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NMRG                                                            A. Galis
Internet-Draft                                 University College London
Intended Status: Informational                                    et al.
Expires: May 4, 2019                                    November 4, 2018


      Management of Precision Network Slicing - Problem Statement
          draft-galis-precision-netslices-problem-statement-00

Abstract

   This document introduces Precision Network Slicing Management
   problems and their context. It represents an initial review of the
   Management of Network Slicing problem statement derived from the
   analysis of the technical gaps in IETF protocols ecosystem.  It
   complements and brings together the efforts being carried out in
   several other IETF working groups covering certain aspects of Network
   Slicing management functions and operations.

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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   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 May 4, 2019.

Copyright Notice

   Copyright (c) 2018 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
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   include Simplified BSD License text as described in Section 4.e of



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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.


Table of Contents

   1  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . .  2
     1.1 Early Definitions of Slicing . . . . . . . . . . . . . . . .  3
     1.2 Definition of Terms  . . . . . . . . . . . . . . . . . . . .  5
       1.2.1 Roles  . . . . . . . . . . . . . . . . . . . . . . . . .  5
       1.2.2 Key Terms  . . . . . . . . . . . . . . . . . . . . . . .  5
       1.2.3 Slicing and Sharing of Resources . . . . . . . . . . . .  6
     1.3 Precision Network Slicing Value Characteristics  . . . . . .  7
     1.4 Precision Network Slicing Work Scope . . . . . . . . . . . .  9
   2. Management of Precision Network Slicing - Selected Problems
      and Work Areas  . . . . . . . . . . . . . . . . . . . . . . . . 11
     2.1 Overall management aspects, APIs and functionality of
         network slices.  . . . . . . . . . . . . . . . . . . . . . . 11
     2.2 Slice Management Characteristics, Capabilities and
         Assurances.  . . . . . . . . . . . . . . . . . . . . . . . . 12
     2.3 E2E Network Slicing. . . . . . . . . . . . . . . . . . . . . 13
   3 Security Considerations  . . . . . . . . . . . . . . . . . . . . 14
   4 IANA Considerations  . . . . . . . . . . . . . . . . . . . . . . 14
   5 Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 14
   6 References . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
     6.1 IETF References  . . . . . . . . . . . . . . . . . . . . . . 14
     6.2  Informative References  . . . . . . . . . . . . . . . . . . 16
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 18


1  Introduction

   Network slicing (NS) is an approach to flexible isolation and
   allocation of network resources and network functions for a logical
   network instance, providing a high level of such network
   customization and quality service guarantee that includes also such
   customized reliability and security levels. NS transforms the
   networking perspective by abstracting, isolating, orchestrating,
   softwarizing, and separating logical network components from the
   underlying physical network supporting the introduction of new
   network architectures ([RFC1958], [RFC3439], [RFC3234]) and new
   service delivery [5G-ICN]. In general, a particular network slice
   consists of a union of subsets of (connectivity, storage, computing)
   resources & (Virtual) Network Functions & Service Functions [RFC7665]
   at the data & control & management planes at a given time that are
   managed together to provide a logical networking infrastructure to
   support a single service or a set of services.




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   NS enables the dynamic and concurrent deployment of multiple logical,
   self-contained and independent, logical networks on a common
   infrastructure.

   The management plane allocates a group of network resources network
   resources can be physical, virtual or a combination thereof), it
   connects with the physical and virtual network and service functions
   ([SFC WG]) as appropriate, and it instantiates all of the network and
   service functions assigned to a slice. On the other hand, for slice
   operations, the slice management plane functionality that may be
   operated by slice tenant takes over the control and governing of all
   the network resources, network functions, and service functions
   assigned to the slice. It (re-) configures them as appropriate and as
   per elasticity needs, in order to provide an end-to-end service. In
   particular, slice ingress routers are configured, so that appropriate
   traffic is bound to the relevant slice.

   Network operators can use NS to enable different services to receive
   different treatment and to allow the allocation and release of
   network resources according to the context and contention policy of
   the operators. Such an approach using NS would allow a significant
   reduction of the operations expenditure. In addition, there is an
   enabling synergy between NS and softwarization. On the one hand, NS
   makes possible softwarization, programmability ([RFC7149]), and the
   innovation necessary to enrich the offered services. On the other
   hand, Network softwarization techniques [IMT2020-2015], [IMT2020-
   2016] may be used to realize and manage [MANO-2014] network slicing.
   NS provides the means for the network operators to provide network
   programmable capabilities to both service providers and other market
   players without changing their physical infrastructure.

   Slices may support dynamic multiple services, multi- tenancy and the
   integration means for vertical market players (e.g.  the automotive
   industry, energy industry, healthcare industry, media and the
   entertainment industry, etc.)

1.1 Early Definitions of Slicing

   The followings are early definitions of slicing:

   (i)  Active / Programmable Networks research Node operating systems &
        resource control frameworks (1995 - 2005) [Programmable
        Networks]

   (ii) Federated Testbed research: Planet Lab USA (2002), PlanetLab EU
        (2005), OneLab EU (2007), PlanetLab Japan (2005), OpenLab EU
        (2012).




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   (iii) GENI Slice (2009): "GENI [GENI-2009] is a shared network
        testbed, i.e., multiple experimenters may be running multiple
        experiments at the same time. A GENI slice is:

        o The unit of isolation for experiments.

        o A container for resources used in an experiment. GENI
          experimenters add GENI resources (compute resources, network
          links, etc..) to slices, and run experiments that use these
          resources.

        o A unit of access control. The experimenter that creates a
          slice can determine which project members have access to the
          slice, i.e., are members of the slice.

   (iv) Slice capabilities (2009) [ChinaCom-2009]

        o 3 Slices Capabilities: "Resource allocation to virtual
          infrastructures or slices of virtual infrastructure.";
          "Dynamic creation and management of virtual
          infrastructures/slices of virtual  infrastructure across
          diverse  resources."; "Dynamic mapping and deployment of a
          service on a virtual infrastructure/slices of virtual
          infrastructure."

        o 17 Orchestration capabilities.

        o 19 Self-functionality mechanisms.

        o 14 Self-functionality infrastructure capabilities.

   (v) ITU-T Slicing (2011) as defined in [SC6], it is the basic concept
        of the Network Softwarization. Slicing allows logically isolated
        network partitions (LINP) with a slice being considered as a
        unit of programmable resources such as network, computation, and
        storage.

   (vi) NGMN Slice capabilities (2016) [NGMN 2016] consist of 3 layers:

        1) Service Instance Layer, 2) Network Slice Instance Layer, and
        3) Resource layer.

        o The Service Instance Layer represents the services (end-user
          service or business services), which are to be supported. Each
          service is represented by a Service Instance. Typically,
          services can be provided by the network operator or by 3rd
          parties.




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        o A Network Slice Instance provides the network characteristics,
          which are required by a Service Instance. A Network Slice
          Instance may also be shared across multiple Service Instances
          provided by the network operator.

   (vii) 3GPP - GPP TR23.799 Study Item "Network Slicing' 2016.

   (viii) ONF Recommendation TR-526 "Applying SDN architecture to
        Network Slicing", 2016.


   Additional characteristics, standard and research activities on
   Infrastructure slicing and references are presented in [NS Tutorial
   2018].

1.2 Definition of Terms

1.2.1 Roles

   Resource Provider - It owns the physical resources and infrastructure
   (network/ cloud/ datacenter) and provides / leases them to
   operators.

   Slice Provider - A slice provider is an entity that has appropriate
   tools for the lifecycle management of network slices. Typically, this
   a telecommunication service provider that in most cases can also play
   a role of the Resource Provider.

   Slice Tenant - A slice tenant is the business owner of a specific
   network/cloud/datacenter slice, in which customized services are
   hosted.

   Infrastructure slice tenants can make requests for the creation of
   new slice through a service model.

1.2.2 Key Terms

   Network Slice - A set of infrastructures (network, cloud, data
   center) run-time network functions, infrastructure resources (i.e.,
   managed connectivity, compute, storage resources) and service
   functions that have attributes specifically designed to meet the
   needs of an industry vertical or a service.

   As such a Network Slice is a managed group of subsets of resources,
   run-time network functions/network virtual functions at the data,
   control, management/orchestration, and service planes at any given
   time. The behavior of the Network Slice is realized via network slice
   instances (i.e., activated slices, dynamically and non-disruptively



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   re-provisioned). The Network Slice key characteristics are provided
   below:

      o A Network Slice supports at least one type of service.

      o A Network Slice may consist of cross-domain components from
        separate domains in the same or different administrations, or
        components applicable to the infrastructure.

      o A resource-only partition is one of the components of a Cloud
        Network Slice, however on its own does not fully represent a
        Network Slice. It can be seen as a slice substrate.

      o A collection of partitions from separate domains is combined and
        aggregated to form a cloud / network slice.

      o Underlays / overlays supporting all services equally (with 'best
        effort" support) are not fully representing a Network Slice.


   Precision Network Slices - a network slice which guarantees QoS
   characteristics (e.g. low latency) and/or KPIs (Key Performance
   Indicators).

   Network Slicing: Network slicing is a technology or an approach to
   create separate network slices in support of services, depending on
   several requirements, on the same physical resources. This is
   possible by combinations of several network technologies.

   End-to-End Network Slice (E2E-NS): An E2E-NS is a virtual network
   connecting between end points of a number of NS subnets (i.e. single
   domain slices). E2E slices are composed of a single NS subnet or
   multiple NS subnets.

   Network Slice as a Service (NSaaS): An NSaaS is a NS distribution
   model in which a third-party provider can manage the lifecycle of NSs
   and makes them available to customers.

1.2.3 Slicing and Sharing of Resources

      o From a business point of view, a Network Slice includes a
        combination of all relevant network and compute resources,
        functions, and assets required to fulfil a specific business
        case or service.

      o From the infrastructure point of view, the infrastructure slice
        instances require the partitioning and assignment of a set of
        resources that can be used in an isolated, disjunctive or non-



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        disjunctive manner for that slice.

      o From the tenant point of view, the infrastructure slice instance
        provides different capabilities, specifically in terms of their
        management and control capabilities, and how much of them the
        network service provider hands over to the slice tenant. As
        such, there are two types of slices:

        (i)  Internal slices, understood as the partitions used for
             internal services of the provider, retaining full control
             and management of them.

        (ii) External slices, being those partitions hosting customer
             services, appearing to the customer as dedicated
             networks/clouds/data centers.

      o From the management plane point of view, infrastructure slices
        refer to the managed fully functional dynamically created
        partitions of physical and/or virtual network resources, network
        physical/virtual and service functions that can act as an
        independent instance of a connectivity network and/or as a
        network / cloud.

      o From the date plane point of view, infrastructure slices refer
        to dynamically created partitions of network forwarding devices
        with guarantees for isolation, customization and security.

1.3 Precision Network Slicing Value Characteristics

   As a differentiation from non-partition networks and those with
   simple partitions of connectivity resources (e.g. VPNs)/ Virtual
   Networks/Other abstractions of the data traffic layer, the following
   Motivation and key value-added characteristics of Network Slicing and
   the corresponding usage is identified:

      o Precision Network slicing considerably transforms the networking
        perspective by abstracting, isolating, orchestrating and
        separating logical network behaviors from the underlying
        physical network resources.

      o Precision Network Slice is a dedicated network that is built on
        an infrastructure mainly composed of, but not limited to,
        connectivity, storage and computing.

      o Each Precision Network Slice has the ability to dynamically
        expose and possibly negotiate the parameters that characterize
        an NS.




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      o Each Precision Network Slice will have its own operator/tenant
        that sees it as a complete network infrastructure (i.e. router
        instances, programmability, using any appropriate communication
        protocol, caches, provide dynamic placement of virtual network
        functions according to traffic patterns, to use its own
        controller, finally, it can manage its network as its own).

      o Provision Network slicing supports tenants that are strongly
        independent on infrastructure.

      o A Precision Network Slicing aware infrastructures allows
        operators to use part of the resources to meet stringent
        resource requirements.

      o Precision Network slicing introduces an additional layer of
        abstraction by the creation of logically or physically isolated
        groups of network resources and network function/virtual network
        functions configurations separating its behavior from the
        underlying physical network.

      o Precision Network slicing covers the full life cycle of slices
        that are managed groups of infrastructure resources, network
        functions and services (e.g. the network slice components are:
        service instance, a network functions instance, resources, slice
        manager, capability exposure and guarantees for QoS
        characteristics and/or KPIs).

      o Precision Network slices are dynamically and non-disruptively
        reprovisioned.

      o Precision Network slices will need to be as far as possible
        self-managed by automated, autonomic and autonomous, systems in
        order to cope with dynamic requirements, such as scalability or
        extensibility of an infrastructure (organically
        growing/shrinking of resources to meet the size of their
        organizations).

      o Precision Network slices are configurable and programmable, and
        they have the ability to expose their capabilities and
        characteristics. The slice protocols and functions are selected
        according to slice required features. The behavior of the
        network slice realized via network slice instance(s).

      o Precision Network slices are concurrently deployed as multiple
        logical, self-contained and independent, partitioned network
        functions and resources on common physical infrastructure.

      o Network slicing supports dynamic multi-services, multi-tenancy



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        and the means for backing vertical market players.

      o Network slicing simplifies the provisioning of services
        manageability of networks and integration and operational
        challenges especially for supporting communication services.

      o Precision Network slicing offers native service customization
        enabled by the selection and configuration of network functions
        for coordinating/orchestration and control of network
        resources.

      o Precision Network Slicing Capability exposure: providers can
        offer Application Programming Interfaces (APIs) to the vertical
        business customers for granting the capability of managing their
        own slices and for the purpose of building of advanced services
        on top of services offered by the network slice. Such management
        actions can include dimensioning, configuration, etc.

      o Hosting applications: providers offer the capability of hosting
        virtualized versions of network functions or applications,
        including the activation of the necessary monitoring information
        for those functions.

      o Hosting on-demand 3rd parties: empower partners (3rd parties /
        OTTs) to directly make offers to the end customers augmenting
        Operator network or other value creation capabilities.

1.4 Precision Network Slicing Work Scope

   The purpose of the NS work in IETF is to develop a set of protocols
   and/or protocol extensions that enable efficient slice lifecycle
   management (creation, activation / update /deactivation), slice
   composition, inter-slice operations (for subslices concatenation,
   that includes slice discovery and description) slice orchestration,
   overall network slicing system management, providing slice isolation=
   as well as management of slice related KPIs (according to SLA), and
   safe and secure operations within a connectivity network or network
   cloud / data center environments [NECOS].

   While there are, isolated efforts being carried out in several IETF
   working groups Network WG [I-D.leeking-actn-problem-statement 03],
   TEAS WG [I-D.teas-actn-requirements-04], [I-D.dong-network-slicing-
   problem-statement], ANIMA WG [I-D.galis-anima-autonomic-slice-
   networking], [IETF-Slicing1], [IETF-Slicing2], [IETF-Slicing3],
   [IETF-Slicing4], [IETF-Slicing5], [IETF-Mobility], [IETF-
   Virtualization], [IETF-Coding], [IETF-Anchoring] to achieve certain
   aspects of network slice functions and operations, there is a clear
   need to look at the complete life-cycle management characteristics of



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   Network Slicing solutions though the discussions based on the
   following architectural tenets:

      o Underlay tenet: support for an IP/MPLS-based underlay data Plane
        (including segment routing).

      o Governance tenet: a logically centralized authority for network
        slices in a domain.

      o Separation tenet: slices may be virtually or physically
        independent of each other and have an appropriate degree of
        isolation (note 1) from each other what includes isolation of
        each slice management systems.

      o Capability exposure tenet: each slice allows third parties to
        access via dedicated interfaces and /or APIs and /or programming
        methods information regarding services provided by the slice
        (e.g., connectivity information, mobility, autonomicity, etc.)
        within limits set by the operator or the slice owner.

   NS approaches that do not adhere to these tenets are explicitly
   outside of the scope of the proposed work at IETF.

   In pursuit of the solutions described above, there is a need to
   document architecture for network slicing within both wide area
   network and edge/central data center environments.

   Elicitation of requirements (examples are [RFC2119], [RFC4364]) for
   both Network Slice control and management planes will be needed,
   Facilitating the selection, extension, and/or development of the
   protocols for each of the functional interfaces identified to support
   the architecture.

   Additionally, documentation on the common use-cases for slice
   validation for 5G is needed, such as mission-critical ultra-low
   latency communication services; massive-connectivity machine
   communication services (e.g. smart metering, smart grid and sensor
   networks); extreme QoS; independent operations and management;
   independent cost and/or energy optimization; independent multi-
   topology routing; multi-tenant operations; multiple infrastructure
   providers; new network architecture enablement, etc.

   The proposed NS work in NMRG would be coordinated with other IETF WGs
   (e.g. TEAS WG, DETNET WG, ANIMA WG, SFC WG, NETCONF WG, SUPA WG, NVO3
   WG, DMM WG, Routing Area WG (RTGWG) to ensure that the commonalities
   and differences in solutions are properly considered. Where suitable
   protocols, models or methods exist, they will be preferred over
   creating new ones.



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2. Management of Precision Network Slicing - Selected Problems and Work
   Areas

   The goal of this proposed work is to develop one or more protocol
   specifications (or extensions to existing protocols) to address
   specific slicing problems that are not met by the existing tools. The
   following problems were selected according to the analysis of the
   technical gaps in the IETF protocols ecosystem.

2.1 Overall management aspects, APIs and functionality of network
   slices.

   These problems include:

   Precision NS Life Cycle Management: (1) The management plane creates
   the grouping of network resources (physical, virtual, or a
   combination thereof), it connects with the physical and virtual
   network and service functions, it instantiates all of the network and
   service functions assigned to the slice and it activates assurance
   loops for precision network functions (i.e. guaranties for QoS
   characteristics and/or KPIs). (2) Template/NS repository assists
   lifecycle management; (3) Resource Registrar manages exposed network
   infrastructure capabilities; (4) NS Manager oversees individual slice
   (with capability exposure to the NS Tenant); (5) Uniform Slice
   lifecycle management: Slice lifecycle management including creation,
   activation / deactivation, protection, elasticity, extensibility,
   safety, and sizing of the slicing model per network and per network
   cloud for slices in access, core and transport networks; for slices
   in data centers/clouds/; (6) Automated instantiation, scaling and
   resource reconfiguration of slices during slice lifetime.

   E2E multi-domain Precision Orchestration (1) Coordination of any
   number of inter-related resources in a number of subordinate domains,
   and assurance of transactional integrity as part of the triggering
   process and assurance of QoS characteristics and or KPIs; (2)
   Automated control of slice lifecycle management, including discovery
   and concatenation of slices in each segment of the infrastructure (in
   data, control, and management planes); (3) Autonomic coordination and
   triggering of slice elasticity and placement; (4) Coordination and
   (re)-configuration of resources by taking over the control of all the
    network functions; (5) reconfiguration of resources taking into
   account e2e guarantees for QoS characteristics and/or KPIs

   Full NS FCAPS: (1) Fault, Configuration, Accounting, Performance,
   Security; (2) Monitoring Subsystem is responsible for monitoring
   continuously the state all components of a NS; Monitoring Subsystem
   receives the detailed service monitoring requests with references to
   resource allocation and Network functions instances in a NS.  (3)



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   Discovery and monitoring probes are needed of all NS components and
   NS itself and for dynamic discovery of service with function
   instances and their capability.

2.2 Slice Management Characteristics, Capabilities and Assurances.

   These problems include:

   Programmability and control of Network Slices; Capability exposure
   for Network Slicing (allowing openness); with APIs for dynamic slice
   management and interaction.

   Autonomic slice management: (1) Network slice is a dynamic entity
   with autonomic characteristics of its lifecycle and operations. (2)
   The problem of efficient allocation of resources between slices
   combined with real-time optimization of slice operations can only be
   solved by continuous autonomic monitoring of slice performance and
   making continuous autonomic adaptations. (3) Autonomic control of
   slice life cycle management, including a concatenation of slices in
   each segment or domain of the infrastructure (in data, control, and
   management planes);

   Slice Element Manager & Capability exposure  / Key APIs: (1)
   Description of exclusive control and/or management interfaces and
   capabilities exposed for a network slice, enabling the deployment of
   different logical network slices over shared resources; (2)
   Description of the Slice Element Manager which guarantees a level of
   service, according to a negotiated SLA between the customer and the
   slice provider.

   Guaranteed Isolation - (1) slice creation and deployment with
   guarantees for separation in each of the Data / Control / Management
   / Service planes. (2) Methods to enable diverse requirements for
   slicing, including guarantees for the end-to-end QoS of a service
   within a slice.

   Guaranteed QoS characteristics and/or KPIs - (1) slice creation and
   deployment with guarantees for QoS characteristics and/or KPIs in
   each of the Data / Control / Management / Service planes. (2) Methods
   to enable diverse requirements for slicing, including guarantees for
   the end-to-end QoS characteristics and/or KPIs of a service within a
   slice.

   Service / data model & mapping (1) service mapping enables on-demand
   processing anywhere in the physically distributed network, with
   dynamic and fine granular service (re)-provisioning; (2) It includes
   a slice-aware information model based on necessary connectivity,
   storage, compute resources, network functions, capabilities exposed



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   and service elements. (3) Network Function as a Service; (4) Network
   Slice as a Service; (5) Slice Network Functions as a Service. (6)
   Slice Templates & Methods for the design of slices to different
   scenarios in Vertical market players (such as the automotive
   industry, energy industry, healthcare industry, media and
   entertainment industry, holograms, etc.). This outlines an
   appropriate slice template definition that may include capability
   exposure of managed partitions of network resources (i.e.
   connectivity compute and storage resources), physical and/or virtual
   network and service functions that can act as an independent
   connectivity network and/or as a network cloud. (7) The Economy of
   Scale in Slicing: The benefits of slicing grow as the number of
   service types that you are trying to launch grows. In addition
   significant automation is needed to be able to do this at scale.
   Otherwise the complexity and operational challenges are likely to
   mount up. It's key objective that the provider gears up to support
   this ambition in development, delivery and operations.

   High level of recursion, namely methods for network slicing
   segmentation allowing a slicing hierarchy with parent-child
   relationships.

2.3 E2E Network Slicing.

   These problems include:

   E2E Network Slicing Scalability:  Scalability: In order to partition
   network resources in a scalable manner, it is required to clearly
   define to what extent slice customers can be accommodated or not on a
   given slice. The application of different SLAs on the offered
   capabilities of management, control and customization of slices will
   directly impact the management scalability issue.

   E2E Precision Slicing (E2E Network Slices with guaranteed QoS /
   KPIs)- E2E multiple logical, self-contained and independent, shared
   or partitioned networks on a common infrastructure with guaranties
   for QoS characteristics and /or KPIs (Key Performance Indicators).

   E2E Network Slices Reliability - Maintaining the reliability of an
   E2E network slice instance, which is being terminated, or after
   resource changes in a subnet.

   E2E Slice composition / decomposition: The stitching of slices is an
   operation that modifies the functionality of an existing slice by
   adding and merging functions of another slice (i.e. enhancing control
   plane properties be functions defined in another slice template).
   Stitching of slices is used to enrich slice services: (1) Slice
   stitching operations are supported by uniform slice descriptors; (2)



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   Efficient stitching/ decomposition (vertically, horizontally,
   vertically + horizontally).

3 Security Considerations

   Security will be a major part of the design of network slicing.

4 IANA Considerations

   This document requests no IANA actions.

5 Acknowledgements

   Thanks to Kevin Smith (Vodafone), Satoru Matsushima (SoftBank),
   Christian Jacquenet (Orange), Mohamed Boucadair (Orange) for their
   contributions to this draft. This work was partially supported by the
   EU project NECOS - "Novel Enablers for Cloud Slicing" [NECOS].

6 References

6.1 IETF References

   [I-D.dong-network-slicing-problem-statement] Dong, J. and S. Bryant,
              "Problem Statement of Network Slicing in IP/MPLS
              Networks", draft-dong-network-slicing-problem-statement-00
              (work in progress), October 2016.

   [I-D.galis-anima-autonomic-slice-networking] Galis, A., Makhijani,
              K., and D. Yu, "Autonomic Slice Networking-Requirements
              and Reference Model", draft-galis-anima-autonomic-slice-
              networking-01 (work in progress), October 2016.

   [RFC7665] Halpern, J., Pignataro, C., "Service Function Chaining
              (SFC) Architecture",  https://tools.ietf.org/html/rfc7665,
              October 2015.

   [I-D.leeking-actn-problem-statement 03] Ceccarelli, D., Lee, Y.,
              "Framework for Abstraction and Control of Traffic
              Engineered Networks", draft-leeking-actn-problem-
              statement-03 (work in progress), September 2014.

   [I-D.teas-actn-requirements-04] Lee, Y., Dhody, D., Belotti, S.,
              Pithewan, K., Ceccarelli, D., "Requirements for
              Abstraction and Control of TE Networks", draft-ietf-teas-
              actn-requirements-04.txt, January 2017.

   [IETF-Slicing1] "Presentations - Network Slicing meeting at IETF 97
              of 15th November 2016", n.d.,



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              <https://www.dropbox.com/s/ax2ofdwygjema8z/0-
              Network%20Slicing%20Side%20Meeting%20Introduction_
              IETF97.pdf>.

   [IETF-Slicing2] "Presentations - Network Slicing meeting at IETF 97
              of 15th November 2016", n.d.,
              <https://www.dropbox.com/s/k2or6sd0ddzrc6c/1-
              Network%20Slicing%20Problem%20Statement_IETF97.pdf>.

   [IETF-Slicing3] "Presentations - Network Slicing meeting at IETF 97
              of 15th November 2016", n.d.,
              <https://www.dropbox.com/s/g8zvfvbrtkysjs1/2-
              Autonomic%20Slice%20Networking_IETF97.pdf>.

   [IETF-Slicing4] "Presentations - Network Slicing meeting at IETF 97
              of 15th November 2016", n.d.,
              <https://www.dropbox.com/s/d3rk4pjeg552ilv/3-
              Architecture%20for%20delivering%20multicast%20mobility
              %20services%20using%20network%20slicing_IETF97.pdf>.

   [IETF-Slicing5] "Presentations - Network Slicing meeting at IETF 97
              of 15th November 2016", n.d.,
              <https://www.dropbox.com/s/e3isn1bxwwhaw8g/4-
              ACTN%20and%20network%20slicing_IETF97.pdf>.

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

   [RFC4364] Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private
              Networks (VPNs)", RFC 4364, DOI 10.17487/RFC4364, February
              2006, <http://www.rfc-editor.org/info/rfc4364>.

   [RFC1958] Carpenter, B., "Architectural Principles of the Internet",
              RFC 1958, <https://www.ietf.org/rfc/rfc1958.txt>.

   [RFC3439] Bush, R., Meyer, D., "Some Internet Architectural
              Guidelines and Philosophy", RFC3439,
              <https://www.ietf.org/rfc/rfc3439.txt>.

   [RFC3234] Carpenter, B., Brim S., "Middleboxes: Taxonomy and Issues",
              RFC3439, <https://tools.ietf.org/html/rfc3234>.

   [RFC7149] Boucadair, M., Jacquenet, C. , " Software-Defined
              Networking: A Perspective from within a Service Provider
              Environment", RFC 7149, March 2014
              <https://tools.ietf.org/html/rfc7149>.



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   [SFG WG] "Service Function Chaining WG"
              <https://datatracker.ietf.org/doc/charter-ietf-sfc/>.

   [CPP] Boucadair M., Jacquenet, C., Wang, N., "IP Connectivity
              Provisioning Profile (CPP)"
              https://tools.ietf.org/html/rfc7297

   [IETF-Mobility] Truong-Xuan Do, Young-Han Kim, "Architecture for
              delivering multicast mobility services using network
              slicing" 2016-10-31<draft-xuan-dmm-multicast-mobility-
              slicing-00.txt>

   [IETF-Virtualization] Carlos Bernardos, Akbar Rahman, Juan Zuniga,
              Luis  Contreras, Pedro Aranda, " Network Virtualization
              Research Challenges" 2016-10-31<draft-irtf-nfvrg-gaps-
              network-virtualization-03.txt>

   [IETF-Coding] M.A. Vazquez-Castro, Tan Do-Duy, Paresh Saxena, Magnus
              Vikstrom, "Network Coding Function Virtualization" 2016-
              11-14 <draft-vazquez-nfvrg-netcod-function-virtualization-
              00.txt>

   [IETF-Anchoring] Anthony Chan, Xinpeng Wei, Jong-Hyouk Lee, Seil
              Jeon, Alexandre Petrescu, Fred Templin "Distributed
              Mobility Anchoring" 2016-12-15 <draft-ietf-dmm-
              distributed-mobility-anchoring-03.txt,.pdf>

   [RFC6291] L. Andersson, H. van Helvoort, R. Bonica, D. Romascanu, S.
              Mansfield "Guidelines for the Use of the "OAM" Acronym in
              the IETF" - June 2011 https://tools.ietf.org/html/rfc6291

6.2  Informative References

   [NECOS]   Novel Enablers for Cloud Slicing - http://www.h2020-
              necos.eu

   [Programmable Networks] "Programmable Networks for IP Service
              Deployment", Galis, A., Denazis, S., Brou, C., Klein, C. -
              ISBN 1-58053-745-6, pp 450, June 2004, Artech House Books,
              Online: http://www.artechhouse.com/International/Books/
              Programmable-Networks-for-IP-Service-Deployment-1017.aspx

   [ChinaCom-2009] A. Galis et al - "Management and Service-aware
              Networking Architectures (MANA) for Future Internet" -
              Invited paper IEEE 2009 Fourth International Conference on
              Communications and Networking in China (ChinaCom09) 26-28
              August 2009, Xi'an, China, n.d.,
              <http://www.chinacom.org/2009/index.html>.



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   [GENI-2009] "GENI Key Concepts - Global Environment for Network
              Innovations (GENI)", n.d.,
              <http://groups.geni.net/geni/wiki/GENIConcepts>.

   [ITU-T 2011] ITU-T Y.3011- http://www.itu.int/rec/T-REC-Y.3001-
              201105-I

   [NGMN 2016] Network Slicing Framework
              https://www.ngmn.org/fileadmin/user_upload/
              161010_NGMN_Network_Slicing_framework_v1.0.8.pdf

   [NS Tutorial 2018] "Infrastructure Slicing Landscape": Galis. A,
              Makhijani, K Tutorial at IEEE NetSoft 2018, Montreal 19
              July 2018; http://discovery.ucl.ac.uk/10051374/

   [GUERZONI-2016] Guerzoni, R., Vaishnavi, I., Perez-Caparros, D.,
              Galis, A., et al "Analysis of End-to-End Multi Domain
              Management and Orchestration Frameworks for Software
              Defined Infrastructures - an Architectural Survey", June
              2016, <onlinelibrary.eiley.com/10.1002/ett.3084/pdf>.

   [IMT2020-2015] "Report on Gap Analysis", ITU-T FG IMT2020, December
              2015, <http://www.itu.int/en/ITU-T/focusgroups/imt-
              2020/Pages/default.aspx>.

   [IMT2020-2016] "Draft Technical Report Application of network
              softwarization to IMT-2020 (O-041)", ITU-T FG IMT2020,
              December 2016, <http://www.itu.int/en/ITU-
              T/focusgroups/imt-2020/Pages/default.aspx>.

   [IMT2020-2016bis] "Draft Terms and definitions for IMT-2020 in ITU-T
              (O-040)", ITU-T FG IMT2020, December 2016,
              <http://www.itu.int/en/ITU-T/focusgroups/imt-
              2020/Pages/default.aspx>.

   [KARL-2016] Karl, H., Peuster, M, Galis, A., et al "DevOps for
              Network Function Virtualization - An Architectural
              Approach", July 2016, <http://onlinelibrary.wiley.com/doi/
              10.1002/ett.3084/full>.

   [MANO-2014] "Network Functions Virtualisation (NFV); Management and
              Orchestration v1.1.1.", ETSI European Telecommunications
              Standards Institute., December 2014,
              <http://www.etsi.org/deliver/etsi_gs/NFV-
              MAN/001_099/001/01.01.01_60/gs_nfv-man001v010101p.pdf>.

   [NGMN-2016] Hedmar,P., Mschner, K., et al - "Description of Network
              Slicing Concept", NGMN Alliance NGS-3GPP-2016, January



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              2016, <https://www.nmn.org/uploads/media/
              160113_Network_Slicing_v1_0.pdf>.

   [NGS-3GPP-2016] "Study on Architecture for Next Generation System -
              latest version v1.0.2", September 2016,
              <http://www.3gpp.org/ftp/tsg_sa/WG2_Arch/Latest_SA2_Specs/
              Latest_draft_S2_Specs>.

   [ONF-2016] Paul, M, Schallen, S., Betts, M., Hood, D., Shirazipor,
              M., Lopes, D., Kaippallimalit, J., - Open Network
              Fundation document "Applying SDN Architecture to 5G
              Slicing", Open Network Fundation, April 2016,
              <https://www.opennetworking.org/images/stories/downloads/
              sdn-resources/technical-reports/
              Applying_SDN_Architecture_to_5G_Slicing_TR-526.pdf>.

   [5G-ICN] Ravi Ravindran, Asit Chakraborti, Syed Obaid Amin, Aytac
              Azgin, G.Q.Wang, "5G-ICN: Delivering ICN Services in 5G
              using Network Slicing", IEEE Communication Magazine, May,
              2017.

   [GRAMMATIKOU-2012] Grammatikou, M; Marinos, C; Martinez-Julia, P;
              Jofre, J; Gheorghiu, S; et al. Proceedings of the
              International Conference on Parallel and Distributed
              Processing Techniques and Applications (PDPTA); Athens: 1-
              5. Athens: The Steering Committee of The World Congress in
              Computer Science, Computer Engineering and Applied
              Computing (WorldComp). (2012)

   [GAL]  A. Galis, Chih-Lin I" Towards 5G Network Slicing - Motivation
              and Challenges" IEEE 5G Tech Focus, Volume 1, Number 1,
              March 2017 - http://5g.ieee.org/tech-focus/march-
              2017#networkslicing

   [GAPS] "Gap Analysis for Network Slicing" draft-qiang-netslices-gap-
              analysis-01

   [NS UseCases] "Network Slicing Use Cases: Network Customization for
              different services" draft-makhijani-netslices-usecase-
              customization-03

   [NS ARCH] "Network Slicing Architecture" draft-geng-netslices-
              architecture-02

Authors' Addresses


      Alex Galis



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      University College London
      Email: a.galis@ucl.ac.uk

      Luis Miguel Contreras Murillo
      Telefonica
      Email: luismiguel.contrerasmurillo@telefonica.com

      Liang Geng
      China Mobile
      Email: gengliang@chinamobile.com

      Slawomir Kuklinski
      Orange Polska
      Email: slawomir.kuklinski@orange.com

      Kiran Makhijani
      Huawei Technologies
      Email: kiran.makhijani@huawei.com

      Li Qiang
      Huawei Technologies
      Email: qiangli3@huawei.com

      Hannu Flinck
      Nokia
      Email: hannu.flinck@nokia-bell-labs.com

      Reza Rokui
      Nokia
      Email: reza.rokui@nokia.com

      Pedro Martinez-Julia
      National Institute of Information and Communications Technology
      (NICT)
      Email: pedro@nict.go.jp

      Christian Rothenberg
      University of Campinas (Unicamp)
      Email: chesteve@dca.fee.unicamp.br

      Joan Serrat
      Universitat Politecnica de Catalunya (UPC)
      Email: serrat@tsc.upc.edu

      Stuart Clayman
      University College London (UCL)
      Email: s.clayman@ucl.ac.uk




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      Francesco Tusa
      University College London (UCL)
      Email: francesco.tusa@ucl.ac.uk
















































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