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Versions: 00 01                                                         
TEAS                                                       LM. Contreras
Internet-Draft                                                Telefonica
Intended status: Informational                                  R. Rokui
Expires: May 6, 2021                                               Nokia
                                                             J. Tantsura
                                                                  Apstra
                                                                   B. Wu
                                                                  Huawei
                                                                  X. Liu
                                                                   Volta
                                                                D. Dhody
                                                                  Huawei
                                                              S. Belloti
                                                                   Nokia
                                                        November 2, 2020


      IETF Network Slice Controller and its associated data models
            draft-contreras-teas-slice-controller-models-00

Abstract

   This document describes the major functional components of an IETF
   Network Slice Controller (NSC) as well as references the data models
   required for supporting the requests of IETF network slices and their
   realization.

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
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   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
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   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 May 6, 2021.








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Copyright Notice

   Copyright (c) 2020 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
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   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified 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
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .   7
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   7
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   7
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   8

1.  Introduction

   Editor's Note: the terminology in this draft will be aligned with the
   final terminology selected for describing the notion of IETF Network
   Slice when applied to IETF technologies, which is currently under
   discussion.  By now same terminology as used in
   [I-D.nsdt-teas-ietf-network-slice-definition] and
   [I-D.nsdt-teas-ns-framework] is primarily used here.  Consensus to
   use "IETF Network Slice" term has been reached.

   The generic idea of network slicing intends to provide tailored end-
   to-end network capabilities to customers in the way that they could
   be perceived as a dedicated network, despite the fact that it makes
   use of shared physical infrastructure facilities.

   Among the capabilities mentioned, connectivity of different parts of
   a network slice with particular characteristics play a central role.
   Thus, the concept of 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 request, realization and lifecycle control
   and management of a transport slice, a new element named IETF Network



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   Slice Controller (NSC) is being proposed in
   [I-D.nsdt-teas-ietf-network-slice-definition] and
   [I-D.nsdt-teas-ns-framework].

   The NSC from its North Bound Interface (NBI) exposes set of APIs that
   allow a higher level system to request an end-to-end transport slice.
   It receives the request of enablement of an IETF Network Slice by a
   customer (i.e. creation, modification or deletion).  Upon receiving a
   request from its NBI, NSC finds the resources needed for realization
   of the IETF Network Slice and in turn interfaces from its South Bound
   Interface (SBI) 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 TSC.



                   +------------------------------------------+
                   |         A higher level system            |
                   |   (e.g E2E network slice orchestrator)   |
                   +------------------------------------------+
                                        A
                                        | NSC NBI
                                        V
                   +------------------------------------------+
                   |   IETF Network Slice Controller (NSC)    |
                   +------------------------------------------+
                                        A
                                        | NSC SBI
                                        V
                   +------------------------------------------+
                   |           Network Controller(s)          |
                   +------------------------------------------+


             Figure 1: Interface of Transport Slice Controller

   This memo 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 the
   IETF Network Slice and its realization.  Then the data models
   referred are mapped to the interfaces among components.

2.  IETF Network Slice data models

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




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   o  Customer's view, mostly 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 agnostics and describes
      the characteristics of the IETF Network Slice from a customer's
      point of view.  It can include the slice topology, performance
      parameters, endpoints of the slice, traffic characteristics of the
      slice, and the KPIs to monitor the slice.

   o  Provider's view, mostly focused on the provisioning and operation
      of the IETF Network Slices in the transport 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, operator's view shows how an IETF
      Network Slice is realized in operator's network along with all the
      resources used during the its realization.

   Both views are complementary, each of them specialized for a given
   purpose.  In consequence, it should be consistency between both in
   order to ensure alignment.

   Currently there are two different models proposed, on for each of the
   categories above.  The model in
   [I-D.wd-teas-ietf-network-slice-nbi-yang] fits into the customer
   view, while the model defined in
   [I-D.liu-teas-transport-network-slice-yang] fits in to the provider
   view.

   It should be noted that for the realization of a transport slice, the
   NSC interacts with one or more Network Controllers.  In that case,
   the data models to be used are particular for each Network Controller
   (e.g., technology dependent), as well as the mapping function from
   its NBI to SBI 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 work with both data models.  The NSC takes first the
   customer's view by analyzing the needs of the customer, processing
   such requests taking into account the overall view of the network and
   the IETF Network Slices already instantiated, normalizing its
   instantiation across different technologies, and finally generates
   the provider view.

   Once the new request is processed and declared as feasible, the NSC
   triggers its realization by interacting with the Network Controllers
   and communicates back to the higher level controller to start the
   billing cycle.



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   In order to accommodate these procedures, the internal structure of
   the NSC can be divided into:

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

   o  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.

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

   o  (a) -> customer's view, e.g.
      [I-D.wd-teas-ietf-network-slice-nbi-yang].

   o  (b) -> provider's view, e.g.
      [I-D.liu-teas-transport-network-slice-yang].

   o  (c) -> models per network controller, out of scope of this
      document




























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

     Figure 2: IETF Network Slice Controller structure and asspociated
                                data models

   TODO item #1 - Breakdown "NS mapper" and "NS Realizer" to their
   logical components.

   TODO item #2- Add complementarity of the models for satisfying Type 1
   and Type 2 Services as per [RFC8453].  Discussion: equivalent to the
   Virtual Network (VN) described in [RFC8453], there are two views of
   an IETF network slices as well:

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

   o  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].  [I-D.wd-teas-ietf-network-slice-nbi-yang] models the Type
   1 service, while [I-D.liu-teas-transport-network-slice-yang] models
   the Type 2 service.  When a customer intends to request a Type 2
   service, [I-D.liu-teas-transport-network-slice-yang] can also be used



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   at the point (a) in Figure 2.  As an example, when ACTN is used to
   realize an IETF network slice, model mappings are described in more
   details in [I-D.ietf-teas-actn-yang].

4.  Security Considerations

   To be done.

5.  IANA Considerations

   This draft does not include any IANA considerations

6.  References

   [I-D.ietf-teas-actn-yang]
              Lee, Y., Zheng, H., Ceccarelli, D., Yoon, B., Dios, O.,
              Shin, J., and S. Belotti, "Applicability of YANG models
              for Abstraction and Control of Traffic Engineered
              Networks", draft-ietf-teas-actn-yang-06 (work in
              progress), August 2020.

   [I-D.liu-teas-transport-network-slice-yang]
              Liu, X., Tantsura, J., Bryskin, I., Contreras, L., WU, Q.,
              Belotti, S., and R. Rokui, "Transport Network Slice YANG
              Data Model", draft-liu-teas-transport-network-slice-
              yang-01 (work in progress), July 2020.

   [I-D.nsdt-teas-ietf-network-slice-definition]
              Rokui, R., Homma, S., Makhijani, K., Contreras, L., and J.
              Tantsura, "Definition of IETF Network Slices", draft-nsdt-
              teas-ietf-network-slice-definition-00 (work in progress),
              October 2020.

   [I-D.nsdt-teas-ns-framework]
              Gray, E. and J. Drake, "Framework for Transport Network
              Slices", draft-nsdt-teas-ns-framework-04 (work in
              progress), July 2020.

   [I-D.wd-teas-ietf-network-slice-nbi-yang]
              Bo, W., Dhody, D., Han, L., and R. Rokui, "A Yang Data
              Model for IETF Network Slice NBI", draft-wd-teas-ietf-
              network-slice-nbi-yang-00 (work in progress), October
              2020.

   [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>.



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Authors' Addresses

   Luis M. Contreras
   Telefonica
   Ronda de la Comunicacion, s/n
   Sur-3 building, 3rd floor
   Madrid  28050
   Spain

   Email: luismiguel.contrerasmurillo@telefonica.com
   URI:   http://lmcontreras.com/


   Reza Rokui
   Nokia
   Canada

   Email: reza.rokui@nokia.com


   Jeff Tantsura
   Apstra
   USA

   Email: jefftant.ietf@gmail.com


   Bo Wu
   Huawei Technologies
   101 Software Avenue, Yuhua District
   Nanjing, Jiangsu  210012
   China

   Email: lana.wubo@huawei.com


   Xufeng Liu
   Volta Networks

   Email: xufeng.liu.ietf@gmail.com











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   Dhruv Dhody
   Huawei Technologies
   Divyashree Techno Park
   Bangalore, Karnataka  560066
   India

   Email: dhruv.ietf@gmail.com


   Sergio Belloti
   Nokia

   Email: sergio.belotti@nokia.com






































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