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A YANG Data Model for the IETF Network Slice Service
draft-ietf-teas-ietf-network-slice-nbi-yang-08

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This is an older version of an Internet-Draft whose latest revision state is "Active".
Authors Bo Wu , Dhruv Dhody , Reza Rokui , Tarek Saad , John Mullooly
Last updated 2023-10-23 (Latest revision 2023-10-20)
Replaces draft-wd-teas-ietf-network-slice-nbi-yang
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draft-ietf-teas-ietf-network-slice-nbi-yang-08
TEAS                                                               B. Wu
Internet-Draft                                                  D. Dhody
Intended status: Standards Track                     Huawei Technologies
Expires: 25 April 2024                                          R. Rokui
                                                                   Ciena
                                                                 T. Saad
                                                             J. Mullooly
                                                      Cisco Systems, Inc
                                                         23 October 2023

          A YANG Data Model for the IETF Network Slice Service
             draft-ietf-teas-ietf-network-slice-nbi-yang-08

Abstract

   This document defines a YANG data model for the IETF Network Slice
   Service.  The model can be used in the IETF Network Slice Service
   interface between a customer and a provider that offers IETF 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 25 April 2024.

Copyright Notice

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

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents (https://trustee.ietf.org/
   license-info) in effect on the date of publication of this document.
   Please review these documents carefully, as they describe your rights
   and restrictions with respect to this document.  Code Components

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   extracted from this document must include Revised BSD License text as
   described in Section 4.e of the Trust Legal Provisions and are
   provided without warranty as described in the Revised BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Conventions used in this document . . . . . . . . . . . . . .   3
     2.1.  Acronyms  . . . . . . . . . . . . . . . . . . . . . . . .   5
   3.  IETF Network Slice Service Overview . . . . . . . . . . . . .   5
   4.  IETF Network Slice Service Model (NSSM) Usage . . . . . . . .   7
   5.  IETF Network Slice Service Model (NSSM) Description . . . . .   8
     5.1.  IETF Network Slice Service SLO and SLE Templates  . . . .   9
     5.2.  IETF Network Slice Services . . . . . . . . . . . . . . .  12
       5.2.1.  IETF Network Slice Service Demarcation Points . . . .  13
       5.2.2.  IETF Network Slice Service Connectivity Constructs  .  18
       5.2.3.  IETF Network Slice Service SLO and SLE Policy . . . .  20
       5.2.4.  IETF Network Slice Service Monitoring . . . . . . . .  23
       5.2.5.  IETF Network Slice Service on Custom Topology . . . .  23
       5.2.6.  IETF Network Slice Service Compute  . . . . . . . . .  24
   6.  IETF Network Slice Service Module . . . . . . . . . . . . . .  25
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .  53
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  53
   9.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  54
   10. Contributors  . . . . . . . . . . . . . . . . . . . . . . . .  54
   11. References  . . . . . . . . . . . . . . . . . . . . . . . . .  54
     11.1.  Normative References . . . . . . . . . . . . . . . . . .  54
     11.2.  Informative References . . . . . . . . . . . . . . . . .  56
   Appendix A.  Augmentation Considerations  . . . . . . . . . . . .  57
   Appendix B.  Examples of Network Slice Services . . . . . . . . .  58
     B.1.  Example-1: Two A2A Slice Services with different match
           approaches  . . . . . . . . . . . . . . . . . . . . . . .  58
     B.2.  Example-2: Two P2P slice services with different match
           approaches  . . . . . . . . . . . . . . . . . . . . . . .  65
     B.3.  Example-3: A Hub and Spoke Slice Service with a P2MP
           Connectivity Construct  . . . . . . . . . . . . . . . . .  71
     B.4.  Example-4: An A2A Slice service with multiple SLOs and DSCP
           Matching  . . . . . . . . . . . . . . . . . . . . . . . .  77
     B.5.  Example-5: An A2A Network Slice Service with SLO Precedence
           Policies  . . . . . . . . . . . . . . . . . . . . . . . .  83
     B.6.  Example-6: SDP at CE, L3 A2A Slice Service  . . . . . . .  89
     B.7.  Example-7: SDP at CE, L3 A2A Slice Service with Network
           Abstraction . . . . . . . . . . . . . . . . . . . . . . .  94
   Appendix C.  Complete Model Tree Structure  . . . . . . . . . . .  99
   Appendix D.  Comparison with the Design Choice of ACTN VN Model
           Augmentation  . . . . . . . . . . . . . . . . . . . . . . 105
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . . 106

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1.  Introduction

   This document defines a YANG [RFC7950] data model for the IETF
   Network Slice Service as defined in
   [I-D.ietf-teas-ietf-network-slices].

   This YANG module can be used in the IETF Network Slice Service
   Interface exposed by a provider to its customers in order to manage
   (e.g., subscribe, delete, or change) IETF Network Slice Services.
   The agreed service will then trigger the appropriate IETF Network
   Slice operation, such as instantiating, modifying, or deleting an
   IETF Network Slice.

   As discussed in [I-D.ietf-teas-ietf-network-slices], the mapping
   between an IETF Network Slice Service and its realization is
   implementation and deployment specific.

   The IETF Network Slice Service Model (NSSM) focuses on the
   requirements of an IETF Network Slice Service from the point of view
   of the customer, not how it is implemented within a provider network.
   The module is classified as customer service model (Section 2 of
   [RFC8309]).

   The IETF Network Slice Service YANG model 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:

   *  "XXXX" -- the assigned RFC value for this draft both in this draft
      and in the YANG models under the revision statement.

   *  The "revision" date in model, in the format XXXX-XX-XX, needs to
      be updated with the date the draft gets approved.

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:

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   *  client

   *  configuration data

   *  state data

   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
   [I-D.ietf-teas-ietf-network-slices]:

   *  Attachment Circuit (AC): See Section 3.2 of
      [I-D.ietf-teas-ietf-network-slices].

   *  Connectivity Construct: See Sections 3.2 and 4.2.1 of
      [I-D.ietf-teas-ietf-network-slices].

   *  Customer: See Section 3.2 of [I-D.ietf-teas-ietf-network-slices].

   *  Customer Higher-level Operation System: See Section 6.3.1 of
      [I-D.ietf-teas-ietf-network-slices].

   *  Service Demarcation Point (SDP): See Sections 3.2 and 5.2
      [I-D.ietf-teas-ietf-network-slices].

   In addition, this document defines the following term:

   *  Connection Group: Refers to one or more connectivity constructs
      that are grouped for administrative purposes, such as the
      following:

         Combine multiple connectivity constructs to support a set of
         well-known connectivity service types, such as bidirectional
         unicast service, multipoint-to-point (MP2P) service, or hub-
         and-spoke service.

         Assign the same SLO/SLE policies to multiple connectivity
         constructs unless SLO/SLE policy is explicitly overridden at
         the individual connectivity construct level.

         Share specific SLO limits within multiple connectivity
         constructs.

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2.1.  Acronyms

   The following acronyms are used in the document:

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

3.  IETF Network Slice Service Overview

   As defined in Section 3.2 of [I-D.ietf-teas-ietf-network-slices], an
   IETF Network Slice Service is specified in terms of a set of SDPs, a
   set of one or more connectivity constructs between subsets of these
   SDPs, and a set of SLOs and 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 IETF Network Slice Service ingress/egress
   points.  An SDP is identified by a unique identifier in the context
   of an IETF Network Slice Service.

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

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          +----------------------------------------------+
          |                                              |
          |                                              |
          |       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
          |                                              |
          |                                              |
          +----------------------------------------------+
          |<----------IETF 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 IETF Network Slice Services

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

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          +----------------------------------------------+
          |                                              |
          |       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
          |\                                           / |
          | +-----------------<-----------------------+  |
          |                                              |
          +----------------------------------------------+
          |<----------IETF Network Slice Services------->|
          |        between endpoints SDP10 to SDP15      |

    Slice Service: IETF Network Slice Service
               CC: Connectivity construct
                O: Represents an SDP
             ----: Represents connectivity construct
             < > : Inbound/outbound directions

             Figure 2: Examples of IETF Network Slice Services

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

4.  IETF Network Slice Service Model (NSSM) Usage

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

   The IETF Network Slices are applicable to use cases, such as (but not
   limited to) network wholesale services, network infrastructure
   sharing among operators, Network Function Virtualization (NFV)
   connectivity, Data Center interconnect, and 5G.

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   An IETF Network Slice Controller (NSC) is an entity that exposes the
   IETF Network Slice Service Interface to customers to manage IETF
   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
   IETF Network Slice Service customer provides, describing the needed
   IETF Network Slices Service in terms of a set of SDPs, the associated
   connectivity constructs, and the service objectives that the customer
   wishes to be fulfilled.  These service requirements are then
   translated into technology-specific actions that are implemented in
   the underlying network using a network-facing interface.  The details
   of how the IETF Network Slices are put into effect are out of scope
   for this document.

   As shown in Figure 3, in all the use cases, the NSSM is used by the
   customer's higher level operation system to communicate with the NSC
   for life cycle management of IETF Network Slices including both
   enablement and monitoring.  For example, in the 5G E2E (End-to-end)
   network slicing use-case the E2E network slice orchestrator acts as
   the higher layer system to request the IETF Network Slices.  The
   interface is used to support dynamic IETF Network Slice creation and
   its lifecycle management to facilitate end-to-end network slice
   services.

             +----------------------------------------+
             |   IETF Network Slice Customer          |
             |                                        |
             +----------------+-----------------------+
                              |
                              |
                              |IETF Network Slice Service Model (NSSM)
                              |
        +---------------------+--------------------------+
        |      IETF Network Slice Controller (NSC)       |
        +------------------------------------------------+

        Figure 3: IETF Network Slice Service Reference Architecture

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

5.  IETF Network Slice Service Model (NSSM) Description

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

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   The "slice-service" list includes the set of IETF Network Slice
   Services that are maintained by a provider. "slice-service" is the
   data structure that abstracts the IETF 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.

   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 IETF Network Slice Services.

   The figure below describes the overall structure of the NSSM:

   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

5.1.  IETF Network Slice Service SLO and SLE Templates

   The "slo-sle-templates" container (Figure 4) is used by an IETF
   Network Slice Service provider to define and maintain a set of common
   IETF Network Slice Service templates that apply to one or several
   IETF Network Slice Services.  The exact definition of the templates
   is deployment specific to each network provider.

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   +--rw slo-sle-templates
      +--rw slo-sle-template* [id]
         +--rw id              string
         +--rw description?    string
         +--rw template-ref?   leafref
         +--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?   decimal64
         |  +--rw mtu?            uint16
         +--rw sle-policy
            +--rw security*               identityref
            +--rw isolation*              identityref
            +--rw max-occupancy-level?    uint8
            +--rw steering-constraints
               +--rw path-constraints
               +--rw service-function

   The NSSM includes the identifiers of SLO and SLE templates and the
   common attributes defined in Section 5.1 of
   [I-D.ietf-teas-ietf-network-slices].  Considering that there are many
   attributes defined and some attributes could vary with service
   requirements, e.g., bandwidth, or latency, multiple standard
   templates as well as custom "service-slo-sle-policy" are defined:

   1:  Standard template with no attribute specified: The exact
       definition of the templates is deployment specific to the
       provider.

   2:  Standard template with attributes specified: Provides the
       customers with the ability to define templates, or reference a
       predefined template "template-ref" and override specific
       attributes, and apply them to IETF Network Slice Service
       configuration.

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

   The following shows an example where two network slice templates can
   be retrieved by the customers:

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   {
     "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": "two-way-delay-percentile",
                   "metric-unit": "milliseconds",
                   "percentile-value": "95",
                   "bound": "50"
                 }
               ]
             },
             "sle-policy": {
               "isolation": ["service-traffic-isolation"]
             }
           },
           {
             "id": "GOLD-template",
             "description": "Two-way bandwidth: 1 Gbps,\
                             maximum latency 100ms",
             "slo-policy": {
               "metric-bound": [
                 {
                   "metric-type": "two-way-delay-maximum",
                   "metric-unit": "milliseconds",
                   "bound": "100"
                 }
               ]
             },
             "sle-policy": {
               "isolation": ["service-traffic-isolation"]
             }
           }
         ]
       }
     }
   }

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

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5.2.  IETF Network Slice Services

   The "slice-service" is the data structure that abstracts an IETF
   Network Slice Service, which is uniquely identified by "id" specified
   in the context of an NSC.

   An IETF Network Slice Service has the following main parameters:

   *  "id": Is an unique identifier for internal management reference of
      the IETF Network Slice Service within an NSC.

   *  "description": Provides a textual description of an IETF 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 IETF Network Slices.
      It might be used by IETF Network Slice Service operator to provide
      additional information to the NSC during the automation of the
      IETF network slices.  E.g. adding tags with "customer-name" when
      multiple actual customers use a same network slice service.
      Another use-case for "service-tag" might be for an operator to
      provide additional attributes to NSC which might be used during
      the realization of IETF Network Slice Services such as type of
      services (e.g., Layer 2 or Layer 3 service).  These additional
      attributes can also be used by an NSC for various use-cases such
      as monitoring and assurance of the IETF Network Slice Services
      where the NSC can notify the customer system by issuing the
      notifications.  Note that all these attributes are OPTIONAL but
      might be useful for some use-cases.

   *  "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 before
      instantiating a Network Slice Service.  More details are provided
      in Section 5.2.6.

   *  "status": Is used to show the operative and administrative status
      of the IETF Network Slice Service, and can be used as indicator to
      detect network slice anomalies.

   *  "sdps": Represents a set of SDPs that are involved in the IETF
      Network Slice Service with each "sdp" belonging to a single
      "slice-service".  More details are provided in Section 5.2.1.

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

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5.2.1.  IETF Network Slice Service Demarcation Points

   An SDP belong to a single IETF Network Slice Service.  An IETF
   Network Slice Service involves two or more SDPs.  An IETF Network
   Slice Service can be modified by adding new "sdp" or removing
   existing "sdp".

   +--rw sdps
      +--rw sdp* [id]
         +--rw id                        string
         +--rw description?              string
         +--rw 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-name*              string
         +--rw attachment-circuits
         |     ...
         +--rw status
         |     ...
         +--ro sdp-monitoring
               ...

   Section 5.2 of [I-D.ietf-teas-ietf-network-slices] describes four
   possible ways in which an SDP may be placed:

   *  Within CE

   *  Provider-facing ports on the CE

   *  Customer-facing ports on the PE

   *  Within PE

   Although there are four options, they can be categorized into two:
   CE-based or PE-based.  To simplify the model, the NSC and the
   customer's system can agree on the choice of these two types without
   marking the type on each SDP.

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   In the four options, the Attachment Circuit (AC) may be part of the
   IETF Network Slice Service or may be external to it.  Based on the
   definition of AC in Section 5.2 of
   [I-D.ietf-teas-ietf-network-slices], the customer and provider may
   agree on a per {IETF 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 an IETF 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 the Network Slice
      Controller (NSC).  The identifier is a string that allows any
      encoding for the local administration of the IETF Network Slice
      Service.

   *  "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.

   *  "sdp-ip-address": The SDP IP information, 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.

   *  "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
      [I-D.ietf-teas-ietf-network-slices].

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   *  "ac-svc-name": Indicates the names of AC services, for association
      purposes, to refer to the ACs that have been created.  When both
      "ac-svc-name" and the attributes of "attachment-circuits" are
      defined, the "ac-svc-name" takes precedence.

   *  "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.

   *  "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.

      -  "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 The
         example protocols of an SDP can be BGP, static routing, etc.

   *  "status": Enables the control of the operative and administrative
      status of the SDP, can be used as indicator to detect SDP
      anomalies.

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

   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 5.  Traffic needs to be explicitly mapped
      into the IETF 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 {IETF Network Slice Service,
      connectivity construct, and SLOs/SLEs} that packet is assigned.

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   *  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-match) 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 is 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
          |\                                           / |
          | +--%-%-%-%-%-%---->---%-%-%-%-%-%-%-%-%---+  |
          |                                              |
          +----------------------------------------------+
          |<----------IETF Network Slice Services------->|
          |        between endpoints SDP10 to SDP17      |

                  Figure 5: Application of Match Criteria

   If an SDP is placed at the port or AC 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 port or AC can be used to 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.

   To illustrate the use of SDP options, the below are two examples.
   How the NSC realize the mapping is out of scope for this document.

*  SDPs at customer-facing ports on the PEs: As shown in Figure 6 , a
   customer of the IETF Network Slice Service would like to connect
   two SDPs to satisfy specific service, e.g., network wholesale
   services.  In this case, the IETF network slice SDPs are mapped to
   customer-facing ports of PE nodes.  The NSC uses "node-id" (PE
   device ID), "attachment-circuits" (ACs) to map SDPs to the
   customer-facing ports on the PEs.

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              SDP1                                     SDP2
       (With PE1 parameters)                       (with PE2 parameters)
               o<--------- IETF Network Slice 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 IETF Network Slice Service
   S1: L0/L1/L2/L3 services used for realization of IETF Network Slice Service
   T1: Tunnels used for realization of IETF Network Slice Service

                             Figure 6

*  SDPs within CEs: As shown in Figure 7 , a customer of the IETF
   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), "sdp-ip-address" (IP of SDP for management), "service-
   match-criteria" (VLAN tag), "attachment-circuits" (CE ACs) to map
   SDPs to the CE.  The NSC can use these CE parameters (and
   optionally the "peer-sap-id") to retrieve the corresponding PE
   device, interface and AC mapping details to complete the end-to-
   end network slice service provisioning (the implementation details
   are left to the NSC provider).

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           SDP3                                     SDP4
    (With CE1 parameters)                       (with CE2 parameters)
    +o<----------------- IETF Network Slice 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 IETF Network Slice Service
S2: L0/L1/L2/L3 services used for realization of the IETF Network Slice Service
T2: Tunnels used for realization of IETF network slice

                             Figure 7

5.2.2.  IETF Network Slice Service Connectivity Constructs

   Based on the customer's service traffic requirements, an IETF Network
   Slice Service connectivity type could be point-to-point (P2P), point-
   to-multipoint (P2MP), any-to-any (A2A) or a combination of these
   types.

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+--rw connection-groups
  +--rw connection-group* [id]
     +--rw id                                 string
     +--rw connectivity-type?                 identityref
     +--rw (slo-sle-policy)?
     |  +--:(standard)
     |  |  +--rw slo-sle-template?            -> /network-slice-services/slo-sle-templates/slo-sle-template/id
     |  +--:(custom)
     |     +--rw service-slo-sle-policy
     |           ...
     +--rw service-slo-sle-policy-override?   identityref
     +--rw connectivity-construct* [id]
     |  +--rw id                                   uint32
     |  +--rw (type)?
     |  |  +--:(p2p)
     |  |  |     ...
     |  |  +--:(p2mp)
     |  |  |     ...
     |  |  +--:(a2a)
     |  |        ...
     |  +--rw (slo-sle-policy)?
     |  |  +--:(standard)
     |  |  |     ...
     |  |  +--:(custom)
     |  |        ...
     |  +--rw service-slo-sle-policy-override?     identityref

   [I-D.ietf-teas-ietf-network-slices] defines the basic connectivity
   construct (CC) for an IETF Network Slice Service, and the
   connectivity construct may have different SLO and SLE requirements.
   "connectivity-construct" represents this connectivity construct, and
   "slo-sle-policy" under it represents the per-connectivity construct
   SLO and SLE requirements.

   Apart from the per-connectivity construct SLO and SLE, slice service
   traffic is usually managed by combining similar types of traffic.
   For example, some connections for video services require high
   bandwidth, and some connections for voice over IP request low latency
   and reliability.

   "connection-group" is thus defined to treat each type as a class with
   per-connection-group SLO and SLE such that the connectivity construct
   can inherit the SLO/SLE from the group if not explicitly defined.
   Additionally, in the case of hub and spoke connectivity, it may be
   inefficient when there are a large number of SDP with the multiple
   CCs.  As illustrated in Appendix B.3, "connectivity-type" of "vpn-
   common:hub-spoke" and "connection-group-sdp-role" of "vpn-common:hub-
   role" or "vpn-common:spoke-role" can be specified [RFC9181].

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5.2.3.  IETF Network Slice Service SLO and SLE Policy

   As defined in section 5 of [I-D.ietf-teas-ietf-network-slices], the
   SLO and SLE policy of the IETF Network Slice Services define some
   common attributes.

   "slo-sle-policy" is used to represent these SLO and SLE policies.
   During the creation of an IETF Network Slice Service, the policy can
   be specified either by a standard SLO and SLO 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 are as follows, including performance metric
   attributes, availability, and MTU.

   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.  And the bandwidth is unidirectional.

      "two-way-bandwidth": Indicates the guaranteed minimum bandwidth
      between any two SDPs.  And the bandwidth is bidirectional.

      "one-way-delay-maximum": Indicates the maximum one-way latency

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      between two SDPs.

      "two-way-delay-maximum": Indicates the maximum round-trip latency
      between two SDPs.

      "one-way-delay-percentile": Indicates the percentile objective of
      the one-way latency between two SDPs.

      "two-way-delay-percentile": Indicates the percentile objective of
      the round-trip latency between two SDPs.

      "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.

      "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.

      "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.

      "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.

      "one-way-packet-loss": Indicates maximum permissible packet loss
      rate, 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, 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 IETF Network Slice is available in accordance with the SLOs
   associated with it.

   "mtu": Refers to the service MTU.  The service provider MUST support
   customer traffic using any PDU up to this size.

   The following common SLEs are defined:

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      "security": The security leaf-list defines the list of security
      functions the customer requests the operator to apply to traffic
      between the two SDPs, including authentication, encryption, etc.

      "isolation": Specifies the isolation types that a customer
      expects.

      "max-occupancy-level": Specifies the number of flows that the
      operator admits.

      "steering-constraints": Specifies the constraints the customer
      requests the operator to route traffic for the IETF Network Slice
      Service.

   The following shows an example where a network slice policy can be
   configured:

   {
     "slice-services": {
       "slice-service": {
         "id": "exp-slice",
         "service-slo-sle-policy": {
           "description": "video-service-policy",
           "slo-policy": {
             "metric-bound": [
               {
                 "metric-type": "one-way-bandwidth",
                 "metric-unit": "Mbps",
                 "bound": "1000"
               },
               {
                 "metric-type": "two-way-delay-maximum",
                 "metric-unit": "milliseconds",
                 "bound": "10"
               }
             ],
             "availability": "ietf-nss:level-4",
             "mtu": "1500"
           }
         }
       }
     }
   }

   For more complex slicing scenarios, for example a multiple
   connectivity-construct slice service, an "override" option is
   provided to completely override all or part of the slo-sle template
   with new values.  For example, if a particular connection-group or a

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   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.  The "service-slo-sle-policy-override" is used
   to specify the requirements.

5.2.4.  IETF Network Slice Service Monitoring

   An IETF Network Slice Service defines connectivity with specific SLO
   characteristics, including bandwidth, latency, etc.  The connectivity
   is a combination of logical unidirectional connections, represented
   by "connectivity-construct".

   This model also describes operational and performance status of an
   IETF Network Slice.  The statistics are described in the following
   granularity:

   *  Per SDP: specified in "sdp-monitoring" under the "sdp".

   *  Per connectivity construct: specified in "connectivity-construct-
      monitoring" under the "connectivity-construct".

   *  Per connection group: specified in "connection-group-monitoring"
      under the "connection-group".

   This model does not define monitoring enabling methods.  The
   mechanism defined in [RFC8640] and [RFC8641] can be used for either
   periodic or on-demand subscription.

   By specifying subtree filters or xpath filters to "sdp",
   "connectivity-construct", or "connection-group", so that only
   interested contents will be sent.  These mechanisms can be used for
   monitoring the IETF Network Slice performance status so that the
   customer management system could initiate modification based on the
   IETF Network Slice running status.

5.2.5.  IETF Network Slice Service on Custom Topology

   The Slice Service customer might ask for some level of control over
   the topology or resources 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 an
   Network Slice Service.  As per Section 1 in [RFC8345] defines a

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   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, termination points).

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

   The following nodes are defined for the custom topology.

      "custom-topology": This container is served as an augmentation
      target for the Slice Service topology context, which can be
      multiple.  This node is located directly under the "Slice
      Services" 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 an Network Slice Service, such
      as a VN topology to customize the service paths in a network slice
      by using type 2 Virtual Network (VN) defined in section 2.2 of
      [I-D.ietf-teas-actn-vn-yang] ,or an SAP topology to request SDP
      feasibility checks on a Service Attachment Points (SAPs) network
      topology described in Section 3 of [RFC9408].

      "tp-ref": A reference to 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 TPs can be access
      points of the VN topology or parent termination points of the SAP
      topology.

5.2.6.  IETF Network Slice Service Compute

   An IETF Network Slice Service is, by default, provisioned so that it
   can instantiated and deliver the service.  The IETF Network Slice
   Service customer may request to check the feasibility before
   instantiating a Network Slice Service.  In such a case, the IETF
   Network Slice Service is configured in "compute-only" mode to
   distinguish it from the default behavior.

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   A "compute-only" Network Slice is configured as usual with the
   associated per slice SLOs/SLEs.  The NSC computes the feasible
   connectivity construct 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 "administrative-status" and
   the connection groups or connectivity construct list are used to
   convey the result.  For example, "admin-pre-deployment" can be used
   to show the status.

               +--------+                                +--------+
               |customer|                                |  NSC   |
               +--------+                                +--------+
                    |                                         |
                    |                                         |
                    |  configuration compute-only             |
   compute the NS   |---------------------------------------->|
   as per the       |                                         |
   SDPs and         |                                         |
   SLOs/SLEs        |                                         |
                    |     HTTP 200 (Computed NS and status )  |
                    |<----------------------------------------|
                    |                                         |

    NS: IETF Network Slice

6.  IETF Network Slice Service Module

   The "ietf-network-slice-service" module uses types defined in
   [RFC6991], [RFC8345], [RFC9181], [RFC8776], and [RFC7640].

   <CODE BEGINS> file "ietf-network-slice-service@2023-10-23.yang"
   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-vpn-common {
       prefix vpn-common;
       reference
         "RFC 9181: A Common YANG Data Model for Layer 2 and Layer 3
                    VPNs";

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     }
     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-te-packet-types {
       prefix te-packet-types;
       reference
         "RFC 8776: Common YANG Data Types for Traffic Engineering,
                 Section 5";
     }

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

        Editor: Bo Wu
             <lana.wubo@huawei.com>
        Editor: Dhruv Dhody
             <dhruv.ietf@gmail.com>
        Editor: Reza Rokui
             <rrokui@ciena.com>
        Editor: Tarek Saad
             <tsaad@cisco.com>
        Editor: John Mullooly
             <jmullool@cisco.com>";
     description
       "This YANG module defines a model for the IETF Network Slice
        Service.

        The model fully conforms to the Network Management
        Datastore Architecture (NMDA).

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

        Redistribution and use in source and binary forms, with or
        without modification, is permitted pursuant to, and subject to

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        the license terms contained in, the Revised BSD License set
        forth in Section 4.c of the IETF Trust's Legal Provisions
        Relating to IETF Documents
        (https://trustee.ietf.org/license-info).

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

     revision 2023-10-23 {
       description
         "Initial revision.";
       reference
         "RFC XXXX: A YANG Data Model for the IETF Network Slice Service";
     }

     /* Features */
     /* Identities */

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

     identity service-tag-customer {
       base service-tag-type;
       description
         "The IETF Network Slice Service customer ID tag type.";
     }

     identity service-tag-service {
       base service-tag-type;
       description
         "The IETF Network Slice service tag type, e.g. Layer 2 or
          Layer 3 service.";
     }

     identity service-tag-opaque {
       base service-tag-type;
       description
         "The IETF Network Slice Service opaque tag type.";
     }

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

     identity vlan-id {

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       base attachment-circuit-tag-type;
       description
         "Identity for VLAN ID tag type, e.g. dot1Q or QinQ VLAN IDs.";
     }

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

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

     identity service-traffic-isolation {
       base service-isolation-type;
       description
         "Specify the requirement for separating the traffic of the
          customer's IETF 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 IETF 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.";
     }

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

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

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

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

     identity one-way-bandwidth {
       base service-slo-metric-type;
       description

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         "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
         "RFC7679: 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
         "RFC7679: 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
         "RFC2681: A Round-trip Delay Metric for IPPM";
     }

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     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
         "RFC2681: 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
         "RFC3393: 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
         "RFC3393: 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
         "RFC5481: 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

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         "RFC5481: 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
          over a period of time.";
       reference
         "RFC7680: 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
          over a period of time.";
       reference
         "RFC7680: A One-Way Loss Metric for IP Performance
          Metrics (IPPM)";
     }

     /*
      * Identity for availability-type
      */

     identity availability-type {
       description
         "Base identity from which specific availability types are
          derived.";
     }

     identity level-1 {
       base availability-type;
       description
         "Specifies the availability level 1: 99.9999%";
     }

     identity level-2 {
       base availability-type;
       description
         "Specifies the availability level 2: 99.999%";
     }

     identity level-3 {

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       base availability-type;
       description
         "Specifies the availability level 3: 99.99%";
     }

     identity level-4 {
       base availability-type;
       description
         "Specifies the availability level 4: 99.9%";
     }

     identity level-5 {
       base availability-type;
       description
         "Specifies the availability level 5: 99%";
     }

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

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

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

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

     identity service-source-ip-prefix-match {
       base service-match-type;
       description
         "Uses source ip prefix as match criteria for the Slice Service

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          traffic. Examples of 'value' of this match type are
          '192.0.2.0/24' and '2001:db8::1/64'.";
     }

     identity service-destination-ip-prefix-match {
       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', '2001:db8::2/128'.";
     }

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

     identity service-acl-match {
       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 service-any-match {
       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 slo-sle-policy-full-override {
       base slo-sle-policy-override;
       description
         "The policy of SLO/SLE(s) that is defined at a
          child level override a parent SLO/SLE policy,
          which means that no SLO/SLE(s) are inherited from parent
          if a child SLO/SLE policy exists.";
     }

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     identity slo-sle-policy-partial-override {
       base slo-sle-policy-override;
       description
         "The policy of SLO/SLE(s) that is defined at a
          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 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.";
     }

     /* Groupings */

     grouping service-slos {
       description
         "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 an entry in the list of metric type
                bounds for the Slice Service.";
           }
           leaf metric-unit {

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             type string;
             mandatory true;
             description
               "The metric unit of the parameter. For example,
                s, ms, ns, and so on.";
           }
           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;
             default "0";
             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 uint16;
           units "bytes";
           description
             "The MTU specifies the maximum length of data
              packets of the Slice Service.
              The value needs to be less than or equal to the
              minimum MTU value of all 'attachment-circuits'
              in the SDPs.";
         }
       }
     }

     grouping service-sles {
       description
         "Indirectly measurable objectives of a Slice Service.";

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       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.";
         }
         container steering-constraints {
           description
             "Container for the policy of steering constraints
              applicable to the Slice Service.";
           container path-constraints {
             description
               "Container for the policy of path constraints
                applicable to the Slice Service.";
           }
           container service-function {
             description
               "Container for the policy of service function
                applicable to the Slice Service.";
           }
         }
       }
     }

     grouping sdp-peering {
       description
         "A grouping for the Slice Service SDP peering.";
       container sdp-peering {

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         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
             "RFC9408: 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.";
         }
       }
     }

     grouping sdp-attachment-circuits {
       description
         "Grouping for the SDP attachment circuit definition.";
       container attachment-circuits {
         description
           "List of attachment circuits.";
         list attachment-circuit {
           key "id";
           description
             "The IETF Network Slice Service SDP attachment circuit
              related parameters.";
           leaf id {
             type string;
             description
               "Uniquely identifies an attachment circuit.";
           }
           leaf description {
             type string;
             description
               "The attachment circuit's description.";
           }
           leaf ac-svc-name {
             type string;
             description
               "Indicates an attachment circuit (AC) service name,

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                for association purposes, to refer to an AC that has been
                created before the slice creation.
                This node can override 'ac-svc-name' of the parent SDP.";
           }
           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 uint16;
             units "bytes";
             description
               "Maximum size of the Slice Service data packet
                that can traverse an SDP.";
           }
           container ac-tags {
             description
               "Container for the attachment circuit tags.";
             list ac-tags {
               key "tag-type";
               description

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                 "The attachment circuit tags 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 'c-vlan' and 's-vlan'.";
               }
             }
           }
           uses service-qos;
           uses sdp-peering;
           uses vpn-common:service-status;
         }
       }
     }

     grouping sdp-monitoring-metrics {
       description
         "Grouping for the SDP monitoring metrics.";
       container sdp-monitoring {
         config false;
         description
           "Container for SDP monitoring metrics.";
         leaf incoming-bw-value {
           type uint64;
           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 decimal64 {
             fraction-digits 5;
             range "0..100";
           }
           units "percent";
           mandatory true;
           description
             "Indicates a percentage of the incoming bandwidth
              at an SDP from the customer network or

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              from another provider's network.";
         }
         leaf outgoing-bw-value {
           type uint64;
           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 decimal64 {
             fraction-digits 5;
             range "0..100";
           }
           units "percent";
           mandatory true;
           description
             "Indicates a percentage of the outgoing bandwidth
              at an SDP towards the customer network or towards
              another provider's network.";
         }
       }
     }

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

     grouping geolocation {
       description
         "A grouping containing a GPS location.";
       container location {
         description
           "A container containing a GPS location.";
         leaf altitude {
           type int64;
           units "millimeter";
           description
             "Distance above the sea level.";
         }
         leaf latitude {
           type decimal64 {
             fraction-digits 8;
             range "-90..90";

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           }
           description
             "Relative position north or south on the Earth's surface.";
         }
         leaf longitude {
           type decimal64 {
             fraction-digits 8;
             range "-180..180";
           }
           description
             "Angular distance east or west on the Earth's surface.";
         }
       }
     }

     grouping bw-rate-limits {
       description
         "Bandwidth rate limits grouping.";
       reference
         "RFC 7640: Traffic Management Benchmarking";
       leaf cir {
         type uint64;
         units "bps";
         description
           "Committed Information Rate. The maximum number of bits
            that a port can receive or send during one-second over an
            interface.";
       }
       leaf cbs {
         type uint64;
         units "bytes";
         description
           "Committed Burst Size. CBS controls the bursty nature
            of the traffic. Traffic that does not use the configured
            CIR accumulates credits until the credits reach the
            configured CBS.";
       }
       leaf eir {
         type uint64;
         units "bps";
         description
           "Excess Information Rate, i.e., excess frame delivery
            allowed not subject to SLA. The traffic rate can be
            limited by EIR.";
       }
       leaf ebs {
         type uint64;
         units "bytes";

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         description
           "Excess Burst Size. The bandwidth available for burst
            traffic from the EBS is subject to the amount of
            bandwidth that is accumulated during periods when
            traffic allocated by the EIR policy is not used.";
       }
       leaf pir {
         type uint64;
         units "bps";
         description
           "Peak Information Rate, i.e., maximum frame delivery
            allowed. It is equal to or less than sum of CIR and EIR.";
       }
       leaf pbs {
         type uint64;
         units "bytes";
         description
           "Peak Burst Size.";
       }
     }

     grouping service-qos {
       description
         "The rate limits grouping.";
       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 bw-rate-limits;
         }
       }
       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;

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           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 bw-rate-limits;
         }
       }
     }

     grouping sdp {
       description
         "Slice Service SDP related information";
       leaf id {
         type string;
         description
           "Unique identifier for the referred Slice Service SDP.";
       }
       leaf description {
         type string;
         description
           "Provides a description of the SDP.";
       }
       uses geolocation;
       leaf node-id {
         type string;
         description
           "Uniquely identifies an edge node of the SDP.";
       }
       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

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           "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 that uniquely identifies a match criteria.";
           }
           leaf match-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 and VLAN ID.";
           }
           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,

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                this helps to create connectivity construct automatically
                , rather than explicitly specifying each one.";
           }
           leaf target-connectivity-construct-id {
             type leafref {
               path "/ietf-nss:network-slice-services"
                  + "/ietf-nss:slice-service"
                  + "/ietf-nss:connection-groups"
                  + "/ietf-nss:connection-group[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 service
              attachment points (SAPs) of provider equipments when
              requesting a service with CE based SDP attributes.";
         }
         container protocols {
           description
             "Serves as an augmentation target.
              Protocols can be augmented into this container,
              e.g. BGP, static routing.";
         }
       }
       leaf-list ac-svc-name {
         type string;
         description
           "Indicates the attachment circuit service name,
            for association purposes, to refer to ACs that have been
            created before the slice creation.";
       }
       uses sdp-attachment-circuits;
       uses vpn-common:service-status;
       uses sdp-monitoring-metrics;
     }

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     grouping connectivity-construct {
       description
         "Grouping for Slice Service connectivity construct.";
       list connectivity-construct {
         key "id";
         description
           "List of connectivity constructs.";
         leaf id {
           type uint32;
           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";
               }

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               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 service-slo-sle-policy
          * overrides the per slice service-slo-sle-policy.
          */
         uses service-slo-sle-policy-override;
         uses vpn-common:service-status;
         container connectivity-construct-monitoring {
           config false;
           description
             "SLO status per connectivity construct.";
           uses connectivity-construct-monitoring-metrics;
         }
       }
     }

     grouping connection-group {
       description
         "Grouping for Slice Service connection group.";
       leaf id {
         type string;
         description
           "The connection group identifier.";
       }
       leaf connectivity-type {
         type identityref {
           base vpn-common:vpn-topology;

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         }
         default "vpn-common:any-to-any";
         description
           "Connection group connectivity type.";
       }
       uses service-slo-sle-policy;
       uses service-slo-sle-policy-override;
       uses connectivity-construct;
       /* Per connection group service-slo-sle-policy overrides
        * the per slice service-slo-sle-policy.
        */
       container connection-group-monitoring {
         config false;
         description
           "SLO status per connection group.";
         uses connectivity-construct-monitoring-metrics;
       }
     }

     grouping slice-service-template {
       description
         "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 leafref {
               path "/ietf-nss:network-slice-services"
                  + "/ietf-nss:slo-sle-templates"
                  + "/ietf-nss:slo-sle-template"
                  + "/ietf-nss:id";
             }

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             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 leafref {
               path "/ietf-nss:network-slice-services"
                  + "/ietf-nss:slo-sle-templates"
                  + "/ietf-nss:slo-sle-template"
                  + "/ietf-nss:id";
             }
             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;
           }
         }
       }

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     }

     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;
         }
         default "ietf-nss:slo-sle-policy-full-override";
         description
           "SLO/SLE policy override option.";
       }
     }

     /* Main IETF Network Slice Services Container */

     container network-slice-services {
       description
         "Contains a list of IETF 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.";
         }
         leaf description {
           type string;
           description
             "Textual description of the Slice Service.";
         }
         container service-tags {
           description
             "Container for the list of service tags.";
           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.";

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             }
             leaf-list value {
               type string;
               description
                 "The tag values, e.g. customer names when multiple
                  customers sharing same Slice Service in 5G scenario.";
             }
           }
         }
         uses service-slo-sle-policy;
         leaf compute-only {
           type empty;
           description
             "When present, the slice is computed. No resources are
              committed or reserved in the network.";
         }
         uses vpn-common:service-status;
         container sdps {
           description
             "Slice Service SDPs.";
           list sdp {
             key "id";
             min-elements 2;
             uses sdp;
             description
               "List of SDPs in this Slice Service.";
           }
         }
         container connection-groups {
           description
             "Contains connection groups.";
           list connection-group {
             key "id";
             description
               "List of connection groups.";
             uses connection-group;
           }
         }
         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;
         }
       }
     }

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   }
   <CODE ENDS>

7.  Security Considerations

   The YANG module defined in this document 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 NETCONF access control model [RFC8341] provides the means to
   restrict access for particular NETCONF or RESTCONF users to a
   preconfigured subset of all available NETCONF or RESTCONF protocol
   operations and content.

   There are a number of data nodes defined in this YANG module that are
   writable/creatable/deletable (i.e., config true, which is the
   default).  These data nodes may be considered sensitive or vulnerable
   in some network environments.  Write operations (e.g., edit-config)
   to these data nodes without proper protection can have a negative
   effect on network operations.

   o /ietf-network-slice-service/network-slice-services/slice-service

   The entries in the list above include the whole network
   configurations corresponding with the 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.

8.  IANA Considerations

   This document registers a URI in the IETF XML registry [RFC3688].
   Following the format in [RFC3688], the following registration is
   requested to be made:

      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 a YANG module in the YANG Module
   Names registry [RFC7950].

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           Name: ietf-network-slice-service
           Namespace: urn:ietf:params:xml:ns:yang:ietf-network-slice-service
           Prefix: ietf-nss
           Reference: RFC XXXX

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: luismiguel.contrerasmurillo@telefonica.com

      Liuyan Han
      China Mobile
      Email: hanliuyan@chinamobile.com

11.  References

11.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC3688]  Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
              DOI 10.17487/RFC3688, January 2004,
              <https://www.rfc-editor.org/info/rfc3688>.

   [RFC6241]  Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
              and A. Bierman, Ed., "Network Configuration Protocol
              (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011,
              <https://www.rfc-editor.org/info/rfc6241>.

   [RFC6242]  Wasserman, M., "Using the NETCONF Protocol over Secure
              Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, June 2011,
              <https://www.rfc-editor.org/info/rfc6242>.

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   [RFC6991]  Schoenwaelder, J., Ed., "Common YANG Data Types",
              RFC 6991, DOI 10.17487/RFC6991, July 2013,
              <https://www.rfc-editor.org/info/rfc6991>.

   [RFC7950]  Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",
              RFC 7950, DOI 10.17487/RFC7950, August 2016,
              <https://www.rfc-editor.org/info/rfc7950>.

   [RFC8040]  Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
              Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
              <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,
              May 2017, <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, March 2018,
              <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, March 2018,
              <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, March 2018,
              <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, March
              2018, <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, August 2018,
              <https://www.rfc-editor.org/info/rfc8446>.

   [RFC8640]  Voit, E., Clemm, A., Gonzalez Prieto, A., Nilsen-Nygaard,
              E., and A. Tripathy, "Dynamic Subscription to YANG Events
              and Datastores over NETCONF", RFC 8640,
              DOI 10.17487/RFC8640, September 2019,
              <https://www.rfc-editor.org/info/rfc8640>.

   [RFC8641]  Clemm, A. and E. Voit, "Subscription to YANG Notifications
              for Datastore Updates", RFC 8641, DOI 10.17487/RFC8641,
              September 2019, <https://www.rfc-editor.org/info/rfc8641>.

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   [RFC8776]  Saad, T., Gandhi, R., Liu, X., Beeram, V., and I. Bryskin,
              "Common YANG Data Types for Traffic Engineering",
              RFC 8776, DOI 10.17487/RFC8776, June 2020,
              <https://www.rfc-editor.org/info/rfc8776>.

   [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, February
              2022, <https://www.rfc-editor.org/info/rfc9181>.

11.2.  Informative References

   [I-D.boro-opsawg-teas-attachment-circuit]
              Boucadair, M., Roberts, R., de Dios, O. G., Barguil, S.,
              and B. Wu, "YANG Data Models for 'Attachment Circuits'-as-
              a-Service (ACaaS)", Work in Progress, Internet-Draft,
              draft-boro-opsawg-teas-attachment-circuit-07, 10 July
              2023, <https://datatracker.ietf.org/doc/html/draft-boro-
              opsawg-teas-attachment-circuit-07>.

   [I-D.boro-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-boro-
              opsawg-teas-common-ac-02, 3 May 2023,
              <https://datatracker.ietf.org/doc/html/draft-boro-opsawg-
              teas-common-ac-02>.

   [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-20, 14 October 2023,
              <https://datatracker.ietf.org/doc/html/draft-ietf-teas-
              actn-vn-yang-20>.

   [I-D.ietf-teas-ietf-network-slices]
              Farrel, A., Drake, J., Rokui, R., Homma, S., Makhijani,
              K., Contreras, L. M., and J. Tantsura, "A Framework for
              Network Slices in Networks Built from IETF Technologies",
              Work in Progress, Internet-Draft, draft-ietf-teas-ietf-
              network-slices-25, 14 September 2023,
              <https://datatracker.ietf.org/doc/html/draft-ietf-teas-
              ietf-network-slices-25>.

   [RFC7640]  Constantine, B. and R. Krishnan, "Traffic Management
              Benchmarking", RFC 7640, DOI 10.17487/RFC7640, September
              2015, <https://www.rfc-editor.org/info/rfc7640>.

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   [RFC8309]  Wu, Q., Liu, W., and A. Farrel, "Service Models
              Explained", RFC 8309, DOI 10.17487/RFC8309, January 2018,
              <https://www.rfc-editor.org/info/rfc8309>.

   [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,
              June 2023, <https://www.rfc-editor.org/info/rfc9408>.

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.boro-opsawg-teas-common-ac].

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-attributes
    |  +--rw description?   string
    |  +--rw peer-as?       inet:as-number
    |  +--rw neighbor*      inet:ip-address
    +--rw static-attributes
       +--rw cascaded-lan-prefixes
          +--rw ip-lan-prefixes* [lan next-hop]
             +--rw lan         inet:ip-prefix
             +--rw next-hop    union
                   ...

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

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

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  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
   dedicatd network resources, similar to a dedicated private network.";
  }

Appendix B.  Examples of Network Slice Services

B.1.  Example-1: Two A2A Slice Services with different match approaches

   The following example describes a simplified service configuration of
   two IETF Network slice instances where the SDPs are the customer-
   facing ports on the PE:

   *  IETF Network Slice 1 on SDP1, SDP11a, and SDP4, with an A2A
      connectivity type.  This is a L3 slice service and using 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.

   *  IETF Network Slice 2 on SDP2, SDP11b, with A2A connectivity type.
      This is a L3 slice service and using 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.

   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 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 up to the operator and
   the NSC on it's need and usage.

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+--------+         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

{
  "data": {
    "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-tag-service",
                "value": ["L3"]
              }
            ]
          },
          "slo-sle-template": "low-latency-template",

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          "status": {
          },
          "sdps": {
            "sdp": [
              {
                "id": "1",
                "node-id": "PE-A",
                "service-match-criteria": {
                  "match-criterion": [
                    {
                      "index": 1,
                      "match-type": "ietf-nss:service-any-match",
                      "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-tags": [
                          {
                            "tag-type": "ietf-nss:vlan-id",
                            "value": ["100"]
                          }
                        ]
                      },
                      "status": {
                      }
                    }
                  ]
                },
                "status": {
                }
              },
              {
                "id": "3a",
                "node-id": "PE-B",
                "service-match-criteria": {
                  "match-criterion": [
                    {

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                      "index": 1,
                      "match-type": "ietf-nss:service-any-match",
                      "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-tags": [
                          {
                            "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": "ietf-nss:service-any-match",
                      "target-connection-group-id": "matrix1",
                      "target-connectivity-construct-id": 1
                    }
                  ]
                },
                "attachment-circuits": {
                  "attachment-circuit": [
                    {

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                      "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-tags": [
                          {
                            "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": {
                    }
                  }
                ]
              }

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            ]
          }
        },
        {
          "id": "slice2",
          "description": "example slice2",
          "service-tags": {
            "tag-type": [
              {
                "tag-type": "ietf-nss:service-tag-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-tags": [
                          {
                            "tag-type": "ietf-nss:vlan-id",
                            "value": ["100"]
                          }
                        ]
                      },
                      "status": {
                      }
                    }
                  ]
                },
                "status": {
                }
              },
              {

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                "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-tags": [
                          {
                            "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": {
                    }
                  }

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                ]
              }
            ]
          }
        }
      ]
    }
  }
}

B.2.  Example-2: Two P2P slice services with different match approaches

   The following example describes a simplified service configuration of
   two IETF Network slice instances where the SDPs are the customer-
   facing ports on the PE:

   *  IETF Network Slice 3 on SDP5 and SDP7a with P2P connectivity type.
      This is a L2 slice service and using the uniform low-latency "slo-
      sle-template" policies between the SDPs.  A connectivity-group
      level slo-policy has been applied with a delay based metric bound
      of 10ms which will apply to both connectivity-constructs.

   *  IETF Network Slice 4 on SDP6 and SDP7b, with P2P connectivity
      type.  This is a L2 slice service and using the the high bandwidth
      "slo-sle-template" policies between the SDPs.  Traffic from SDP6
      and SDP7b is requesting a bandwidth of 1000Mbps, while in the
      reverse direction from SDP7b to SDP6, 5000Mbps is being requested.

   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 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 up to the operator and the NSC
   on it's need and usage.

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   +--------+
   |  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

{
  "data": {
    "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",
          "slo-sle-template": "low-latency-template",
          "status": {
          },
          "sdps": {
            "sdp": [
              {
                "id": "5",
                "node-id": "PE-A",
                "service-match-criteria": {
                  "match-criterion": [
                    {

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                      "index": 1,
                      "match-type": "ietf-nss:service-any-match",
                      "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-tags": [
                          {
                            "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": "ietf-nss:service-any-match",
                      "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",

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                      "ac-tags": {
                        "ac-tags": [
                          {
                            "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": {
                    }

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                  }
                ]
              }
            ]
          }
        },
        {
          "id": "slice4",
          "description": "example slice4",
          "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-tags": [
                          {
                            "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",

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                      "ac-node-id": "PE-B",
                      "ac-tp-id": "GigabitEthernet8/0/0/5",
                      "ac-tags": {
                        "ac-tags": [
                          {
                            "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",

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                    "service-slo-sle-policy": {
                      "slo-policy": {
                        "metric-bound": [
                          {
                            "metric-type": ietf-nss:one-way-bandwidth",
                            "metric-unit": "Mbps",
                            "bound": "5000"
                           }
                         ]
                       }
                    },
                    "status": {
                    }
                  }
                ]
              }
            ]
          }
        }
      ]
    }
  }
}

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

   The following example describes a simplified service configuration of
   one IETF Network slice instance where the SDPs are the customer-
   facing ports on the PE:

      IETF Network Slice 5 is a hub-spoke slice with SDP14 as the hub
      and SDP11, SDP12, SDP13a, SDP13b as spokes.  This is a L3 slice
      service and using 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.

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+--------+         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

{
  "data": {
    "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-tag-service",
                "value": ["L3"]
              }
            ]
          },
          "slo-sle-template": "low-latency-template",
          "status": {

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          },
          "sdps": {
            "sdp": [
              {
                "id": "11",
                "node-id": "PE-A",
                "service-match-criteria": {
                  "match-criterion": [
                    {
                      "index": 1,
                      "match-type": "ietf-nss:service-any-match",
                      "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-tags": [
                          {
                            "tag-type": "ietf-nss:vlan-id",
                            "value": ["100"]
                          }
                        ]
                      },
                      "status": {
                      }
                    }
                  ]
                },
                "status": {
                }
              },
              {
                "id": "12",
                "node-id": "PE-A",
                "service-match-criteria": {
                  "match-criterion": [
                    {
                      "index": 1,

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                      "match-type": "ietf-nss:service-any-match",
                      "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-tags": [
                          {
                            "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": "ietf-nss:service-any-match",
                      "target-connection-group-id": "matrix5",
                      "connection-group-sdp-role": "ietf-vpn-common:spoke-role"
                    }
                  ]
                },
                "attachment-circuits": {
                  "attachment-circuit": [
                    {
                      "id": "ac13a",

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                      "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-tags": [
                          {
                            "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": "ietf-nss:service-any-match",
                      "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-tags": [
                          {
                            "tag-type": "ietf-nss:vlan-id",
                            "value": ["201"]

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                          }
                        ]
                      },
                      "status": {
                      }
                    }
                  ]
                },
                "status": {
                }
              },
              {
                "id": "14",
                "node-id": "PE-C",
                "service-match-criteria": {
                  "match-criterion": [
                    {
                      "index": 1,
                      "match-type": "ietf-nss:service-any-match",
                      "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-tags": [
                          {
                            "tag-type": "ietf-nss:vlan-id",
                            "value": ["100"]
                          }
                        ]
                      },
                      "status": {
                      }
                    }
                  ]
                },
                "status": {
                }

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              }
            ]
          },
          "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": {
                    }
                  }
                ]
              }
            ]
          }
        }
      ]
    }
  }
}

B.4.  Example-4: An A2A Slice service with multiple SLOs and DSCP
      Matching

   The following example describes a simplified service configuration of
   an IETF Network slice instance where the SDPs are the customer-facing
   ports on the PE:

      IETF Network Slice 6 on SDP21, SDP23a, and SDP24, with A2A

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      connectivity type.  This is a L3 slice service and using 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.

+--------+         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              |      |
+--------+              +------+

{
  "data": {
    "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": [

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              {
                "tag-type": "ietf-nss:service-tag-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": "ietf-nss:service-dscp-match",
                      "value": ["EF"],
                      "target-connection-group-id": "matrix6",
                      "target-connectivity-construct-id": 2
                    },
                    {
                      "index": 2,
                      "match-type": "ietf-nss:service-any-match",
                      "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-tags": [
                          {
                            "tag-type": "ietf-nss:vlan-id",
                            "value": ["100"]
                          }
                        ]
                      },

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                      "status": {
                      }
                    }
                  ]
                },
                "status": {
                }
              },
              {
                "id": "23a",
                "node-id": "PE-B",
                "service-match-criteria": {
                  "match-criterion": [
                    {
                      "index": 1,
                      "match-type": "ietf-nss:service-dscp-match",
                      "value": ["EF"],
                      "target-connection-group-id": "matrix6",
                      "target-connectivity-construct-id": 2
                    },
                    {
                      "index": 2,
                      "match-type": "ietf-nss:service-any-match",
                      "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-tags": [
                          {
                            "tag-type": "ietf-nss:vlan-id",
                            "value": ["101"]
                          }
                        ]
                      },
                      "status": {
                      }
                    }

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                  ]
                },
                "status": {
                }
              },
              {
                "id": "24",
                "node-id": "PE-C",
                "service-match-criteria": {
                  "match-criterion": [
                    {
                      "index": 1,
                      "match-type": "ietf-nss:service-dscp-match",
                      "value": ["EF"],
                      "target-connection-group-id": "matrix6",
                      "target-connectivity-construct-id": 2
                    },
                    {
                      "index": 2,
                      "match-type": "ietf-nss:service-any-match",
                      "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-tags": [
                          {
                            "tag-type": "ietf-nss:vlan-id",
                            "value": ["100"]
                          }
                        ]
                      },
                      "status": {
                      }
                    }
                  ]
                },
                "status": {

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                }
              }
            ]
          },
          "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",
                        "slo-sle-template": "low-latency-template"
                      }
                    ],
                    "status": {
                    }
                  },
                  {
                    "id": 2,
                    "a2a-sdp": [
                      {
                        "sdp-id": "21"
                      },
                      {
                        "sdp-id": "23a"
                      },
                      {
                        "sdp-id": "24"
                      }
                    ],
                    "status": {
                    }
                  }
                ]
              }
            ]
          }
        }

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      ]
    }
  }
}

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

   The following examples describes a simplified service configuration
   of an IETF 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
   connecitivty- construct level take precedence to 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 |
                        +------+           +---+--+           +--------+

   {
     "data": {
       "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",

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               "description": "lowest BW forwarding behavior"
             }
           ]
         },
         "slice-service": [
           {
             "id": "slice-7",
             "description": "Foo",
             "service-tags": {
               "tag-type": [
                 {
                   "tag-type": "ietf-nss:service-tag-customer",
                   "value": ["Customer-FOO"]
                 },
                 {
                   "tag-type": "ietf-nss:service-tag-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": "ietf-nss:service-vlan-match",
                         "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,

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                         "ac-tags": {
                           "ac-tags": [
                             {
                               "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": "ietf-nss:service-vlan-match",
                         "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",

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                         "ac-ipv6-prefix-length": 64,
                         "ac-tags": {
                           "ac-tags": [
                             {
                               "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": "ietf-nss:service-vlan-match",
                         "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",

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                         "ac-ipv6-address": "2001:db8:0:3::1",
                         "ac-ipv6-prefix-length": 64,
                         "ac-tags": {
                           "ac-tags": [
                             {
                               "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": "ietf-nss:service-vlan-match",
                         "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",

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                         "ac-tp-id": "GigabitEthernet4/0/0/0",
                         "ac-ipv6-address": "2001:db8:0:4::1",
                         "ac-ipv6-prefix-length": 64,
                         "ac-tags": {
                           "ac-tags": [
                             {
                               "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"
                         },
                         {

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                           "sdp-id": "SDP3"
                         },
                         {
                           "sdp-id": "SDP4"
                         }
                       ],
                       "status": {
                       }
                     }
                   ]
                 }
               ]
             }
           }
         ]
       }
     }
   }

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

   The following example describes a simplified service configuration of
   one IETF Network slice instances where the SDPs are located at the
   PE-facing ports on the CE:

   *  IETF Network Slice 8 with SDP31 on CE Device1, SDP33 (with two
      ACs) on Device 3 and SDP34 on Device 4, with an A2A connectivity
      type.  This is a L3 slice service and using the uniform low-
      latency slo-sle-template policy between all SDPs.

   *  This example also introduces the optional attribute of "sdp-ip".
      In this example it could be a loopback on the device.  How this
      sdp-ip is used by the NSC is out-of-scope here, but an example
      could be it is the management interface of the device.  The SDP
      and AC details are from the perspective of the CE in this example.
      How the CE ACs are mapped to the PE ACs are up to the NSC
      implementation and out-of-scope in this example.

      SDP31 ac-id=ac31, node-id=Device1, interface: GigabitEthernet0
      vlan 100

      SDP33 ac-id=ac33a, node-id=Device3, interface: GigabitEthernet0
      vlan 101

      SDP33 ac-id=ac33b, node-id=Device3, interface: GigabitEthernet1
      vlan 201

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      SDP34 ac-id=ac34, node-id=Device4, interface: GigabitEthernet3
      vlan 100

SDP31
SDP-ip 203.0.113.1
(Loopback)
    |
    |     192.0.2.2/26
    v      VLAN200      +------+
+--------+ ac31         | PE A +---------------+
|  CE1   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 CE2    |
+--------+ ac33a            |              +---+--+    ac34   +--------+
|        o------/           |                  |       VLAN201
|        |      |       +---+---+              |       198.51.100.66/26
|  CE3   |      +------o| PE B  +--------------+
|        o-------/-----o|       |
+--------+ ac33b        +-------+
           VLAN201
           198.51.100.2/26

{
  "data": {
    "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": [
              {

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                "tag-type": "ietf-nss:service-tag-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": "ietf-nss:service-any-match",
                      "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-tags": [
                          {
                            "tag-type": "ietf-nss:vlan-id",
                            "value": ["100"]
                          }
                        ]
                      },
                      "status": {
                      }
                    }
                  ]
                },
                "status": {
                }

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              },
              {
                "id": "33",
                "node-id": "Device-3",
                "sdp-ip-address": ["203.0.113.65"],
                "service-match-criteria": {
                  "match-criterion": [
                    {
                      "index": 1,
                      "match-type": "ietf-nss:service-any-match",
                      "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-tags": [
                          {
                            "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-tags": [
                          {
                            "tag-type": "ietf-nss:vlan-id",
                            "value": ["201"]
                          }

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                        ]
                      },
                      "status": {
                      }
                    }
                  ]
                },
                "status": {
                }
              },
              {
                "id": "34",
                "node-id": "Device-4",
                "sdp-ip-address": ["203.0.113.129"],
                "service-match-criteria": {
                  "match-criterion": [
                    {
                      "index": 1,
                      "match-type": "ietf-nss:service-any-match",
                      "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-tags": [
                          {
                            "tag-type": "ietf-nss:vlan-id",
                            "value": ["100"]
                          }
                        ]
                      },
                      "status": {
                      }
                    }
                  ]
                },
                "status": {
                }

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              }
            ]
          },
          "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": {
                    }
                  }
                ]
              }
            ]
          }
        }
      ]
    }
  }
}

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

   The following example describes a simplified service configuration of
   one IETF Network slice instances 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.

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   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.

   *  IETF Network Slice 9 with SDP31 on CPE Device1, SDP33 (with two
      ACs) on Device 3 and SDP34 on Device 4, with an A2A connectivity
      type.  This is a L3 slice service and using the uniform low-
      latency slo-sle-template policy between all SDPs.

      SDP31 ac-id=ac31, node-id=Device1, peer-sap-id= foo.com-
      circuitID-12345

      SDP33 ac-id=ac33a, node-id=Device3, peer-sap-id=foo.com-
      circuitID-67890

      SDP33 ac-id=ac33b, node-id=Device3, peer-sap-id=foo.com-circuitID-
      54321ABC

      SDP34 ac-id=ac34, node-id=Device4, peer-sap-id=foo.com-
      circuitID-9876

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        +-------------------------+

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{
  "data": {
    "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-tag-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": "ietf-nss:service-any-match",
                      "target-connection-group-id": "matrix1"
                    }
                  ]
                },
                "attachment-circuits": {
                  "attachment-circuit": [
                    {

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                      "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": "ietf-nss:service-any-match",
                      "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": {
                }

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              },
              {
                "id": "34",
                "node-id": "Device-4",
                "sdp-ip-address": ["2001:db8:0:3::1"],
                "service-match-criteria": {
                  "match-criterion": [
                    {
                      "index": 1,
                      "match-type": "ietf-nss:service-any-match",
                      "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"

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                      }
                    ],
                    "status": {
                    }
                  }
                ]
              }
            ]
          }
        }
      ]
    }
  }
}

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?   leafref
      |     +--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
      |     +--rw sle-policy
      |        +--rw security*               identityref
      |        +--rw isolation*              identityref
      |        +--rw max-occupancy-level?    uint8
      |        +--rw steering-constraints
      |           +--rw path-constraints
      |           +--rw service-function
      +--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)?

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         |  +--:(standard)
         |  |  +--rw slo-sle-template?         leafref
         |  +--:(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?            uint16
         |        +--rw sle-policy
         |           +--rw security*               identityref
         |           +--rw isolation*              identityref
         |           +--rw max-occupancy-level?    uint8
         |           +--rw steering-constraints
         |              +--rw path-constraints
         |              +--rw service-function
         +--rw compute-only?                   empty
         +--rw status
         |  +--rw admin-status
         |  |  +--rw status?        identityref
         |  |  +--rw last-change?   yang:date-and-time
         |  +--ro oper-status
         |     +--ro status?        identityref
         |     +--ro last-change?   yang:date-and-time
         +--rw sdps
         |  +--rw sdp* [id]
         |     +--rw id                        string
         |     +--rw description?              string
         |     +--rw location
         |     |  +--rw altitude?    int64
         |     |  +--rw latitude?    decimal64
         |     |  +--rw longitude?   decimal64
         |     +--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
         |     |     |       identityref
         |     |     +--rw value*
         |     |     |       string

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         |     |     +--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 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 sdp-peering
         |     |  +--rw peer-sap-id*   string
         |     |  +--rw protocols
         |     +--rw ac-svc-name*              string
         |     +--rw attachment-circuits
         |     |  +--rw attachment-circuit* [id]
         |     |     +--rw id                       string
         |     |     +--rw description?             string
         |     |     +--rw ac-svc-name?             string
         |     |     +--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?                     uint16
         |     |     +--rw ac-tags
         |     |     |  +--rw ac-tags* [tag-type]
         |     |     |     +--rw tag-type    identityref
         |     |     |     +--rw value*      string
         |     |     +--rw incoming-qos-policy
         |     |     |  +--rw qos-policy-name?   string
         |     |     |  +--rw rate-limits
         |     |     |     +--rw cir?   uint64

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         |     |     |     +--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 sdp-peering
         |     |     |  +--rw peer-sap-id?   string
         |     |     |  +--rw protocols
         |     |     +--rw status
         |     |        +--rw admin-status
         |     |        |  +--rw status?        identityref
         |     |        |  +--rw last-change?   yang:date-and-time
         |     |        +--ro oper-status
         |     |           +--ro status?        identityref
         |     |           +--ro last-change?   yang:date-and-time
         |     +--rw status
         |     |  +--rw admin-status
         |     |  |  +--rw status?        identityref
         |     |  |  +--rw last-change?   yang:date-and-time
         |     |  +--ro oper-status
         |     |     +--ro status?        identityref
         |     |     +--ro last-change?   yang:date-and-time
         |     +--ro sdp-monitoring
         |        +--ro incoming-bw-value?     uint64
         |        +--ro incoming-bw-percent    decimal64
         |        +--ro outgoing-bw-value?     uint64
         |        +--ro outgoing-bw-percent    decimal64
         +--rw connection-groups
         |  +--rw connection-group* [id]
         |     +--rw id                                 string
         |     +--rw connectivity-type?
         |     |       identityref
         |     +--rw (slo-sle-policy)?
         |     |  +--:(standard)
         |     |  |  +--rw slo-sle-template?            leafref
         |     |  +--:(custom)
         |     |     +--rw service-slo-sle-policy
         |     |        +--rw description?   string
         |     |        +--rw slo-policy

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         |     |        |  +--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
         |     |        +--rw sle-policy
         |     |           +--rw security*
         |     |           |       identityref
         |     |           +--rw isolation*
         |     |           |       identityref
         |     |           +--rw max-occupancy-level?    uint8
         |     |           +--rw steering-constraints
         |     |              +--rw path-constraints
         |     |              +--rw service-function
         |     +--rw service-slo-sle-policy-override?
         |     |       identityref
         |     +--rw connectivity-construct* [id]
         |     |  +--rw id
         |     |  |       uint32
         |     |  +--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?         leafref
         |     |  |           +--:(custom)
         |     |  |              +--rw service-slo-sle-policy
         |     |  |                 +--rw description?   string
         |     |  |                 +--rw slo-policy
         |     |  |                 |  +--rw metric-bound*
         |     |  |                 |  |       [metric-type]

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         |     |  |                 |  |  +--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
         |     |  |                 +--rw sle-policy
         |     |  |                    +--rw security*
         |     |  |                    |       identityref
         |     |  |                    +--rw isolation*
         |     |  |                    |       identityref
         |     |  |                    +--rw max-occupancy-level?
         |     |  |                    |       uint8
         |     |  |                    +--rw steering-constraints
         |     |  |                       +--rw path-constraints
         |     |  |                       +--rw service-function
         |     |  +--rw (slo-sle-policy)?
         |     |  |  +--:(standard)
         |     |  |  |  +--rw slo-sle-template?              leafref
         |     |  |  +--:(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?            uint16
         |     |  |        +--rw sle-policy
         |     |  |           +--rw security*
         |     |  |           |       identityref
         |     |  |           +--rw isolation*
         |     |  |           |       identityref
         |     |  |           +--rw max-occupancy-level?    uint8
         |     |  |           +--rw steering-constraints

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         |     |  |              +--rw path-constraints
         |     |  |              +--rw service-function
         |     |  +--rw service-slo-sle-policy-override?
         |     |  |       identityref
         |     |  +--rw status
         |     |  |  +--rw admin-status
         |     |  |  |  +--rw status?        identityref
         |     |  |  |  +--rw last-change?   yang:date-and-time
         |     |  |  +--ro oper-status
         |     |  |     +--ro status?        identityref
         |     |  |     +--ro last-change?   yang:date-and-time
         |     |  +--ro connectivity-construct-monitoring
         |     |     +--ro one-way-min-delay?         uint32
         |     |     +--ro one-way-max-delay?         uint32
         |     |     +--ro one-way-delay-variation?   uint32
         |     |     +--ro one-way-packet-loss?       decimal64
         |     |     +--ro two-way-min-delay?         uint32
         |     |     +--ro two-way-max-delay?         uint32
         |     |     +--ro two-way-delay-variation?   uint32
         |     |     +--ro two-way-packet-loss?       decimal64
         |     +--ro connection-group-monitoring
         |        +--ro one-way-min-delay?         uint32
         |        +--ro one-way-max-delay?         uint32
         |        +--ro one-way-delay-variation?   uint32
         |        +--ro one-way-packet-loss?       decimal64
         |        +--ro two-way-min-delay?         uint32
         |        +--ro two-way-max-delay?         uint32
         |        +--ro two-way-delay-variation?   uint32
         |        +--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 IETF Network Slice
   Service requirements is that the IETF Network Slice Service interface
   is a technology-agnostic interface, whereas the VN model is bound to
   the IETF TE Topologies.  The realization of the IETF 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:

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   *  VN: A Virtual Network (VN) is a network provided by a service
      provider to a customer for use and two types of VN has defined.
      The Type 1 VN can be seen as a set of edge-to-edge abstract links.
      Each link is an abstraction of the underlying network which can
      encompass edge points of the customer's network, access links,
      intra-domain paths, and inter-domain links.

   *  AP: An AP is a logical identifier used to identify the access link
      which is shared between the customer and the IETF scoped Network.

   *  VN-AP: A VN-AP is a logical binding between an AP and a given VN.

   *  VN-member: A VN-member is an abstract edge-to-edge link between
      any two APs or VN-APs.  Each link is formed as an E2E tunnel
      across the underlying networks.

   The Type 1 VN can be used to describe IETF Network Slice connection
   requirements.  However, the Network Slice SLO and Network Slice SDP
   are not clearly defined and there's no direct equivalent.  For
   example, the SLO requirement of the VN is defined through the IETF 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
   IETF Network Slice Service.

Authors' Addresses

   Bo Wu
   Huawei Technologies
   101 Software Avenue, Yuhua District
   Nanjing
   Jiangsu, 210012
   China
   Email: lana.wubo@huawei.com

   Dhruv Dhody
   Huawei Technologies
   Divyashree Techno Park
   Bangalore 560066
   Karnataka
   India
   Email: dhruv.ietf@gmail.com

   Reza Rokui
   Ciena
   Email: rrokui@ciena.com

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Internet-Draft      Network Slice Service YANG Model        October 2023

   Tarek Saad
   Cisco Systems, Inc
   Email: tsaad@cisco.com

   John Mullooly
   Cisco Systems, Inc
   Email: jmullool@cisco.com

Wu, et al.                Expires 25 April 2024               [Page 107]