IETF Network Slice Controller and its Associated Data Models
draft-ietf-teas-ns-controller-models-06

TEAS                                                 L.M. Contreras, Ed.
Internet-Draft                                                Telefonica
Intended status: Informational                                  R. Rokui
Expires: 23 April 2026                                             Ciena
                                                             J. Tantsura
                                                                  Nvidia
                                                                   B. Wu
                                                                  Huawei
                                                                  X. Liu
                                                               Alef Edge
                                                            October 2025

      IETF Network Slice Controller and its Associated Data Models
                draft-ietf-teas-ns-controller-models-06

Abstract

   This document describes an approach for structuring the IETF Network
   Slice Controller as well as how to use different data models being
   defined for IETF Network Slice Service provision (and how they are
   related).  It is not the purpose of this document to standardize or
   constrain the implementation the IETF Network Slice Controller.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on 4 April 2026.

Copyright Notice

   Copyright (c) 2025 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

Contreras, et al.         Expires 23 April 2026                 [Page 1]
Internet-Draft    Slice Controller and its Data Models      October 2025

   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  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  IETF Network Slice Data Models  . . . . . . . . . . . . . . .   3
   3.  Structure of the IETF Network Slice Controller (NSC)  . . . .   4
     3.1.  NS Mapper . . . . . . . . . . . . . . . . . . . . . . . .   7
     3.2.  NS Realizer . . . . . . . . . . . . . . . . . . . . . . .   8
   4.  Model Types in IETF Network Slice Controller Interfaces . . .   8
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   9
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   9
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   9
   Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . .  11
   Contributors  . . . . . . . . . . . . . . . . . . . . . . . . . .  11
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  11

1.  Introduction

   A main promise of network slicing is to provide tailored end-to-end
   network capabilities to customers in the way that they could be
   perceived as a dedicated infrastructure, despite that it makes use of
   shared physical infrastructure facilities.

   Particularly, the connectivity within and between different segments
   of a network slice with specific performance characteristics are key
   in characterizing a slice.  Thus, the IETF Network Slice, realized by
   any of the IETF technologies, emerges as complementary but essential
   part of an end-to-end network slice.

   In order to facilitate the service exposure, service order handling,
   realization, and lifecycle control and management of a transport
   slice, a dedicated element called IETF Network Slice Controller (NSC)
   is proposed in [RFC9543].

   The NSC from its customer-facing interface, i.e., the IETF Network
   Slice Service interface, exposes a set of APIs that allow a third
   party system to request a transport slice.  The NSC receives slice
   service requests from customers to manage an IETF Network Slice
   (i.e., creation, modification or deletion).  Upon receipt of a
   request to create a slice, the NSC assess and then identifies the

Contreras, et al.         Expires 23 April 2026                 [Page 2]
Internet-Draft    Slice Controller and its Data Models      October 2025

   resources needed for realization of the IETF Network Slice.  To that
   end, the NSC may interact with one or more Network Controllers for
   the realization of the requested IETF Network Slice request and the
   management of its lifecycle.  Figure 1 presents a high-level view of
   the IETF NSC [RFC9543].

             +------------------------------------------+
             | Customer higher level operation system   |
             |   (e.g., E2E network slice orchestrator, |
             |      customer network management system) |
             +------------------------------------------+
                                  A
                                  | IETF Network Slice Service Interface
                                  V
             +------------------------------------------+
             |    IETF Network Slice Controller (NSC)   |
             +------------------------------------------+
                                  A
                                  | Network Configuration Interface
                                  V
             +------------------------------------------+
             |           Network Controllers            |
             +------------------------------------------+

             Figure 1: Interface of Transport Slice Controller

   This document describes the characteristics of the NSC as well as a
   detailed structure of the NSC and its major components.  In addition,
   it describes the characteristics of the data models to identify an
   IETF Network Slice and its realization.  Then the referred data
   models are mapped to the interfaces among components.

   This document describes a potential way of structuring the IETF
   Network Slice Controller as well as how to use different data models
   being defined for IETF Network Slice Service provision (and how they
   are related).  It is not the purpose of this document to standardize
   or constrain the implementation the IETF Network Slice Controllers.

2.  IETF Network Slice Data Models

   At the time of provisioning and operating IETF Network Slices
   different views can be identified as necessary:

   *  The customer’s view.  It is focused on the individual IETF Network
      Slice request process, reflecting the needs of each particular
      customer, including SLOs and other characteristics of the slice
      relevant for it.  This view is technology-agnostic and describes

Contreras, et al.         Expires 23 April 2026                 [Page 3]
Internet-Draft    Slice Controller and its Data Models      October 2025

      the characteristics of the IETF Network Slice from a customer’s
      point of view.  It can include the customer slice topology intent,
      performance parameters, endpoints of the slice, traffic
      characteristics of the slice, and the KPIs to monitor the slice.

   *  The provider’s view.  In addition to the view that is exposed to
      customers, the provider maintains an more network-centric view
      that focuses on the provisioning and operation of IETF Network
      Slices in the underlay network, considering how a particular IETF
      Network Slice interplays with other IETF Network Slices maintained
      by the provider on a shared infrastructure.  In other words, the
      provider’s view shows how an IETF Network Slice is implemented in
      the operator’s network along with all the resources used during
      the its realization.  This view is not exposed to the customers.

   Both views are complementary as they are invoked in different stages
   of service provisioning and delivery lifecycles.  For the sake of
   automated procedures, some consistency should be ensured between
   these views to ease the service mapping as per [RFC8969].

   It should be noted that for the realization of an IETF Network Slice,
   the NSC interacts with one or more Network Controllers underneath.
   Whether one or more NSCs/Network Controllers are used is deployment
   specific.  The data models to be used are specific for each Network
   Controller (e.g., technology-dependent), as well as the mapping
   function from its customer-facing interface (i.e., IETF Network Slice
   Service interface) to network-facing interfaces (i.e., Network
   Configuration Interface) and the details of this mapping function are
   both out of the scope of this document.

3.  Structure of the IETF Network Slice Controller (NSC)

   The NSC should support both service and network data models.  The NSC
   exposes service models to customers.  Customers use those models for
   their slice service request placements.  The NSC then process
   customers requests taking into account local policies and guidelines
   (e.g., mapping strategy 1:1/1:M/N:M), the overall view of the network
   resources (e.g., service functions) and the IETF Network Slices
   already instantiated.  Finally, the NSC normalizes the slice
   instantiation across different technologies, and maps such slice to
   the provider view.

   Once a new request is processed and tagged as feasible, an NSC
   triggers its realization by interacting with the relevant Network
   Controllers underneath and reporting to the higher level controller
   for accounting/billing purposes.  The actual start of the billing
   process is deployment specific and depends on whether a slice request
   is a scheduled request or has immediate effect.

Contreras, et al.         Expires 23 April 2026                 [Page 4]
Internet-Draft    Slice Controller and its Data Models      October 2025

   In order to accommodate these procedures, an NSC may be structured to
   embed the following components:

   *  IETF Network Slice Service Mapper: this high-level component
      processes the customer requests, putting it into the context of
      the overall IETF Network Slices in the network.

   *  IETF Network Slice Realizer: this high-level component processes
      the complete view of transport slices including the one requested
      by the customer, decides the proper technologies for realizing the
      IETF Network Slice and triggers its realization.

   The IETF Network Slice Mapper and Realizer are considered to be
   internal modules of the IETF Network Slice Controller.  However,
   anything prevents that these modules could be separated components,
   communicating through standard protocols.  The intention of this
   document is to figure out how different models interplay in the
   transition from the technology-agnostic IETF Network Slice request up
   to the technology-specific IETF Network Slice realization.  Whatever
   implementation guideline is out of scope of this document.

   Figure 2 illustrates the components described and the associated
   models, as follows

   *  (a) -> customer’s view, e.g.
      [I-D.ietf-teas-ietf-network-slice-nbi-yang], which can be
      complemented by [RFC9834] and / or
      [I-D.ietf-teas-network-slice-topology-yang].

   *  (b) -> provider’s view, including more detailed but yet
      technology-agnostic resource view as e.g.
      [I-D.ietf-teas-network-slice-topology-yang], and/or alternative
      technology-specific augmentations as e.g. for OTN
      [I-D.ietf-ccamp-yang-otn-slicing] or for IP/MPLS NRP
      [I-D.ietf-teas-nrp-yang].  Note that the provider view could
      permit network operators to retrieve information about the slices
      being provided and how they are realized.

   *  (c) -> models per network controller, out of scope of this
      document.  An example of applicability of existing models is in
      [I-D.ietf-teas-ns-models-applicability].

Contreras, et al.         Expires 23 April 2026                 [Page 5]
Internet-Draft    Slice Controller and its Data Models      October 2025

                                    Higher Level System
                                             |
                                             |
                                +-------------------------+
                                | NSC        | (a)        |
                                |            v            |
                                |   +-----------------+   |
                                |   |                 |   |
                                |   |    NS Mapper    |   |
                                |   |                 |   |
                                |   +-----------------+   |
                           (b)  |            | (b)        |
                 Operator -------------------+            |
                                |            |            |
                                |            v            |
                                |   +-----------------+   |
                                |   |                 |   |
                                |   |    NS Realizer  |   |
                                |   |                 |   |
                                |   +-----------------+   |
                                |            | (c)        |
                                +-------------------------+
                                             |
                                             v
                                    Network Controllers

      Figure 2: IETF Network Slice Controller Structure and associated
                                Data Models

   IETF Network Slices with different level of detail could be
   requested:

   *  The IETF network slice can be abstracted as a set of edge-to-edge
      links (Type 1).

   *  The IETF network slice can be abstracted as a topology of virtual
      nodes and virtual links (Type 2) which represent the partitioning
      of underlay network resources for use by network slice
      connectivity.

   The use cases of these two types of networks are further described by
   [RFC8453].

   Regarding IETF Network Slice service requests, it is possible to
   model the Type 1 service by means of
   [I-D.ietf-teas-ietf-network-slice-nbi-yang] , while it is possible to
   model the Type 2 service using
   [I-D.ietf-teas-network-slice-topology-yang].  Moreover, when a

Contreras, et al.         Expires 23 April 2026                 [Page 6]
Internet-Draft    Slice Controller and its Data Models      October 2025

   customer intends to request a Type 2 service,
   [I-D.ietf-teas-network-slice-topology-yang] can also be used at the
   point (a) in Figure 2 for expressing intent-based topologies for
   resource reservation or realization intentions within the provider's
   network.  It should be noted that according to [RFC9543], the
   customer might ask for some level of control of the IETF Network
   Slice, for instance to customize the service paths in a network
   slice.  The abstract topology defined in
   [I-D.ietf-teas-network-slice-topology-yang] could serve to enable
   this capability and optimize the resource utilization for network
   slice connections activated on top of the abstract topology.

   In respect to IETF Network Slice realization, as an example, when
   ACTN is used to realize an IETF network slice, model mappings are
   described in more detail in [I-D.ietf-teas-actn-yang].

3.1.  NS Mapper

   The Mapper will receive an IETF Network Slice Service request from
   the customer.  It will process it obtaining an overall view of how
   this new request complements or fits with the rest of IETF Network
   Slices, if any, as provisioned in the network.  As part of that
   processing, a single customer IETF Network Slice Service request
   could result in the need of actually provisioning different IETF
   Network Slices in the network.  The Mapper will maintain the
   relationship among customer IETF Network Slice request and
   provisioned IETF Network Slices.  The Mapper also will provide
   performance notifications in relation with the SLOs dictated in the
   slice request by the customer.

   The Mapper performs resource partitions of the filtered topologies
   provided by the Realizer component, generating specific Network
   Resource Partitions (NRPs).  An NRP represents a collection of
   resources such as buffers or queues of the links of a filtered
   topology.  The Mapper, when processing the slice request, will map
   the connectivity constructs to one or more NRPs, e.g., according to
   specific SLOs.

   As part of the performance monitoring of the IETF Network Slice
   service, the Mapper will aggregate performance information from the
   distinct NRPs used for mapping the connectivity constructs forming
   the slice.

Contreras, et al.         Expires 23 April 2026                 [Page 7]
Internet-Draft    Slice Controller and its Data Models      October 2025

3.2.  NS Realizer

   The Realizer will receive from the Mapper one or more requests for
   provision of IETF Network Slices, potentially including some
   technology-specific information (e.g., an indication about the use of
   Layer 2 or Layer 3 capabilities to put into effect a slice).  With
   that information, the Realizer will determine the realization of each
   IETF Network Slice Service interacting with technology-specific
   Network Controllers.

   The Realizer will be in charge of generating filtered topologies from
   the underlying (physical) network information provided by the Network
   Controllers.  The handling of filtered topologies is optional, then
   if not filtering is applied, the Realizer could expose the physical
   network.  The filtered topologies represent a selection of nodes and
   links from the underlying network(s), e.g., as result of applying
   certain policies.

   The Realizer will provide the telemetry information from the filtered
   topologies to the Mapper for further processing in support of the
   performance assurance of the IETF Network Slices.

4.  Model Types in IETF Network Slice Controller Interfaces

   Both [RFC8309] and [RFC8969] offer a complete view of customer,
   service and network model types.  In this sense a potential mapping
   of models to IETF Network Slice Controller interfaces is as follows:

   *  IETF Network Slice Service interface (interface (a) in Figure 2)
      -> Customer service model.  According to [RFC8309] “a customer's
      service request is (or should be) technology agnostic.  That is, a
      customer is unaware of the technology that the network operator
      has available to deliver the service, so the customer does not
      make requests specific to the underlying technology but is limited
      to making requests specific to the service that is to be
      delivered”. This definition matches the expected behavior of the
      IETF NSC Slice Service interface as considered in [RFC9543].

   *  Interface between NS Mapper and NS Realizer (interface (b) in
      Figure 2) -> Service Delivery model.  According to [RFC8309] "a
      service delivery module is expressed as a core set of parameters
      that are common across a network type and technology […] Service
      delivery modules include technology-specific modules.”.
      Furthermore, [RFC8969] (in its Figures 3 and 5) considers L3SM or
      VN Service models to be later on fed into a controller.

Contreras, et al.         Expires 23 April 2026                 [Page 8]
Internet-Draft    Slice Controller and its Data Models      October 2025

   *  Network Configuration interface (interface (c) in Figure 2) ->
      Network Configuration model.  According to [RFC8309] “the
      orchestrator must map the service request to its view, and this
      mapping may include a choice of which networks and technologies to
      use depending on which service features have been requested”. This
      is coincident with the expected behavior of the IETF NSC network
      configuration as considered in in [RFC9543].

5.  Security Considerations

   This document considers both the Mapper and the Realizer component as
   internal modules of the IETF Network Slice Controller.  However,
   nothing prevents that these modules could be separated components,
   communicating through standard protocols (i.e., not as an internal
   communication to the IETF NSC).

   In that case, some security requirements apply such as:

   *  Authentication between Mapper and Realizer, to prevent malicious
      behaviors.

   *  Privacy of the information shared between components.

   *  Secure transport between components based on the kind of interface
      used in the communication (e.g., NETCONF, RESTCONF, etc).

6.  IANA Considerations

   This draft does not include any IANA considerations

7.  References

   [I-D.ietf-ccamp-yang-otn-slicing]
              Guo, A., Contreras, L. M., Belotti, S., Rokui, R., Xu, Y.,
              Zhao, Y., and X. Liu, "Framework and Data Model for OTN
              Network Slicing", Work in Progress, Internet-Draft, draft-
              ietf-ccamp-yang-otn-slicing-09, 3 July 2025,
              <https://datatracker.ietf.org/doc/html/draft-ietf-ccamp-
              yang-otn-slicing-09>.

   [I-D.ietf-teas-actn-yang]
              Lee, Y., Zheng, H., Ceccarelli, D., Yoon, B. Y., and S.
              Belotti, "Applicability of YANG models for Abstraction and
              Control of Traffic Engineered Networks", Work in Progress,
              Internet-Draft, draft-ietf-teas-actn-yang-11, 7 March
              2023, <https://datatracker.ietf.org/doc/html/draft-ietf-
              teas-actn-yang-11>.

Contreras, et al.         Expires 23 April 2026                 [Page 9]
Internet-Draft    Slice Controller and its Data Models      October 2025

   [I-D.ietf-teas-ietf-network-slice-nbi-yang]
              Wu, B., Dhody, D., Rokui, R., Saad, T., and J. Mullooly,
              "A YANG Data Model for the RFC 9543 Network Slice
              Service", Work in Progress, Internet-Draft, draft-ietf-
              teas-ietf-network-slice-nbi-yang-25, 9 May 2025,
              <https://datatracker.ietf.org/doc/html/draft-ietf-teas-
              ietf-network-slice-nbi-yang-25>.

   [I-D.ietf-teas-network-slice-topology-yang]
              Liu, X., Contreras, L. M., Belotti, S., Guo, A., and I.
              Busi, "IETF Network Slice Topology YANG Data Model", Work
              in Progress, Internet-Draft, draft-ietf-teas-network-
              slice-topology-yang-02, 21 July 2025,
              <https://datatracker.ietf.org/doc/html/draft-ietf-teas-
              network-slice-topology-yang-02>.

   [I-D.ietf-teas-nrp-yang]
              Wu, B., Dhody, D., Beeram, V. P., Saad, T., and S. Peng,
              "YANG Data Models for Network Resource Partitions (NRPs)",
              Work in Progress, Internet-Draft, draft-ietf-teas-nrp-
              yang-04, 21 July 2025,
              <https://datatracker.ietf.org/doc/html/draft-ietf-teas-
              nrp-yang-04>.

   [I-D.ietf-teas-ns-models-applicability]
              Barguil, S., Contreras, L. M., Lopez, V., de Dios, O. G.,
              and M. Boucadair, "Applicability of IETF-Defined Service
              and Network Data Models for Network Slice Service
              Management", Work in Progress, Internet-Draft, draft-ietf-
              teas-ns-models-applicability-01, 24 June 2025,
              <https://datatracker.ietf.org/doc/html/draft-ietf-teas-ns-
              models-applicability-01>.

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

   [RFC8453]  Ceccarelli, D., Ed. and Y. Lee, Ed., "Framework for
              Abstraction and Control of TE Networks (ACTN)", RFC 8453,
              DOI 10.17487/RFC8453, August 2018,
              <https://www.rfc-editor.org/info/rfc8453>.

   [RFC8969]  Wu, Q., Ed., Boucadair, M., Ed., Lopez, D., Xie, C., and
              L. Geng, "A Framework for Automating Service and Network
              Management with YANG", RFC 8969, DOI 10.17487/RFC8969,
              January 2021, <https://www.rfc-editor.org/info/rfc8969>.

Contreras, et al.         Expires 23 April 2026                [Page 10]
Internet-Draft    Slice Controller and its Data Models      October 2025

   [RFC9543]  Farrel, A., Ed., Drake, J., Ed., Rokui, R., Homma, S.,
              Makhijani, K., Contreras, L., and J. Tantsura, "A
              Framework for Network Slices in Networks Built from IETF
              Technologies", RFC 9543, DOI 10.17487/RFC9543, March 2024,
              <https://www.rfc-editor.org/info/rfc9543>.

   [RFC9834]  Boucadair, M., Ed., Roberts, R., Ed., Gonzalez de Dios,
              O., Barguil, S., and B. Wu, "YANG Data Models for Bearers
              and Attachment Circuits as a Service (ACaaS)", RFC 9834,
              DOI 10.17487/RFC9834, September 2025,
              <https://www.rfc-editor.org/info/rfc9834>.

Acknowledgments

   The authors would like to thank (in alphabetical order) to
   Swamynathan B, Adrian Farrel, Aihua Guo, Joel Halpern and Kiran
   Makhijani for their valuable comments received.

Contributors

   The following people (in alphabetical order) contributed
   substantially to the content of this document and should be
   considered coauthors.

   Sergio Belotti, Nokia (sergio.belotti@nokia.com)

   Med Boucadair, Orange (mohamed.boucadair@orange.com)

   Dhruv Dhody, Huawei Technologies (dhruv.ietf@gmail.com)

Authors' Addresses

   Luis M. Contreras (editor)
   Telefonica
   Ronda de la Comunicacion, s/n
   Sur-3 building, 3rd floor
   28050 Madrid
   Spain
   Email: luismiguel.contrerasmurillo@telefonica.com
   URI:   http://lmcontreras.com/

   Reza Rokui
   Ciena
   Canada
   Email: rrokui@ciena.com

Contreras, et al.         Expires 23 April 2026                [Page 11]
Internet-Draft    Slice Controller and its Data Models      October 2025

   Jeff Tantsura
   Nvidia
   United States of America
   Email: jefftant.ietf@gmail.com

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

   Xufeng
   Alef Edge
   Email: xufeng.liu.ietf@gmail.com

Contreras, et al.         Expires 23 April 2026                [Page 12]