Internet-Draft Network Slice Service YANG Model August 2024
Wu, et al. Expires 1 March 2025 [Page]
Workgroup:
TEAS
Internet-Draft:
draft-ietf-teas-ietf-network-slice-nbi-yang-16
Published:
Intended Status:
Standards Track
Expires:
Authors:
B. Wu
Huawei Technologies
D. Dhody
Huawei Technologies
R. Rokui
Ciena
T. Saad
Cisco Systems, Inc
J. Mullooly
Cisco Systems, Inc

A YANG Data Model for the RFC 9543 Network Slice Service

Abstract

This document defines a YANG data model for RFC 9543 Network Slice Service. The model can be used in the Network Slice Service interface between a customer and a provider that offers RFC 9543 Network Slice Services.

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 1 March 2025.

Table of Contents

1. Introduction

[RFC9543] discusses a framework and interface for Network Slice using IETF technologies. The Network Slice Services may be referred to as RFC 9543 Network Slice Services. In this document, we simply use the term "Network Slice Service" to refer to this concept.

This document defines a YANG [RFC7950] data model for [RFC9543] Network Slice Service. The Network Slice Service Model (NSSM) can be used in the Network Slice Service Interface exposed by a provider to its customers (including for provider's internal use) in order to manage (e.g., subscribe, delete, or change) Network Slice Services. The agreed service will then trigger the appropriate Network Slice operation, such as instantiating, modifying, or deleting a Network Slice.

The NSSM focuses on the requirements of a Network Slice Service from the point of view of the customer, not how it is implemented within a provider network. As discussed in [RFC9543], the mapping between a Network Slice Service and its realization is implementation and deployment specific.

The NSSM is classified as a customer service model (Section 2 of [RFC8309]).

The NSSM conforms to the Network Management Datastore Architecture (NMDA) [RFC8342].

Editorial Note: (To be removed by RFC Editor)

This document contains several placeholder values that need to be replaced with finalized values at the time of publication. Please apply the following replacements:

2. Conventions used in this document

The keywords "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 BCP14, [RFC2119], [RFC8174] when, and only when, they appear in all capitals, as shown here.

The following terms are defined in [RFC6241] and are used in this specification:

This document makes use of the terms defined in [RFC7950].

The tree diagrams used in this document follow the notation defined in [RFC8340].

This document also makes use of the terms defined in [RFC9543]:

In addition, this document defines the following term:

2.1. Acronyms

The following acronyms are used in the document:

A2A
Any-to-any
AC
Attachment Circuit
CE
Customer Edge
MTU
Maximum Transmission Unit
NSC
Network Slice Controller
NSS
Network Slice Service
NSSM
Network Slice Service Model
P2P
Point-to-point
P2MP
Point-to-multipoint
PE
Provider Edge
QoS
Quality of Service
SDP
Service Demarcation Point
SLE
Service Level Expectation
SLO
Service Level Objective

3. Network Slice Service Overview

As defined in Section 3.2 of [RFC9543], a Network Slice Service is specified in terms of a set of Service Demarcation Points (SDPs), a set of one or more connectivity constructs between subsets of these SDPs, and a set of Service Level Objectives (SLOs) and Service Level Expectations (SLEs) for each SDP sending to each connectivity construct. A communication type (point-to-point (P2P), point-to-multipoint (P2MP), or any-to-any (A2A)) is specified for each connectivity construct.

The SDPs serve as the Network Slice Service ingress/egress points. An SDP is identified by a unique identifier in the context of a Network Slice Service.

Examples of Network Slice Services that contain only one connectivity construct are shown in Figure 1.

       +----------------------------------------------+
       |                                              |
       |                                              |
       |       Slice Service 1 with 1 P2P CC          |
 SDP1  O------------------->--------------------------O SDP2
       |                                              |
       |                                              |
       |       Slice Service 2 with 1 P2MP CC
       |                  +---------------------------O SDP4
 SDP3  O----------->------+                           |
       |                  +---------------------------O SDP5
       |                                              |
       |                                              |
       |       Slice Service 3 with 1 A2A  CC
 SDP6  O-----------<>-----+---------<>----------------O SDP8
       |                  |                           |
 SDP7  O-----------<>-----+---------<>----------------O SDP9
       |                                              |
       |                                              |
       +----------------------------------------------+
       |<------------Network Slice Services---------->|
       |        between endpoints SDP1 to SDP9        |

  CC: Connectivity construct
   O: Represents an SDP
----: Represents connectivity construct
< > : Inbound/outbound directions
Figure 1: Examples of Network Slice Services of Single Connectivity Construct

An example of Network Slice Services that contains multiple connectivity constructs is shown in Figure 2.

       +----------------------------------------------+
       |                                              |
       |       Slice Service 4 with 2 P2P CCs         |
 SDP10 O------------------->--------------------------O SDP12
 SDP11 O------------------->--------------------------O SDP13
       |                                              |
       |                                              |
       |      Slice Service 5 with 2 P2P CCs          |
       | +----------------->-----------------------+  |
 SDP14 O/                                           \ O SDP15
       |\                                           / |
       | +-----------------<-----------------------+  |
       |                                              |
       +----------------------------------------------+
       |<-----------Network Slice Services----------->|
       |        between endpoints SDP10 to SDP15      |


 Slice Service: Network Slice Service
            CC: Connectivity construct
             O: Represents an SDP
          ----: Represents connectivity construct
          < > : Inbound/outbound directions
Figure 2: Examples of Network Slice Services of Multiple Connectivity Constructs

As shown in Figure 2, the Network Slice Service 4 contains two P2P connectivity constructs between the set of SDPs. The Network Slice Service 5 is a bidirectional unicast service between SDP14 and SDP15 that consists of two unidirectional P2P connectivity constructs.

4. Network Slice Service Model (NSSM) Usage

The NSSM can be used by a provider to expose its Network Slice Services, and by a customer to manage its Network Slices Services (e.g., request, delete, or modify). The details about how service requests are handled by a provider (specifically, a controller), including which network operations are triggered, are internal to the provider. The details of the Network Slices realization are hidden from customers.

The Network Slices are applicable to use cases, such as (but not limited to) 5G, network wholesale services, network infrastructure sharing among operators, Network Function Virtualization (NFV) connectivity, and Data Center interconnect. [I-D.ietf-teas-ietf-network-slice-use-cases] provides a more detailed description of the use cases for Network Slices.

A Network Slice Controller (NSC) is an entity that exposes the Network Slice Service Interface to customers to manage Network Slice Services. Typically, an NSC receives requests from its customer-facing interface (e.g., from a management system). During service creation, this interface can convey data objects that the Network Slice Service customer provides, describing the needed Network Slices Service in terms of SDPs, the associated connectivity constructs, and the service objectives that the customer wishes to be fulfilled. Depending on whether the requirements and authorization checks are successfully met, these service requirements are then translated into technology-specific actions that are implemented in the underlying network(s) using a network-facing interface. The details of how the Network Slices are put into effect are out of scope for this document.

As shown in Figure 3, the NSSM is used by the customer's higher level operation system to communicate with an NSC for life cycle management of Network Slice Services including both enablement and monitoring. For example, in the 5G End-to-end network slicing use case, the 5G network slice orchestrator acts as the higher layer system to manage the Network Slice Services. The interface is used to support dynamic Network Slice management to facilitate end-to-end 5G network slice services.

          +----------------------------------------+
          |        Network Slice Customer          |
          |   (e.g., 5G network slice orchestrator)|
          +----------------+-----------------------+
                           |
                           |
                           | Network Slice Service Model (NSSM)
                           |
     +---------------------+--------------------------+
     |           Network Slice Controller (NSC)       |
     +------------------------------------------------+
Figure 3: Network Slice Service Reference Architecture

Note: The NSSM can be used recursively (hierarchical mode), i.e., an NSS can map to child NSSes. As described in Section A.5 of [RFC9543], the Network Slice Service can support a recursive composite architecture that allows one layer of Network Slice Services to be used by other layers.

5. Network Slice Service Model (NSSM) Description

The NSSM, "ietf-network-slice-service", includes two main data nodes: "slo-sle-templates" and "slice-service" ( Figure 4).

module: ietf-network-slice-service
  +--rw network-slice-services
     +--rw slo-sle-templates
     |  +--rw slo-sle-template* [id]
     |        ...
     +--rw slice-service* [id]
        +--rw id                              string
        +--rw description?                    string
        +--rw service-tags
        |     ...
        +--rw (slo-sle-policy)?
        |     ...
        +--rw compute-only?                   empty
        +--rw status
        |     ...
        +--rw sdps
        |     ...
        +--rw connection-groups
        |     ...
        +--rw custom-topology
              ...

Figure 4: The NSSM Overall Tree Structure

The "slo-sle-templates" container is used by an NSC to maintain a set of common Network Slice SLO and SLE templates that apply to one or several Network Slice Services. Refer to Section 5.1 for further details on the properties of NSS templates.

The "slice-service" list includes the set of Network Slice Services that are maintained by a provider for a given customer. "slice-service" is the data structure that abstracts the Network Slice Service. Under the "slice-service", the "sdp" list is used to abstract the SDPs. The "connection-group" is used to abstract connectivity constructs between SDPs. Refer to Section 5.2 for further details on the properties of an NSS.

5.1. SLO and SLE Templates

The "slo-sle-templates" container (Figure 5) is used by a Network Slice Service provider to define and maintain a set of common Network Slice Service templates that apply to one or several Network Slice Services. The templates are assumed to be known to both the customers and the provider. The exact definition of the templates is deployment specific.

     +--rw slo-sle-templates
     |  +--rw slo-sle-template* [id]
     |     +--rw id              string
     |     +--rw description?    string
     |     +--rw template-ref?   slice-template-ref
     |     +--rw slo-policy
     |     |  +--rw metric-bound* [metric-type]
     |     |  |  +--rw metric-type          identityref
     |     |  |  +--rw metric-unit          string
     |     |  |  +--rw value-description?   string
     |     |  |  +--rw percentile-value?    percentile
     |     |  |  +--rw bound?               uint64
     |     |  +--rw availability?   identityref
     |     |  +--rw mtu?            uint32
     |     +--rw sle-policy
     |        +--rw security*              identityref
     |        +--rw isolation*             identityref
     |        +--rw max-occupancy-level?   uint8
     |        +--rw path-constraints
     |           +--rw service-functions
     |           +--rw diversity
     |              +--rw diversity-type?
     |                      te-types:te-path-disjointness
Figure 5: Slo Sle Templates Subtree Structure

The NSSM provides the SLO and SLE templates identifiers and templates, and the common attributes of the templates are defined in Section 5.1 of [RFC9543]. Standard templates provided by the provider as well as custom "service-slo-sle-policy" are defined, since there are many attributes defined and some attributes could vary with service requirements, e.g., bandwidth or latency. A customer may choose either a standard template provided by the provider or a customized "service-slo-sle-policy".

  1. Standard template: The exact definition of the templates is deployment specific. The attributes configuration of a standard template is optional. When specifying attributes, a standard template can use "template-ref" to inherit some attributes of a predefined standard template and override the specific attributes.

  2. Custom "service-slo-sle-policy": More description is provided in Section 5.2.3.

Figure 6 shows an example where two standard network slice templates are retrieved by the customers.

========== NOTE: '\' line wrapping per RFC 8792 ===========

{
  "ietf-network-slice-service:network-slice-services": {
    "slo-sle-templates": {
      "slo-sle-template": [
        {
          "id": "PLATINUM-template",
          "description": "Two-way bandwidth: 1 Gbps,\
                          95th percentile latency 50ms",
          "slo-policy": {
            "metric-bound": [
              {
                "metric-type": "ietf-nss:two-way-delay-percentile",
                "metric-unit": "milliseconds",
                "percentile-value": "95.000",
                "bound": "50"
              }
            ]
          },
          "sle-policy": {
            "isolation": ["ietf-nss:traffic-isolation"]
          }
        },
        {
          "id": "GOLD-template",
          "description": "Two-way bandwidth: 1 Gbps,\
                          maximum latency 100ms",
          "slo-policy": {
            "metric-bound": [
              {
                "metric-type": "ietf-nss:two-way-delay-maximum",
                "metric-unit": "milliseconds",
                "bound": "100"
              }
            ]
          },
          "sle-policy": {
            "isolation": ["ietf-nss:traffic-isolation"]
          }
        }
      ]
    }
  }
}
Figure 6: Example of Template Retrieval

Figure 6 uses folding as defined in [RFC8792] for long lines.

5.2. Network Slice Services

The "slice-service" is the data structure that abstracts a Network Slice Service. Each "slice-service" is uniquely identified within an NSC by "id".

A Network Slice Service has the following main data nodes:

  • "description": Provides a textual description of a Network Slice Service.

  • "service-tags": Indicates a management tag (e.g., "customer name" ) that is used to correlate the operational information of Customer Higher-level Operation System and Network Slices. It might be used by a Network Slice Service provider to provide additional information to an NSC during the operation of the Network Slices. For example, adding tags with "customer name" when multiple actual customers use the same Network Slice Service. Another use case for "service-tag" might be for a provider to provide additional attributes to an NSC which might be used during the realization of Network Slice Services such as type of services (e.g., use Layer 2 or Layer 3 technology for the realization). These additional attributes can also be used by an NSC for various purposes such as monitoring and assurance of the Network Slice Services where the NSC can issue notifications to the customer system. All these attributes are optional.

  • "slo-sle-policy": Defines SLO and SLE policies for the "slice-service". More details are provided in Section 5.2.3.

  • "compute-only": Is used to check the feasibility of the service before instantiating a Network Slice Service in a network. More details are provided in Section 5.2.6.

  • "status": Indicates both the operational and administrative status of a Network Slice Service. Mismatches between the admin/oper status can be used as an indicator to detect Network Slice Service anomalies.

  • "sdps": Represents a set of SDPs that are involved in the Network Slice Service. More details are provided in Section 5.2.1.

  • "connection-groups": Abstracts the connections to the set of SDPs of the Network Slice Service.

  • "custom-topology": Represents custom topology constraints for the Network Slice Service. More details are provided in Section 5.2.5

5.2.1. Service Demarcation Points

A Network Slice Service involves two or more SDPs. A Network Slice Service can be modified by adding new "sdp"s.

+--rw sdps
   +--rw sdp* [id]
      +--rw id                        string
      +--rw description?              string
      +--rw geo-location
      |     ...
      +--rw node-id?                  string
      +--rw sdp-ip-address*           inet:ip-address
      +--rw tp-ref?                   leafref
      +--rw service-match-criteria
      |     ...
      +--rw incoming-qos-policy
      |     ...
      +--rw outgoing-qos-policy
      |     ...
      +--rw sdp-peering
      |     ...
      +--rw ac-svc-ref*
      |       ac-svc:attachment-circuit-reference
      +--rw ce-mode?                  boolean
      +--rw attachment-circuits
      |     ...
      +--rw status
      |     ...
      +--ro sdp-monitoring
            ...
Figure 7: SDP Subtree Structure

Section 5.2 of [RFC9543] describes four possible ways in which an SDP may be placed:

  • Within a CE

  • Provider-facing ports on a CE

  • Customer-facing ports on a PE

  • Within a PE

Although there are four options, they can be categorized into two categories: CE-based or PE-based.

In the four options, the Attachment Circuit (AC) may be part of the Network Slice Service or may be external to it. Based on the AC definition in Section 5.2 of [RFC9543], the customer and provider may agree on a per {Network Slice Service, connectivity construct, and SLOs/SLEs} basis to police or shape traffic on the AC in both the ingress (CE to PE) direction and egress (PE to CE) direction, which ensures that the traffic is within the capacity profile that is agreed in a Network Slice Service. Excess traffic is dropped by default, unless specific out-of-profile policies are agreed between the customer and the provider.

To abstract the SDP options and SLOs/SLEs profiles, an SDP has the following characteristics:

  • "id": Uniquely identifies the SDP within an NSC. The identifier is a string that allows any encoding for the local administration of the Network Slice Service.

  • "geo-location": Indicates SDP location information, which helps the NSC to identify an SDP.

  • "node-id": A reference to the node that hosts the SDP, which helps the NSC to identify an SDP. This document assumes that higher-level systems can obtain the node information, PE and CE, prior to the service requests. For example, Service Attachment Points (SAPs) [RFC9408] can obtain PE-related node information. The implementation details are left to the NSC provider.

  • "sdp-ip-address": The SDP IP address, which helps the NSC to identify an SDP.

  • "tp-ref": A reference to a Termination Point (TP) in the custom topology defined in Section 5.2.5.

  • "service-match-criteria": Defines matching policies for the Network Slice Service traffic to apply on a given SDP.

  • "incoming-qos-policy" and "outgoing-qos-policy": Sets the incoming and outgoing QoS policies to apply on a given SDP, including QoS policy and specific ingress and egress traffic limits to ensure access security. When applied in the incoming direction, the policy is applicable to the traffic that passes through the AC from the customer network or from another provider's network to the Network Slice. When applied in the outgoing direction, the policy is applied to the traffic from the Network Slice towards the customer network or towards another provider's network. If an SDP has multiple ACs, the "rate-limits" of "attachment-circuit" can be set to an AC specific value, but the rate cannot exceed the "rate-limits" of the SDP. If an SDP only contains a single AC, then the "rate-limits" of "attachment-circuit" is the same with the SDP. The definition of AC refers to Section 5.2 [RFC9543].

  • "sdp-peering": Specifies the peers and peering protocols for an SDP to exchange control-plane information, e.g., Layer 1 signaling protocol or Layer 3 routing protocols, etc. As shown in Figure 8

    +--rw sdp-peering
    |  +--rw peer-sap-id*   string
    |  +--rw protocols
    Figure 8: SDP Peering Subtree Structure
    • "peer-sap-id": Indicates the references to the remote endpoints of attachment circuits. This information can be used for correlation purposes, such as identifying Service Attachment Points (SAPs) defined in [RFC9408], which defines a model of an abstract view of the provider network topology that contains the points from which the services can be attached.

    • "protocols": Serves as an augmentation target. Appendix A shows an example where BGP and static routing are augmented to the model.

  • "ac-svc-ref": Refers to the ACs that have been created, which is defined in Section 5.2 of [I-D.ietf-opsawg-teas-attachment-circuit]. When both "ac-svc-ref" and the attributes of "attachment-circuits" are defined, the "ac-svc-ref" may take precedence or act as the parent AC depending on the use cases.

  • "ce-mode": A flag node that marks the SDP as CE type.

  • "attachment-circuits": Specifies the list of ACs by which the service traffic is received. This is an optional SDP attribute. When an SDP has multiple ACs and some AC specific attributes are needed, each "attachment-circuit" can specify attributes, such as interface specific IP addresses, service MTU, etc.

  • "status": Enables the control of the administrative status and reporting of the operational status of the SDP. These status values can be used as indicators to detect SDP anomalies.

  • "sdp-monitoring": Provides SDP bandwidth statistics.

Depending on the requirements of different cases, "service-match-criteria" can be used for the following purposes:

  • Specify the AC type: physical or logical connection.

  • Distinguish the SDP traffic if the SDP is located in the CE or PE.

  • Distinguish the traffic of different connection groups (CGs) or connectivity constructs (CCs) when multiple CGs/CCs of different SLO/SLE may be set up between the same pair of SDPs, as illustrated in Figure 9. Traffic needs to be explicitly mapped into the Network Slice's specific connectivity construct. The policies, "service-match-criteria", are based on the values in which combination of Layer 2 and Layer 3 header and payload fields within a packet to identify to which {Network Slice Service, connectivity construct, and SLOs/SLEs} that packet is assigned. For example, VLAN ([IEEE802.1Q]), C-VLAN/S-VLAN ([IEEE802.1ad]), or IP addresses.

  • Define specific out-of-profile policies: The customer may choose to use an explicit "service-match-criteria" to map any SDP's traffic or a subset of the SDP's traffic to a specific connection group or connectivity construct. If a subset of traffic is matched (e.g., "dscp" and/or IP addresses) and mapped to a connectivity construct, the customer may choose to add a subsequent "match-any" to explicitly map the remaining SDP traffic to a separate connectivity construct. If the customer chooses to implicitly map remaining traffic and if there are no additional connectivity constructs where the "sdp/id" source is specified, then that traffic will be dropped.

       |                                              |
       |                                              |
       |      Slice Service 6 with 2 P2P CCs          |
       v +--x-x-x-x-x-x---->---x-x-x-x-x-x-x-x-x---+  |
 SDP16 o/                                           \ o SDP17
       |\                                           / |
       | +--%-%-%-%-%-%---->---%-%-%-%-%-%-%-%-%---+  |
       |                                              |
       +----------------------------------------------+
       |<----------Network Slice Services------->|
       |        between endpoints SDP16 to SDP17      |
Figure 9: Application of Match Criteria

If an SDP is placed at the port of a CE or PE, and there is only one single connectivity construct with a source at the SDP, traffic can be implicitly mapped to this connectivity construct since the AC information (e.g., VLAN tag) can be used to unambiguously identify the traffic and the SDP is the only source of the connectivity-construct. Appendix B.1 shows an example of both the implicit and explicit approaches. While explicit matching is optional in some use cases, it provides a more clear and readable implementation, but the choice is left to the operator.

Figure 10 and Figure 11 provide examples that illustrate the use of SDP options. How an NSC realizes the mapping is out of scope for this document.

  • SDPs at customer-facing ports on the PEs: As shown in Figure 10, a customer of the Network Slice Service would like to connect two SDPs to satisfy specific service needs, e.g., network wholesale services. In this case, the Network Slice SDPs are mapped to customer-facing ports of PE nodes. The NSC uses "node-id" (PE device ID), "attachment-circuits", or "ac-svc-ref" to map SDPs to the customer-facing ports on the PEs.

                  SDP1                                     SDP2
           (With PE1 parameters)                       (with PE2 parameters)
                   o<--------- Network Slice (NS) 1 -------->o
                   +     |                            |     +
                   +     |<----------- S1 ----------->|     +
                   +     |                            |     +
                   +     |    |<------ T1 ------>|    |     +
                     +   v    v                  v    v   +
                       + +----+                  +----+ +
        +-----+    |     | PE1|==================| PE2|          +-----+
        |     |----------X    |                  |    |     |    |     |
        |     |    |     |    |                  |    X----------|     |
        |     |----------X    |                  |    |     |    |     |
        +-----+    |     |    |==================|    |     |    +-----+
                   AC    +----+                  +----+     AC
        Customer         Provider                Provider        Customer
        Edge 1           Edge 1                  Edge 2           Edge 2
    
    
      Legend:
        o: Representation of an SDP
        +: Mapping of an SDP to customer-facing ports on the PE
        X: Physical interfaces used for realization of the NS Service
       S1: L0/L1/L2/L3 services used for realization of NS Service
       T1: Tunnels used for realization of NS Service
    
    Figure 10: An Example of SDPs Placing at PEs
  • SDPs within CEs: As shown in Figure 11, a customer of the Network Slice Service would like to connect two SDPs to provide connectivity between transport portion of 5G RAN to 5G Core network functions. In this scenario, the NSC uses "node-id" (CE device ID), "geo-location", "sdp-ip-address" (IP address of SDP for management), "service-match-criteria" (VLAN tag), "attachment-circuits" or "ac-svc-ref" (CE ACs) to map SDPs to the CE. The NSC can use these CE parameters (and optionally other information to uniquely identify a CE within an NSC, such as "peer-sap-id" [RFC9408]) to retrieve the corresponding PE device, interface and AC mapping details to complete the Network Slice Service provisioning.

               SDP3                                     SDP4
        (With CE1 parameters)                       (with CE2 parameters)
        +o<--------------- Network Slice (NS) 2 --------------->o
        +                                                       +
        +|<------------------------- S2 ---------------------->|+
        +|                                                     |+
        +|                 |<------ T2 ------>|                |+
        +|                 v                  v                |+
        +v            +----+                  +----+           v+
     +--+--+    |     | PE1|==================| PE2|     |    +-+---+
     |  +  X----------X    |                  |    |     |    | +   |
     |  o  |    |     |    |                  |    X----------X o   |
     |     X----------X    |                  |    |     |    |     |
     +-----+    |     |    |==================|    |     |    +-----+
                AC    +----+                  +----+     AC
     Customer         Provider                Provider         Customer
     Edge 1           Edge 1                  Edge 2           Edge 2
    
    
    Legend:
     o: Representation of an SDP
     +: Mapping of an SDP to CE
     X: Physical interfaces used for realization of the NS Service
    S2: L0/L1/L2/L3 services used for realization of the NS Service
    T2: Tunnels used for realization of NS Service
    
    Figure 11: An Example of SDPs Placing at CEs

5.2.2. Connectivity Constructs

Section 4.2.1 of [RFC9543] defines the basic connectivity construct (CC) and CC types of a Network Slice Service, including P2P, P2MP, and A2A.

A Network Slice Service involves one or more connectivity constructs. The "connection-groups" container is used to abstract CC, CC groups, and their SLO-SLE policies and the structure is shown in Figure 12.

+--rw connection-groups
   +--rw connection-group* [id]
      +--rw id                                 string
      +--rw connectivity-type?
      |       identityref
      +--rw (slo-sle-policy)?
      |  +--:(standard)
      |  |     ...
      |  +--:(custom)
      |        ...
      +--rw service-slo-sle-policy-override?
      |       identityref
      +--rw connectivity-construct* [id]
      |  +--rw id
      |  |       string
      |  +--rw (type)?
      |  |     ...
      |  +--rw (slo-sle-policy)?
      |  |     ...
      |  +--rw service-slo-sle-policy-override?
      |  |       identityref
      |  +--rw status
      |  |     ...
Figure 12: Connection Groups Subtree Structure

The description of the "connection-groups" data nodes is as follows:

  • "connection-group": Represents a group of CCs. In the case of hub and spoke connectivity of the Slice Service, it may be inefficient when there are a large number of SDPs with multiple CCs. As illustrated in Appendix B.3, "connectivity-type" of "ietf-vpn-common:hub-spoke" and "connection-group-sdp-role" of "ietf-vpn-common:hub-role" or "ietf-vpn-common:spoke-role" can be specified [RFC9181]. Another use is for optimizing "slo-sle-policy" configurations, treating CCs with the same SLO and SLE characteristics as a connection group such that the connectivity construct can inherit the SLO/SLE from the group if not explicitly defined.

  • "connectivity-type": Indicates the type of the connection group, extending "vpn-common:vpn-topology" specified [RFC9181] with the NS connectivity type, e.g., P2P and P2MP.

  • "connectivity-construct": Represents single connectivity construct, and "slo-sle-policy" under it represents the per-connectivity construct SLO and SLE requirements.

  • "slo-sle-policy" and "service-slo-sle-policy-override": The details of "slo-sle-policy" are defined in Section 5.2.3. In addition to "slo-sle-policy" nodes of "connection-group" and "connectivity-construct", a leaf node "service-slo-sle-policy-override" is provided for scenarios with complex SLO-SLE requirements to completely override all or part of a "slo-sle-policy" with new values. For example, if a particular "connection-group" or a "connectivity-construct" has a unique bandwidth or latency setting, that are different from those defined in the Slice Service, a new set of SLOs/SLEs with full or partial override can be applied. In the case of partial override, only the newly specified parameters are replaced from the original template, while maintaining on pre-existing parameters not specified. While a full override removes all pre-existing parameters, and in essence starts a new set of SLOs/SLEs which are specified.

5.2.3. SLO and SLE Policy

As defined in Section 5 of [RFC9543], the SLO and SLE policy of the Network Slice Services define some common attributes.

"slo-sle-policy" is used to represent these SLO and SLE policies. During the creation of a Network Slice Service, the policy can be specified either by a standard SLO and SLE template or a customized SLO and SLE policy.

The policy can apply to per-network Slice Service, per-connection group "connection group", or per-connectivity construct "connectivity-construct". Since there are multiple mechanisms for assigning a policy to a single connectivity construct, an override precedence order among them is as follows:

  • Connectivity-construct at an individual sending SDP

  • Connectivity-construct

  • Connection-group

  • Slice-level

That is, the policy assigned through the sending SDP has highest precedence, and the policy assigned by the slice level has lowest precedence. Therefore, the policy assigned through the sending SDP takes precedence over the policy assigned through the connection-construct entry. Appendix B.5 gives an example of the preceding policy, which shows a Slice Service having an A2A connectivity as default and several specific SLO connections.

The SLO attributes include performance metric attributes, availability, and MTU. The SLO structure is shown in Figure 13. Figure 26 shows an example "slice5" with a custom network slice "slo-policy".

+--rw slo-policy
|  +--rw metric-bound* [metric-type]
|  |  +--rw metric-type
|  |  |       identityref
|  |  +--rw metric-unit          string
|  |  +--rw value-description?   string
|  |  +--rw percentile-value?
|  |  |       percentile
|  |  +--rw bound?               uint64
|  +--rw availability?   identityref
|  +--rw mtu?            uint16
Figure 13: SLO Policy Subtree Structure

The list "metric-bound" supports the generic performance metric variations and the combinations and each "metric-bound" could specify a particular "metric-type". "metric-type" is defined with YANG identity and supports the following options:

"one-way-bandwidth": Indicates the guaranteed minimum bandwidth between any two SDPs. The bandwidth is unidirectional.
"two-way-bandwidth": Indicates the guaranteed minimum bandwidth between any two SDPs. The bandwidth is bidirectional.
"shared-bandwidth": Indicates the shared SLO bandwidth bound, which is the limit on the bandwidth that can be shared amongst a group of connectivity constructs of a Slice Service.
"one-way-delay-maximum": Indicates the maximum one-way latency between two SDPs, defined in [RFC7679].
"two-way-delay-maximum": Indicates the maximum round-trip latency between two SDPs, defined in [RFC2681].
"one-way-delay-percentile": Indicates the percentile objective of the one-way latency between two SDPs ( [RFC7679]).
"two-way-delay-percentile": Indicates the percentile objective of the round-trip latency between two SDPs (See [RFC2681]).
"one-way-delay-variation-maximum": Indicates the jitter constraint of the slice maximum permissible delay variation, and is measured by the difference in the one-way latency between sequential packets in a flow, as defined in [RFC3393].
"two-way-delay-variation-maximum": Indicates the jitter constraint of the slice maximum permissible delay variation, and is measured by the difference in the two-way latency between sequential packets in a flow, as defined in [RFC3393].
"one-way-delay-variation-percentile": Indicates the percentile objective of the delay variation, and is measured by the difference in the one-way latency between sequential packets in a flow, as defined in [RFC3393].
"two-way-delay-variation-percentile": Indicates the percentile objective of the delay variation, and is measured by the difference in the two-way latency between sequential packets in a flow, as defined in [RFC5481].
"one-way-packet-loss": Indicates maximum permissible packet loss rate (See [RFC7680], which is defined by the ratio of packets dropped to packets transmitted between two SDPs.
"two-way-packet-loss": Indicates maximum permissible packet loss rate (See [RFC7680], which is defined by the ratio of packets dropped to packets transmitted between two SDPs.

"availability": Specifies service availability defined as the ratio of uptime to the sum of uptime and downtime, where uptime is the time the Network Slice is available in accordance with the SLOs associated with it.

"mtu": Specifies the maximum length of Layer 2 data packets of the Slice Service, in bytes. If the customer sends packets that are longer than the requested service MTU, the network may discard them (or for IPv4, fragment them). This service MTU takes precedence over the MTUs of all ACs. The value needs to be smaller than or equal to the minimum MTU value of all ACs in the SDPs.

As shown in Figure 14, the following SLEs data nodes are defined.

"security": The security leaf-list defines the list of security functions that the customer requests the operator to apply to traffic between the two SDPs, including authentication, encryption, etc., which is defined in Section 5.1.2.1 [RFC9543].
"isolation": Specifies the isolation types that a customer expects, as defined in Section 8 of [RFC9543].
"max-occupancy-level": Specifies the number of flows that the operator admits (See Section 5.1.2.1 of [RFC9543]).
"path-constraints": Specifies the path constraints the customer requests for the Network Slice Service, including geographic restrictions and diversity which is defined in Section 5.1.2.1 of [RFC9543].
+--rw sle-policy
   +--rw security*              identityref
   +--rw isolation*             identityref
   +--rw max-occupancy-level?   uint8
   +--rw path-constraints
      +--rw service-functions
      +--rw diversity
         +--rw diversity-type?
                 te-types:te-path-disjointness
Figure 14: SLE Policy Subtree Structure

5.2.4. Network Slice Service Performance Monitoring

The operation and performance status of Network Slice Services is also a key component of the NSSM. The model provides SLO monitoring information with the following granularity:

  • Per SDP: The incoming and outgoing bandwidths of an SDP are specified in "sdp-monitoring" under the "sdp".

  • Per connectivity construct: The delay, delay variation, and packet loss status are specified in "connectivity-construct-monitoring" under the "connectivity-construct".

  • Per connection group: The delay, delay variation, and packet loss status are specified in "connection-group-monitoring" under the "connection-group".

[RFC8639] and [RFC8641] define a subscription mechanism and a push mechanism for YANG datastores. These mechanisms currently allow the user to subscribe to notifications on a per-client basis and specify either periodic or on-demand notifications. By specifying subtree filters or xpath filters to "sdp", "connectivity-construct", or "connection-group", so that only interested contents will be sent. The example in Figure 23 shows the way for a customer to subscribe to the monitoring information for a particular Network Slice Service.

Additionally, a customer can use the NSSM to obtain a snapshot of the Network Slice Service performance status through [RFC8040] or [RFC6241] interfaces. For example, retrieve the per-connectivity-construct data by specifying "connectivity-construct" as the filter in the RESTCONF GET request.

5.2.5. Custom Topology Constraints

A Slice Service customer might request for some level of control over the topology or resource constraints. "custom-topology" is defined as an augmentation target that references the context topology. The leaf "network-ref" under this container is used to reference a predefined topology as a customized topology constraint for a Network Slice Service. Section 1 of [RFC8345] defines a general abstract topology concept to accommodate both the provider's resource capability and the customer's preferences. The abstract topology is a topology that contains abstract topological elements (nodes, links, and termination points).

This document defines only the minimum attributes of a custom topology, which can be extended based on the implementation requirements.

The following nodes are defined for the custom topology:

"custom-topology": This container serves as an augmentation target for the Slice Service topology context, which can be multiple. This node is located directly under the "slice-service" list.
"network-ref": This leaf is under the container "custom-topology", which is defined to reference a predefined topology as a customized topology constraint for a Network Slice Service, e.g., a SAP topology to request SDP feasibility checks on SAPs network described in Section 3 of [RFC9408], an abstract Traffic Engineering (TE) topology defined in Section 3.13 of [RFC8795] to customize the service paths in a Network Slice Service.
"tp-ref": A reference to a Termination Point (TP) in the custom topology, under the list "sdp", can be used to associate an SDP with a TP of the customized topology. The example TPs could be parent termination points of the SAP topology.

5.2.6. Network Slice Service Compute

A Network Slice Service customer may request to check the feasibility of a request before instantiating or modifying a Network Slice Service, e.g., network resources such as service access points for service delivery. In such a case, the Network Slice Service is configured in "compute-only" mode to distinguish it from the default behavior.

A "compute-only" Network Slice Service is configured as usual with the associated per slice SLOs/SLEs. The NSC computes the feasible connectivity constructs to the configured SLOs/SLEs. This computation does not create the Network Slice or reserve any resources in the provider's network, it simply computes the resulting Network Slice based on the request. The Network Slice "admin-status" and the connection groups or connectivity construct list are used to convey the result. For example, "admin-compute-only" can be used to show the status. Customers can query the "compute-only" connectivity constructs attributes, or can subscribe to be notified when the connectivity constructs status change.

The "compute-only" applies only if the data model is used with a protocol that does not natively support such operation, e.g., [RFC8040]. When using NETCONF, <edit-config> operation (Section 7.2 of [RFC6241]), "test-only" of the <test-option> parameter also applies.

            +--------+                                +--------+
            |customer|                                |  NSC   |
            +--------+                                +--------+
                 |                                         |
                 |                                         |
                 |  Configuration "compute-only"           |
Compute the NS   |---------------------------------------->|
as per the       |                                         |
SDPs and         |                                         |
SLOs/SLEs        |                                         |
                 |    Computed NS and status               |
                 |<----------------------------------------|
                 |                                         |

 NS: Network Slice
Figure 15: An Example of Network Slice Service Compute

6. Network Slice Service Module

The "ietf-network-slice-service" module uses types defined in [RFC6991], [RFC8345], [RFC8519], [RFC9179], [RFC9181], [I-D.ietf-opsawg-teas-attachment-circuit], [I-D.ietf-opsawg-teas-common-ac], and [I-D.ietf-teas-rfc8776-update].

<CODE BEGINS> file "[email protected]"

module ietf-network-slice-service {
  yang-version 1.1;
  namespace
    "urn:ietf:params:xml:ns:yang:ietf-network-slice-service";
  prefix ietf-nss;

  import ietf-inet-types {
    prefix inet;
    reference
      "RFC 6991: Common YANG Types";
  }
  import ietf-yang-types {
    prefix yang;
    reference
      "RFC 6991: Common YANG Data Types";
  }
  import ietf-geo-location {
    prefix geo;
    reference
      "RFC 9179: A YANG Grouping for Geographic Locations";
  }
  import ietf-vpn-common {
    prefix vpn-common;
    reference
      "RFC 9181: A Common YANG Data Model for Layer 2 and Layer 3
                 VPNs";
  }
  import ietf-network {
    prefix nw;
    reference
      "RFC 8345: A YANG Data Model for Network Topologies";
  }
  import ietf-network-topology {
    prefix nt;
    reference
      "RFC 8345: A YANG Data Model for Network
                 Topologies, Section 6.2";
  }
  import ietf-ac-common {
    prefix ac-common;
    reference
      "RFC BBBB: A Common YANG Data Model for Attachment Circuits";
  }
  import ietf-ac-svc {
    prefix ac-svc;
    reference
      "RFC CCCC: YANG Data Models for Bearers and 'Attachment
                 Circuits'-as-a-Service (ACaaS)";
  }
  import ietf-te-types {
    prefix te-types;
    reference
      "RFC DDDD: Common YANG Types for Traffic Engineering";
  }
  import ietf-te-packet-types {
    prefix te-packet-types;
    reference
      "RFC DDDD: Common YANG Data Types for Traffic Engineering";
  }

  organization
    "IETF Traffic Engineering Architecture and Signaling (TEAS)
     Working Group";
  contact
    "WG Web:  <https://datatracker.ietf.org/wg/teas/>
     WG List:  <mailto:[email protected]>

     Editor: Bo Wu
             <[email protected]>
     Editor: Dhruv Dhody
             <[email protected]>
     Editor: Reza Rokui
             <[email protected]>
     Editor: Tarek Saad
             <[email protected]>
     Editor: John Mullooly
             <[email protected]>";
  description
    "This YANG module defines a service model for the RFC 9543
     Network Slice Service.

     Copyright (c) 2024 IETF Trust and the persons identified as
     authors of the code.  All rights reserved.

     Redistribution and use in source and binary forms, with or
     without modification, is permitted pursuant to, and subject to
     the license terms contained in, the 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 AAAA; see the
     RFC itself for full legal notices.";

  revision 2024-08-28 {
    description
      "Initial revision.";
    reference
      "RFC AAAA: A YANG Data Model for the RFC 9543 Network Slice
       Service";
  }

  /* Identities */

  identity service-tag-type {
    description
      "Base identity of Network Slice Service tag type, which is
       used for management purposes, such as classification
       (e.g., customer names) and policy constraints
       (e.g., Layer 2 or Layer 3 technology realization).";
  }

  identity customer {
    base service-tag-type;
    description
      "The Network Slice Service customer name tag type,
       e.g., adding tags with 'customer name' when multiple actual
       customers use the same Network Slice Service.";
  }

  identity service {
    base service-tag-type;
    description
      "The Network Slice Service tag type, which can indicate the
       technical constraints used during service realization,
       for example, Layer 2 or Layer 3 technologies.";
  }

  identity opaque {
    base service-tag-type;
    description
      "An opaque type, which can be used for future use,
       such as filtering of services.";
  }

  identity attachment-circuit-tag-type {
    description
      "Base identity for the attachment circuit tag type.";
  }

  identity vlan-id {
    base attachment-circuit-tag-type;
    description
      "Identity for VLAN ID tag type, 802.1Q dot1Q.";
    reference
      "IEEE Std 802.1Q: IEEE Standard for Local and Metropolitan
                        Area Networks--Bridges and Bridged
                        Networks";
  }

  identity cvlan-id {
    base attachment-circuit-tag-type;
    description
      "Identity for C-VLAN ID tag type, 802.1ad QinQ VLAN IDs.";
    reference
      "IEEE Std 802.1ad: IEEE Standard for Local and Metropolitan
                         Area Networks---Virtual Bridged Local
                         Area Networks---Amendment 4: Provider
                         Bridges";
  }

  identity svlan-id {
    base attachment-circuit-tag-type;
    description
      "Identity for S-VLAN ID tag type, 802.1ad QinQ VLAN IDs.";
    reference
      "IEEE Std 802.1ad: IEEE Standard for Local and Metropolitan
                         Area Networks---Virtual Bridged Local
                         Area Networks---Amendment 4: Provider
                         Bridges";
  }

  identity ip-address-mask {
    base attachment-circuit-tag-type;
    description
      "Identity for IP address mask tag type.";
  }

  identity service-isolation-type {
    description
      "Base identity for Network Slice Service isolation type.";
  }

  identity traffic-isolation {
    base service-isolation-type;
    description
      "Specify the requirement for separating the traffic of the
       customer's Network Slice Service from other services,
       which may be provided by the service provider using VPN
       technologies, such as L3VPN, L2VPN, EVPN, etc.";
  }

  identity service-security-type {
    description
      "Base identity for Network Slice Service security type.";
  }

  identity authentication {
    base service-security-type;
    description
      "Indicates that the Slice Service requires authentication.";
  }

  identity integrity {
    base service-security-type;
    description
      "Indicates that the Slice Service requires data integrity.";
  }

  identity encryption {
    base service-security-type;
    description
      "Indicates that the Slice Service requires data encryption.";
  }

  identity point-to-point {
    base vpn-common:vpn-topology;
    description
      "Identity for point-to-point Network Slice
       Service connectivity.";
  }

  identity point-to-multipoint {
    base vpn-common:vpn-topology;
    description
      "Identity for point-to-multipoint Network Slice
       Service connectivity.";
  }

  identity multipoint-to-multipoint {
    base vpn-common:vpn-topology;
    description
      "Identity for multipoint-to-multipoint Network Slice
       Service connectivity.";
  }

  identity multipoint-to-point {
    base vpn-common:vpn-topology;
    description
      "Identity for multipoint-to-point Network Slice
       Service connectivity.";
  }

  identity sender-role {
    base vpn-common:role;
    description
      "Indicates that an SDP is acting as a sender.";
  }

  identity receiver-role {
    base vpn-common:role;
    description
      "Indicates that an SDP is acting as a receiver.";
  }

  identity service-slo-metric-type {
    description
      "Base identity for Network Slice Service SLO metric type.";
  }

  identity one-way-bandwidth {
    base service-slo-metric-type;
    description
      "SLO bandwidth metric. Minimum guaranteed bandwidth between
       two SDPs at any time and is measured unidirectionally.";
  }

  identity two-way-bandwidth {
    base service-slo-metric-type;
    description
      "SLO bandwidth metric. Minimum guaranteed bandwidth between
       two SDPs at any time.";
  }

  identity shared-bandwidth {
    base service-slo-metric-type;
    description
      "The shared SLO bandwidth bound. It is the limit on the
       bandwidth that can be shared amongst a group of
       connectivity constructs of a Slice Service.";
  }

  identity one-way-delay-maximum {
    base service-slo-metric-type;
    description
      "The SLO objective of this metric is the upper bound of network
       delay when transmitting between two SDPs.";
    reference
      "RFC 7679: A One-Way Delay Metric for IP Performance
                 Metrics (IPPM)";
  }

  identity one-way-delay-percentile {
    base service-slo-metric-type;
    description
      "The SLO objective of this metric is percentile objective of
       network delay when transmitting between two SDPs.
       The metric is defined in RFC7679.";
    reference
      "RFC 7679: A One-Way Delay Metric for IP Performance
                 Metrics (IPPM)";
  }

  identity two-way-delay-maximum {
    base service-slo-metric-type;
    description
      "SLO two-way delay is the upper bound of network delay when
       transmitting between two SDPs";
    reference
      "RFC 2681: A Round-trip Delay Metric for IPPM";
  }

  identity two-way-delay-percentile {
    base service-slo-metric-type;
    description
      "The SLO objective of this metric is the percentile
       objective of network delay when the traffic transmitting
       between two SDPs.";
    reference
      "RFC 2681: A Round-trip Delay Metric for IPPM";
  }

  identity one-way-delay-variation-maximum {
    base service-slo-metric-type;
    description
      "The SLO objective of this metric is maximum bound of the
       difference in the one-way delay between sequential packets
       between two SDPs.";
    reference
      "RFC 3393: IP Packet Delay Variation Metric for IP Performance
                 Metrics (IPPM)";
  }

  identity one-way-delay-variation-percentile {
    base service-slo-metric-type;
    description
      "The SLO objective of this metric is the percentile objective
       in the one-way delay between sequential packets between two
       SDPs.";
    reference
      "RFC 3393: IP Packet Delay Variation Metric for IP Performance
                 Metrics (IPPM)";
  }

  identity two-way-delay-variation-maximum {
    base service-slo-metric-type;
    description
      "SLO two-way delay variation is the difference in the
       round-trip delay between sequential packets between two
       SDPs.";
    reference
      "RFC 5481: Packet Delay Variation Applicability Statement";
  }

  identity two-way-delay-variation-percentile {
    base service-slo-metric-type;
    description
      "The SLO objective of this metric is the percentile objective
       in the round-trip delay between sequential packets between
       two SDPs.";
    reference
      "RFC 5481: Packet Delay Variation Applicability Statement";
  }

  identity one-way-packet-loss {
    base service-slo-metric-type;
    description
      "This metric type refers to the ratio of packets dropped
       to packets transmitted between two SDPs in one-way.";
    reference
      "RFC 7680: A One-Way Loss Metric for IP Performance
                 Metrics (IPPM)";
  }

  identity two-way-packet-loss {
    base service-slo-metric-type;
    description
      "This metric type refers to the ratio of packets dropped
       to packets transmitted between two SDPs in two-way.";
    reference
      "RFC 7680: A One-Way Loss Metric for IP Performance
                 Metrics (IPPM)";
  }

  identity availability-type {
    description
      "Base identity for availability.";
  }

  identity six-nines {
    base availability-type;
    description
      "Specifies the availability level: 99.9999%";
  }

  identity five-nines {
    base availability-type;
    description
      "Specifies the availability level: 99.999%";
  }

  identity four-nines {
    base availability-type;
    description
      "Specifies the availability level: 99.99%";
  }

  identity three-nines {
    base availability-type;
    description
      "Specifies the availability level: 99.9%";
  }

  identity two-nines {
    base availability-type;
    description
      "Specifies the availability level: 99%";
  }

  identity service-match-type {
    description
      "Base identity for Network Slice Service traffic
       match type.";
  }

  identity phy-interface {
    base service-match-type;
    description
      "Uses the physical interface as match criteria for
       Slice Service traffic.";
  }

  identity vlan {
    base service-match-type;
    description
      "Uses the VLAN ID as match criteria for the Slice Service
       traffic.";
  }

  identity label {
    base service-match-type;
    description
      "Uses the MPLS label as match criteria for the Slice Service
       traffic.";
  }

  identity source-ip-prefix {
    base service-match-type;
    description
      "Uses source IP prefix as match criteria for the Slice Service
       traffic. Examples of 'value' of this match type are
       '192.0.2.0/24' and '2001:db8::1/64'.";
  }

  identity destination-ip-prefix {
    base service-match-type;
    description
      "Uses destination IP prefix as match criteria for the Slice
       Service traffic. Examples of 'value' of this match type are
       '203.0.113.1/32' and '2001:db8::2/128'.";
  }

  identity dscp {
    base service-match-type;
    description
      "Uses DSCP field in the IP packet header as match criteria
       for the Slice Service traffic.";
  }

  identity acl {
    base service-match-type;
    description
      "Uses Access Control List (ACL) as match criteria
       for the Slice Service traffic.";
    reference
      "RFC 8519: YANG Data Model for Network Access Control
                 Lists (ACLs)";
  }

  identity any {
    base service-match-type;
    description
      "Matches any Slice Service traffic.";
  }

  identity slo-sle-policy-override {
    description
      "Base identity for SLO/SLE policy override options.";
  }

  identity full-override {
    base slo-sle-policy-override;
    description
      "The SLO/SLE policy defined at the child level overrides a
       parent SLO/SLE policy, which means that no SLO/SLEs are
       inherited from parent if a child SLO/SLE policy exists.";
  }

  identity partial-override {
    base slo-sle-policy-override;
    description
      "The SLO/SLE policy defined at the child level updates the
       parent SLO/SLE policy. For example, if a specific SLO is
       defined at the child level, that specific SLO overrides
       the one inherited from a parent SLO/SLE policy, while all
       other SLOs in the parent SLO-SLE policy still apply.";
  }

  /* Typedef */

  typedef percentage {
    type decimal64 {
      fraction-digits 5;
      range "0..100";
    }
    description
      "Percentage to 5 decimal places.";
  }

  typedef percentile {
    type decimal64 {
      fraction-digits 3;
      range "0..100";
    }
    description
      "The percentile is a value between 0 and 100
       to 3 decimal places, e.g., 10.000, 99.900,99.990, etc.
       For example, for a given one-way delay measurement,
       if the percentile is set to 95.000 and the 95th percentile
       one-way delay is 2 milliseconds, then the 95 percent of
       the sample value is less than or equal to 2 milliseconds.";
  }

  typedef slice-template-ref {
    type leafref {
      path "/ietf-nss:network-slice-services"
         + "/ietf-nss:slo-sle-templates"
         + "/ietf-nss:slo-sle-template"
         + "/ietf-nss:id";
    }
    description
      "This type is used by data models that need to reference
       Network Slice templates.";
  }

  typedef slice-service-ref {
    type leafref {
      path
        "/ietf-nss:network-slice-services/ietf-nss:slice-service"
      + "/ietf-nss:id";
    }
    description
      "Defines a reference to a slice service that can be used
       by other modules.";
  }

  /* Groupings */

  grouping service-slos {
    description
      "A reusable grouping for directly measurable objectives of
       a Slice Service.";
    container slo-policy {
      description
        "Contains the SLO policy.";
      list metric-bound {
        key "metric-type";
        description
          "List of Slice Service metric bounds.";
        leaf metric-type {
          type identityref {
            base service-slo-metric-type;
          }
          description
            "Identifies SLO metric type of the Slice Service.";
        }
        leaf metric-unit {
          type string;
          mandatory true;
          description
            "The metric unit of the parameter. For example,
             for time units, where the options are hours, minutes,
             seconds, milliseconds, microseconds, and nanoseconds;
             for bandwidth units, where the options are bps, Kbps,
             Mbps, Gbps; for the packet loss rate unit,
             the options can be a percentage.";
        }
        leaf value-description {
          type string;
          description
            "The description of the provided value.";
        }
        leaf percentile-value {
          type percentile;
          description
            "The percentile value of the metric type.";
        }
        leaf bound {
          type uint64;
          description
            "The bound on the Slice Service connection metric.
             When set to zero, this indicates an unbounded
             upper limit for the specific metric-type.";
        }
      }
      leaf availability {
        type identityref {
          base availability-type;
        }
        description
          "Service availability level";
      }
      leaf mtu {
        type uint32;
        units "bytes";
        description
          "Specifies the maximum length of Layer 2 data
           packets of the Slice Service.
           If the customer sends packets that are longer than the
           requested service MTU, the network may discard them
           (or for IPv4, fragment them).
           This service MTU takes precedence over the MTUs of
           all attachment circuits (ACs). The value needs to be
           less than or equal to the minimum MTU value of
           all ACs in the SDPs.";
      }
    }
  }

  grouping service-sles {
    description
      "A reusable grouping for indirectly measurable objectives of
       a Slice Service.";
    container sle-policy {
      description
        "Contains the SLE policy.";
      leaf-list security {
        type identityref {
          base service-security-type;
        }
        description
          "The security functions that the customer requests
           the operator to apply to traffic between the two SDPs.";
      }
      leaf-list isolation {
        type identityref {
          base service-isolation-type;
        }
        description
          "The Slice Service isolation requirement.";
      }
      leaf max-occupancy-level {
        type uint8 {
          range "1..100";
        }
        description
          "The maximal occupancy level specifies the number of flows
           to be admitted and optionally a maximum number of
           countable resource units (e.g., IP or MAC addresses)
           a Network Slice Service can consume.";
      }
      container path-constraints {
        description
          "Container for the policy of path constraints
           applicable to the Slice Service.";
        container service-functions {
          description
            "Container for the policy of service function
             applicable to the Slice Service.";
        }
        container diversity {
          description
            "Container for the policy of disjointness
             applicable to the Slice Service.";
          leaf diversity-type {
            type te-types:te-path-disjointness;
            description
              "The type of disjointness on Slice Service, i.e.,
               across all connectivity constructs.";
          }
        }
      }
    }
  }

  grouping slice-service-template {
    description
      "A reusable grouping for Slice Service templates.";
    container slo-sle-templates {
      description
        "Contains a set of Slice Service templates.";
      list slo-sle-template {
        key "id";
        description
          "List for SLO and SLE template identifiers.";
        leaf id {
          type string;
          description
            "Identification of the Service Level Objective (SLO)
             and Service Level Expectation (SLE) template to be used.
             Local administration meaning.";
        }
        leaf description {
          type string;
          description
            "Describes the SLO and SLE policy template.";
        }
        leaf template-ref {
          type slice-template-ref;
          description
            "The reference to a standard template. When set it
              indicates the base template over which further
              SLO/SLE policy changes are made.";
        }
        uses service-slos;
        uses service-sles;
      }
    }
  }

  grouping service-slo-sle-policy {
    description
      "Slice service policy grouping.";
    choice slo-sle-policy {
      description
        "Choice for SLO and SLE policy template.
         Can be standard template or customized template.";
      case standard {
        description
          "Standard SLO template.";
        leaf slo-sle-template {
          type slice-template-ref;
          description
            "Standard SLO and SLE template to be used.";
        }
      }
      case custom {
        description
          "Customized SLO and SLE template.";
        container service-slo-sle-policy {
          description
            "Contains the SLO and SLE policy.";
          leaf description {
            type string;
            description
              "Describes the SLO and SLE policy.";
          }
          uses service-slos;
          uses service-sles;
        }
      }
    }
  }

  grouping service-qos {
    description
      "Grouping for the Slice Service QoS policy.";
    container incoming-qos-policy {
      description
        "The QoS policy imposed on ingress direction of the traffic,
         from the customer network or from another provider's
         network.";
      leaf qos-policy-name {
        type string;
        description
          "The name of the QoS policy that is applied to the
           attachment circuit. The name can reference a QoS
           profile that is pre-provisioned on the device.";
      }
      container rate-limits {
        description
          "Container for the asymmetric traffic control.";
        uses ac-common:bandwidth-parameters;
        container classes {
          description
            "Container for service class bandwidth control.";
          list cos {
            key "cos-id";
            description
              "List of Class of Services.";
            leaf cos-id {
              type uint8;
              description
                "Identifier of the CoS, indicated by
                 a Differentiated Services Code Point
                 (DSCP) or a CE-CLAN CoS (802.1p)
                 value in the service frame.";
              reference
                "IEEE Std 802.1Q: Bridges and Bridged
                                  Networks";
            }
            uses ac-common:bandwidth-parameters;
          }
        }
      }
    }
    container outgoing-qos-policy {
      description
        "The QoS policy imposed on egress direction of the traffic,
         towards the customer network or towards another
         provider's network.";
      leaf qos-policy-name {
        type string;
        description
          "The name of the QoS policy that is applied to the
           attachment circuit. The name can reference a QoS
           profile that is pre-provisioned on the device.";
      }
      container rate-limits {
        description
          "The rate-limit imposed on outgoing traffic.";
        uses ac-common:bandwidth-parameters;
        container classes {
          description
            "Container for classes.";
          list cos {
            key "cos-id";
            description
              "List of Class of Services.";
            leaf cos-id {
              type uint8;
              description
                "Identifier of the CoS, indicated by
                 a Differentiated Services Code Point
                 (DSCP) or a CE-CLAN CoS (802.1p)
                 value in the service frame.";
              reference
                "IEEE Std 802.1Q: Bridges and Bridged
                                  Networks";
            }
            uses ac-common:bandwidth-parameters;
          }
        }
      }
    }
  }

  grouping service-slo-sle-policy-override {
    description
      "Slice Service policy override grouping.";
    leaf service-slo-sle-policy-override {
      type identityref {
        base slo-sle-policy-override;
      }
      description
        "SLO/SLE policy override option.";
    }
  }

  grouping connectivity-construct-monitoring-metrics {
    description
      "Grouping for connectivity construct monitoring metrics.";
    uses
      te-packet-types:one-way-performance-metrics-gauge-packet;
    uses
      te-packet-types:two-way-performance-metrics-gauge-packet;
  }

  /* Main Network Slice Services Container */

  container network-slice-services {
    description
      "Contains a list of Network Slice Services";
    uses slice-service-template;
    list slice-service {
      key "id";
      description
        "A Slice Service is identified by a service id.";
      leaf id {
        type string;
        description
          "A unique Slice Service identifier within an NSC.";
      }
      leaf description {
        type string;
        description
          "Textual description of the Slice Service.";
      }
      container service-tags {
        description
          "Container for a list of service tags for management
           purposes, such as policy constraints
           (e.g., Layer 2 or Layer 3 technology realization),
           classification (e.g., customer names, opaque values).";
        list tag-type {
          key "tag-type";
          description
            "The service tag list.";
          leaf tag-type {
            type identityref {
              base service-tag-type;
            }
            description
              "Slice Service tag type, e.g., realization technology
               constraints, customer name, or other customer-defined
               opaque types.";
          }
          leaf-list value {
            type string;
            description
              "The tag values, e.g., 5G customer names when multiple
               customers share the same Slice Service in 5G scenario,
               or Slice realization technology (such as Layer 2 or
               Layer 3).";
          }
        }
      }
      uses service-slo-sle-policy;
      leaf compute-only {
        type empty;
        description
          "When present, this is a feasibility check. That is, no
           resources are reserved in the network.";
      }
      uses ac-common:service-status;
      container sdps {
        description
          "Slice Service SDPs.";
        list sdp {
          key "id";
          min-elements 2;
          description
            "List of SDPs in this Slice Service.";
          leaf id {
            type string;
            description
              "The unique identifier of the SDP within the scope of
               an NSC.";
          }
          leaf description {
            type string;
            description
              "Provides a description of the SDP.";
          }
          uses geo:geo-location;
          leaf node-id {
            type string;
            description
              "A unique identifier of an edge node of the SDP
               within the scope of the NSC.";
          }
          leaf-list sdp-ip-address {
            type inet:ip-address;
            description
              "IPv4 or IPv6 address of the SDP.";
          }
          leaf tp-ref {
            type leafref {
              path
                "/nw:networks/nw:network[nw:network-id="
              + "current()/../../../custom-topology/network-ref]/"
              + "nw:node/nt:termination-point/nt:tp-id";
            }
            description
              "A reference to Termination Point (TP) in the custom
               topology";
            reference
              "RFC 8345: A YANG Data Model for Network Topologies";
          }
          container service-match-criteria {
            description
              "Describes the Slice Service match criteria.";
            list match-criterion {
              key "index";
              description
                "List of the Slice Service traffic match criteria.";
              leaf index {
                type uint32;
                description
                  "The identifier of a match criteria.";
              }
              list match-type {
                key "type";
                description
                  "List of the Slice Service traffic match types.";
                leaf type {
                  type identityref {
                    base service-match-type;
                  }
                  mandatory true;
                  description
                    "Indicates the match type of the entry in the
                     list of the Slice Service match criteria.";
                }
                leaf-list value {
                  type string;
                  description
                    "Provides a value for the Slice Service match
                     criteria, e.g., IP prefix, VLAN ID, or
                     ACL name.";
                }
              }
              leaf target-connection-group-id {
                type leafref {
                  path
                    "../../../../../ietf-nss:connection-groups"
                  + "/ietf-nss:connection-group"
                  + "/ietf-nss:id";
                }
                mandatory true;
                description
                  "Reference to the Slice Service connection group.";
              }
              leaf connection-group-sdp-role {
                type identityref {
                  base vpn-common:role;
                }
                default "vpn-common:any-to-any-role";
                description
                  "Specifies the role of SDP in the connection group
                   When the service connection type is MP2MP,
                   such as hub and spoke service connection type.
                   In addition, this helps to create connectivity
                   construct automatically, rather than explicitly
                   specifying each one.";
              }
              leaf target-connectivity-construct-id {
                type leafref {
                  path
                    "../../../../../ietf-nss:connection-groups"
                  + "/ietf-nss:connection-group[ietf-nss:id="
                  + "current()/../target-connection-group-id]"
                  + "/ietf-nss:connectivity-construct/ietf-nss:id";
                }
                description
                  "Reference to a Network Slice connection
                   construct.";
              }
            }
          }
          uses service-qos;
          container sdp-peering {
            description
              "Describes SDP peering attributes.";
            leaf-list peer-sap-id {
              type string;
              description
                "Indicates the reference to the remote endpoints of
                 the attachment circuits. This information can be
                 used for correlation purposes, such as identifying
                 SAPs of provider equipments when requesting
                 a service with CE based SDP attributes.";
              reference
                "RFC 9408: A YANG Network Data Model for Service
                 Attachment Points (SAPs)";
            }
            container protocols {
              description
                "Serves as an augmentation target.
                 Protocols can be augmented into this container,
                 e.g., BGP, static routing.";
            }
          }
          leaf-list ac-svc-ref {
            type ac-svc:attachment-circuit-reference;
            description
              "A reference to the ACs that have been created before
               the slice creation.";
            reference
              "RFC CCCC: YANG Data Models for Bearers and
                'Attachment Circuits'-as-a-Service (ACaaS)";
          }
          leaf ce-mode {
            type boolean;
            description
              "Indicates that SDP is on the CE.";
          }
          container attachment-circuits {
            description
              "List of attachment circuits.";
            list attachment-circuit {
              key "id";
              description
                "The Network Slice Service SDP attachment circuit
                 related parameters.";
              leaf id {
                type string;
                description
                  "The identifier of attachment circuit.";
              }
              leaf description {
                type string;
                description
                  "The attachment circuit's description.";
              }
              leaf ac-svc-ref {
                type ac-svc:attachment-circuit-reference;
                description
                  "A reference to the AC service that has been
                   created before the slice creation.";
                reference
                  "RFC CCCC: YANG Data Models for Bearers and
                    'Attachment Circuits'-as-a-Service (ACaaS)";
              }
              leaf ac-node-id {
                type string;
                description
                  "The attachment circuit node ID in the case of
                   multi-homing.";
              }
              leaf ac-tp-id {
                type string;
                description
                  "The termination port ID of the
                   attachment circuit.";
              }
              leaf ac-ipv4-address {
                type inet:ipv4-address;
                description
                  "The IPv4 address of the AC.";
              }
              leaf ac-ipv4-prefix-length {
                type uint8;
                description
                  "The IPv4 subnet prefix length expressed in bits.";
              }
              leaf ac-ipv6-address {
                type inet:ipv6-address;
                description
                  "The IPv6 address of the AC.";
              }
              leaf ac-ipv6-prefix-length {
                type uint8;
                description
                  "The IPv6 subnet prefix length expressed in bits.";
              }
              leaf mtu {
                type uint32;
                units "bytes";
                description
                  "Maximum size of the Slice Service Layer 2 data
                   packet that can traverse an SDP.";
              }
              container ac-tags {
                description
                  "Container for the attachment circuit tags.";
                list ac-tag {
                  key "tag-type";
                  description
                    "The attachment circuit tag list.";
                  leaf tag-type {
                    type identityref {
                      base attachment-circuit-tag-type;
                    }
                    description
                      "The attachment circuit tag type.";
                  }
                  leaf-list value {
                    type string;
                    description
                      "The attachment circuit tag values.
                       For example, the tag may indicate
                       multiple VLAN identifiers.";
                  }
                }
              }
              uses service-qos;
              container sdp-peering {
                description
                  "Describes SDP peering attributes.";
                leaf peer-sap-id {
                  type string;
                  description
                    "Indicates a reference to the remote endpoints
                     of an attachment circuit. This information can
                     be used for correlation purposes, such as
                     identifying a service attachment point (SAP)
                     of a provider equipment when requesting a
                     service with CE based SDP attributes.";
                  reference
                    "RFC 9408: A YANG Network Data Model for
                               Service Attachment Points (SAPs)";
                }
                container protocols {
                  description
                    "Serves as an augmentation target.
                     Protocols can be augmented into this container,
                     e.g., BGP or static routing.";
                }
              }
              uses ac-common:service-status;
            }
          }
          uses ac-common:service-status;
          container sdp-monitoring {
            config false;
            description
              "Container for SDP monitoring metrics.";
            leaf incoming-bw-value {
              type yang:gauge64;
              units "bps";
              description
                "Indicates the absolute value of the incoming
                 bandwidth at an SDP from the customer network or
                 from another provider's network.";
            }
            leaf incoming-bw-percent {
              type percentage;
              units "percent";
              description
                "Indicates a percentage of the incoming bandwidth
                 at an SDP from the customer network or
                 from another provider's network.";
            }
            leaf outgoing-bw-value {
              type yang:gauge64;
              units "bps";
              description
                "Indicates the absolute value of the outgoing
                 bandwidth at an SDP towards the customer network or
                 towards another provider's network.";
            }
            leaf outgoing-bw-percent {
              type percentage;
              units "percent";
              description
                "Indicates a percentage of the outgoing bandwidth
                 at an SDP towards the customer network or towards
                 another provider's network.";
            }
          }
        }
      }
      container connection-groups {
        description
          "Contains connection groups.";
        list connection-group {
          key "id";
          description
            "List of connection groups.";
          leaf id {
            type string;
            description
              "The connection group identifier.";
          }
          leaf connectivity-type {
            type identityref {
              base vpn-common:vpn-topology;
            }
            default "vpn-common:any-to-any";
            description
              "Connection group connectivity type.";
          }
          uses service-slo-sle-policy;
          /* Per connection group SLO/SLE policy
           * overrides the per Slice SLO/SLE policy.
           */
          uses service-slo-sle-policy-override;
          list connectivity-construct {
            key "id";
            description
              "List of connectivity constructs.";
            leaf id {
              type string;
              description
                "The connectivity construct identifier.";
            }
            choice type {
              default "p2p";
              description
                "Choice for connectivity construct type.";
              case p2p {
                description
                  "P2P connectivity construct.";
                leaf p2p-sender-sdp {
                  type leafref {
                    path "../../../../sdps/sdp/id";
                  }
                  description
                    "Reference to a sender SDP.";
                }
                leaf p2p-receiver-sdp {
                  type leafref {
                    path "../../../../sdps/sdp/id";
                  }
                  description
                    "Reference to a receiver SDP.";
                }
              }
              case p2mp {
                description
                  "P2MP connectivity construct.";
                leaf p2mp-sender-sdp {
                  type leafref {
                    path "../../../../sdps/sdp/id";
                  }
                  description
                    "Reference to a sender SDP.";
                }
                leaf-list p2mp-receiver-sdp {
                  type leafref {
                    path "../../../../sdps/sdp/id";
                  }
                  description
                    "Reference to a receiver SDP.";
                }
              }
              case a2a {
                description
                  "A2A connectivity construct.";
                list a2a-sdp {
                  key "sdp-id";
                  description
                    "List of included A2A SDPs.";
                  leaf sdp-id {
                    type leafref {
                      path "../../../../../sdps/sdp/id";
                    }
                    description
                      "Reference to an SDP.";
                  }
                  uses service-slo-sle-policy;
                }
              }
            }
            uses service-slo-sle-policy;
            /* Per connectivity construct SLO/SLE policy
             * overrides the per slice SLO/SLE policy.
             */
            uses service-slo-sle-policy-override;
            uses ac-common:service-status;
            container connectivity-construct-monitoring {
              config false;
              description
                "SLO status per connectivity construct.";
              uses connectivity-construct-monitoring-metrics;
            }
          }
          container connection-group-monitoring {
            config false;
            description
              "SLO status per connection group.";
            uses connectivity-construct-monitoring-metrics;
          }
        }
      }
      container custom-topology {
        description
          "Serves as an augmentation target.
           Container for custom topology, which is indicated by the
           referenced topology predefined, e.g., an abstract RFC8345
           topology.";
        uses nw:network-ref;
      }
    }
  }
}

<CODE ENDS>
Figure 16: Network Slice Service YANG Module

7. 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 these YANG modules 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-network-slice-service" module:

* /ietf-network-slice-service/network-slice-services/slo-sle-templates

This subtree specifies the Network Slice Service SLO templates and SLE templates. Modifying the configuration in the subtree will change the related Network Slice Service configuration in the future. By making such modifications, a malicious attacker may degrade the Slice Service functions configured at a certain time in the future.

* /ietf-network-slice-service/network-slice-services/slice-service

The entries in the list above include the whole network configurations corresponding with the Network Slice Service which the higher management system requests, and indirectly create or modify the PE or P device configurations. Unexpected changes to these entries could lead to service disruption and/or network misbehavior.

Some of the readable data nodes in these YANG modules 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-network-slice-service" module:

* /ietf-network-slice-service/network-slice-services/slo-sle-templates

Unauthorized access to the subtree may disclose the SLO and SLE templates of the Network Slice Service.

* /ietf-network-slice-service/network-slice-services/slice-service

Unauthorized access to the subtree may disclose the operation status information of the Network Slice Service.

* /ietf-network-slice-service/network-slice-services/slice-service/service-tags

Unauthorized access to the subtree may disclose privacy data such as customer names of the Network Slice Service.

8. IANA Considerations

This document requests to register the following URI in the IETF XML registry [RFC3688]:

   URI: urn:ietf:params:xml:ns:yang:ietf-network-slice-service
   Registrant Contact: The IESG.
   XML: N/A, the requested URI is an XML namespace.


This document requests to register the following YANG module in the YANG Module Names registry [RFC6020].

   Name: ietf-network-slice-service
   Namespace: urn:ietf:params:xml:ns:yang:ietf-network-slice-service
   Prefix: ietf-nss
   Maintained by IANA? N
   Reference: RFC AAAA

9. Acknowledgments

The authors wish to thank Mohamed Boucadair, Kenichi Ogaki, Sergio Belotti, Qin Wu, Yao Zhao, Susan Hares, Eric Grey, Daniele Ceccarelli, Ryan Hoffman, Adrian Farrel, Aihua Guo, Italo Busi, and many others for their helpful comments and suggestions.

Thanks to Ladislav Lhotka for the YANG Doctors review.

10. Contributors

The following authors contributed significantly to this document:

   Luis M. Contreras
   Telefonica
   Spain
   Email: [email protected]

   Liuyan Han
   China Mobile
   Email: [email protected]

11. References

11.1. 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 Bearers and 'Attachment Circuits'-as-a-Service (ACaaS)", Work in Progress, Internet-Draft, draft-ietf-opsawg-teas-attachment-circuit-15, , <https://datatracker.ietf.org/doc/html/draft-ietf-opsawg-teas-attachment-circuit-15>.
[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-12, , <https://datatracker.ietf.org/doc/html/draft-ietf-opsawg-teas-common-ac-12>.
[I-D.ietf-teas-rfc8776-update]
Busi, I., Guo, A., Liu, X., Saad, T., and I. Bryskin, "Common YANG Data Types for Traffic Engineering", Work in Progress, Internet-Draft, draft-ietf-teas-rfc8776-update-12, , <https://datatracker.ietf.org/doc/html/draft-ietf-teas-rfc8776-update-12>.
[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/info/rfc2119>.
[RFC2681]
Almes, G., Kalidindi, S., and M. Zekauskas, "A Round-trip Delay Metric for IPPM", RFC 2681, DOI 10.17487/RFC2681, , <https://www.rfc-editor.org/info/rfc2681>.
[RFC3393]
Demichelis, C. and P. Chimento, "IP Packet Delay Variation Metric for IP Performance Metrics (IPPM)", RFC 3393, DOI 10.17487/RFC3393, , <https://www.rfc-editor.org/info/rfc3393>.
[RFC3688]
Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, DOI 10.17487/RFC3688, , <https://www.rfc-editor.org/info/rfc3688>.
[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/info/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/info/rfc6241>.
[RFC6242]
Wasserman, M., "Using the NETCONF Protocol over Secure Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, , <https://www.rfc-editor.org/info/rfc6242>.
[RFC6991]
Schoenwaelder, J., Ed., "Common YANG Data Types", RFC 6991, DOI 10.17487/RFC6991, , <https://www.rfc-editor.org/info/rfc6991>.
[RFC7679]
Almes, G., Kalidindi, S., Zekauskas, M., and A. Morton, Ed., "A One-Way Delay Metric for IP Performance Metrics (IPPM)", STD 81, RFC 7679, DOI 10.17487/RFC7679, , <https://www.rfc-editor.org/info/rfc7679>.
[RFC7680]
Almes, G., Kalidindi, S., Zekauskas, M., and A. Morton, Ed., "A One-Way Loss Metric for IP Performance Metrics (IPPM)", STD 82, RFC 7680, DOI 10.17487/RFC7680, , <https://www.rfc-editor.org/info/rfc7680>.
[RFC7950]
Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language", RFC 7950, DOI 10.17487/RFC7950, , <https://www.rfc-editor.org/info/rfc7950>.
[RFC8040]
Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF Protocol", RFC 8040, DOI 10.17487/RFC8040, , <https://www.rfc-editor.org/info/rfc8040>.
[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/info/rfc8174>.
[RFC8340]
Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams", BCP 215, RFC 8340, DOI 10.17487/RFC8340, , <https://www.rfc-editor.org/info/rfc8340>.
[RFC8341]
Bierman, A. and M. Bjorklund, "Network Configuration Access Control Model", STD 91, RFC 8341, DOI 10.17487/RFC8341, , <https://www.rfc-editor.org/info/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/info/rfc8342>.
[RFC8345]
Clemm, A., Medved, J., Varga, R., Bahadur, N., Ananthakrishnan, H., and X. Liu, "A YANG Data Model for Network Topologies", RFC 8345, DOI 10.17487/RFC8345, , <https://www.rfc-editor.org/info/rfc8345>.
[RFC8446]
Rescorla, E., "The Transport Layer Security (TLS) Protocol Version 1.3", RFC 8446, DOI 10.17487/RFC8446, , <https://www.rfc-editor.org/info/rfc8446>.
[RFC8519]
Jethanandani, M., Agarwal, S., Huang, L., and D. Blair, "YANG Data Model for Network Access Control Lists (ACLs)", RFC 8519, DOI 10.17487/RFC8519, , <https://www.rfc-editor.org/info/rfc8519>.
[RFC8639]
Voit, E., Clemm, A., Gonzalez Prieto, A., Nilsen-Nygaard, E., and A. Tripathy, "Subscription to YANG Notifications", RFC 8639, DOI 10.17487/RFC8639, , <https://www.rfc-editor.org/info/rfc8639>.
[RFC8641]
Clemm, A. and E. Voit, "Subscription to YANG Notifications for Datastore Updates", RFC 8641, DOI 10.17487/RFC8641, , <https://www.rfc-editor.org/info/rfc8641>.
[RFC9179]
Hopps, C., "A YANG Grouping for Geographic Locations", RFC 9179, DOI 10.17487/RFC9179, , <https://www.rfc-editor.org/info/rfc9179>.
[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/info/rfc9181>.
[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/info/rfc9408>.
[RFC9543]
Farrel, A., Ed., Drake, J., Ed., Rokui, R., Homma, S., Makhijani, K., Contreras, L., and J. Tantsura, "A Framework for Network Slices in Networks Built from IETF Technologies", RFC 9543, DOI 10.17487/RFC9543, , <https://www.rfc-editor.org/info/rfc9543>.

11.2. Informative References

[I-D.ietf-teas-actn-vn-yang]
Lee, Y., Dhody, D., Ceccarelli, D., Bryskin, I., and B. Y. Yoon, "A YANG Data Model for Virtual Network (VN) Operations", Work in Progress, Internet-Draft, draft-ietf-teas-actn-vn-yang-29, , <https://datatracker.ietf.org/doc/html/draft-ietf-teas-actn-vn-yang-29>.
[I-D.ietf-teas-ietf-network-slice-use-cases]
Contreras, L. M., Homma, S., Ordonez-Lucena, J. A., Tantsura, J., and H. Nishihara, "IETF Network Slice Use Cases and Attributes for the Slice Service Interface of IETF Network Slice Controllers", Work in Progress, Internet-Draft, draft-ietf-teas-ietf-network-slice-use-cases-01, , <https://datatracker.ietf.org/doc/html/draft-ietf-teas-ietf-network-slice-use-cases-01>.
[IEEE802.1ad]
"Amendment to IEEE 802.1Q-2005. IEEE Standard for Local and Metropolitan Area Networks - Virtual Bridged Local Area Networks Revision-Amendment 4: Provider Bridges", IEEE Std 802.1ad, .
[IEEE802.1Q]
"IEEE Standard for Local and metropolitan area networks--Bridges and Bridged Networks", IEEE Std 802.1Q, .
[RFC5481]
Morton, A. and B. Claise, "Packet Delay Variation Applicability Statement", RFC 5481, DOI 10.17487/RFC5481, , <https://www.rfc-editor.org/info/rfc5481>.
[RFC8309]
Wu, Q., Liu, W., and A. Farrel, "Service Models Explained", RFC 8309, DOI 10.17487/RFC8309, , <https://www.rfc-editor.org/info/rfc8309>.
[RFC8792]
Watsen, K., Auerswald, E., Farrel, A., and Q. Wu, "Handling Long Lines in Content of Internet-Drafts and RFCs", RFC 8792, DOI 10.17487/RFC8792, , <https://www.rfc-editor.org/info/rfc8792>.
[RFC8795]
Liu, X., Bryskin, I., Beeram, V., Saad, T., Shah, H., and O. Gonzalez de Dios, "YANG Data Model for Traffic Engineering (TE) Topologies", RFC 8795, DOI 10.17487/RFC8795, , <https://www.rfc-editor.org/info/rfc8795>.

Appendix A. Augmentation Considerations

The NSSM defines the minimum attributes of Slice Services. In some scenarios, further extension, e.g., the definition of AC technology specific attributes and the "isolation" SLE characteristics are required.

For AC technology specific attributes, if the customer and provider need to agree, through configuration, on the technology parameter values, such as the protocol types and protocol parameters between the PE and the CE. The following shows an example where BGP and static routing are augmented to the Network Slice Service model. The protocol types and definitions can reference [I-D.ietf-opsawg-teas-common-ac].

module: ietf-network-slice-service-proto-ex
  augment /ietf-nss:network-slice-services/ietf-nss:slice-service
            /ietf-nss:sdps/ietf-nss:sdp/ietf-nss:sdp-peering
            /ietf-nss:protocols:
    +--rw bgp
    |  +--rw name?             string
    |  +--ro local-as?         inet:as-number
    |  +--rw peer-as?          inet:as-number
    |  +--rw address-family?   identityref
    +--rw static-routing-ipv4
    |  +--rw lan?        inet:ipv4-prefix
    |  +--rw lan-tag?    string
    |  +--rw next-hop?   union
    |  +--rw metric?     uint32
    +--rw static-routing-ipv6
       +--rw lan?        inet:ipv6-prefix
       +--rw lan-tag?    string
       +--rw next-hop?   union
       +--rw metric?     uint32
Figure 17: Example YANG Tree Augmenting SDP Peering Protocols

In some scenarios, for example, when multiple Slice Services share one or more ACs, independent AC services, defined in [I-D.ietf-opsawg-teas-attachment-circuit], can be used.

For "isolation" SLE characteristics, the following identities can be defined.

  identity service-interference-isolation-dedicated {
    base service-isolation-type;
    description
      "Specify the requirement that the Slice Service is not impacted
       by the existence of other customers or services in the same
       network, which may be provided by the service provider using
       dedicated network resources, similar to a dedicated
       private network.";
  }
Figure 18: Example "isolation" Identity Augmentation

Appendix B. Examples of Network Slice Services

B.1. Example-1: Two A2A Slice Services with Different Match Approaches

Figure 19 shows an example of two Network Slice Service instances where the SDPs are the customer-facing ports on the PE:

  • Network Slice 1 on SDP1, SDP11a, and SDP4, with an A2A connectivity type. This is an L3 Slice Service that uses the uniform low latency "slo-sle-template" policy between all SDPs. These SDPs will also have AC eBGP peering sessions with unmanaged CE elements (not shown) using an AC augmentation model such as the one shown above.

  • Network Slice 2 on SDP2, SDP11b, with A2A connectivity type. This is an L3 Slice Service that uses the uniform high bandwidth "slo-sle-template" policy between all SDPs.

Slice 1 uses the explicit match approach for mapping SDP traffic to a "connectivity-construct", while slice 2 uses the implicit approach. Both approaches are supported. The "slo-sle-templates" templates are known to the customer.

Note: These two slices both use service-tags of "L3". This "service-tag" is operator defined and has no specific meaning in the YANG model other than to give a hint to the NSC on the service expectation being L3 forwarding. In other examples, we may choose to eliminate it. The usage of this tag is arbitrary and depends on the needs of the operator and the NSC.

+--------+         192.0.2.1/26
|CE1     o------/  VLAN100
+--------+      |  SDP1 +------+
+--------+      +------o|  PE A+-------------+
|CE2     o-------/-----o|      |             |
+--------+         SDP2 +---+--+             |
             198.51.100.1/26|                |    192.0.2.129/26
                  VLAN200   |            +---+--+ VLAN100
                            |            |      | SDP4      +--------+
                            |            |PE C  o-----/-----o CE21   |
+--------+    192.0.2.65/26 |            +---+--+           +--------+
|        o------/ VLAN101   |                |
|        |      | SDP11a+---+---+            |
|CE11    |      +------o|PE B   +------------+
|        o-------/-----o|       |
+--------+        SDP11b+------ +
                  198.51.100.65/26
                  VLAN201

Figure 19: Example of Two A2A Slice Services

Figure 20 shows an example YANG JSON data for the body of the Network Slice Service instances request.

{
  "ietf-network-slice-service:network-slice-services": {
    "slo-sle-templates": {
      "slo-sle-template": [
        {
          "id": "high-BW-template",
          "description": "take the highest BW forwarding path"
        },
        {
          "id": "low-latency-template",
          "description": "lowest possible latency forwarding behavior"
        }
      ]
    },
    "slice-service": [
      {
        "id": "slice1",
        "description": "example slice1",
        "service-tags": {
          "tag-type": [
            {
              "tag-type": "ietf-nss:service",
              "value": ["L3"]
            }
          ]
        },
        "slo-sle-template": "low-latency-template",
        "status": {},
        "sdps": {
          "sdp": [
            {
              "id": "1",
              "node-id": "PE-A",
              "service-match-criteria": {
                "match-criterion": [
                  {
                    "index": 1,
                     "match-type": [
                      {"type": "ietf-nss:any"}
                    ],
                    "target-connection-group-id": "matrix1",
                    "target-connectivity-construct-id": "1"
                  }
                ]
              },
              "attachment-circuits": {
                "attachment-circuit": [
                  {
                    "id": "ac1",
                    "description": "AC1 connected to device 1",
                    "ac-node-id": "PE-A",
                    "ac-tp-id": "GigabitEthernet5/0/0/0.100",
                    "ac-ipv4-address": "192.0.2.1",
                    "ac-ipv4-prefix-length": 26,
                    "ac-tags": {
                      "ac-tag": [
                        {
                          "tag-type": "ietf-nss:vlan-id",
                          "value": ["100"]
                        }
                      ]
                    },
                    "status": {}
                  }
                ]
              },
              "status": {}
            },
            {
              "id": "3a",
              "node-id": "PE-B",
              "service-match-criteria": {
                "match-criterion": [
                  {
                    "index": 1,
                    "match-type": [
                      {"type": "ietf-nss:any"}
                    ],
                    "target-connection-group-id": "matrix1",
                    "target-connectivity-construct-id": "1"
                  }
                ]
              },
              "attachment-circuits": {
                "attachment-circuit": [
                  {
                    "id": "ac3a",
                    "description": "AC3a connected to device 3",
                    "ac-node-id": "PE-B",
                    "ac-tp-id": "GigabitEthernet8/0/0/4.101",
                    "ac-ipv4-address": "192.0.2.65",
                    "ac-ipv4-prefix-length": 26,
                    "ac-tags": {
                      "ac-tag": [
                        {
                          "tag-type": "ietf-nss:vlan-id",
                          "value": ["101"]
                        }
                      ]
                    },
                    "status": {}
                  }
                ]
              },
              "status": {}
            },
            {
              "id": "4",
              "node-id": "PE-C",
              "service-match-criteria": {
                "match-criterion": [
                  {
                    "index": 1,
                    "match-type": [
                      {"type": "ietf-nss:any"}
                    ],
                    "target-connection-group-id": "matrix1",
                    "target-connectivity-construct-id": "1"
                  }
                ]
              },
              "attachment-circuits": {
                "attachment-circuit": [
                  {
                    "id": "ac4",
                    "description": "AC4 connected to device 4",
                    "ac-node-id": "PE-C",
                    "ac-tp-id": "GigabitEthernet4/0/0/3.100",
                    "ac-ipv4-address": "192.0.2.129",
                    "ac-ipv4-prefix-length": 26,
                    "ac-tags": {
                      "ac-tag": [
                        {
                          "tag-type": "ietf-nss:vlan-id",
                          "value": ["100"]
                        }
                      ]
                    },
                    "status": {}
                  }
                ]
              },
              "status": {}
            }
          ]
        },
        "connection-groups": {
          "connection-group": [
            {
              "id": "matrix1",
              "connectivity-type": "ietf-vpn-common:any-to-any",
              "connectivity-construct": [
                {
                  "id": "1",
                  "a2a-sdp": [
                    {
                      "sdp-id": "1"
                    },
                    {
                      "sdp-id": "3a"
                    },
                    {
                      "sdp-id": "4"
                    }
                  ],
                  "status": {}
                }
              ]
            }
          ]
        }
      },
      {
        "id": "slice2",
        "description": "example slice2",
        "service-tags": {
          "tag-type": [
            {
              "tag-type": "ietf-nss:service",
              "value": ["L3"]
            }
          ]
        },
        "slo-sle-template": "high-BW-template",
        "status": {},
        "sdps": {
          "sdp": [
            {
              "id": "2",
              "node-id": "PE-A",
              "attachment-circuits": {
                "attachment-circuit": [
                  {
                    "id": "ac2",
                    "description": "AC2 connected to device 2",
                    "ac-node-id": "PE-A",
                    "ac-tp-id": "GigabitEthernet7/0/0/3.200",
                    "ac-ipv4-address": "198.51.100.1",
                    "ac-ipv4-prefix-length": 26,
                    "ac-tags": {
                      "ac-tag": [
                        {
                          "tag-type": "ietf-nss:vlan-id",
                          "value": ["100"]
                        }
                      ]
                    },
                    "status": {}
                  }
                ]
              },
              "status": {}
            },
            {
              "id": "3b",
              "node-id": "PE-B",
              "attachment-circuits": {
                "attachment-circuit": [
                  {
                    "id": "ac3b",
                    "description": "AC3b connected to device 3",
                    "ac-node-id": "PE-B",
                    "ac-tp-id": "GigabitEthernet8/0/0/4.201",
                    "ac-ipv4-address": "198.51.100.65",
                    "ac-ipv4-prefix-length": 26,
                    "ac-tags": {
                      "ac-tag": [
                        {
                          "tag-type": "ietf-nss:vlan-id",
                          "value": ["201"]
                        }
                      ]
                    },
                    "status": {}
                  }
                ]
              },
              "status": {}
            }
          ]
        },
        "connection-groups": {
          "connection-group": [
            {
              "id": "matrix2",
              "connectivity-type": "ietf-vpn-common:any-to-any",
              "connectivity-construct": [
                {
                  "id": "1",
                  "a2a-sdp": [
                    {
                      "sdp-id": "2"
                    },
                    {
                      "sdp-id": "3b"
                    }
                  ],
                  "status": {}
                }
              ]
            }
          ]
        }
      }
    ]
  }
}
Figure 20: Example of a Message Body to Create Two A2A Slice Services

B.2. Example-2: Two P2P Slice Services with Different Match Approaches

Figure 21 shows an example of two Network Slice Service instances where the SDPs are the customer-facing ports on the PE:

Slice 3 uses the explicit match approach for mapping SDP traffic to a "connectivity-group", while slice 2 uses the implicit approach. Both approaches are supported.

Note: These two slices both use service-tags of "L2". This "service-tag" is operator defined and has no specific meaning in the YANG model other than to give a hint to the NSC on the service expectation being L2 forwarding. Other examples we may choose to eliminate it. The usage of this tag is arbitrary and depends on the needs of the operator and the NSC.

+--------+
|  CE5   o------/  VLAN100
+--------+      |  SDP5 +------+
+--------+      +------o| PE A +---------------+
|  CE6   o-------/-----o|      |               |
+--------+         SDP6 +---+--+               |
                 VLAN200    |                  |
                            |              +---+--+
                            |              |      |
                            |              | PE C o
+--------+                  |              +---+--+
|        o------/ VLAN101   |                  |
|        |      | SDP7a +---+--+               |
| CE7    |      +------o| PE B +---------------+
|        o-------/-----o|      |
+--------+        SDP7b +------+
                  VLAN201
Figure 21: Example of Two P2P Slice Services

Figure 22 shows an example YANG JSON data for the body of the Network Slice Service instances request.

{
  "ietf-network-slice-service:network-slice-services": {
    "slo-sle-templates": {
      "slo-sle-template": [
        {
          "id": "high-BW-template",
          "description": "take the highest BW forwarding path"
        },
        {
          "id": "low-latency-template",
          "description": "lowest possible latency forwarding behavior"
        }
      ]
    },
    "slice-service": [
      {
        "id": "slice3",
        "description": "example slice3",
        "service-tags": {
          "tag-type": [
            {
              "tag-type": "ietf-nss:service",
              "value": ["L2"]
            }
          ]
        },
        "slo-sle-template": "low-latency-template",
        "status": {},
        "sdps": {
          "sdp": [
            {
              "id": "5",
              "node-id": "PE-A",
              "service-match-criteria": {
                "match-criterion": [
                  {
                    "index": 1,
                    "match-type": [
                      {"type": "ietf-nss:any"}
                    ],
                    "target-connection-group-id": "matrix3"
                  }
                ]
              },
              "attachment-circuits": {
                "attachment-circuit": [
                  {
                    "id": "ac5",
                    "description": "AC5 connected to device 5",
                    "ac-node-id": "PE-A",
                    "ac-tp-id": "GigabitEthernet5/0/0/1",
                    "ac-tags": {
                      "ac-tag": [
                        {
                          "tag-type": "ietf-nss:vlan-id",
                          "value": ["100"]
                        }
                      ]
                    },
                    "status": {}
                  }
                ]
              },
              "status": {}
            },
            {
              "id": "7a",
              "node-id": "PE-B",
              "service-match-criteria": {
                "match-criterion": [
                  {
                    "index": 1,
                    "match-type": [
                      {"type": "ietf-nss:any"}
                    ],
                    "target-connection-group-id": "matrix3"
                  }
                ]
              },
              "attachment-circuits": {
                "attachment-circuit": [
                  {
                    "id": "ac7a",
                    "description": "AC7a connected to device 7",
                    "ac-node-id": "PE-B",
                    "ac-tp-id": "GigabitEthernet8/0/0/5",
                    "ac-tags": {
                      "ac-tag": [
                        {
                          "tag-type": "ietf-nss:vlan-id",
                          "value": ["200"]
                        }
                      ]
                    },
                    "status": {}
                  }
                ]
              },
              "status": {}
            }
          ]
        },
        "connection-groups": {
          "connection-group": [
            {
              "id": "matrix3",
              "connectivity-type": "ietf-nss:point-to-point",
              "service-slo-sle-policy": {
                "slo-policy": {
                  "metric-bound": [
                    {
                      "metric-type": "ietf-nss:one-way-delay-maximum",
                      "metric-unit": "milliseconds",
                      "bound": "10"
                    }
                  ]
                }
              },
              "connectivity-construct": [
                {
                  "id": "1",
                  "p2p-sender-sdp": "5",
                  "p2p-receiver-sdp": "7a",
                  "status": {}
                },
                {
                  "id": "2",
                  "p2p-sender-sdp": "7a",
                  "p2p-receiver-sdp": "5",
                  "status": {}
                }
              ]
            }
          ]
        }
      },
      {
        "id": "slice4",
        "description": "example slice4",
        "service-tags": {
          "tag-type": [
            {
              "tag-type": "ietf-nss:service",
              "value": ["L2"]
            }
          ]
        },
        "slo-sle-template": "high-BW-template",
        "status": {},
        "sdps": {
          "sdp": [
            {
              "id": "6",
              "node-id": "PE-A",
              "attachment-circuits": {
                "attachment-circuit": [
                  {
                    "id": "ac6",
                    "description": "AC6 connected to device 6",
                    "ac-node-id": "PE-A",
                    "ac-tp-id": "GigabitEthernet7/0/0/4",
                    "ac-tags": {
                      "ac-tag": [
                        {
                          "tag-type": "ietf-nss:vlan-id",
                          "value": ["101"]
                        }
                      ]
                    },
                    "status": {}
                  }
                ]
              },
              "status": {}
            },
            {
              "id": "7b",
              "node-id": "PE-B",
              "attachment-circuits": {
                "attachment-circuit": [
                  {
                    "id": "ac7b",
                    "description": "AC7b connected to device 7",
                    "ac-node-id": "PE-B",
                    "ac-tp-id": "GigabitEthernet8/0/0/5",
                    "ac-tags": {
                      "ac-tag": [
                        {
                          "tag-type": "ietf-nss:vlan-id",
                          "value": ["201"]
                        }
                      ]
                    },
                    "status": {}
                  }
                ]
              },
              "status": {}
            }
          ]
        },
        "connection-groups": {
          "connection-group": [
            {
              "id": "matrix4",
              "connectivity-type": "ietf-nss:point-to-point",
              "connectivity-construct": [
                {
                  "id": "1",
                  "p2p-sender-sdp": "6",
                  "p2p-receiver-sdp": "7b",
                  "service-slo-sle-policy": {
                    "slo-policy": {
                      "metric-bound": [
                        {
                          "metric-type": "ietf-nss:one-way-bandwidth",
                          "metric-unit": "Mbps",
                          "bound": "1000"
                        }
                      ]
                    }
                  },
                  "status": {}
                },
                {
                  "id": "2",
                  "p2p-sender-sdp": "7b",
                  "p2p-receiver-sdp": "6",
                  "service-slo-sle-policy": {
                    "slo-policy": {
                      "metric-bound": [
                        {
                          "metric-type": "ietf-nss:one-way-bandwidth",
                          "metric-unit": "Mbps",
                          "bound": "5000"
                        }
                      ]
                    }
                  },
                  "status": {}
                }
              ]
            }
          ]
        }
      }
    ]
  }
}
Figure 22: Example of a Message Body to Create Two P2P Slice Services

The example shown in Figure 23 illustrates how a customer subscribes to the monitoring information of "slice3". The customer is interested in the operational and performance status of SDPs and connectivity constructs.

============== NOTE: '\' line wrapping per RFC 8792 ===============

POST /restconf/operations/ietf-subscribed-notifications:establish-\
                                   subscription
Host: example.com
Content-Type: application/yang-data+json

{
  "ietf-subscribed-notifications:input": {
    "stream-subtree-filter": {
      "ietf-network-slice-service:network-slice-services": {
        "slice-service": [
          {
            "id": "slice3",
            "sdps": {
              "sdp": [
                {
                  "id": "5",
                  "status": {
                    "oper-status": {
                      "status": {}
                    }
                  },
                  "sdp-monitoring": {
                    "incoming-bw-value": {},
                    "outgoing-bw-value": {}
                  }
                },
                {
                  "id": "7a",
                  "status": {
                    "oper-status": {
                      "status": {}
                    }
                  },
                  "sdp-monitoring": {
                    "incoming-bw-value": {},
                    "outgoing-bw-value": {}
                  }
                }
              ]
            },
            "connection-groups": {
              "connection-group": [
                {
                  "id": "matrix3",
                  "connectivity-type": "ietf-nss:point-to-point",
                  "connectivity-construct": [
                    {
                      "id": "1",
                      "p2p-sender-sdp": "5",
                      "p2p-receiver-sdp": "7a",
                      "status": {
                        "oper-status": {
                          "status": "{}"
                        }
                      },
                      "connectivity-construct-monitoring": {
                        "one-way-min-delay": {},
                        "one-way-max-delay": {}
                      }
                    },
                    {
                      "id": "2",
                      "p2p-sender-sdp": "7a",
                      "p2p-receiver-sdp": "5",
                      "status": {
                        "oper-status": {
                          "status": {}
                        }
                      },
                      "connectivity-construct-monitoring": {
                        "one-way-min-delay": {},
                        "one-way-max-delay": {}
                      }
                    }
                  ]
                }
              ]
            }
          }
        ]
      }
    },
    "ietf-yang-push:periodic": {
      "period": "500"
    }
  }
}
Figure 23: Example of a Message Body to Subscribe Monitoring Information of the Slice Service

The example Figure 24 shows a snapshot of YANG JSON data for the body of operational and performance status of the Network Slice Service "slice3".

{
  "ietf-network-slice-service:network-slice-services": {
    "slice-service": [
      {
        "id": "slice3",
        "description": "example slice3",
        "slo-sle-template": "low-latency-template",
        "status": {
          "oper-status": {
            "status": "ietf-vpn-common:op-up"
          }
        },
        "sdps": {
          "sdp": [
            {
              "id": "5",
              "node-id": "PE-A",
              "status": {
                "oper-status": {
                  "status": "ietf-vpn-common:op-up"
                }
              },
              "sdp-monitoring": {
                "incoming-bw-value": "10000",
                "outgoing-bw-value": "10000"
              }
            },
            {
              "id": "7a",
              "node-id": "PE-B",
              "status": {
                "oper-status": {
                  "status": "ietf-vpn-common:op-up"
                }
              },
              "sdp-monitoring": {
                "incoming-bw-value": "10000",
                "outgoing-bw-value": "10000"
              }
            }
          ]
        },
        "connection-groups": {
          "connection-group": [
            {
              "id": "matrix3",
              "connectivity-type": "ietf-nss:point-to-point",
              "connectivity-construct": [
                {
                  "id": "1",
                  "p2p-sender-sdp": "5",
                  "p2p-receiver-sdp": "7a",
                  "status": {
                    "oper-status": {
                      "status": "ietf-vpn-common:op-up"
                    }
                  },
                  "connectivity-construct-monitoring": {
                    "one-way-min-delay": "15",
                    "one-way-max-delay": "20"
                  }
                },
                {
                  "id": "2",
                  "p2p-sender-sdp": "7a",
                  "p2p-receiver-sdp": "5",
                  "status": {
                    "oper-status": {
                      "status": "ietf-vpn-common:op-up"
                    }
                  },
                  "connectivity-construct-monitoring": {
                    "one-way-min-delay": "15",
                    "one-way-max-delay": "20"
                  }
                }
              ]
            }
          ]
        }
      },
      {
        "id": "slice4",
        "description": "example slice4",
        "slo-sle-template": "high-BW-template",
        "status": {
          "oper-status": {
            "status": "ietf-vpn-common:op-up"
          }
        },
        "sdps": {
          "sdp": [
            {
              "id": "6",
              "node-id": "PE-A",
              "status": {
                "oper-status": {
                  "status": "ietf-vpn-common:op-up"
                }
              },
              "sdp-monitoring": {
                "incoming-bw-value": "10000000",
                "outgoing-bw-value": "10000000"
              }
            },
            {
              "id": "7b",
              "node-id": "PE-B",
              "status": {
                "oper-status": {
                  "status": "ietf-vpn-common:op-up"
                }
              },
              "sdp-monitoring": {
                "incoming-bw-value": "10000000",
                "outgoing-bw-value": "10000000"
              }
            }
          ]
        },
        "connection-groups": {
          "connection-group": [
            {
              "id": "matrix4",
              "connectivity-type": "ietf-nss:point-to-point",
              "connectivity-construct": [
                {
                  "id": "1",
                  "p2p-sender-sdp": "6",
                  "p2p-receiver-sdp": "7b",
                  "status": {
                    "oper-status": {
                      "status": "ietf-vpn-common:op-up"
                    }
                  },
                  "connectivity-construct-monitoring": {
                    "one-way-min-delay": "150",
                    "one-way-max-delay": "200"
                  }
                },
                {
                  "id": "2",
                  "p2p-sender-sdp": "7b",
                  "p2p-receiver-sdp": "6",
                  "status": {
                    "oper-status": {
                      "status": "ietf-vpn-common:op-up"
                    }
                  },
                  "connectivity-construct-monitoring": {
                    "one-way-min-delay": "150",
                    "one-way-max-delay": "200"
                  }
                }
              ]
            }
          ]
        }
      }
    ]
  }
}
Figure 24: Example of a Message Body of a Snapshot of Monitoring of the Slice Service

B.3. Example-3: A Hub and Spoke Slice Service with a P2MP Connectivity Construct

Figure 25 shows an example of one Network Slice Service instance where the SDPs are the customer-facing ports on the PE:

Network Slice 5 is a hub-spoke slice with SDP14 as the hub and SDP11, SDP12, SDP13a, SDP13b as spokes. This is an L3 Slice Service that uses the uniform low-latency "slo-sle-template" policies between all spokes and the hub SDPs, but using an explicit set of SLO policies with a latency metric of 10ms for hub to spoke traffic.
+--------+         192.0.2.1/26
|Device11o------/  VLAN100
+--------+      |  SDP11+------+
+--------+      +------o|  A   +-------------+
|Device12o-------/-----o|      |             |
+--------+         SDP12+---+--+             |
            198.51.100.1/26 |                |    192.0.2.129/26
                  VLAN200   |            +---+--+ VLAN100
                            |            |      | SDP14     +--------+
                            |            |   C  o-----/-----oDevice14|
+--------+    192.0.2.65/26 |            +---+--+           +--------+
|        o------/ VLAN101   |                |
|        |      | SDP13a+---+--+             |
|Device13|      +------o|  B   +-------------+
|        o-------/-----o|      |
+--------+        SDP13b+------+
                  198.51.100.65/26
                  VLAN201

Figure 25: Example of A Hub and Spoke Slice Service

Figure 26 shows an example YANG JSON data for the body of the hub-spoke Network Slice Service instances request.

============== NOTE: '\' line wrapping per RFC 8792 ===============

{
  "ietf-network-slice-service:network-slice-services": {
    "slo-sle-templates": {
      "slo-sle-template": [
        {
          "id": "high-BW-template",
          "description": "take the highest BW forwarding path"
        },
        {
          "id": "low-latency-template",
          "description": "lowest possible latency forwarding behavior"
        }
      ]
    },
    "slice-service": [
      {
        "id": "slice5",
        "description": "example slice5",
        "service-tags": {
          "tag-type": [
            {
              "tag-type": "ietf-nss:service",
              "value": ["L3"]
            }
          ]
        },
        "service-slo-sle-policy": {
          "description": "video-policy",
          "slo-policy": {
            "metric-bound": [
              {
                "metric-type": "ietf-nss:one-way-bandwidth",
                "metric-unit": "Mbps",
                "bound": "1000"
              },
              {
                "metric-type": "ietf-nss:two-way-delay-maximum",
                "metric-unit": "milliseconds",
                "bound": "100"
              }
            ],
            "availability": "ietf-nss:three-nines",
            "mtu": "1500"
          }
        },
        "status": {},
        "sdps": {
          "sdp": [
            {
              "id": "11",
              "node-id": "PE-A",
              "service-match-criteria": {
                "match-criterion": [
                  {
                    "index": 1,
                    "match-type": [
                      {"type": "ietf-nss:any"}
                    ],
                    "target-connection-group-id": "matrix5",
                    "connection-group-sdp-role": \
                      "ietf-vpn-common:spoke-role"
                  }
                ]
              },
              "attachment-circuits": {
                "attachment-circuit": [
                  {
                    "id": "ac11",
                    "description": "AC11 connected to device 11",
                    "ac-node-id": "PE-A",
                    "ac-tp-id": "GigabitEthernet5/0/0/2",
                    "ac-ipv4-address": "192.0.2.1",
                    "ac-ipv4-prefix-length": 26,
                    "ac-tags": {
                      "ac-tag": [
                        {
                          "tag-type": "ietf-nss:vlan-id",
                          "value": ["100"]
                        }
                      ]
                    },
                    "status": {}
                  }
                ]
              },
              "status": {}
            },
            {
              "id": "12",
              "node-id": "PE-A",
              "service-match-criteria": {
                "match-criterion": [
                  {
                    "index": 1,
                    "match-type": [
                      {"type": "ietf-nss:any"}
                    ],
                    "target-connection-group-id": "matrix5",
                    "connection-group-sdp-role": \
                      "ietf-vpn-common:spoke-role"
                  }
                ]
              },
              "attachment-circuits": {
                "attachment-circuit": [
                  {
                    "id": "ac12",
                    "description": "AC12 connected to device 12",
                    "ac-node-id": "PE-A",
                    "ac-tp-id": "GigabitEthernet7/0/0/5",
                    "ac-ipv4-address": "198.51.100.1",
                    "ac-ipv4-prefix-length": 26,
                    "ac-tags": {
                      "ac-tag": [
                        {
                          "tag-type": "ietf-nss:vlan-id",
                          "value": ["200"]
                        }
                      ]
                    },
                    "status": {}
                  }
                ]
              },
              "status": {}
            },
            {
              "id": "13a",
              "node-id": "PE-B",
              "service-match-criteria": {
                "match-criterion": [
                  {
                    "index": 1,
                    "match-type": [
                      {"type": "ietf-nss:any"}
                    ],
                    "target-connection-group-id": "matrix5",
                    "connection-group-sdp-role": \
                      "ietf-vpn-common:spoke-role"
                  }
                ]
              },
              "attachment-circuits": {
                "attachment-circuit": [
                  {
                    "id": "ac13a",
                    "description": "AC13a connected to device 13",
                    "ac-node-id": "PE-B",
                    "ac-tp-id": "GigabitEthernet8/0/0/6",
                    "ac-ipv4-address": "192.0.2.65",
                    "ac-ipv4-prefix-length": 26,
                    "ac-tags": {
                      "ac-tag": [
                        {
                          "tag-type": "ietf-nss:vlan-id",
                          "value": ["101"]
                        }
                      ]
                    },
                    "status": {}
                  }
                ]
              },
              "status": {}
            },
            {
              "id": "13b",
              "node-id": "PE-B",
              "service-match-criteria": {
                "match-criterion": [
                  {
                    "index": 1,
                    "match-type": [
                      {"type": "ietf-nss:any"}
                    ],
                    "target-connection-group-id": "matrix5",
                    "connection-group-sdp-role": \
                      "ietf-vpn-common:spoke-role"
                  }
                ]
              },
              "attachment-circuits": {
                "attachment-circuit": [
                  {
                    "id": "ac13b",
                    "description": "AC3b connected to device 13",
                    "ac-node-id": "PE-B",
                    "ac-tp-id": "GigabitEthernet8/0/0/4",
                    "ac-ipv4-address": "198.51.100.65",
                    "ac-ipv4-prefix-length": 26,
                    "ac-tags": {
                      "ac-tag": [
                        {
                          "tag-type": "ietf-nss:vlan-id",
                          "value": ["201"]
                        }
                      ]
                    },
                    "status": {}
                  }
                ]
              },
              "status": {}
            },
            {
              "id": "14",
              "node-id": "PE-C",
              "service-match-criteria": {
                "match-criterion": [
                  {
                    "index": 1,
                    "match-type": [
                      {"type": "ietf-nss:any"}
                    ],
                    "target-connection-group-id": "matrix5",
                    "connection-group-sdp-role": \
                      "ietf-vpn-common:hub-role"
                  }
                ]
              },
              "attachment-circuits": {
                "attachment-circuit": [
                  {
                    "id": "ac14",
                    "description": "AC14 connected to device 14",
                    "ac-node-id": "PE-C",
                    "ac-tp-id": "GigabitEthernet4/0/0/3",
                    "ac-ipv4-address": "192.0.2.129",
                    "ac-ipv4-prefix-length": 26,
                    "ac-tags": {
                      "ac-tag": [
                        {
                          "tag-type": "ietf-nss:vlan-id",
                          "value": ["100"]
                        }
                      ]
                    },
                    "status": {}
                  }
                ]
              },
              "status": {}
            }
          ]
        },
        "connection-groups": {
          "connection-group": [
            {
              "id": "matrix5",
              "connectivity-type": "ietf-vpn-common:hub-spoke",
              "connectivity-construct": [
                {
                  "id": "1",
                  "p2mp-sender-sdp": "14",
                  "p2mp-receiver-sdp": [
                    "11",
                    "12",
                    "13a",
                    "13b"
                  ],
                  "service-slo-sle-policy": {
                    "slo-policy": {
                      "metric-bound": [
                        {
                          "metric-type": \
                            "ietf-nss:one-way-delay-maximum",
                          "metric-unit": "milliseconds",
                          "bound": "10"
                        }
                      ]
                    }
                  },
                  "status": {}
                }
              ]
            }
          ]
        }
      }
    ]
  }
}
Figure 26: Example of a Message Body to Create A Hub and Spoke Slice Service

B.4. Example-4: An A2A Slice Service with Multiple SLOs and DSCP Matching

Figure 27 shows an example of a Network slice instance where the SDPs are the customer-facing ports on the PE:

Network Slice 6 on SDP21, SDP23a, and SDP24, with A2A connectivity type. This is an L3 Slice Service that uses the uniform "standard" slo-sle-template policies between all SDPs. For traffic matching the DSCP of EF, a slo-sle-template policy of "low-latency" will be used. The slice uses the explicit match approach for mapping SDP traffic to a connectivity construct.
In some use cases, the Slice Service may also need to map traffic based on a combination of the DSCP and IP address, not DSCP only, which is shown in the example of "service-match-criteria" Figure 29.
+--------+         192.0.2.1/24
| CE21   o------/  VLAN100
+--------+      |  SDP21+------+
                +------o| PE A +-------------+
                        |      |             |
                        +---+--+             |
                            |                |    203.0.113.1/24
                            |            +---+--+ VLAN100
                            |            |      | SDP24     +--------+
                            |            | PE C o-----/-----o CE24   |
+--------+  198.51.100.1/24 |            +---+--+           +--------+
|        o------/ VLAN101   |                |
|        |      | SDP23a+---+--+             |
|CE23    |      +------o| PE B +-------------+
|        o              |      |
+--------+              +------+
Figure 27: Example of An A2A Slice Service with DSCP Matching

Figure 28 shows an example YANG JSON data for the body of the Network Slice Service instances request.

{
  "ietf-network-slice-service:network-slice-services": {
    "slo-sle-templates": {
      "slo-sle-template": [
        {
          "id": "high-BW-template",
          "description": "take the highest BW forwarding path"
        },
        {
          "id": "low-latency-template",
          "description": "lowest possible latency forwarding behavior"
        },
        {
          "id": "standard-template",
          "description": "take the standard forwarding path"
        }
      ]
    },
    "slice-service": [
      {
        "id": "slice6",
        "description": "example slice6",
        "service-tags": {
          "tag-type": [
            {
              "tag-type": "ietf-nss:service",
              "value": ["L3"]
            }
          ]
        },
        "slo-sle-template": "standard-template",
        "status": {},
        "sdps": {
          "sdp": [
            {
              "id": "21",
              "node-id": "PE-A",
              "service-match-criteria": {
                "match-criterion": [
                  {
                    "index": 1,
                    "match-type": [
                      {
                        "type": "ietf-nss:dscp",
                        "value": ["EF"]
                      }
                    ],
                    "target-connection-group-id": "matrix6",
                    "target-connectivity-construct-id": "2"
                  },
                  {
                    "index": 2,
                    "match-type": [
                      {"type": "ietf-nss:any"}
                    ],
                    "target-connection-group-id": "matrix6",
                    "target-connectivity-construct-id": "1"
                  }
                ]
              },
              "attachment-circuits": {
                "attachment-circuit": [
                  {
                    "id": "ac21",
                    "description": "AC21 connected to device 21",
                    "ac-node-id": "PE-A",
                    "ac-tp-id": "GigabitEthernet5/0/0/0",
                    "ac-ipv4-address": "192.0.2.1",
                    "ac-ipv4-prefix-length": 24,
                    "ac-tags": {
                      "ac-tag": [
                        {
                          "tag-type": "ietf-nss:vlan-id",
                          "value": ["100"]
                        }
                      ]
                    },
                    "status": {}
                  }
                ]
              },
              "status": {}
            },
            {
              "id": "23a",
              "node-id": "PE-B",
              "service-match-criteria": {
                "match-criterion": [
                  {
                    "index": 1,
                    "match-type": [
                      {
                        "type": "ietf-nss:dscp",
                        "value": ["EF"]
                      }
                    ],
                    "target-connection-group-id": "matrix6",
                    "target-connectivity-construct-id": "2"
                  },
                  {
                    "index": 2,
                    "match-type": [
                      {"type": "ietf-nss:any"}
                    ],
                    "target-connection-group-id": "matrix6",
                    "target-connectivity-construct-id": "1"
                  }
                ]
              },
              "attachment-circuits": {
                "attachment-circuit": [
                  {
                    "id": "ac23a",
                    "description": "AC23a connected to device 23",
                    "ac-node-id": "PE-B",
                    "ac-tp-id": "GigabitEthernet8/0/0/4",
                    "ac-ipv4-address": "198.51.100.1",
                    "ac-ipv4-prefix-length": 24,
                    "ac-tags": {
                      "ac-tag": [
                        {
                          "tag-type": "ietf-nss:vlan-id",
                          "value": ["101"]
                        }
                      ]
                    },
                    "status": {}
                  }
                ]
              },
              "status": {}
            },
            {
              "id": "24",
              "node-id": "PE-C",
              "service-match-criteria": {
                "match-criterion": [
                  {
                    "index": 1,
                    "match-type": [
                      {
                        "type": "ietf-nss:dscp",
                        "value": ["EF"]
                      }
                    ],
                    "target-connection-group-id": "matrix6",
                    "target-connectivity-construct-id": "2"
                  },
                  {
                    "index": 2,
                    "match-type": [
                      {"type": "ietf-nss:any"}
                    ],
                    "target-connection-group-id": "matrix6",
                    "target-connectivity-construct-id": "1"
                  }
                ]
              },
              "attachment-circuits": {
                "attachment-circuit": [
                  {
                    "id": "ac24",
                    "description": "AC24 connected to device 24",
                    "ac-node-id": "PE-C",
                    "ac-tp-id": "GigabitEthernet4/0/0/3",
                    "ac-ipv4-address": "203.0.113.1",
                    "ac-ipv4-prefix-length": 24,
                    "ac-tags": {
                      "ac-tag": [
                        {
                          "tag-type": "ietf-nss:vlan-id",
                          "value": ["100"]
                        }
                      ]
                    },
                    "status": {}
                  }
                ]
              },
              "status": {}
            }
          ]
        },
        "connection-groups": {
          "connection-group": [
            {
              "id": "matrix6",
              "connectivity-type": "ietf-vpn-common:any-to-any",
              "connectivity-construct": [
                {
                  "id": "1",
                  "a2a-sdp": [
                    {
                      "sdp-id": "21"
                    },
                    {
                      "sdp-id": "23a"
                    },
                    {
                      "sdp-id": "24",
                    }
                  ],
                  "status": {}
                },
                {
                  "id": "2",
                  "a2a-sdp": [
                    {
                      "sdp-id": "21"
                    },
                    {
                      "sdp-id": "23a"
                    },
                    {
                      "sdp-id": "24"
                      "slo-sle-template": "low-latency-template"
                    }
                  ],
                  "status": {}
                }
              ]
            }
          ]
        }
      }
    ]
  }
}
Figure 28: Example of a Message Body to Create An A2A Slice Service with DSCP Matching

Figure 29 shows an example of "service-match-criteria" with a combination of both DSCP and IP Address for the Slice Service traffic matching.

{
  "service-match-criteria": {
    "match-criterion": [
      {
        "index": 1,
        "match-type": [
          {
            "type": "ietf-nss:dscp",
            "value": ["EF"]
          },
          {
            "type": "ietf-nss: destination-ip-prefix",
            "value": "192.0.2.254"
          }
        ],
        "target-connection-group-id": "matrix6",
        "target-connectivity-construct-id": "2"
      }
    ]
  }
}
Figure 29: An Example of Match Criterion with Combination of DSCP and IP Address Matching

B.5. Example-5: An A2A Network Slice Service with SLO Precedence Policies

Figure 30 shows an example of a Network slice instance "slice-7" with four SDPs: SDP1, SDP2, SDP3 and SDP4 with A2A connectivity type. All SDPs are designated as customer-facing ports on the PE.

The service is realized using a single A2A connectivity construct, and a low-bandwidth "slo-sle-template" policy applied to SDP4 and SDP3, while a high-bandwidth "slo-sle-template" policy applied to SDP1 and SDP2. Notice that the "slo-sle-templates" at the connectivity construct level takes precedence over the one specified at the group level.

+--------+         2001:db8:0:1::1                2001:db8:0:3::1
|CE1     o------/  VLAN100                        VLAN100
+--------+      |  SDP1 +------+         +------+ SDP3
                +------o| PE A +---------|-PE C |           +--------+
                        |      |         |      |-----/-----o CE3    |
                        +---+--+         +------+           +--------+
                            |                |
                            |                |
                            |                |
                            |                |
+--------+  2001:db8:0:2::1 |                |
|CE2     o------/ VLAN100   |                |    2001:db8:0:4::1
+--------+      | SDP2  +---+--+         +---+--+ VLAN100
                +------o| PE B +---------|PE D  | SDP4      +--------+
                        |      |         |      o-----/-----o    CE4 |
                        +------+         +------+           +--------+
Figure 30: Example of An A2A Slice Service with SLO Precedence

Figure 31 shows an example YANG JSON data for the body of the Network Slice Service instances request.

{
  "ietf-network-slice-service:network-slice-services": {
    "slo-sle-templates": {
      "slo-sle-template": [
        {
          "id": "high-BW-template",
          "description": "take the highest BW forwarding path"
        },
        {
          "id": "low-BW-template",
          "description": "lowest BW forwarding behavior"
        }
      ]
    },
    "slice-service": [
      {
        "id": "slice-7",
        "description": "Foo",
        "service-tags": {
          "tag-type": [
            {
              "tag-type": "ietf-nss:customer",
              "value": ["Customer-FOO"]
            },
            {
              "tag-type": "ietf-nss:service",
              "value": ["L3"]
            }
          ]
        },
        "status": {},
        "sdps": {
          "sdp": [
            {
              "id": "SDP1",
              "description": "Central Office 1 at location PE-A",
              "node-id": "PE-A",
              "sdp-ip-address": ["2001:db8:0:1::1"],
              "service-match-criteria": {
                "match-criterion": [
                  {
                    "index": 1,
                    "match-type": [
                      {
                        "type": "ietf-nss:vlan",
                        "value": ["100"]
                      }
                    "target-connection-group-id": "matrix1"
                  }
                ]
              },
              "attachment-circuits": {
                "attachment-circuit": [
                  {
                    "id": "AC-SDP1",
                    "description": "Device 1 to PE-A",
                    "ac-node-id": "PE-A",
                    "ac-tp-id": "GigabitEthernet1/0/0/0",
                    "ac-ipv6-address": "2001:db8:0:1::1",
                    "ac-ipv6-prefix-length": 64,
                    "ac-tags": {
                      "ac-tag": [
                        {
                          "tag-type": "ietf-nss:vlan-id",
                          "value": ["100"]
                        }
                      ]
                    },
                    "incoming-qos-policy": {
                      "qos-policy-name": "QoS-Gold",
                      "rate-limits": {
                        "cir": "1000000",
                        "cbs": "1000",
                        "pir": "5000000",
                        "pbs": "1000"
                      }
                    },
                    "status": {}
                  }
                ]
              },
              "status": {}
            },
            {
              "id": "SDP2",
              "description": "Central Office 2 at location PE-B",
              "node-id": "PE-B",
              "sdp-ip-address": ["2001:db8:0:2::1"],
              "service-match-criteria": {
                "match-criterion": [
                  {
                    "index": 1,
                    "match-type": [
                      {
                        "type": "ietf-nss:vlan",
                        "value": ["100"]
                      }
                    "target-connection-group-id": "matrix1"
                  }
                ]
              },
              "attachment-circuits": {
                "attachment-circuit": [
                  {
                    "id": "AC-SDP2",
                    "description": "Device 2 to PE-B",
                    "ac-node-id": "PE-B",
                    "ac-tp-id": "GigabitEthernet2/0/0/0",
                    "ac-ipv6-address": "2001:db8:0:2::1",
                    "ac-ipv6-prefix-length": 64,
                    "ac-tags": {
                      "ac-tag": [
                        {
                          "tag-type": "ietf-nss:vlan-id",
                          "value": ["100"]
                        }
                      ]
                    },
                    "incoming-qos-policy": {
                      "qos-policy-name": "QoS-Gold",
                      "rate-limits": {
                        "cir": "1000000",
                        "cbs": "1000",
                        "pir": "5000000",
                        "pbs": "1000"
                      }
                    },
                    "status": {}
                  }
                ]
              },
              "status": {}
            },
            {
              "id": "SDP3",
              "description": "Remote Office 1 at location PE-C",
              "node-id": "PE-C",
              "sdp-ip-address": [
                "2001:db8:0:3::1"
              ],
              "service-match-criteria": {
                "match-criterion": [
                  {
                    "index": 1,
                    "match-type": [
                      {
                        "type": "ietf-nss:vlan",
                        "value": ["100"]
                      }
                    "target-connection-group-id": "matrix1"
                  }
                ]
              },
              "attachment-circuits": {
                "attachment-circuit": [
                  {
                    "id": "AC-SDP3",
                    "description": "Device 3 to PE-C",
                    "ac-node-id": "PE-C",
                    "ac-tp-id": "GigabitEthernet3/0/0/0",
                    "ac-ipv6-address": "2001:db8:0:3::1",
                    "ac-ipv6-prefix-length": 64,
                    "ac-tags": {
                      "ac-tag": [
                        {
                          "tag-type": "ietf-nss:vlan-id",
                          "value": ["100"]
                        }
                      ]
                    },
                    "incoming-qos-policy": {
                      "qos-policy-name": "QoS-Gold",
                      "rate-limits": {
                        "cir": "1000000",
                        "cbs": "1000",
                        "pir": "5000000",
                        "pbs": "1000"
                      }
                    },
                    "status": {}
                  }
                ]
              },
              "status": {}
            },
            {
              "id": "SDP4",
              "description": "Remote Office 2 at location PE-D",
              "node-id": "PE-D",
              "sdp-ip-address": ["2001:db8:0:4::1"],
              "service-match-criteria": {
                "match-criterion": [
                  {
                    "index": 1,
                    "match-type": [
                      {
                        "type": "ietf-nss:vlan",
                        "value": ["100"]
                      }
                    "target-connection-group-id": "matrix1"
                  }
                ]
              },
              "attachment-circuits": {
                "attachment-circuit": [
                  {
                    "id": "AC-SDP4",
                    "description": "Device 4 to PE-D",
                    "ac-node-id": "PE-A",
                    "ac-tp-id": "GigabitEthernet4/0/0/0",
                    "ac-ipv6-address": "2001:db8:0:4::1",
                    "ac-ipv6-prefix-length": 64,
                    "ac-tags": {
                      "ac-tag": [
                        {
                          "tag-type": "ietf-nss:vlan-id",
                          "value": ["100"]
                        }
                      ]
                    },
                    "incoming-qos-policy": {
                      "qos-policy-name": "QoS-Gold",
                      "rate-limits": {
                        "cir": "1000000",
                        "cbs": "1000",
                        "pir": "5000000",
                        "pbs": "1000"
                      }
                    },
                    "status": {}
                  }
                ]
              },
              "status": {}
            }
          ]
        },
        "connection-groups": {
          "connection-group": [
            {
              "id": "matrix1",
              "slo-sle-template": "low-BW-template",
              "connectivity-construct": [
                {
                  "id": "1",
                  "a2a-sdp": [
                    {
                      "sdp-id": "SDP1",
                      "slo-sle-template": "high-BW-template"
                    },
                    {
                      "sdp-id": "SDP2",
                      "slo-sle-template": "high-BW-template"
                    },
                    {
                      "sdp-id": "SDP3"
                    },
                    {
                      "sdp-id": "SDP4"
                    }
                  ],
                  "status": {}
                }
              ]
            }
          ]
        }
      }
    ]
  }
}
Figure 31: Example of a Message Body to Create an A2A Slice Service with SLO Precedence

B.6. Example-6: SDP at CE, L3 A2A Slice Service

Figure 32 shows an example of one Network slice instance where the SDPs are located at the PE-facing ports on the CE:

SDP31
SDP-ip 203.0.113.1
(Loopback)
    |
    |     192.0.2.2/26
    v      VLAN200      +------+
+--------+ ac31         | PE A +-------------+
|Device1 o-------/-----o|      |             |                   SDP34
+--------+              +---+--+             |    SDP-ip 203.0.113.129
                            |                |                 |
SDP33                       |                |                 |
SDP-ip 203.0.113.65         |            +---+--+              v
    |      192.0.2.66/26    |            |      |           +--------+
    v      VLAN101          |            | PE C o-----/-----o Device4|
+--------+ ac33a            |            +---+--+    ac34   +--------+
|        o------/           |                |       VLAN201
|        |      |       +---+---+            |       198.51.100.66/26
|Device3 |      +------o| PE B  +------------+
|        o-------/-----o|       |
+--------+ ac33b        +-------+
           VLAN201
           198.51.100.2/26

Figure 32: Example of an A2A Slice Service with CE Based SDP

Figure 33 shows an example YANG JSON data for the body of the Network Slice Service instances request.

{
  "ietf-network-slice-service:network-slice-services": {
    "slo-sle-templates": {
      "slo-sle-template": [
        {
          "id": "high-BW-template",
          "description": "take the highest BW forwarding path"
        },
        {
          "id": "low-latency-template",
          "description": "lowest possible latency forwarding behavior"
        }
      ]
    },
    "slice-service": [
      {
        "id": "slice8",
        "description": "slice-8",
        "service-tags": {
          "tag-type": [
            {
              "tag-type": "ietf-nss:service",
              "value": ["L3"]
            }
          ]
        },
        "slo-sle-template": "low-latency-template",
        "status": {},
        "sdps": {
          "sdp": [
            {
              "id": "31",
              "node-id": "Device-1",
              "sdp-ip-address": ["203.0.113.1"],
              "service-match-criteria": {
                "match-criterion": [
                  {
                    "index": 1,
                    "match-type": [
                      {"type": "ietf-nss:any"}
                    ],
                    "target-connection-group-id": "matrix1",
                    "target-connectivity-construct-id": "1"
                  }
                ]
              },
              "attachment-circuits": {
                "attachment-circuit": [
                  {
                    "id": "ac31",
                    "description": "AC1 connected to PE-A",
                    "ac-node-id": "Device-1",
                    "ac-tp-id": "GigabitEthernet0",
                    "ac-ipv4-address": "192.0.2.2",
                    "ac-ipv4-prefix-length": 26,
                    "ac-tags": {
                      "ac-tag": [
                        {
                          "tag-type": "ietf-nss:vlan-id",
                          "value": ["100"]
                        }
                      ]
                    },
                    "status": {}
                  }
                ]
              },
              "status": {}
            },
            {
              "id": "33",
              "node-id": "Device-3",
              "sdp-ip-address": ["203.0.113.65"],
              "service-match-criteria": {
                "match-criterion": [
                  {
                    "index": 1,
                    "match-type": [
                      {"type": "ietf-nss:any"}
                    ],
                    "target-connection-group-id": "matrix1",
                    "target-connectivity-construct-id": "1"
                  }
                ]
              },
              "attachment-circuits": {
                "attachment-circuit": [
                  {
                    "id": "ac33a",
                    "description": "AC33a connected to PE-B",
                    "ac-node-id": "Device-3",
                    "ac-tp-id": "GigabitEthernet0",
                    "ac-ipv4-address": "192.0.2.66",
                    "ac-ipv4-prefix-length": 26,
                    "ac-tags": {
                      "ac-tag": [
                        {
                          "tag-type": "ietf-nss:vlan-id",
                          "value": ["101"]
                        }
                      ]
                    },
                    "status": {}
                  },
                  {
                    "id": "ac33b",
                    "description": "AC33b connected to PE-B",
                    "ac-node-id": "Device-3",
                    "ac-tp-id": "GigabitEthernet1",
                    "ac-ipv4-address": "198.51.100.2",
                    "ac-ipv4-prefix-length": 26,
                    "ac-tags": {
                      "ac-tag": [
                        {
                          "tag-type": "ietf-nss:vlan-id",
                          "value": ["201"]
                        }
                      ]
                    },
                    "status": {}
                  }
                ]
              },
              "status": {}
            },
            {
              "id": "34",
              "node-id": "Device-4",
              "sdp-ip-address": ["203.0.113.129"],
              "service-match-criteria": {
                "match-criterion": [
                  {
                    "index": 1,
                    "match-type": [
                      {"type": "ietf-nss:any"}
                    ],
                    "target-connection-group-id": "matrix1",
                    "target-connectivity-construct-id": "1"
                  }
                ]
              },
              "attachment-circuits": {
                "attachment-circuit": [
                  {
                    "id": "ac34",
                    "description": "AC34 connected to PE-C",
                    "ac-node-id": "Device-4",
                    "ac-tp-id": "GigabitEthernet3",
                    "ac-ipv4-address": "198.51.100.66",
                    "ac-ipv4-prefix-length": 26,
                    "ac-tags": {
                      "ac-tag": [
                        {
                          "tag-type": "ietf-nss:vlan-id",
                          "value": ["100"]
                        }
                      ]
                    },
                    "status": {}
                  }
                ]
              },
              "status": {}
            }
          ]
        },
        "connection-groups": {
          "connection-group": [
            {
              "id": "matrix1",
              "connectivity-type": "ietf-vpn-common:any-to-any",
              "connectivity-construct": [
                {
                  "id": "1",
                  "a2a-sdp": [
                    {
                      "sdp-id": "31"
                    },
                    {
                      "sdp-id": "33"
                    },
                    {
                      "sdp-id": "34"
                    }
                  ],
                  "status": {}
                }
              ]
            }
          ]
        }
      }
    ]
  }
}
Figure 33: Example of a Message Body to Create an CE based A2A Slice Services

B.7. Example-7: SDP at CE, L3 A2A Slice Service with Network Abstraction

Figure 34 shows an example of one Network slice instance where the SDPs are located at the PE-facing ports on the CE.

In this example, it is assumed that the NSC already has circuit binding details between the CE and PE which were previously assigned (method is out-of-scope) or the NSC has mechanisms to determine this mapping. While the NSC capabilities are out-of-scope of this document, the NSC may use the CE device name, "sdp-id", "sdp-ip", "ac-id" or the "peer-sap-id" to complete this AC circuit binding.

We are introducing the "peer-sap-id" in this example, which in this case, is an operator provided identifier that the slice requester can use for the NSC to identify the service attachment point (saps) in an abstracted way. How the NSC uses the "peer-sap-id" is out of scope of this document, but a possible implementation would be that the NSC was previously provisioned with a "peer-sap-id" to PE device/interface/VLAN mapping table. Alternatively, the NSC can request this mapping from an external database.

SDP31
2001:db8:0:1::1
(Loopback,etc)
    |
    |
    v                   +-----------------------+
+--------+ ac31         |                       |
|Device1 o-------/-----o|sap                    |             SDP34
+--------+              |                       |      2001:db8:0:3::1
                        |     Abstracted        |              |
SDP33                   |   Provider Network    |              |
2001:db8:0:2::1         |                       |              v
    |                   |                       |           +--------+
    v                   |                    sap|-----/-----o Device4|
+--------+ ac33a        |                       |    ac41   +--------+
|        o------/       |                       |
|        |      |       |                       |
|Device3 |      +------o|sap                    |
|        o-------/-----o|sap                    |
+--------+ ac33b        +-----------------------+

Figure 34: Example of a Message Body to Create an A2A CE Based Slice Service with Abstraction

Figure 35 shows an example YANG JSON data for the body of the Network Slice Service instances request.

{
  "ietf-network-slice-service:network-slice-services": {
    "slo-sle-templates": {
      "slo-sle-template": [
        {
          "id": "high-BW-template",
          "description": "take the highest BW forwarding path"
        },
        {
          "id": "low-latency-template",
          "description": "lowest possible latency forwarding behavior"
        }
      ]
    },
    "slice-service": [
      {
        "id": "slice-9",
        "description": "example slice7",
        "service-tags": {
          "tag-type": [
            {
              "tag-type": "ietf-nss:service",
              "value": ["L3"]
            }
          ]
        },
        "slo-sle-template": "low-latency-template",
        "status": {},
        "sdps": {
          "sdp": [
            {
              "id": "31",
              "node-id": "Device-1",
              "sdp-ip-address": ["2001:db8:0:1::1"],
              "service-match-criteria": {
                "match-criterion": [
                  {
                    "index": 1,
                    "match-type": [
                      {"type": "ietf-nss:any"}
                    ],
                    "target-connection-group-id": "matrix1"
                  }
                ]
              },
              "attachment-circuits": {
                "attachment-circuit": [
                  {
                    "id": "ac31",
                    "sdp-peering": {
                      "peer-sap-id": "foo.com-circuitID-12345"
                    },
                    "status": {}
                  }
                ]
              },
              "status": {}
            },
            {
              "id": "33",
              "node-id": "Device-3",
              "sdp-ip-address": ["2001:db8:0:2::1"],
              "service-match-criteria": {
                "match-criterion": [
                  {
                    "index": 1,
                    "match-type": [
                      {"type": "ietf-nss:any"}
                    ],
                    "target-connection-group-id": "matrix1",
                    "target-connectivity-construct-id": "1"
                  }
                ]
              },
              "attachment-circuits": {
                "attachment-circuit": [
                  {
                    "id": "ac33a",
                    "sdp-peering": {
                      "peer-sap-id": "foo.com-circuitID-67890"
                    },
                    "status": {}
                  },
                  {
                    "id": "ac33b",
                    "sdp-peering": {
                      "peer-sap-id": "foo.com-circuitID-54321ABC"
                    },
                    "status": {}
                  }
                ]
              },
              "status": {}
            },
            {
              "id": "34",
              "node-id": "Device-4",
              "sdp-ip-address": [
                "2001:db8:0:3::1"
              ],
              "service-match-criteria": {
                "match-criterion": [
                  {
                    "index": 1,
                    "match-type": [
                      {"type": "ietf-nss:any"}
                    ],
                    "target-connection-group-id": "matrix1"
                  }
                ]
              },
              "attachment-circuits": {
                "attachment-circuit": [
                  {
                    "id": "ac34",
                    "sdp-peering": {
                      "peer-sap-id": "foo.com-circuitID-9876"
                    },
                    "status": {}
                  }
                ]
              },
              "status": {}
            }
          ]
        },
        "connection-groups": {
          "connection-group": [
            {
              "id": "matrix1",
              "connectivity-type": "ietf-vpn-common:any-to-any",
              "connectivity-construct": [
                {
                  "id": "1",
                  "a2a-sdp": [
                    {
                      "sdp-id": "31"
                    },
                    {
                      "sdp-id": "33"
                    },
                    {
                      "sdp-id": "34"
                    }
                  ],
                  "status": {}
                }
              ]
            }
          ]
        }
      }
    ]
  }
}
Figure 35: Example of a Message Body to Create an A2A Slice Service with Abstraction

Appendix C. Complete Model Tree Structure

module: ietf-network-slice-service
  +--rw network-slice-services
     +--rw slo-sle-templates
     |  +--rw slo-sle-template* [id]
     |     +--rw id              string
     |     +--rw description?    string
     |     +--rw template-ref?   slice-template-ref
     |     +--rw slo-policy
     |     |  +--rw metric-bound* [metric-type]
     |     |  |  +--rw metric-type          identityref
     |     |  |  +--rw metric-unit          string
     |     |  |  +--rw value-description?   string
     |     |  |  +--rw percentile-value?    percentile
     |     |  |  +--rw bound?               uint64
     |     |  +--rw availability?   identityref
     |     |  +--rw mtu?            uint32
     |     +--rw sle-policy
     |        +--rw security*              identityref
     |        +--rw isolation*             identityref
     |        +--rw max-occupancy-level?   uint8
     |        +--rw path-constraints
     |           +--rw service-functions
     |           +--rw diversity
     |              +--rw diversity-type?
     |                      te-types:te-path-disjointness
     +--rw slice-service* [id]
        +--rw id                              string
        +--rw description?                    string
        +--rw service-tags
        |  +--rw tag-type* [tag-type]
        |     +--rw tag-type    identityref
        |     +--rw value*      string
        +--rw (slo-sle-policy)?
        |  +--:(standard)
        |  |  +--rw slo-sle-template?         slice-template-ref
        |  +--:(custom)
        |     +--rw service-slo-sle-policy
        |        +--rw description?   string
        |        +--rw slo-policy
        |        |  +--rw metric-bound* [metric-type]
        |        |  |  +--rw metric-type          identityref
        |        |  |  +--rw metric-unit          string
        |        |  |  +--rw value-description?   string
        |        |  |  +--rw percentile-value?    percentile
        |        |  |  +--rw bound?               uint64
        |        |  +--rw availability?   identityref
        |        |  +--rw mtu?            uint32
        |        +--rw sle-policy
        |           +--rw security*              identityref
        |           +--rw isolation*             identityref
        |           +--rw max-occupancy-level?   uint8
        |           +--rw path-constraints
        |              +--rw service-functions
        |              +--rw diversity
        |                 +--rw diversity-type?
        |                         te-types:te-path-disjointness
        +--rw compute-only?                   empty
        +--rw status
        |  +--rw admin-status
        |  |  +--rw status?        identityref
        |  |  +--ro last-change?   yang:date-and-time
        |  +--ro oper-status
        |     +--ro status?        identityref
        |     +--ro last-change?   yang:date-and-time
        +--rw sdps
        |  +--rw sdp* [id]
        |     +--rw id                        string
        |     +--rw description?              string
        |     +--rw geo-location
        |     |  +--rw reference-frame
        |     |  |  +--rw alternate-system?    string
        |     |  |  |       {alternate-systems}?
        |     |  |  +--rw astronomical-body?   string
        |     |  |  +--rw geodetic-system
        |     |  |     +--rw geodetic-datum?    string
        |     |  |     +--rw coord-accuracy?    decimal64
        |     |  |     +--rw height-accuracy?   decimal64
        |     |  +--rw (location)?
        |     |  |  +--:(ellipsoid)
        |     |  |  |  +--rw latitude?    decimal64
        |     |  |  |  +--rw longitude?   decimal64
        |     |  |  |  +--rw height?      decimal64
        |     |  |  +--:(cartesian)
        |     |  |     +--rw x?           decimal64
        |     |  |     +--rw y?           decimal64
        |     |  |     +--rw z?           decimal64
        |     |  +--rw velocity
        |     |  |  +--rw v-north?   decimal64
        |     |  |  +--rw v-east?    decimal64
        |     |  |  +--rw v-up?      decimal64
        |     |  +--rw timestamp?         yang:date-and-time
        |     |  +--rw valid-until?       yang:date-and-time
        |     +--rw node-id?                  string
        |     +--rw sdp-ip-address*           inet:ip-address
        |     +--rw tp-ref?                   leafref
        |     +--rw service-match-criteria
        |     |  +--rw match-criterion* [index]
        |     |     +--rw index
        |     |     |       uint32
        |     |     +--rw match-type* [type]
        |     |     |  +--rw type     identityref
        |     |     |  +--rw value*   string
        |     |     +--rw target-connection-group-id          leafref
        |     |     +--rw connection-group-sdp-role?
        |     |     |       identityref
        |     |     +--rw target-connectivity-construct-id?   leafref
        |     +--rw incoming-qos-policy
        |     |  +--rw qos-policy-name?   string
        |     |  +--rw rate-limits
        |     |     +--rw cir?       uint64
        |     |     +--rw cbs?       uint64
        |     |     +--rw eir?       uint64
        |     |     +--rw ebs?       uint64
        |     |     +--rw pir?       uint64
        |     |     +--rw pbs?       uint64
        |     |     +--rw classes
        |     |        +--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
        |     +--rw outgoing-qos-policy
        |     |  +--rw qos-policy-name?   string
        |     |  +--rw rate-limits
        |     |     +--rw cir?       uint64
        |     |     +--rw cbs?       uint64
        |     |     +--rw eir?       uint64
        |     |     +--rw ebs?       uint64
        |     |     +--rw pir?       uint64
        |     |     +--rw pbs?       uint64
        |     |     +--rw classes
        |     |        +--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
        |     +--rw sdp-peering
        |     |  +--rw peer-sap-id*   string
        |     |  +--rw protocols
        |     +--rw ac-svc-ref*
        |     |       ac-svc:attachment-circuit-reference
        |     +--rw ce-mode?                  boolean
        |     +--rw attachment-circuits
        |     |  +--rw attachment-circuit* [id]
        |     |     +--rw id                       string
        |     |     +--rw description?             string
        |     |     +--rw ac-svc-ref?
        |     |     |       ac-svc:attachment-circuit-reference
        |     |     +--rw ac-node-id?              string
        |     |     +--rw ac-tp-id?                string
        |     |     +--rw ac-ipv4-address?
        |     |     |       inet:ipv4-address
        |     |     +--rw ac-ipv4-prefix-length?   uint8
        |     |     +--rw ac-ipv6-address?
        |     |     |       inet:ipv6-address
        |     |     +--rw ac-ipv6-prefix-length?   uint8
        |     |     +--rw mtu?                     uint32
        |     |     +--rw ac-tags
        |     |     |  +--rw ac-tag* [tag-type]
        |     |     |     +--rw tag-type    identityref
        |     |     |     +--rw value*      string
        |     |     +--rw incoming-qos-policy
        |     |     |  +--rw qos-policy-name?   string
        |     |     |  +--rw rate-limits
        |     |     |     +--rw cir?       uint64
        |     |     |     +--rw cbs?       uint64
        |     |     |     +--rw eir?       uint64
        |     |     |     +--rw ebs?       uint64
        |     |     |     +--rw pir?       uint64
        |     |     |     +--rw pbs?       uint64
        |     |     |     +--rw classes
        |     |     |        +--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
        |     |     +--rw outgoing-qos-policy
        |     |     |  +--rw qos-policy-name?   string
        |     |     |  +--rw rate-limits
        |     |     |     +--rw cir?       uint64
        |     |     |     +--rw cbs?       uint64
        |     |     |     +--rw eir?       uint64
        |     |     |     +--rw ebs?       uint64
        |     |     |     +--rw pir?       uint64
        |     |     |     +--rw pbs?       uint64
        |     |     |     +--rw classes
        |     |     |        +--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
        |     |     +--rw sdp-peering
        |     |     |  +--rw peer-sap-id?   string
        |     |     |  +--rw protocols
        |     |     +--rw status
        |     |        +--rw admin-status
        |     |        |  +--rw status?        identityref
        |     |        |  +--ro last-change?   yang:date-and-time
        |     |        +--ro oper-status
        |     |           +--ro status?        identityref
        |     |           +--ro last-change?   yang:date-and-time
        |     +--rw status
        |     |  +--rw admin-status
        |     |  |  +--rw status?        identityref
        |     |  |  +--ro last-change?   yang:date-and-time
        |     |  +--ro oper-status
        |     |     +--ro status?        identityref
        |     |     +--ro last-change?   yang:date-and-time
        |     +--ro sdp-monitoring
        |        +--ro incoming-bw-value?     yang:gauge64
        |        +--ro incoming-bw-percent?   percentage
        |        +--ro outgoing-bw-value?     yang:gauge64
        |        +--ro outgoing-bw-percent?   percentage
        +--rw connection-groups
        |  +--rw connection-group* [id]
        |     +--rw id                                 string
        |     +--rw connectivity-type?
        |     |       identityref
        |     +--rw (slo-sle-policy)?
        |     |  +--:(standard)
        |     |  |  +--rw slo-sle-template?
        |     |  |          slice-template-ref
        |     |  +--:(custom)
        |     |     +--rw service-slo-sle-policy
        |     |        +--rw description?   string
        |     |        +--rw slo-policy
        |     |        |  +--rw metric-bound* [metric-type]
        |     |        |  |  +--rw metric-type
        |     |        |  |  |       identityref
        |     |        |  |  +--rw metric-unit          string
        |     |        |  |  +--rw value-description?   string
        |     |        |  |  +--rw percentile-value?
        |     |        |  |  |       percentile
        |     |        |  |  +--rw bound?               uint64
        |     |        |  +--rw availability?   identityref
        |     |        |  +--rw mtu?            uint32
        |     |        +--rw sle-policy
        |     |           +--rw security*
        |     |           |       identityref
        |     |           +--rw isolation*
        |     |           |       identityref
        |     |           +--rw max-occupancy-level?   uint8
        |     |           +--rw path-constraints
        |     |              +--rw service-functions
        |     |              +--rw diversity
        |     |                 +--rw diversity-type?
        |     |                         te-types:te-path-disjointness
        |     +--rw service-slo-sle-policy-override?
        |     |       identityref
        |     +--rw connectivity-construct* [id]
        |     |  +--rw id
        |     |  |       string
        |     |  +--rw (type)?
        |     |  |  +--:(p2p)
        |     |  |  |  +--rw p2p-sender-sdp?
        |     |  |  |  |       -> ../../../../sdps/sdp/id
        |     |  |  |  +--rw p2p-receiver-sdp?
        |     |  |  |          -> ../../../../sdps/sdp/id
        |     |  |  +--:(p2mp)
        |     |  |  |  +--rw p2mp-sender-sdp?
        |     |  |  |  |       -> ../../../../sdps/sdp/id
        |     |  |  |  +--rw p2mp-receiver-sdp*
        |     |  |  |          -> ../../../../sdps/sdp/id
        |     |  |  +--:(a2a)
        |     |  |     +--rw a2a-sdp* [sdp-id]
        |     |  |        +--rw sdp-id
        |     |  |        |       -> ../../../../../sdps/sdp/id
        |     |  |        +--rw (slo-sle-policy)?
        |     |  |           +--:(standard)
        |     |  |           |  +--rw slo-sle-template?
        |     |  |           |          slice-template-ref
        |     |  |           +--:(custom)
        |     |  |              +--rw service-slo-sle-policy
        |     |  |                 +--rw description?   string
        |     |  |                 +--rw slo-policy
        |     |  |                 |  +--rw metric-bound*
        |     |  |                 |  |       [metric-type]
        |     |  |                 |  |  +--rw metric-type
        |     |  |                 |  |  |       identityref
        |     |  |                 |  |  +--rw metric-unit
        |     |  |                 |  |  |       string
        |     |  |                 |  |  +--rw value-description?
        |     |  |                 |  |  |       string
        |     |  |                 |  |  +--rw percentile-value?
        |     |  |                 |  |  |       percentile
        |     |  |                 |  |  +--rw bound?
        |     |  |                 |  |          uint64
        |     |  |                 |  +--rw availability?
        |     |  |                 |  |       identityref
        |     |  |                 |  +--rw mtu?
        |     |  |                 |          uint32
        |     |  |                 +--rw sle-policy
        |     |  |                    +--rw security*
        |     |  |                    |       identityref
        |     |  |                    +--rw isolation*
        |     |  |                    |       identityref
        |     |  |                    +--rw max-occupancy-level?
        |     |  |                    |       uint8
        |     |  |                    +--rw path-constraints
        |     |  |                       +--rw service-functions
        |     |  |                       +--rw diversity
        |     |  |                          +--rw diversity-type?
        |     |  |                                  te-types:
te-path-disjointness
        |     |  +--rw (slo-sle-policy)?
        |     |  |  +--:(standard)
        |     |  |  |  +--rw slo-sle-template?
        |     |  |  |          slice-template-ref
        |     |  |  +--:(custom)
        |     |  |     +--rw service-slo-sle-policy
        |     |  |        +--rw description?   string
        |     |  |        +--rw slo-policy
        |     |  |        |  +--rw metric-bound* [metric-type]
        |     |  |        |  |  +--rw metric-type
        |     |  |        |  |  |       identityref
        |     |  |        |  |  +--rw metric-unit          string
        |     |  |        |  |  +--rw value-description?   string
        |     |  |        |  |  +--rw percentile-value?
        |     |  |        |  |  |       percentile
        |     |  |        |  |  +--rw bound?               uint64
        |     |  |        |  +--rw availability?   identityref
        |     |  |        |  +--rw mtu?            uint32
        |     |  |        +--rw sle-policy
        |     |  |           +--rw security*
        |     |  |           |       identityref
        |     |  |           +--rw isolation*
        |     |  |           |       identityref
        |     |  |           +--rw max-occupancy-level?   uint8
        |     |  |           +--rw path-constraints
        |     |  |              +--rw service-functions
        |     |  |              +--rw diversity
        |     |  |                 +--rw diversity-type?
        |     |  |                         te-types:
te-path-disjointness
        |     |  +--rw service-slo-sle-policy-override?
        |     |  |       identityref
        |     |  +--rw status
        |     |  |  +--rw admin-status
        |     |  |  |  +--rw status?        identityref
        |     |  |  |  +--ro last-change?   yang:date-and-time
        |     |  |  +--ro oper-status
        |     |  |     +--ro status?        identityref
        |     |  |     +--ro last-change?   yang:date-and-time
        |     |  +--ro connectivity-construct-monitoring
        |     |     +--ro one-way-min-delay?         yang:gauge64
        |     |     +--ro one-way-max-delay?         yang:gauge64
        |     |     +--ro one-way-delay-variation?   yang:gauge64
        |     |     +--ro one-way-packet-loss?       decimal64
        |     |     +--ro two-way-min-delay?         yang:gauge64
        |     |     +--ro two-way-max-delay?         yang:gauge64
        |     |     +--ro two-way-delay-variation?   yang:gauge64
        |     |     +--ro two-way-packet-loss?       decimal64
        |     +--ro connection-group-monitoring
        |        +--ro one-way-min-delay?         yang:gauge64
        |        +--ro one-way-max-delay?         yang:gauge64
        |        +--ro one-way-delay-variation?   yang:gauge64
        |        +--ro one-way-packet-loss?       decimal64
        |        +--ro two-way-min-delay?         yang:gauge64
        |        +--ro two-way-max-delay?         yang:gauge64
        |        +--ro two-way-delay-variation?   yang:gauge64
        |        +--ro two-way-packet-loss?       decimal64
        +--rw custom-topology
           +--rw network-ref?
                   -> /nw:networks/network/network-id

Appendix D. Comparison with the Design Choice of ACTN VN Model Augmentation

The difference between the ACTN VN model and the Network Slice Service requirements is that the Network Slice Service interface is a technology-agnostic interface, whereas the VN model is bound to the TE Topologies. The realization of the Network Slice does not necessarily require the slice network to support the TE technology.

The ACTN VN (Virtual Network) model introduced in[I-D.ietf-teas-actn-vn-yang] is the abstract customer view of the TE network. Its YANG structure includes four components:

The Type 1 VN can be used to describe Network Slice Service connection requirements. However, the Network Slice SLOs and Network Slice SDPs are not clearly defined and there's no direct equivalent. For example, the SLO requirement of the VN is defined through the TE Topologies YANG model, but the TE Topologies model is related to a specific implementation technology. Also, VN-AP does not define "service-match-criteria" to specify a specific SDP belonging to an Network Slice Service.

Authors' Addresses

Bo Wu
Huawei Technologies
101 Software Avenue, Yuhua District
Nanjing
Jiangsu, 210012
China
Dhruv Dhody
Huawei Technologies
Divyashree Techno Park
Bangalore 560066
Karnataka
India
Reza Rokui
Ciena
Tarek Saad
Cisco Systems, Inc
John Mullooly
Cisco Systems, Inc