IETF Network Slice Service Mapping YANG Model

Status of This Memo

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Copyright Notice

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

This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Revised BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Revised BSD License.¶

Table of Contents

1. Introduction

Data models are a representation of objects that can be configured or monitored within a system. Within the IETF, YANG [RFC7950] is the language of choice for documenting data models, and YANG models have been produced to allow configuration or modeling of a variety of network devices, protocol instances, and network services.¶

The YANG model discussed in this document augments the IETF Network Slice Service YANG model [I-D.ietf-teas-ietf-network-slices], which is used to operate IETF Network Slices during the IETF Network Slice instantiation. This provides a way to map IETF network slice service to Traffic Engineering (TE) models (e.g., the Virtual Network (VN) model or the TE Tunnel etc). Alternatively, it also supports mapping to the VPN Network models and Network Resource Partition (NRP) models.¶

The model supports:¶

• A mapping of the IETF Network Slice with the Network Resource Partition (NRP). As per [I-D.ietf-teas-ietf-network-slices], NRP is a collection of resources (bufferage, queuing, scheduling, etc.) in the underlay network. The NRP YANG model is specified in [I-D.wdbsp-teas-nrp-yang]. The IETF Network Slice can be mapped to the NRP directly.¶
• A mapping of the IETF Network Slice with the VPN network models - LxNM. This mapping can be populated at the time of IETF network service realization. This mapping information is internal and used for monitoring and diagnostics purpose such as telemetry, auto-scaling, closed-loop automation. Note that the LxNM may further map to other TE resources as specified in [I-D.ietf-teas-te-service-mapping-yang]. Optionally, a mapping to the NRP can also be populated.¶
• A mapping of the IETF Network Slice with the underlying TE resources directly. The TE resources could be in a form of VN, set of TE tunnels, TE abstract topology etc. This mapping can be populated by the network at the time of realization of the IETF network slice service. It is also possible to configure the mapping provided one is aware of NRP/VN/tunnels. This mapping mode is used only when the there is an awareness of VN or TE by the consumer of the model. Otherwise this mapping information is internal and used for monitoring and diagnostics purpose such as telemetry, auto-scaling, closed-loop automation.¶
• Possibility to request creation of a new VN/Tunnel to be binded to IETF network slice.¶
• Indication to share the VN/Tunnel sharing (with or without modification) for the IETF network slice.¶
• Support for configuration of underlying TE properties (as opposed to existing VN or tunnels).¶

Note: The RFC Editor will replace XXXX with the number assigned to the RFC once this draft becomes an RFC.¶

2. Conventions

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.¶

3. Model Design

The YANG model specified in this document augments the IETF network slice service YANG model [I-D.ietf-teas-ietf-network-slice-nbi-yang].¶

Currently following mapping are supported:¶

• L3NM: The L3 network model (L3NM) describes a L3VPN Service in the Service Provider Network. It contains information of the Service Provider network and might include allocated resources. It can be used by network controllers to manage and control the L3VPN Service configuration in the Service Provider network. This model maps an IETF network slice to a L3VPN ID.¶
• L2NM: The L2 network model (L2NM) describes a L2VPN Service in the Service Provider Network. It contains information of the Service Provider network and might include allocated resources. It can be used by network controllers to manage and control the L2VPN Service configuration in the Service Provider network. This model maps an IETF network slice to a L2VPN ID.¶

• TE: The TE mapping is specified in [I-D.ietf-teas-te-service-mapping-yang]. The mapping can be done to the following TE resouces:¶

  • Virtual Networks (VN) [RFC8453]¶
  • TE-Tunnels¶
  • TE-Topology¶
• NRP: [I-D.ietf-teas-ietf-network-slices] defines IETF network slice services that provide connectivity coupled with network resources commitment between a number of endpoints over a shared network infrastructure and, for scalability concerns, defines NRP to host one or a group of network slice services according to characteristics including SLOs and SLEs. Along with mapping to VPN, this model maps an IETF network slice to a NRP ID.¶

4. Tree Structure

module: ietf-network-slice-mapping

  augment /ietf-nss:network-slice-services/ietf-nss:slice-service:
    +--rw mapping!
       +--rw ns-mapping
          +--rw map-to?                               identityref
          +--rw (map)?
             +--:(nrp)
             |  +--rw nrp?
             |          -> /nw:networks/nrp:nrp-policies/nrp-policy/name
             +--:(l3vpn)
             |  +--rw l3vpn-id?                       leafref
             |  +--rw l3vpn-nrp?
             |          -> /nw:networks/nrp:nrp-policies/nrp-policy/name
             +--:(l2vpn)
             |  +--rw l2vpn-id?                       leafref
             |  +--rw l2vpn-nrp?
             |          -> /nw:networks/nrp:nrp-policies/nrp-policy/name
             +--:(te)
                +--rw type?                           identityref
                +--rw te-policy
                |  +--rw path-affinities-values
                |  |  +--rw path-affinities-value* [usage]
                |  |        ...
                |  +--rw path-affinity-names
                |  |  +--rw path-affinity-name* [usage]
                |  |        ...
                |  +--rw protection-type?          identityref
                |  +--rw availability-type?        identityref
                +--rw (te)?
                |  +--:(vn)
                |  |  +--rw vn*
                |  |          -> /vn:virtual-network/vn/vn-id
                |  +--:(te-topo)
                |  |  +--rw te-topology-identifier
                |  |  |     ...
                |  |  +--rw abstract-node?
                |  |          -> /nw:networks/network/node/node-id
                |  +--:(te-tunnel)
                |     +--rw te-tunnel*                te:tunnel-ref
                |     +--rw sr-policy* [headend color-ref endpoint-ref]
                |             {sr-policy}?
                |           ...
                +--rw template-ref?                   leafref
                        {template}?

5. YANG Model

<CODE BEGINS> file "ietf-network-slice-mapping@2023-09-12.yang"
module ietf-network-slice-mapping {
  yang-version 1.1;
  namespace
    "urn:ietf:params:xml:ns:yang:ietf-network-slice-mapping";
  prefix ietf-nsm;

  import ietf-network {
    prefix nw;
    reference
      "RFC 8345: A YANG Data Model for Network Topologies";
  }
  import ietf-network-slice-service {
    prefix ietf-nss;
    reference
      "I-D.ietf-teas-ietf-network-slice-nbi-yang: A YANG Data
       Model for the IETF Network Slice Service";
  }
  import ietf-te-service-mapping-types {
    prefix tsmt;
    reference
      "I-D.ietf-teas-te-service-mapping-yang: Traffic Engineering
       (TE) and Service Mapping YANG Data Model";
  }
  import ietf-l3vpn-ntw {
    prefix l3vpn-ntw;
    reference
      "RFC 9182: A YANG Network Data Model for Layer 3 VPNs";
  }
  import ietf-l2vpn-ntw {
    prefix l2vpn-ntw;
    reference
      "RFC 9291: A Layer 2 VPN Network YANG Model";
  }
  import ietf-nrp {
    prefix nrp;
    reference
      "I-D.wdbsp-teas-nrp-yang: A YANG Data Model for Network
       Resource Partitions (NRPs)";
  }

  organization
    "IETF Traffic Engineering Architecture and Signaling (TEAS)
     Working Group";
  contact
    "WG Web:  <https://datatracker.ietf.org/wg/teas/>
     WG List:  <mailto:teas@ietf.org>
     Editor: Dhruv Dhody <dhruv.ietf@gmail.com>
             Bo Wu <lana.wubo@huawei.com>";
  description
    "This module contains a YANG module to map the IETF Network
     Slice with Traffic Engineering (TE) or VPN Network models.

     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 2023-09-12 {
    description
      "initial version.";
    reference
      "RFC XXXX: IETF Network Slice Service Mapping YANG Model";
  }

  identity map-to {
    description
      "Base identity from which specific map-to are derived.";
  }

  identity map-to-nrp {
    base map-to;
    description
      "Map to Network Resource Partition (NRP)";
  }

  identity map-to-vpn {
    base map-to;
    description
      "Map to VPN";
  }

  identity map-to-l3vpn {
    base map-to-vpn;
    description
      "Map to L3VPN";
  }

  identity map-to-l2vpn {
    base map-to-vpn;
    description
      "Map to L2VPN";
  }

  identity map-to-l1vpn {
    base map-to-vpn;
    description
      "Map to L1VPN";
  }

  identity map-to-te {
    base map-to;
    description
      "Map to TE directly";
  }

  grouping ns-mapping {
    description
      "Mapping between IETF network slice and Network
       Resource Partition (NRP)/VPN/TE";
    container ns-mapping {
      description
        "The container for the mapping";
      leaf map-to {
        type identityref {
          base map-to;
        }
        description
          "Mapping to NRP/VPN/TE";
      }
      choice map {
        description
          "Mapping to NRP/VPN/TE";
        case nrp {
          leaf nrp {
            type leafref {
              path "/nw:networks/nrp:nrp-policies"
                 + "/nrp:nrp-policy/nrp:name";
            }
            description
              "A reference to NRP name";
            reference
              "I-D.wdbsp-teas-nrp-yang: A YANG Data Model for
               Network Resource Partitions (NRPs)";
          }
        }
        case l3vpn {
          leaf l3vpn-id {
            type leafref {
              path "/l3vpn-ntw:l3vpn-ntw"
                 + "/l3vpn-ntw:vpn-services"
                 + "/l3vpn-ntw:vpn-service"
                 + "/l3vpn-ntw:vpn-id";
            }
            description
              "A reference to VPN ID";
          }
          leaf l3vpn-nrp {
            type leafref {
              path "/nw:networks/nrp:nrp-policies"
                 + "/nrp:nrp-policy/nrp:name";
            }
            description
              "An optional reference to NRP name";
            reference
              "I-D.ietf-teas-ietf-network-slices: Framework
               for IETF Network Slices";
          }
          description
            "Mapping to L3NM";
          reference
            "RFC9182: A YANG Network Data Model for
             Layer 3 VPNs";
        }
        case l2vpn {
          leaf l2vpn-id {
            type leafref {
              path "/l2vpn-ntw:l2vpn-ntw"
                 + "/l2vpn-ntw:vpn-services"
                 + "/l2vpn-ntw:vpn-service"
                 + "/l2vpn-ntw:vpn-id";
            }
            description
              "A reference to VPN ID";
          }
          leaf l2vpn-nrp {
            type leafref {
              path "/nw:networks/nrp:nrp-policies"
                 + "/nrp:nrp-policy/nrp:name";
            }
            description
              "An optional reference to NRP";
            reference
              "I-D.ietf-teas-ietf-network-slices: Framework
               for IETF Network Slices";
          }
          description
            "Mapping to L2NM";
          reference
            "RFC 9291: A Layer 2 VPN Network YANG Model";
        }
        case te {
          uses tsmt:te-mapping;
          description
            "Mapping to TE directly";
          reference
            "I-D.ietf-teas-te-service-mapping-yang:
             Traffic Engineering (TE) and Service
             Mapping YANG Model";
        }
      }
    }
  }

  augment "/ietf-nss:network-slice-services/ietf-nss:slice-service" {
    description
      "IETF Network Slice augmented to include the mapping
       information to the network slice realization";
    container mapping {
      presence "Indicates Mapping information";
      description
        "Container to augment IETF network slice to
         include NRP / VPN / TE mappings";
      uses ns-mapping;
    }
  }
}
<CODE ENDS>

6. Security Considerations

TBD¶

7. IANA Considerations

IANA is requested to make the following allocation for the URIs in the "ns" subregistry within the "IETF XML Registry" [RFC3688]:¶

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

IANA is requested to make the following allocation for the YANG module in the "YANG Module Names" registry [RFC6020]:¶

   --------------------------------------------------------------------
   name:         ietf-network-slice-mapping
   namespace:    urn:ietf:params:xml:ns:yang:ietf-network-slice-mapping
   prefix:       ietf-nsm
   reference:    RFC XXXX
   --------------------------------------------------------------------

Appendix A. Acknowledgments

Thanks to Jie Dong for the initial discussion behind this document.¶

Appendix B. Examples

TO be added in future revisions.¶

Authors' Addresses