451"+------+ CE2|
'----'   ^  '-----'   |              |   '-----'   ^  '----'
         |            |     Core     |             |
    Bearer:1234       '--------------'         Bearer:5678
Figure 18: Topology Example

The AC service model [I-D.ietf-opsawg-teas-attachment-circuit] can be used by the provider to manage and expose the ACs over existing bearers as shown in Figure 19.

{
   "ietf-ac-svc:attachment-circuits":{
      "ac-group-profile":[
         {
            "name":"an-ac-profile",
            "l2-connection":{
               "encapsulation":{
                  "encap-type":"ietf-vpn-common:dot1q",
                  "dot1q":{
                     "tag-type":"ietf-vpn-common:c-vlan",
                     "cvlan-id":550
                  }
               }
            },
            "service":{
               "mtu":1550,
               "svc-pe-to-ce-bandwidth":{
                  "pe-to-ce-bandwidth":[
                     {
                        "bw-type":"ietf-vpn-common:bw-per-port",
                        "cir":"20480000"
                     }
                  ]
               },
               "svc-ce-to-pe-bandwidth":{
                  "ce-to-pe-bandwidth":[
                     {
                        "bw-type":"ietf-vpn-common:bw-per-port",
                        "cir":"20480000"
                     }
                  ]
               },
               "qos":{
                  "qos-profile":{
                     "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"
            }
         }
      ]
   }
}
Figure 19: ACs Created Using ACaaS

The provisionned AC at PE1 can be retrieved using the AC network model as depicted in Figure 20. A similar query can be used for the AC at PE2.

{
   "ietf-ac-ntw:ac":[
      {
         "name":"ac-11",
         "ac-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":{
               "pe-to-ce-bandwidth":[
                  {
                     "cir":"20480000"
                  }
               ]
            },
            "svc-ce-to-pe-bandwidth":{
               "ce-to-pe-bandwidth":[
                  {
                     "cir":"20480000"
                  }
               ]
            },
            "qos":{
               "qos-profile":{
                  "qos-profile":[
                     {
                        "profile":"QoS_Profile_A",
                        "direction":"ietf-vpn-common:both"
                     }
                  ]
               }
            }
         }
      }
   ]
}
Figure 20: Example of AC Network Response (Message Body)

Also, the AC network model can be used to retrieve the list of SAPs to which the ACs are bound as shown in Figure 20.

{
   "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-1"
               ]
            }
         ]
      }
   ]
}
Figure 21: Example of AC Network Response to Retrieve the SAP (Message Body)

A.2. Parent AC

In reference to the topology depicted in Figure 1, PE2 has a SAP which terminates an AC with two peer SAPs (CE2 and CE5). In order to control data that is specific to each of these peer SAPs over the same AC, child ACs can be instantiated as depicted in Figure 22.

{
   "ietf-ac-ntw:ac":[
      {
         "name":"ac-1",
         "peer-sap-id":[
            "CE2",
            "CE5"
         ],
         "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"
         }
      },
      {
         "name":"ac-1-to-ce2",
         "ac-parent-ref":"ac-1",
         "peer-sap-id":[
            "CE2"
         ]
      },
      {
         "name":"ac-1-to-ce5",
         "ac-parent-ref":"ac-1",
         "peer-sap-id":[
            "CE5"
         ]
      }
   ]
}
Figure 22: Example of Child ACs

Figure 23 shows how to bind the parent AC to a SAP.

{
   "ietf-sap-ntw:service":[
      {
         "service-type":"ietf-vpn-common:l3vpn",
         "sap":[
            {
               "sap-id":"sap#14587",
               "description":"A 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-1"
               ]
            }
         ]
      }
   ]
}
Figure 23: Example of Binding Parent AC to SAPs

Acknowledgments

This document builds on [RFC9182] and [RFC9291].

Thanks to Moti Morgenstern for the review and comments.

Contributors

Victor Lopez
Nokia
Ivan Bykov
Ribbon Communications
Qin Wu
Huawei
Ogaki Kenichi
KDDI
Luis Angel Munoz
Vodafone

Authors' Addresses

Mohamed Boucadair (editor)
Orange
Richard Roberts
Juniper
Oscar Gonzalez de Dios
Telefonica
Samier Barguil Giraldo
Nokia
Bo Wu
Huawei Technologies