Internet-Draft Network Slice Service YANG Model March 2023
Wu, et al. Expires 14 September 2023 [Page]
Workgroup:
TEAS
Internet-Draft:
draft-ietf-teas-ietf-network-slice-nbi-yang-04
Published:
Intended Status:
Standards Track
Expires:
Authors:
B. Wu
Huawei Technologies
D. Dhody
Huawei Technologies
R. Rokui
Ciena
T. Saad
Cisco Systems, Inc
L. Han
China Mobile
J. Mullooly
Cisco Systems, Inc

A YANG Data Model for the IETF Network Slice Service

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 Slices.

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/.

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This Internet-Draft will expire on 14 September 2023.

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Table of Contents

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 YANG model focuses on the requirements of an IETF Network Slice Service from the point of view of the customer, not how it is implemented by a provider. 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 [RFC8342].

Editorial Note: (To be removed by RFC Editor)

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

2. Conventions used in this document

The keywords "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP14, [RFC2119], [RFC8174] when, and only when, they appear in all capitals, as shown here.

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

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

This document also makes use of the terms defined in [I-D.ietf-teas-ietf-network-slices]:

In addition, this document defines the following term:

2.1. Acronyms

The following acronyms are used in the document:

A2A
Any-to-any
AC
Attachment Circuit
CE
Customer Edge
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 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.

       +----------------------------------------------+
       |                                              |
       |                                              |
       |       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 Service Demarcation Point
----: 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 are shown in Figure 2.

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


 Slice Service: IETF Network Slice Service
 CC:   Connectivity Construct
 o  : Represents Service Demarcation Point
----: 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 Usage

The NSSM can be used by a provider to expose its Slice Service, and by a customer to manage its IETF Network Slices Services (e.g., request, delete, or change). 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, NFV (Network Function Virtualization) connectivity, Data Center Interconnect, and 5G E2E network slice.

The 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, the NSC receives requests from its customer-facing interface (e.g., from a management system). During service creation, this interface can carry data objects 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 model 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 model can be recursive (hierarchical mode), i.e. an NSSM can map a child NSSM. As described in Section 5.3 of [I-D.ietf-teas-ietf-network-slices], the IETF Network Slice can support a recursive composite architecture that allows one layer of IETF network slices to be used by other layers.

5. IETF Network Slice Service Modeling Description

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

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

The figure below describes the overall structure of the YANG module:

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-ref
              ...
Figure 4

5.1. IETF Network Slice Service SLO and SLE Templates

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

     +--rw slo-sle-templates
        +--rw slo-sle-template* [id]
           +--rw id                        string
           +--rw description?              string
           +--rw template-ref?             -> /network-slice-services/slo-sle-templates/slo-sle-template/id
           +--rw service-slo-sle-policy
              +--rw policy-description?     string
              +--rw metric-bounds
              |  +--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 security*               identityref
              +--rw isolation?              identityref
              +--rw max-occupancy-level?    uint8
              +--rw mtu?                    uint16
              +--rw steering-constraints
                 +--rw path-constraints
                 +--rw service-function

The model includes the identifiers of SLO and SLE templates and the common attributes defined in [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 NS 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:

{
  "network-slice-services": {
    "slo-sle-templates": {
      "slo-sle-template": [
        {
          "id": "PLATINUM-template",
          "description": "Two-way bandwidth: 1 Gbps,\
       95th percentile latency 50ms",
          "service-slo-sle-policy": {
            "metric-bounds": {
              "metric-bound": [
                {
                  "metric-type": "service-slo-two-way-delay-percentile",
                  "metric-unit": "milliseconds",
                  "percentile-value": "95",
                  "bound": 50
                }
              ]
            },
            "isolation": "service-isolation-dedicated"
          }
        },
        {
          "id": "GOLD-template",
          "description": "Two-way bandwidth: 1 Gbps,\
         maximum latency 100ms",
          "service-slo-sle-policy": {
            "metric-bounds": {
              "metric-bound": [
                {
                  "metric-type": "service-slo-two-way-delay-maximum",
                  "metric-unit": "milliseconds",
                  "bound": 100
                }
              ],
              "isolation": "service-isolation-shared"
            }
          }
        }
      ]
    }
  }
}

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

5.2. IETF Network Slice Services

The 'slice-service' is the data structure that abstracts an IETF Network Slice Service. Each 'slice-service' is uniquely identified by an identifier: 'service-id' in the context of an NSC.

An IETF Network Slice service has the following main parameters:

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?                   -> /nw:networks/network[nw:network-id =current()/../../../custom-topology-ref/network-ref]/node/nt:termination-point/tp-id
     +--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 the 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.

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 3.2 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 several 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": The SDP IP information, which helps the NSC to identify an SDP.
  • "incoming-qos-policy" and "outgoing-qos-policy": Sets the incoming and outgoing QoS policies to apply on a given SDP, including QoS policy and specific ingress and egress traffic limits to ensure access security. When applied in the incoming direction, the rate-limit is applicable to the traffic from the SDP to the IETF scope Network that passes through the AC. When Bandwidth is applied to the outgoing direction, it is applied to the traffic from the IETF Network to the SDP of that particular slice service. 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 3.1 [I-D.ietf-teas-ietf-network-slices].
  • "ac-svc-name": Indicates an attachment circuit service name, for association purposes, to refer to an AC that has been created when an AC is used by multiple slices.
  • "attachment-circuit": 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 the AC specific attributes is needed, each "attachment-circuit" can specify attributes such as interface specific IP addresses, service MTU, etc.

  • "sdp-peering": Specifies the protocol for an SDP for exchanging control-plane information, e.g. L1 signaling protocol or L3 routing protocols, etc.

    • "peer-sap-id": Indicates a reference to the remote endpoints of an attachment circuit. A unique identifier that identifies a given Service Attachment Point (SAP) defined in [I-D.ietf-opsawg-sap], which defines a model of an abstract view of the provider network topology that contains the points from which its 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 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 CGs or 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.
  • Define specific out-of-profile policies: The customer may choose to use an explicit "service-match-criteria" to map all the 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 , 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-circuit' (ACs) to map SDPs to the customer-facing ports on the PEs.

                  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 the IETF network slice endpoints (SDP)
   +: Mapping of SDP to customer-facing ports on the PE
   X: Physical interfaces used for realization of 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 , 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' (IP of SDP for management), 'service-match-criteria' (VLAN tag), 'attachment-circuit' (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).

               SDP3                                     SDP4
    (With CE1 parameters)                       (with CE2 parameters)
    +<----------------- 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 the IETF network slice endpoints (SDP)
+: Mapping of SDP to CE
X: Physical interfaces used for realization of IETF network slice
S2: L0/L1/L2/L3 services used for realization of IETF network slice
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.

+--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 for a network slice, 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&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.

5.2.3. IETF Network Slice Service SLO and SLE Policy

As defined in section 4 [I-D.ietf-teas-ietf-network-slices], the SLO and SLE policy of an IETF Network Slice service defines some common attributes.

"slo-sle-policy" is used to represent specific 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 any-to-any connectivity as default and several specific SLO connections.

The container "metric-bounds" supports all the variations and combinations of SLOs, which includes a list of "metric-bound" and each "metric-bound" could specify a particular "metric-type". "metric-type" is defined with YANG identity and supports the following options:

"service-slo-one-way-bandwidth": Indicates the guaranteed minimum bandwidth between any two SDPs. And the bandwidth is unidirectional.
"service-slo-two-way-bandwidth": Indicates the guaranteed minimum bandwidth between any two SDPs. And the bandwidth is bidirectional.
"service-slo-one-way-delay-maximum": Indicates the maximum one-way latency between two SDPs.
"service-slo-two-way-delay-maximum": Indicates the maximum round-trip latency between two SDPs.
"service-slo-one-way-delay-percentile": Indicates the percentile objective of the one-way latency between two SDPs.
"service-slo-two-way-delay-percentile": Indicates the percentile objective of the round-trip latency between two SDPs.
"service-slo-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.
"service-slo-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.
"service-slo-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.
"service-slo-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.
"service-slo-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.
"service-slo-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.
"service-slo-availability": Is defined as the ratio of up-time to total_time(up-time+down-time), where up-time is the time the IETF Network Slice is available in accordance with the SLOs associated with it.

The following common SLEs are defined:

"mtu": Refers to the service MTU, which is the maximum PDU size that the customer may use.
"security": The security leaf-list defines the list of security techniques to traffic flowing between the two SDPs, including authentication, encryption, etc.
"isolation": Specifies the isolation level that a customer expects, including dedicated, shared, or other level.
"max-occupancy-level": Specifies the number of flows to be admitted and optionally a maximum number of countable resource units (e.g., IP or MAC addresses) an IETF Network Slice Service can consume.
"steering-constraints": Specifies the constraints how the provider routes 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",
        "metric-bounds": {
          "metric-bound": [
            {
              "metric-type": "service-slo-one-way-bandwidth",
              "metric-unit": "mbps",
              "bound": "1000"
            },
            {
              "metric-type": "service-slo-availability",
              "bound": "99.9%"
            }
          ]
        }
      }
    }
  }
}

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 connectivity-construct has a unique bandwidth or latency setting, that are different from those defined in the slice-service, a new set of SLO&SLE 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 IETF Network Slice customer might ask for some level of control of, e.g., to customize the service paths in a network slice.

Section 3.13 in [RFC8345] defines 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). The following nodes are the extensions for this use case

"custom-topology-ref": The container under the list "slice-service" is defined to reference the prebuilt topology as a customized topology constraint for a slice service.
"tp-ref": A reference to Termination Point (TP) in the custom topology, under the list "sdp", is used to associate an SDP with the customized topology to create point-to-point abstract links. These abstract links can be used as the underlying links of the connectivity-construct when a NS service is created.

The model can be extended if some implementations require path control with specific constraints.

5.2.6. IETF Network Slice Service Compute

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

A 'compute-only' NS is configured as usual with the associated per slice SLOs/SLEs. The NSC computes the feasible CC to the configured SLOs/SLEs. This computation does not create a NS or reserve any resources in the system, it simply computes the resulting NS based on information. The Network Slice “administrative-status” and the CG or CC 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 )  |
                 |<----------------------------------------|
                 |                                         |

6. IETF Network Slice Service Module

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

<CODE BEGINS> file "ietf-network-slice-service@2023-03-13.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.";
  }
  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 TE Types */

  import ietf-te-types {
    prefix te-types;
    reference
      "RFC 8776: Common YANG Data Types for Traffic Engineering.";
  }
  import ietf-te-packet-types {
    prefix te-packet-types;
    reference
      "RFC 8776: Common YANG Data Types for Traffic Engineering.";
  }

  organization
    "IETF Traffic Engineering Architecture and Signaling (TEAS)
     Working Group";
  contact
    "WG Web:  <https://tools.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
          <reza.rokui@nokia.com>
     Editor: Tarek Saad
          <tsaad@cisco.com>
     Author: Liuyan Han
          <hanliuyan@chinamobile.com>
     Editor: John Mullooly
          <jmullool@cisco.com>";
  description
    "This module defines a model for the IETF Network Slice Service.

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

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

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

  revision 2023-03-13 {
    description
      "initial version.";
    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. L2 or L3
       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 attachment-circuit-tag-vlan-id {
    base attachment-circuit-tag-type;
    description
      "The attachment circuit VLAN ID tag type. e.g. dot1Q or QinQ
       VLAN IDs.";
  }

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

  identity service-isolation-type {
    description
      "Base identity for IETF Network slice service isolation level.";
  }

  identity service-isolation-shared {
    base service-isolation-type;
    description
      "Shared resources (e.g. queues) are associated with the
       slice service traffic. Hence, the traffic can be impacted
       by effects of other services traffic
       sharing the same physical and logical resources.";
  }

  identity service-isolation-dedicated {
    base service-isolation-type;
    description
      "Dedicated resources (e.g. physical interfaces, queues)
       are associated with the Network Slice service traffic.
       Hence, the service traffic is isolated from other services
       traffic, though sharing the same physical resources
       in some cases.";
  }

  identity service-security-type {
    description
      "Base identity for slice service security level.";
  }

  identity service-security-authenticate {
    base service-security-type;
    description
      "Indicates the slice service requires authentication.";
  }

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

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

  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-point IETF Network Slice
       service connectivity.";
  }

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

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

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

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

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

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

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

  identity service-slo-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 service-slo-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. The metric is defined
       in RFC7679.";
  }

  identity service-slo-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.";
  }

  identity service-slo-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. The metric is defined in
       RFC2681.";
  }

  identity service-slo-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. The metric is defined in RFC2681.";
  }

  identity service-slo-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. The metric of one-way delay variation
       is defined in RFC3393.";
  }

  identity service-slo-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.
       One-way delay variation percentile is defined by RFC3393.";
  }

  identity service-slo-two-way-delay-variation-maximum {
    base service-slo-metric-type;
    description
      "SLO two-way delay variation is defined by RFC5481, is the
       difference in the round-trip delay between sequential packets
       between two SDPs.";
  }

  identity service-slo-two-way-delay-variation-percentile {
    base service-slo-metric-type;
    description
      "The delay variation percentile is defined by RFC5481.
       The SLO objective of this metric is the percentile objective
       in the round-trip delay between sequential packets between
       two SDPs.";
  }

  identity service-slo-one-way-packet-loss {
    base service-slo-metric-type;
    description
      "SLO loss metric. The ratio of packets dropped to packets
       transmitted between two SDPs in one-way
       over a period of time as specified in RFC7680.";
  }

  identity service-slo-two-way-packet-loss {
    base service-slo-metric-type;
    description
      "SLO loss metric. The ratio of packets dropped to packets
       transmitted between two SDPs in two-way
       over a period of time as specified in RFC7680.";
  }

  identity service-slo-availability {
    base service-slo-metric-type;
    description
      "SLO availability level.";
  }

  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
      "Use the physical interface as match criteria for
       slice service traffic.";
  }

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

  identity service-label-match {
    base service-match-type;
    description
      "Use the MPLS label as match criteria for the slice service
       traffic.";
  }

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

  identity service-destination-ip-prefix-match {
    base service-match-type;
    description
      "Use destination ip prefix as match criteria for the slice
       service traffic. Examples of 'value' of this match type is
       '203.0.113.1/32', '2001:db8::2/128'.";
  }

  identity service-dscp-match {
    base service-match-type;
    description
      "Use DSCP in the IP packet header as match criteria
       for the slice service traffic.";
  }

  identity service-acl-match {
    base service-match-type;
    description
      "Use 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
      "Match all slice service traffic.";
  }

  /*
   * Identity for availability-type
   */

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

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

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

  identity level-3 {
    base availability-type;
    description
      "level 3: 99.99%";
  }

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

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

  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.";
  }

  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.";
  }

  /* grouping */

  grouping service-sles {
    description
      "Indirectly Measurable Objectives of a slice service.";
    leaf-list security {
      type identityref {
        base service-security-type;
      }
      description
        "The slice service security SLE(s)";
    }
    leaf isolation {
      type identityref {
        base service-isolation-type;
      }
      default "service-isolation-shared";
      description
        "The slice service isolation SLE requirement.";
    }
    leaf max-occupancy-level {
      type uint8 {
        range "1..100";
      }
      description
        "The maximal occupancy level specifies the number of flows
         to be admitted.";
    }
    leaf mtu {
      type uint16;
      units "bytes";
      description
        "The MTU specifies the maximum length in octets of data
         packets that can be transmitted by the slice service.
         The value needs to be less than or equal to the
         minimum MTU value of all 'attachment-circuits'
         in the SDPs.";
    }
    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 service-metric-bounds {
    description
      "Slice service metric bounds grouping.";
    container metric-bounds {
      description
        "Slice service metric bounds container.";
      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 {
          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 previous 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.
             A zero indicate an unbounded upper limit for the
             specific metric-type.";
        }
      }
    }
  }

  grouping sdp-peering {
    description
      "A grouping for the slice service SDP peering.";
    container sdp-peering {
      description
        "Describes SDP peering attributes.";
      leaf peer-sap-id {
        type string;
        description
          "Indicates a reference to the remote endpoints of an
           attachment circuit. This information can be used for
           correlation purposes, such as identifying a service
           attachment point (SAP) of a provider equipment when
           requesting a service with CE based SDP attributes.";
      }
      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 circuit.";
      list attachment-circuit {
        key "id";
        description
          "The IETF Network Slice service SDP attachment circuit
           related parameters.";
        leaf id {
          type string;
          description
            "Uniquely identifier a attachment circuit.";
        }
        leaf ac-svc-name {
          type string;
          description
            "Indicates an attachment circuit service name,
             for association purposes, to refer to an AC that has been
             created when an AC is used by multiple slices.
             This node can override 'ac-svc-name' of the parent SDP.";
        }
        leaf description {
          type string;
          description
            "The attachment circuit description.";
        }
        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 in octets 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
              "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'.";
            }
          }
        }
        /* Per ac rate limits */
        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 te-types:te-bandwidth;
        description
          "Indicates, in octets per second, incoming bandwidth at
           an SDP.";
      }
      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.";
      }
      leaf outgoing-bw-value {
        type te-types:te-bandwidth;
        description
          "Indicates, in octets per second, outgoing bandwidth at
           an SDP.";
      }
      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.";
      }
    }
  }

  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-container {
    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";
        }
        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.";
      }
    }
    // gps-location
  }

  // geolocation-container

  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";
      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
        "Container for the asymmetric traffic control.";
      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 outgoing traffic.";
      leaf qos-policy-name {
        type string;
        description
          "The name of the QoS policy that is applied to the
           attachment circuit. The name can reference a QoS
           profile that is pre-provisioned on the device.";
      }
      container rate-limits {
        description
          "The rate-limit imposed on outgoing traffic.";
        uses 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
        "Give more description of the SDP.";
    }
    uses geolocation-container;
    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-ref/network-ref]/"
        + "nw:node/nt:termination-point/nt:tp-id";
      }
      description
        "A reference to Termination Point (TP) in the custom
         topology";
      reference
        "RFC 8345: A YANG Data Model for Network Topologies";
    }
    container service-match-criteria {
      description
        "Describes the slice service match criteria.";
      list match-criterion {
        key "index";
        description
          "List of the slice service traffic match criteria.";
        leaf index {
          type uint32;
          description
            "The entry index.";
        }
        leaf match-type {
          type identityref {
            base service-match-type;
          }
          mandatory true;
          description
            "Identifies an entry in the list of the slice service
             match criteria.";
        }
        leaf-list value {
          type string;
          description
            "Describes the slice service match criteria, e.g.
             IP prefix, VLAN, etc.";
        }
        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 multi-point,
             such as hub-spoke service connection type. In addition,
             this helps to create connectivity construct automatically
             , rather than explicitly specifying each one.";
        }
        leaf target-connectivity-construct-id {
          type leafref {
            path "/ietf-nss: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;
    uses sdp-peering;
    leaf ac-svc-name {
      type string;
      description
        "Indicates an attachment circuit service name,
         for association purposes, to refer to an AC that has been
         created when an AC is used by multiple slices.";
    }
    uses sdp-attachment-circuits;
    uses vpn-common:service-status;
    uses sdp-monitoring-metrics;
  }

  //service-sdp

  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";
            }
            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;
      }
    }
  }

  //connectivity-construct

  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;
      }
      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;
    }
  }

  //connection-group

  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
            "Description of 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";
          }
          description
            "The reference to a standard template. When set it
              indicates the base template over which further
              SLO/SLE policy changes are made.";
        }
        container service-slo-sle-policy {
          description
            "Contains the SLO and SLE policy.";
          leaf description {
            type string;
            description
              "Description of the SLO and SLE policy.";
          }
          uses service-metric-bounds;
          uses service-sles;
        }
      }
    }
  }

  /* Configuration data nodes */

  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
              "Description of the SLO and SLE policy.";
          }
          uses service-metric-bounds;
          uses service-sles;
        }
      }
    }
  }

  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.";
    }
  }

  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.";
          }
          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 connections group.";
        list connection-group {
          key "id";
          description
            "List of connection groups.";
          uses connection-group;
        }
      }
      container custom-topology-ref {
        description
          "Container for the custom topology reference.";
        uses nw:network-ref;
      }
    }
    //ietf-network-slice-service list
  }
}

<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].

           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.

10. Contributors

The following authors contributed significantly to this document:

   Luis M. Contreras
   Telefonica
   Spain

   Email: luismiguel.contrerasmurillo@telefonica.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, , <https://www.rfc-editor.org/info/rfc2119>.
[RFC3688]
Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, DOI 10.17487/RFC3688, , <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, , <https://www.rfc-editor.org/info/rfc6241>.
[RFC6242]
Wasserman, M., "Using the NETCONF Protocol over Secure Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, , <https://www.rfc-editor.org/info/rfc6242>.
[RFC6991]
Schoenwaelder, J., Ed., "Common YANG Data Types", RFC 6991, DOI 10.17487/RFC6991, , <https://www.rfc-editor.org/info/rfc6991>.
[RFC7640]
Constantine, B. and R. Krishnan, "Traffic Management Benchmarking", RFC 7640, DOI 10.17487/RFC7640, , <https://www.rfc-editor.org/info/rfc7640>.
[RFC7950]
Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language", RFC 7950, DOI 10.17487/RFC7950, , <https://www.rfc-editor.org/info/rfc7950>.
[RFC8040]
Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF Protocol", RFC 8040, DOI 10.17487/RFC8040, , <https://www.rfc-editor.org/info/rfc8040>.
[RFC8174]
Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, , <https://www.rfc-editor.org/info/rfc8174>.
[RFC8340]
Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams", BCP 215, RFC 8340, DOI 10.17487/RFC8340, , <https://www.rfc-editor.org/info/rfc8340>.
[RFC8341]
Bierman, A. and M. Bjorklund, "Network Configuration Access Control Model", STD 91, RFC 8341, DOI 10.17487/RFC8341, , <https://www.rfc-editor.org/info/rfc8341>.
[RFC8342]
Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K., and R. Wilton, "Network Management Datastore Architecture (NMDA)", RFC 8342, DOI 10.17487/RFC8342, , <https://www.rfc-editor.org/info/rfc8342>.
[RFC8345]
Clemm, A., Medved, J., Varga, R., Bahadur, N., Ananthakrishnan, H., and X. Liu, "A YANG Data Model for Network Topologies", RFC 8345, DOI 10.17487/RFC8345, , <https://www.rfc-editor.org/info/rfc8345>.
[RFC8446]
Rescorla, E., "The Transport Layer Security (TLS) Protocol Version 1.3", RFC 8446, DOI 10.17487/RFC8446, , <https://www.rfc-editor.org/info/rfc8446>.
[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, , <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, , <https://www.rfc-editor.org/info/rfc8641>.
[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, , <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, , <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-05, , <https://datatracker.ietf.org/doc/html/draft-boro-opsawg-teas-attachment-circuit-05>.
[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-01, , <https://datatracker.ietf.org/doc/html/draft-boro-opsawg-teas-common-ac-01>.
[I-D.ietf-opsawg-sap]
Boucadair, M., de Dios, O. G., Barguil, S., Wu, Q., and V. Lopez, "A YANG Network Model for Service Attachment Points (SAPs)", Work in Progress, Internet-Draft, draft-ietf-opsawg-sap-15, , <https://datatracker.ietf.org/doc/html/draft-ietf-opsawg-sap-15>.
[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-17, , <https://datatracker.ietf.org/doc/html/draft-ietf-teas-actn-vn-yang-17>.
[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 IETF Network Slices", Work in Progress, Internet-Draft, draft-ietf-teas-ietf-network-slices-19, , <https://datatracker.ietf.org/doc/html/draft-ietf-teas-ietf-network-slices-19>.
[I-D.liu-teas-transport-network-slice-yang]
Liu, X., Tantsura, J., Bryskin, I., Contreras, L. M., Wu, Q., Belotti, S., and R. Rokui, "IETF Network Slice YANG Data Model", Work in Progress, Internet-Draft, draft-liu-teas-transport-network-slice-yang-05, , <https://datatracker.ietf.org/doc/html/draft-liu-teas-transport-network-slice-yang-05>.
[RFC8309]
Wu, Q., Liu, W., and A. Farrel, "Service Models Explained", RFC 8309, DOI 10.17487/RFC8309, , <https://www.rfc-editor.org/info/rfc8309>.

Appendix A. Attachment Circuit Augmentation Considerations

An AC is technology specific. 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.

Appendix B. Examples of Network Slice Services

B.1. Example-1: Two Any-to-any 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 any-to-any 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 any-to-any connectivity type. This is a L3 slice service and using the uniform high-BW 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.

+--------+         192.0.2.1
|CE1     o------/  VLAN100
+--------+      |  SDP1 +------+
+--------+      +------o|  PE A+---------------+
|CE2     o-------/-----o|      |               |
+--------+         SDP2 +---+--+               |
               198.51.100.1 |                  |    192.0.4.1
                  VLAN200   |              +---+--+ VLAN100
                            |              |      | SDP4      +--------+
                            |              |PE C  o-----/-----o CE21   |
+--------+        192.0.3.1 |              +---+--+           +--------+
|        o------/ VLAN101   |                  |
|        |      | SDP11a+---+---+              |
|CE11    |      +------o|PE B   +--------------+
|        o-------/-----o|       |
+--------+        SDP11b+------ +
                  198.51.101.1
                  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 latencey forwarding behavior"
          }
        ]
      },
      "slice-service": [
        {
          "id": "slice1",
          "description": "example slice1",
          "service-tags": {
            "tag-type": [
              {
                "tag-type": "ietf-network-slice-service:service-tag-service",
                "value": ["L3"]
              }
            ]
          },
          "slo-sle-template": "low-latency-template",
          "status": {
          },
          "sdps": {
            "sdp": [
              {
                "id": "1",
                "node-id": "PE-A",
                "service-match-criteria": {
                  "match-criterion": [
                    {
                      "index": 1,
                      "match-type": "ietf-network-slice-service: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": 24,
                      "ac-tags": {
                        "ac-tags": [
                          {
                            "tag-type": "ietf-nss:attachment-circuit-tag-vlan-id",
                            "value": ["100"]
                          }
                        ]
                      },
                      "status": {
                      }
                    }
                  ]
                },
                "status": {
                }
              },
              {
                "id": "3a",
                "node-id": "PE-B",
                "service-match-criteria": {
                  "match-criterion": [
                    {
                      "index": 1,
                      "match-type": "ietf-network-slice-service: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": "192.0.3.1",
                      "ac-ipv4-prefix-length": 24,
                      "ac-tags": {
                        "ac-tags": [
                          {
                            "tag-type": "ietf-nss:attachment-circuit-tag-vlan-id",
                            "value": ["101"]
                          }
                        ]
                      },
                      "status": {
                      }
                    }
                  ]
                },
                "status": {
                }
              },
              {
                "id": "4",
                "node-id": "PE-C",
                "service-match-criteria": {
                  "match-criterion": [
                    {
                      "index": 1,
                      "match-type": "ietf-network-slice-service:service-any-match",
                      "target-connection-group-id": "matrix1",
                      "target-connectivity-construct-id": 1
                    }
                  ]
                },
                "attachment-circuits": {
                  "attachment-circuit": [
                    {
                      "id": "ac4",
                      "description": "AC4 connected to device 4",
                      "ac-node-id": "PE-C",
                      "ac-tp-id": "GigabitEthernet4/0/0/3.100",
                      "ac-ipv4-address": "192.0.4.1",
                      "ac-ipv4-prefix-length": 24,
                      "ac-tags": {
                        "ac-tags": [
                          {
                            "tag-type": "ietf-network-slice-service:attachment-circuit-tag-vlan-id",
                            "value": ["100"]
                          }
                        ]
                      },
                      "status": {
                      }
                    }
                  ]
                },
                "status": {
                }
              }
            ]
          },
          "connection-groups": {
            "connection-group": [
              {
                "id": "matrix1",
                "connectivity-type": "ietf-vpn-common:any-to-any",
                "connectivity-construct": [
                  {
                    "id": 1,
                    "a2a-sdp": [
                      {
                        "sdp-id": "1"
                      },
                      {
                        "sdp-id": "3a"
                      },
                      {
                        "sdp-id": "4"
                      }
                    ],
                    "status": {
                    }
                  }
                ]
              }
            ]
          }
        },
        {
          "id": "slice2",
          "description": "example slice2",
          "service-tags": {
            "tag-type": [
              {
                "tag-type": "ietf-nss:service-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": 24,
                      "ac-tags": {
                        "ac-tags": [
                          {
                            "tag-type": "ietf-nss:attachment-circuit-tag-vlan-id",
                            "value": ["100"]
                          }
                        ]
                      },
                      "status": {
                      }
                    }
                  ]
                },
                "status": {
                }
              },
              {
                "id": "3b",
                "node-id": "PE-B",
                "attachment-circuits": {
                  "attachment-circuit": [
                    {
                      "id": "ac3b",
                      "description": "AC3b connected to device 3",
                      "ac-node-id": "PE-B",
                      "ac-tp-id": "GigabitEthernet8/0/0/4.201",
                      "ac-ipv4-address": "198.51.101.1",
                      "ac-ipv4-prefix-length": 24,
                      "ac-tags": {
                        "ac-tags": [
                          {
                            "tag-type": "ietf-network-slice-service:attachment-circuit-tag-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": {
                    }
                  }
                ]
              }
            ]
          }
        }
      ]
    }
  }
}

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:

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.

+--------+
|  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 latencey 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": [
                    {
                      "index": 1,
                      "match-type": "ietf-network-slice-service: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-network-slice-service:attachment-circuit-tag-vlan-id",
                            "value": ["100"]
                          }
                        ]
                      },
                      "status": {
                      }
                    }
                  ]
                },
                "status": {
                }
              },
              {
                "id": "7a",
                "node-id": "PE-B",
                "service-match-criteria": {
                  "match-criterion": [
                    {
                      "index": 1,
                      "match-type": "ietf-network-slice-service: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",
                      "ac-tags": {
                        "ac-tags": [
                          {
                            "tag-type": "ietf-network-slice-service:attachment-circuit-tag-vlan-id",
                            "value": ["200"]
                          }
                        ]
                      },
                      "status": {
                      }
                    }
                  ]
                },
                "status": {
                }
              }
            ]
          },
          "connection-groups": {
            "connection-group": [
              {
                "id": "matrix3",
                "connectivity-type": "ietf-network-slice-service:point-to-point",
                "connectivity-construct": [
                  {
                    "id": 1,
                    "p2p-sender-sdp": "5",
                    "p2p-receiver-sdp": "7a",
                    "status": {
                    }
                  },
                  {
                    "id": 2,
                    "p2p-sender-sdp": "7a",
                    "p2p-receiver-sdp": "5",
                    "status": {
                    }
                  }
                ]
              }
            ]
          }
        },
        {
          "id": "slice4",
          "description": "example slice4",
          "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-network-slice-service:attachment-circuit-tag-vlan-id",
                            "value": ["101"]
                          }
                        ]
                      },
                      "status": {
                      }
                    }
                  ]
                },
                "status": {
                }
              },
              {
                "id": "7b",
                "node-id": "PE-B",
                "attachment-circuits": {
                  "attachment-circuit": [
                    {
                      "id": "ac7b",
                      "description": "AC7b connected to device 7",
                      "ac-node-id": "PE-B",
                      "ac-tp-id": "GigabitEthernet8/0/0/5",
                      "ac-tags": {
                        "ac-tags": [
                          {
                            "tag-type": "ietf-network-slice-service:attachment-circuit-tag-vlan-id",
                            "value": ["201"]
                          }
                        ]
                      },
                      "status": {
                      }
                    }
                  ]
                },
                "status": {
                }
              }
            ]
          },
          "connection-groups": {
            "connection-group": [
              {
                "id": "matrix4",
                "connectivity-type": "ietf-network-slice-service:point-to-point",
                "connectivity-construct": [
                  {
                    "id": 1,
                    "p2p-sender-sdp": "6",
                    "p2p-receiver-sdp": "7b",
                    "service-slo-sle-policy": {
                      "metric-bounds": {
                        "metric-bound": [
                          {
                            "metric-type": "ietf-network-slice-service:service-slo-one-way-bandwidth",
                            "metric-unit": "Mbps",
                            "value-description": "1000"
                          }
                        ]
                      }
                    },
                    "status": {
                    }
                  },
                  {
                    "id": 2,
                    "p2p-sender-sdp": "7b",
                    "p2p-receiver-sdp": "6",
                    "service-slo-sle-policy": {
                      "metric-bounds": {
                        "metric-bound": [
                          {
                            "metric-type": "ietf-network-slice-service:service-slo-one-way-bandwidth",
                            "metric-unit": "Mbps",
                            "value-description": "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 SDP, but using an explicit set of slo policies with a latency metric of 10ms for hub to spoke traffic. 
+--------+         196.0.2.1
|Device11o------/  VLAN100
+--------+      |  SDP11+------+
+--------+      +------o|  A   +---------------+
|Device12o-------/-----o|      |               |
+--------+         SDP12+---+--+               |
               196.51.100.1 |                  |    196.0.4.1
                  VLAN200   |              +---+--+ VLAN100
                            |              |      | SDP14     +--------+
                            |              |   C  o-----/-----oDevice14|
+--------+        196.0.3.1 |              +---+--+           +--------+
|        o------/ VLAN101   |                  |
|        |      | SDP13a+---+--+               |
|Device13|      +------o|  B   +---------------+
|        o-------/-----o|      |
+--------+        SDP13b+------+
                  196.51.101.1
                  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 latencey forwarding behavior"
          }
        ]
      },
      "slice-service": [
        {
          "id": "slice5",
          "description": "example slice5",
          "service-tags": {
            "tag-type": [
              {
                "tag-type": "ietf-network-slice-service:service-tag-service",
                "value": ["L3"]
              }
            ]
          },
          "slo-sle-template": "low-latency-template",
          "status": {
          },
          "sdps": {
            "sdp": [
              {
                "id": "11",
                "node-id": "PE-A",
                "service-match-criteria": {
                  "match-criterion": [
                    {
                      "index": 1,
                      "match-type": "ietf-network-slice-service: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": "196.0.2.1",
                      "ac-ipv4-prefix-length": 24,
                      "ac-tags": {
                        "ac-tags": [
                          {
                            "tag-type": "ietf-network-slice-service:attachment-circuit-tag-vlan-id",
                            "value": ["100"]
                          }
                        ]
                      },
                      "status": {
                      }
                    }
                  ]
                },
                "status": {
                }
              },
              {
                "id": "12",
                "node-id": "PE-A",
                "service-match-criteria": {
                  "match-criterion": [
                    {
                      "index": 1,
                      "match-type": "ietf-network-slice-service: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": "196.51.100.1",
                      "ac-ipv4-prefix-length": 24,
                      "ac-tags": {
                        "ac-tags": [
                          {
                            "tag-type": "ietf-network-slice-service:attachment-circuit-tag-vlan-id",
                            "value": ["200"]
                          }
                        ]
                      },
                      "status": {
                      }
                    }
                  ]
                },
                "status": {
                }
              },
              {
                "id": "13a",
                "node-id": "PE-B",
                "service-match-criteria": {
                  "match-criterion": [
                    {
                      "index": 1,
                      "match-type": "ietf-network-slice-service:service-any-match",
                      "target-connection-group-id": "matrix5",
                      "connection-group-sdp-role": "ietf-vpn-common:spoke-role"
                    }
                  ]
                },
                "attachment-circuits": {
                  "attachment-circuit": [
                    {
                      "id": "ac13a",
                      "description": "AC13a connected to device 13",
                      "ac-node-id": "PE-B",
                      "ac-tp-id": "GigabitEthernet8/0/0/6",
                      "ac-ipv4-address": "196.0.3.1",
                      "ac-ipv4-prefix-length": 24,
                      "ac-tags": {
                        "ac-tags": [
                          {
                            "tag-type": "ietf-network-slice-service:attachment-circuit-tag-vlan-id",
                            "value": ["101"]
                          }
                        ]
                      },
                      "status": {
                      }
                    }
                  ]
                },
                "status": {
                }
              },
              {
                "id": "13b",
                "node-id": "PE-B",
                "service-match-criteria": {
                  "match-criterion": [
                    {
                      "index": 1,
                      "match-type": "ietf-network-slice-service: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": "196.51.101.1",
                      "ac-ipv4-prefix-length": 24,
                      "ac-tags": {
                        "ac-tags": [
                          {
                            "tag-type": "ietf-network-slice-service:attachment-circuit-tag-vlan-id",
                            "value": ["201"]
                          }
                        ]
                      },
                      "status": {
                      }
                    }
                  ]
                },
                "status": {
                }
              },
              {
                "id": "14",
                "node-id": "PE-C",
                "service-match-criteria": {
                  "match-criterion": [
                    {
                      "index": 1,
                      "match-type": "ietf-network-slice-service: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": "196.0.4.1",
                      "ac-ipv4-prefix-length": 24,
                      "ac-tags": {
                        "ac-tags": [
                          {
                            "tag-type": "ietf-network-slice-service:attachment-circuit-tag-vlan-id",
                            "value": ["100"]
                          }
                        ]
                      },
                      "status": {
                      }
                    }
                  ]
                },
                "status": {
                }
              }
            ]
          },
          "connection-groups": {
            "connection-group": [
              {
                "id": "matrix5",
                "connectivity-type": "ietf-vpn-common:hub-spoke",
                "connectivity-construct": [
                  {
                    "id": 1,
                    "p2mp-sender-sdp": "14",
                    "p2mp-receiver-sdp": ["11", "12", "13a", "13b"],
                    "service-slo-sle-policy": {
                      "metric-bounds": {
                        "metric-bound": [
                          {
                            "metric-type": "ietf-network-slice-service:service-slo-one-way-delay-maximum",
                            "metric-unit": "milliseconds",
                            "bound": "10"
                          }
                        ]
                      }
                    },
                    "status": {
                    }
                  }
                ]
              }
            ]
          }
        }
      ]
    }
  }
}

B.4. Example-4: An Any-to-any 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 any-to-any 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. 
+--------+         194.0.2.1
| CE21   o------/  VLAN100
+--------+      |  SDP21+------+
                +------o| PE A +---------------+
                        |      |               |
                        +---+--+               |
                            |                  |    194.0.4.1
                            |              +---+--+ VLAN100
                            |              |      | SDP24     +--------+
                            |              | PE C o-----/-----o CE24   |
+--------+        194.0.3.1 |              +---+--+           +--------+
|        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 latencey forwarding behavior"
          },
          {
            "id": "standard-template",
            "description": "take the standard forwarding path"
          }
        ]
      },
      "slice-service": [
        {
          "id": "slice6",
          "description": "example slice6",
          "service-tags": {
            "tag-type": [
              {
                "tag-type": "ietf-network-slice-service: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-network-slice-service:service-dscp-match",
                      "value": ["EF"],
                      "target-connection-group-id": "matrix6",
                      "target-connectivity-construct-id": 2
                    },
                    {
                      "index": 2,
                      "match-type": "ietf-network-slice-service: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": "194.0.2.1",
                      "ac-ipv4-prefix-length": 24,
                      "ac-tags": {
                        "ac-tags": [
                          {
                            "tag-type": "ietf-network-slice-service:attachment-circuit-tag-vlan-id",
                            "value": ["100"]
                          }
                        ]
                      },
                      "status": {
                      }
                    }
                  ]
                },
                "status": {
                }
              },
              {
                "id": "23a",
                "node-id": "PE-B",
                "service-match-criteria": {
                  "match-criterion": [
                    {
                      "index": 1,
                      "match-type": "ietf-network-slice-service:service-dscp-match",
                      "value": ["EF"],
                      "target-connection-group-id": "matrix6",
                      "target-connectivity-construct-id": 2
                    },
                    {
                      "index": 2,
                      "match-type": "ietf-network-slice-service: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": "194.0.3.1",
                      "ac-ipv4-prefix-length": 24,
                      "ac-tags": {
                        "ac-tags": [
                          {
                            "tag-type": "ietf-network-slice-service:attachment-circuit-tag-vlan-id",
                            "value": ["101"]
                          }
                        ]
                      },
                      "status": {
                      }
                    }
                  ]
                },
                "status": {
                }
              },
              {
                "id": "24",
                "node-id": "PE-C",
                "service-match-criteria": {
                  "match-criterion": [
                    {
                      "index": 1,
                      "match-type": "ietf-network-slice-service:service-dscp-match",
                      "value": ["EF"],
                      "target-connection-group-id": "matrix6",
                      "target-connectivity-construct-id": 2
                    },
                    {
                      "index": 2,
                      "match-type": "ietf-network-slice-service: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": "194.0.4.1",
                      "ac-ipv4-prefix-length": 24,
                      "ac-tags": {
                        "ac-tags": [
                          {
                            "tag-type": "ietf-network-slice-service:attachment-circuit-tag-vlan-id",
                            "value": ["100"]
                          }
                        ]
                      },
                      "status": {
                      }
                    }
                  ]
                },
                "status": {
                }
              }
            ]
          },
          "connection-groups": {
            "connection-group": [
              {
                "id": "matrix6",
                "connectivity-type": "ietf-vpn-common:any-to-any",
                "connectivity-construct": [
                  {
                    "id": 1,
                    "a2a-sdp": [
                      {
                        "sdp-id": "21"
                      },
                      {
                        "sdp-id": "23a"
                      },
                      {
                        "sdp-id": "24"
                      }
                    ],
                    "status": {
                    }
                  },
                  {
                    "id": 2,
                    "a2a-sdp": [
                      {
                        "sdp-id": "21"
                      },
                      {
                        "sdp-id": "23a"
                      },
                      {
                        "sdp-id": "24"
                      }
                    ],
                    "slo-sle-template": "low-latency-template",
                    "status": {
                    }
                  }
                ]
              }
            ]
          }
        }
      ]
    }
  }
}

B.5. Example-5: An any-to-any 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 any-to-any connectivity type. All SDPs are designated as customer-facing ports on the PE.

The service is realized using a single any-to-any connectivity construct, and a uniform low-bandwidth slo-sle-template policy applied to SDP4, SDP3, while a high-bandwidth slo-sle-template policy applied to SDP1 and SDP2.

+--------+         192.0.1.1                        192.0.3.1
|CE1     o------/  VLAN100                          VLAN100
+--------+      |  SDP1 +------+           +------+ SDP3
                +------o| PE A +-----------| PE C |           +--------+
                        |      |           |      |-----/-----o CE3    |
                        +---+--+           +------+           +--------+
                            |                  |
                            |                  |
                            |                  |
                            |                  |
+--------+        192.0.2.1 |                  |
|CE2     o------/ VLAN100   |                  |    192.0.4.1
+--------+      | 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",
            "description": "lowest BW forwarding behavior"
          }
        ]
      },
      "slice-service": [
        {
          "id": "slice-7",
          "description": "URLLC",
          "service-tags": {
            "tag-type": [
              {
                "tag-type": "ietf-network-slice-service:service-tag-customer",
                "value": ["Customer-FOO"]
              },
              {
                "tag-type": "ietf-network-slice-service: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": ["192.0.1.1"],
                "service-match-criteria": {
                  "match-criterion": [
                    {
                      "index": 1,
                      "match-type": "ietf-network-slice-service: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-ipv4-address": "192.0.1.1",
                      "ac-ipv4-prefix-length": 24,
                      "ac-tags": {
                        "ac-tags": [
                          {
                            "tag-type": "ietf-network-slice-service:attachment-circuit-tag-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": ["192.0.2.1"],
                "service-match-criteria": {
                  "match-criterion": [
                    {
                      "index": 1,
                      "match-type": "ietf-network-slice-service: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-ipv4-address": "192.0.2.1",
                      "ac-ipv4-prefix-length": 24,
                      "ac-tags": {
                        "ac-tags": [
                          {
                            "tag-type": "ietf-network-slice-service:attachment-circuit-tag-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": ["192.0.3.1"],
                "service-match-criteria": {
                  "match-criterion": [
                    {
                      "index": 1,
                      "match-type": "ietf-network-slice-service: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",
                      "ac-ipv4-address": "192.0.3.1",
                      "ac-ipv4-prefix-length": 24,
                      "ac-tags": {
                        "ac-tags": [
                          {
                            "tag-type": "ietf-network-slice-service:attachment-circuit-tag-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": ["192.0.4.1"],
                "service-match-criteria": {
                  "match-criterion": [
                    {
                      "index": 1,
                      "match-type": "ietf-network-slice-service: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",
                      "ac-tp-id": "GigabitEthernet4/0/0/0",
                      "ac-ipv4-address": "192.0.4.1",
                      "ac-ipv4-prefix-length": 24,
                      "ac-tags": {
                        "ac-tags": [
                          {
                            "tag-type": "ietf-network-slice-service:attachment-circuit-tag-vlan-id",
                            "value": ["100"]
                          }
                        ]
                      },
                      "incoming-qos-policy": {
                        "qos-policy-name": "Qos-Gold",
                        "rate-limits": {
                          "cir": "1000000",
                          "cbs": "1000",
                          "pir": "5000000",
                          "pbs": "1000"
                        }
                      },
                      "status": {
                      }
                    }
                  ]
                },
                "status": {
                }
              }
            ]
          },
          "connection-groups": {
            "connection-group": [
              {
                "id": "matrix1",
                "slo-sle-template": "low-BW-template",
                "connectivity-construct": [
                  {
                    "id": 1,
                    "a2a-sdp": [
                      {
                        "sdp-id": "SDP1",
                        "slo-sle-template": "high-BW-template"
                      },
                      {
                        "sdp-id": "SDP2",
                        "slo-sle-template": "high-BW-template"
                      },
                      {
                        "sdp-id": "SDP3"
                      },
                      {
                        "sdp-id": "SDP4"
                      }
                    ],
                    "status": {
                    }
                  }
                ]
              }
            ]
          }
        }
      ]
    }
  }
}

B.6. Example-6: SDP at CE, L3 any-to-any 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:

SDP31
SDP-ip 10.1.1.1
(Loopback)
    |
    |     192.0.2.2
    v      VLAN200      +------+
+--------+ ac31         | PE   +---------------+
|  CE1   o-------/-----o|      |               |                SDP34
+--------+              +---+--+               |       SDP-ip 10.1.1.4
                            |                  |                 |
SDP33                                                            |
SDP-ip 10.1.3.1             |              +---+--+              v
    |      192.0.3.2        |              |      |           +--------+
    v      VLAN101          |              | PE   o-----/-----o CE2    |
+--------+ ac33a            |              +---+--+    ac34   +--------+
|        o------/           |                  |       VLAN201
|        |      |       +---+---+              |       198.51.101.2
|  CE3   |      +------o| PE    +--------------+
|        o-------/-----o|       |
+--------+ ac33b        +-------+
           VLAN201
           198.51.101.2


{
  "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 latencey forwarding behavior"
          }
        ]
      },
      "slice-service": [
        {
          "id": "slice8",
          "description": "slice-6",
          "service-tags": {
            "tag-type": [
              {
                "tag-type": "ietf-network-slice-service:service-tag-service",
                "value": ["L3"]
              }
            ]
          },
          "slo-sle-template": "low-latency-template",
          "status": {
          },
          "sdps": {
            "sdp": [
              {
                "id": "31",
                "node-id": "Device-1",
                "sdp-ip-address": ["10.1.1.1"],
                "service-match-criteria": {
                  "match-criterion": [
                    {
                      "index": 1,
                      "match-type": "ietf-network-slice-service: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": 24,
                      "ac-tags": {
                        "ac-tags": [
                          {
                            "tag-type": "ietf-network-slice-service:attachment-circuit-tag-vlan-id",
                            "value": ["100"]
                          }
                        ]
                      },
                      "status": {
                      }
                    }
                  ]
                },
                "status": {
                }
              },
              {
                "id": "33",
                "node-id": "Device-3",
                "sdp-ip-address": ["10.1.3.1"],
                "service-match-criteria": {
                  "match-criterion": [
                    {
                      "index": 1,
                      "match-type": "ietf-network-slice-service: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": "192.0.3.2",
                      "ac-ipv4-prefix-length": 24,
                      "ac-tags": {
                        "ac-tags": [
                          {
                            "tag-type": "ietf-network-slice-service:attachment-circuit-tag-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": "198.51.101.2",
                      "ac-ipv4-prefix-length": 24,
                      "ac-tags": {
                        "ac-tags": [
                          {
                            "tag-type": "ietf-network-slice-service:attachment-circuit-tag-vlan-id",
                            "value": ["201"]
                          }
                        ]
                      },
                      "status": {
                      }
                    }
                  ]
                },
                "status": {
                }
              },
              {
                "id": "34",
                "node-id": "Device-4",
                "sdp-ip-address": ["10.1.4.1"],
                "service-match-criteria": {
                  "match-criterion": [
                    {
                      "index": 1,
                      "match-type": "ietf-network-slice-service: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": "192.0.4.2",
                      "ac-ipv4-prefix-length": 24,
                      "ac-tags": {
                        "ac-tags": [
                          {
                            "tag-type": "ietf-network-slice-service:attachment-circuit-tag-vlan-id",
                            "value": ["100"]
                          }
                        ]
                      },
                      "status": {
                      }
                    }
                  ]
                },
                "status": {
                }
              }
            ]
          },
          "connection-groups": {
            "connection-group": [
              {
                "id": "matrix1",
                "connectivity-type": "ietf-vpn-common:any-to-any",
                "connectivity-construct": [
                  {
                    "id": 1,
                    "a2a-sdp": [
                      {
                        "sdp-id": "31"
                      },
                      {
                        "sdp-id": "33"
                      },
                      {
                        "sdp-id": "34"
                      }
                    ],
                    "status": {
                    }
                  }
                ]
              }
            ]
          }
        }
      ]
    }
  }
}

B.7. Example-7: SDP at CE, L3 any-to-any 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 already configured or AC circuit binding details between the CE and PE which were previously has mechanisms to determine this. The NSC can use various mapping configured or the NSC has mechanisms to determine this mapping. mechanisms depending on the capabilities of the NSC including which The NSC capabilities are out-of-scope of this document, but (for example) parameters the NSC considers as unique (this mapping is out-of-scope The NSC can use the CE device name, sdp-id, sdp-ip, ac-id or the peer-sap-id to complete this AC circuit binding.

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

SDP31
SDP-ip 10.1.1.1
(Loopback,etc)
    |
    |
    v                   +-------------------------+
+--------+ ac31         |                         |
|Device1 o-------/-----o|sap                      |             SDP34
+--------+              |                         |    SDP-ip 10.1.4.1
                        |     Abstracted          |              |
SDP33                   |   Provider Network      |              |
SDP-ip 10.1.3.1         |                         |              v
    |                   |                         |           +--------+
    v                   |                      sap|-----/-----o Device4|
+--------+ ac33a        |                         |    ac41   +--------+
|        o------/       |                         |
|        |      |       |                         |
|Device3 |      +------o|sap                      |
|        o-------/-----o|sap                      |
+--------+ ac33b        +-------------------------+


{
  "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 latencey forwarding behavior"
          }
        ]
      },
      "slice-service": [
        {
          "id": "slice-9",
          "description": "example slice7",
          "service-tags": {
            "tag-type": [
              {
                "tag-type": "ietf-network-slice-service:service-tag-service",
                "value": ["L3"]
              }
            ]
          },
          "slo-sle-template": "low-latency-template",
          "status": {
          },
          "sdps": {
            "sdp": [
              {
                "id": "31",
                "node-id": "Device-1",
                "sdp-ip-address": ["10.1.1.1"],
                "service-match-criteria": {
                  "match-criterion": [
                    {
                      "index": 1,
                      "match-type": "ietf-network-slice-service:service-any-match",
                      "target-connection-group-id": "matrix1"
                    }
                  ]
                },
                "attachment-circuits": {
                  "attachment-circuit": [
                    {
                      "id": "ac31",
                      "sdp-peering": {
                        "peer-sap-id": "foo.com-circuitID-12345"
                      },
                      "status": {
                      }
                    }
                  ]
                },
                "status": {
                }
              },
              {
                "id": "33",
                "node-id": "Device-3",
                "sdp-ip-address": ["10.1.3.1"],
                "service-match-criteria": {
                  "match-criterion": [
                    {
                      "index": 1,
                      "match-type": "ietf-network-slice-service: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": {
                }
              },
              {
                "id": "34",
                "node-id": "Device-4",
                "sdp-ip-address": ["10.1.4.1"],
                "service-match-criteria": {
                  "match-criterion": [
                    {
                      "index": 1,
                      "match-type": "ietf-network-slice-service: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"
                      }
                    ],
                    "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 service-slo-sle-policy
     |        +--rw description?            string
     |        +--rw metric-bounds
     |        |  +--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 security*               identityref
     |        +--rw isolation?              identityref
     |        +--rw max-occupancy-level?    uint8
     |        +--rw mtu?                    uint16
     |        +--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)?
        |  +--:(standard)
        |  |  +--rw slo-sle-template?         leafref
        |  +--:(custom)
        |     +--rw service-slo-sle-policy
        |        +--rw description?            string
        |        +--rw metric-bounds
        |        |  +--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 security*               identityref
        |        +--rw isolation?              identityref
        |        +--rw max-occupancy-level?    uint8
        |        +--rw mtu?                    uint16
        |        +--rw steering-constraints
        |           +--rw path-constraints
        |           +--rw service-function
        +--rw compute-only?                   empty
        +--rw status
        |  +--rw admin-status
        |  |  +--rw status?         identityref
        |  |  +--rw last-updated?   yang:date-and-time
        |  +--ro oper-status
        |     +--ro status?         identityref
        |     +--ro last-updated?   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
        |     |     +--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 ac-svc-name?             string
        |     |     +--rw description?             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
        |     |     |     +--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-updated?
        |     |        |          yang:date-and-time
        |     |        +--ro oper-status
        |     |           +--ro status?         identityref
        |     |           +--ro last-updated?
        |     |                   yang:date-and-time
        |     +--rw status
        |     |  +--rw admin-status
        |     |  |  +--rw status?         identityref
        |     |  |  +--rw last-updated?   yang:date-and-time
        |     |  +--ro oper-status
        |     |     +--ro status?         identityref
        |     |     +--ro last-updated?   yang:date-and-time
        |     +--ro sdp-monitoring
        |        +--ro incoming-bw-value?
        |        |       te-types:te-bandwidth
        |        +--ro incoming-bw-percent    decimal64
        |        +--ro outgoing-bw-value?
        |        |       te-types:te-bandwidth
        |        +--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 metric-bounds
        |     |        |  +--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 security*               identityref
        |     |        +--rw isolation?              identityref
        |     |        +--rw max-occupancy-level?    uint8
        |     |        +--rw mtu?                    uint16
        |     |        +--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 metric-bounds
        |     |  |                 |  +--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 security*
        |     |  |                 |       identityref
        |     |  |                 +--rw isolation?
        |     |  |                 |       identityref
        |     |  |                 +--rw max-occupancy-level?
        |     |  |                 |       uint8
        |     |  |                 +--rw mtu?
        |     |  |                 |       uint16
        |     |  |                 +--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 metric-bounds
        |     |  |        |  +--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 security*
        |     |  |        |       identityref
        |     |  |        +--rw isolation?
        |     |  |        |       identityref
        |     |  |        +--rw max-occupancy-level?    uint8
        |     |  |        +--rw mtu?                    uint16
        |     |  |        +--rw steering-constraints
        |     |  |           +--rw path-constraints
        |     |  |           +--rw service-function
        |     |  +--rw service-slo-sle-policy-override?
        |     |  |       identityref
        |     |  +--rw status
        |     |  |  +--rw admin-status
        |     |  |  |  +--rw status?         identityref
        |     |  |  |  +--rw last-updated?   yang:date-and-time
        |     |  |  +--ro oper-status
        |     |  |     +--ro status?         identityref
        |     |  |     +--ro last-updated?   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-ref
           +--rw network-ref?
                   -> /nw:networks/network/network-id

Appendix D. Comparison with Other Possible Design choices for IETF Network Slice Service Interface

According to the 5.3.1 IETF Network Slice Service Interface [I-D.ietf-teas-ietf-network-slices], the Network Slice service Interface is a technology-agnostic interface, which is used for a customer to express requirements for a particular IETF Network Slice. Customers operate on abstract IETF Network Slices, with details related to their realization hidden. As classified by [RFC8309], the Network Slice service Interface is classified as Customer Service Model.

This draft analyzes the following existing IETF models to identify the gap between the IETF Network Slice service Interface requirements.

D.1. 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:

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.

D.2. RFC8345 Augmentation Model

The difference between the IETF Network Slice service requirements and the IETF basic network model is that the IETF Network Slice service requests abstract customer IETF Network Slices, with details related to the slice Network hidden. But the IETF network model is used to describe the interconnection details of a Network. The customer service model does not need to provide details on the Network.

For example, IETF Network Topologies YANG data model extension introduced in Transport Network Slice YANG Data Model [I-D.liu-teas-transport-network-slice-yang] includes three major parts:

Based on this structure, the IETF Network Slice-specific SLO attributes nodes are augmented on the Network Topologies model,, e.g. isolation etc. However, this modeling design requires the slice network to expose a lot of details of the network, such as the actual topology including nodes interconnection and different network layers interconnection.

Authors' Addresses

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