[Docs] [txt|pdf] [Tracker] [Email] [Diff1] [Diff2] [Nits]

Versions: 00 01

No Working Group                                       A. Galis (editor)
Internet-Draft                                 University College London
Intended Status: Informational                                    et al.
Expires: January 3, 2018                                    July 3, 2017


              Network Slicing - Revised Problem Statement
           draft-galis-netslices-revised-problem-statement-01

Abstract

   This document introduces Network Slicing problems and the motivation
   for new work areas. It represents an initial revision of the 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 to
   achieve certain aspects of Network Slicing 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
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://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 January 2, 2018.

Copyright Notice

   Copyright (c) 2017 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
   (http://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 Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as



Galis, et al.           Expires January 3, 2018                 [Page 1]


INTERNET DRAFT Network Slicing Revised Problem Statement       July 2017


   described in the Simplified BSD License.

Table of Contents

   1  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . .  3
     1.1 Network Slicing Value Characteristics  . . . . . . . . . . .  4
     1.2 Network Slicing Work Scope . . . . . . . . . . . . . . . . .  5
     1.3 Notes  . . . . . . . . . . . . . . . . . . . . . . . . . . .  7
   2. Network Slicing - Selected Problems and Work Areas  . . . . . .  7
     2.1 Global Issues - Problems (GP)  . . . . . . . . . . . . . . .  7
       2.1.1 Problem GI1: Uniform Reference Model (***) . . . . . . .  7
       2.1.2 Problem GI2: Requirements for operations and
             interactions (**)  . . . . . . . . . . . . . . . . . . .  8
       2.1.3 Problem GI3: Slice Templates (***) . . . . . . . . . . .  9
     2.2 Network Slice Capabilities - Problems (NSC)  . . . . . . . . 10
       2.2.1 Problem NSC1: Guarantees for isolation  (***)  . . . . . 10
       2.2.2 Problem NSC2: Fulfilling diverse requirements (*)  . . . 10
       2.2.3 Problem NSC3: Efficiency in slicing (*)  . . . . . . . . 11
       2.2.4 Problem NSC4: Slice Recursion (**) . . . . . . . . . . . 11
       2.2.5 Problem NSC5: Customized security mechanisms per slice
             (*)  . . . . . . . . . . . . . . . . . . . . . . . . . . 12
       2.2.6 Problem NSC6: flexibility and efficiency trade-offs
             (*)  . . . . . . . . . . . . . . . . . . . . . . . . . . 12
       2.2.7 Problem NSC7: Optimisation  (**) . . . . . . . . . . . . 12
       2.2.8 Problem NSC8: Monitoring and Discovery (**)  . . . . . . 13
       2.2.9 Problem NSC9: Capability exposure and APIs (***) . . . . 13
       2.2.10 Problem NSC10: Programmability of Operations of
              Network Slices (**) . . . . . . . . . . . . . . . . . . 14
     2.3 Network Slice Operations - Problems (NSO)  . . . . . . . . . 15
       2.3.1 Problem NSO1: Slice life cycle management  (***) . . . . 15
       2.3.2 Problem NSO2: Autonomic slice management and operation
             (**) . . . . . . . . . . . . . . . . . . . . . . . . . . 15
       2.3.3 Problem NSO3 - Slice stitching / composition (***) . . . 16
       2.3.4 Problem NSO4: E2E Network Orchestration (***)  . . . . . 17
       2.3.5 Problem NSO5: Service Mapping in a single domain and
             Cross-Domain Coordination (***)  . . . . . . . . . . . . 18
       2.3.6 Problem NSO6: Roles in Network Slicing (*) . . . . . . . 18
       2.3.7 Problem NSO7: Efficient enablers and methods for
             integration (*)  . . . . . . . . . . . . . . . . . . . . 19
     2.4 Notes  . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
   3. OAM Operation with Customized Granularity . . . . . . . . . . . 21
   4 Summary  . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
   5  Security Considerations . . . . . . . . . . . . . . . . . . . . 23
   6  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 23
   7 Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 23
   8  References  . . . . . . . . . . . . . . . . . . . . . . . . . . 23
     7.1 IETF References  . . . . . . . . . . . . . . . . . . . . . . 23
     7.2  Informative References  . . . . . . . . . . . . . . . . . . 26



Galis, et al.           Expires January 3, 2018                 [Page 2]


INTERNET DRAFT Network Slicing Revised Problem Statement       July 2017


   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 27


1  Introduction

   Network slicing (NS) is an approach of flexible isolation and
   allocation of network resources and network functions for a network
   instance, providing high level of customization and quality service
   guarantee. It transform 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 in support of a variety
   of services.

   Network slicing enables at a given time the dynamic creation of
   multiple, parallel sub-networks of different features by flexible
   isolation of allocated to a slice network resources and network
   functions and providing high level of customization and quality
   guarantee.

   The management plane allocates the grouping of network resources
   (whereby 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 the slice. On the
   other hand, for slice operations, the slice control 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.

   Allocation of traffic flows to slices as may be based on simple rules
   (relying on a subset of the transport coordinate, DSCP/traffic class,
   or flow label), or may be a more sophisticated one (to be further
   defined) such as enabling new slice specific constructs in the data
   plane. Also, the flows to slice allocation rules that are specified
   for a slice can be changed dynamically, based on some events (e.g.
   triggered by a service request). The slice control plane is
   responsible for instructing the involved elements to honor such



Galis, et al.           Expires January 3, 2018                 [Page 3]


INTERNET DRAFT Network Slicing Revised Problem Statement       July 2017


   needs.

   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 significant
   reduction of the operations expenditure. In addition, there is a
   enabling link between NS and softwarization. On 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 realise 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. NS enables
   the concurrent deployment of multiple logical, self-contained and
   independent, shared or partitioned networks on a common
   infrastructure. Slices may support dynamic multiple services, multi-
   tenancy, and the integration means for vertical market players (e.g.
   automotive industry, energy industry, healthcare industry, media and
   entertainment industry, etc.)

   Please refer to [I-D.geng-netslices-architecture] for related
   terminologies and definitions.

1.1 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
   key value-added characteristics of Network Slicing and corresponding
   usage are identified:

      * Network Slice is a dedicated network that is build on an
        infrastructure mainly composed of, but not limited to,
        connectivity, storage and computing.
      * Each network slice has the ability to dynamically expose and
        possibly negotiate the parameters that characterize an NS.
      * Each network slice will have its own operator 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).
      * Network slicing support tenants that are strongly independent on
        infrastructure.
      * A Network Slicing aware infrastructure allows operators to use
        part of the network resources to meet stringent resource



Galis, et al.           Expires January 3, 2018                 [Page 4]


INTERNET DRAFT Network Slicing Revised Problem Statement       July 2017


        requirements
      * 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.
      * 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
        and capability exposure).
      * Network slices are dynamically and non-disruptively
        reprovisioned
      * Network slices will need to be 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)
      * 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 behaviour of the network slice
        realized via network slice instance(s).
      * Network slices are concurrently deployed as multiple logical,
        self-contained and independent, partitioned network functions
        and resources on a common physical infrastructure.
      * Network slicing supports dynamic multi-services, multi-tenancy
        and the means for backing vertical market players.
      * Network slicing simplifies the provisioning of services
        manageability of networks and integration and operational
        challenges especially for supporting. communication services.
      * Network slicing offers native service customization enabled by
        the selection and configuration of network functions for
        coordinating/orchestration and control of network resource.
      * Network slicing considerably transforms the networking
        perspective by abstracting, isolating, orchestrating and
        separating logical network behaviors from the underlying
        physical network resources


1.2 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 creation,
   activation / deactivation, composition, elasticity,
   coordination/orchestration, management, isolation, guaranteed SLA,
   and safe and secure operations within a connectivity network or
   network cloud / data centre environment that assumes an IP and/or



Galis, et al.           Expires January 3, 2018                 [Page 5]


INTERNET DRAFT Network Slicing Revised Problem Statement       July 2017


   MPLS-based underlay.

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

      * Underlay tenet: support for an IP/MPLS-based underlay data
        plane.
      * Governance tenet: a logically centralized authority for network
        slices in a domain.
      * Separation tenet: slices may be virtually or physically
        independent of each other and have an appropriate degree of
        isolation (note 1) from each other.
      * 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 the 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 an 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 optimisation; independent multi-
   topology routing; multi-tenant operations; new network architecture
   enablement, etc.



Galis, et al.           Expires January 3, 2018                 [Page 6]


INTERNET DRAFT Network Slicing Revised Problem Statement       July 2017


   The proposed NS work 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), Network Management Research Group
   (NMRG) and NFV Research Group (NFVRG)) 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.

1.3 Notes

      (1) This issue requires efficient interaction between an upper
          layer in the hierarchy and a lower layer for QoS guarantees
          and for most of the operations on slicing.

2. 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 IETF protocols ecosystem. Each problem is
   associated with one identified IETF gap (draft-qiang-netslices-gap-
   analysis-01). In addition an initial priority level is attached to
   each problem. [(***) high priority, (**) medium priority and (*) low
   priority]. The proposed WG charter would include at least the high
   priority problems.

2.1 Global Issues - Problems (GP)

2.1.1 Problem GI1: Uniform Reference Model (***)

   Related Identified IETF Gap: "A detailed specification of Network
   Slicing Specification".

   Uniform Reference Model for Network Slicing (Architecture document):

      * Description of all of the functional elements required for
        network slicing.
      * Description of shared non-sliced network parts. Establishes the
        boundaries to the basic network slice operations (creation,
        management, exposure, consumption).
      * Describes the minimum functional roles derived from basic
        network slice operations including infrastructure owner
        (creation, exposure, management), slice operator (exposure,
        management, consumption), slice customer (management,
        consumption). Describe the interactions between infrastructure
        owner <-> slice operator, slice operator <-> slice operator,
        slice operator <-> slice customer.



Galis, et al.           Expires January 3, 2018                 [Page 7]


INTERNET DRAFT Network Slicing Revised Problem Statement       July 2017


      * Additionally, this working area will normalize nomenclature and
        definitions for Network Slicing.

   Short explanation: A uniform definition and architecture of Network
   slicing is presented in the NS Architecture draft. A Network slice is
   a managed group of subsets of resources, network functions/network
   virtual functions at the data, control, management/orchestration
   planes and services at a given time. Network slice is programmable
   and has the ability to expose its capabilities. The behaviour of the
   network slice realized via network slice instance(s).

    (1) The Service Instance Component represents the end-user service
        or business services. An instance of an end-user service or a
        business service that is realized within or by a NS. Would be
        provided by the network operator or by 3rd parties.
    (2) A Network Slice Instance component
          a. Represented by a set of network functions, virtual network
             functions and resources at a given time
          b. Forms a complete instantiated logical network to meet
             certain network characteristics required by the Service
             Instance(s).
          c. Provides network characteristics which are required by a
             Service Instance.
          d. May also be shared across multiple Service Instances
    (3) Resources component - it includes: Physical, Logical & Virtual
        resources
          a. Physical & Logical resources - An independently manageable
             partition of a physical resource, which inherits the same
             characteristics as the physical resource and whose
             capability is bound to the capability of the physical
             resource. It is dedicated to a Network Function or shared
             between a set of Network Functions.
          b. Virtual resources - An abstraction of a physical or logical
             resource, which may have different characteristics from
             that resource, and whose capability may not be bound to the
             capability of that resource.
    (4) Slice Element Manager (SEM) and Capability exposure component
          a. Slice Element Manager (SEM) is instantiated in each Network
             Slice and it manages all access permissions and all
             interaction between a Network Slice and external functions
             (i.e. other Network Slices, Orchestrators, etc). Each SEM
             converts requirements from orchestrator into virtual
             resources and manages
   Consolidation and versification of the above definition is required.
   New protocols are needed for the creation, for discovery and for
   orchestrating network slicing.

2.1.2 Problem GI2: Requirements for operations and interactions (**)



Galis, et al.           Expires January 3, 2018                 [Page 8]


INTERNET DRAFT Network Slicing Revised Problem Statement       July 2017


   Related Identified IETF Gap: "A detailed specification of Network
   Slicing Specification".

   Review common scenarios from the requirements for operations and
   interactions point of view. Describes the roles (owner, operator,
   user) which are played by entities with single /multiple entities
   playing different roles.

   Short explanation: Review of the functional and non- functional NS
   requirements is needed to ensure that resource utilization is
   maximized and infrastructure costs are minimized as services will
   need to operate over a union of shared network infrastructures, as
   against the traditional monolithic model operated either as dedicated
   network or as an overlay.

2.1.3 Problem GI3: Slice Templates (***)

   Related Identified IETF Gap: "A detailed specification of Network
   Slicing Specification".

   Design the slices to different scenarios [ChinaCom-2009], [GENI-
   2009], [IMT2020-2016bis], [NGMN-2016], [NGS-3GPP-2016], [ONF-2016]);
   Outlines an appropriate slice template definition that may include
   capability exposure of managed partitions of network resources (i.e.
   connectivity ([CPP]), 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.

   Short explanation: A network slice template based on uniform
   reference model would enable the creation of a network slice
   instance. A template defines an abstraction of the overall network
   resources and functions requirement for a particular network slice
   instance. Different templates can also be regarded as definitions of
   individual network slice types. Besides the reference model for
   network resources and functions, each template has a complete
   description of the structure, configuration and the plans/work flows
   for how a certain type of network slice instance should be
   instantiated and managed during its life cycle.

   There should be a clear definition of the level of abstraction of the
   network slice template according to the arrangement and specification
   of network slice life cycle management system. A valid network slice
   instance profile created based on specific network slice template is
   going to be decomposed into configuration profiles to certain OAM
   domains for the purpose of network slice instance creation.

   The creation of a specific network slice template strictly relies on
   the exposed network capabilities. The network slice life cycle



Galis, et al.           Expires January 3, 2018                 [Page 9]


INTERNET DRAFT Network Slicing Revised Problem Statement       July 2017


   management system should not allow a template with parameters
   exceeding the capabilities to be created.

2.2 Network Slice Capabilities - Problems (NSC)

2.2.1 Problem NSC1: Guarantees for isolation  (***)

   Related Identified IETF Gap: "Slicing specific extension on
   Isolation".

   Four-dimensional efficient slice creation with guarantees for
   isolation in each of the Data /Control /Management /Service planes.
   Enablers for safe, secure and efficient multi-tenancy in slices.

   Short explanation: Network slices MUST support multi-tenancy,
   ensuring that isolation and performance guarantees are provided at
   the data, control, management and service planes. This involves the
   following:

      * A network slice SHOULD provide a guaranteed level of service,
        according to a negotiated SLA between the customer and the slice
        provider
      * Slices MUST be isolated at service level (e.g., one slice must
        not impact on the level of service of the other slides, even if
        sharing resources).
      * Slices MUST be isolated at data level, even if sharing
        resources. Security and privacy mechanisms should be in place to
        ensure this.
      * A network slice SHOULD be provided with exclusive control and/or
        management interfaces (depending on the type of network slice),
        enabling the deployment of different logical network slices over
        shared resources.

2.2.2 Problem NSC2: Fulfilling diverse requirements (*)

   Related Identified IETF Gap: "A detailed specification of Network
   Slicing Specification".

   Methods to enable diverse requirements for NS including guarantee for
   the end-to-end QoS of service in a slice.

   Short explanation: The main goal of fulfilling NS requirements is to
   ensure that service operators can utilize or benefit from Network
   Slicing through multi-tenancy, enabling different customized
   infrastructures for different group of services across different
   network segments and operating them independently. It includes the
   tasks that go into determining the needs or conditions to meet for NS
   systems, taking account of the possibly conflicting requirements of



Galis, et al.           Expires January 3, 2018                [Page 10]


INTERNET DRAFT Network Slicing Revised Problem Statement       July 2017


   the various stakeholders and a prioritisation of requirements. New
   protocols are needed for interoperability between diverse type of
   network slices which are fulfilling diverse requirements

2.2.3 Problem NSC3: Efficiency in slicing (*)

   Related Identified IETF Gap: "A detailed specification of Network
   Slicing Specification".

   Specifying policies and methods to realize diverse requirements
   without re-engineering the infrastructure.

   Short explanation: This item is deployment-specific and cannot be
   promised as a problem to be solved entirely by protocols. An
   underlying infrastructure will always be needed to be reengineered
   and maintained to support up-to-date technologies and emerging
   requirements (including instantiating new service functions or
   withdrawing service functions, adding new nodes to absorb for
   traffic, ...). It is a local decision to figure out whether many
   services will be bound to the same slice, how many slices are to be
   instantiated and so on. Exposing standard interfaces to capture
   requirements will help to rationale the use of resources and how the
   requirements are fulfilled, however it is a challenge to guarantee in
   an absolute manner that slicing allows "diverse requirements without
   re-engineering the infrastructure".


2.2.4 Problem NSC4: Slice Recursion (**)

   Related Identified IETF Gap: "A detailed specification of Network
   Slicing Specification".

   Short explanation: Recursion is a property of some functional blocks:
   a larger functional block can be created by aggregating a number of a
   smaller functional block and interconnecting them with a specific
   topology. As such recursive network slice definition is defined as
   the ability to build a new network slice out of existing network
   slice (s). A certain resource or network function /virtual network
   function could scale recursively, meaning that a certain pattern
   could replace part of itself. This leads to a more elastic network
   slice definition, where a network slice template, describing the
   functionality, can be filled by a specific pattern or implementation,
   depending on the required performance, required QoS or available
   infrastructure.

   New protocols are needed for use of network slice template
   segmentation allowing a slicing hierarchy with parent - child
   relationships.



Galis, et al.           Expires January 3, 2018                [Page 11]


INTERNET DRAFT Network Slicing Revised Problem Statement       July 2017


2.2.5 Problem NSC5: Customized security mechanisms per slice (*)

   Related Identified IETF Gap: "Mechanisms for customized granularity
   OAM (Operations, Administration, and Maintenance)".

   Short explanation: Customized securing mechanisms will be needed on a
   per slice basis. This may be provided by enabling dedicated service
   functions. For such cases, SFC techniques can be used here.
   Soliciting distinct SFs per slice can be provided with existing
   tools. I don't see a new problem out there.

   This may be provided by configuring dedicated policies in a given
   security service function. In such case, I2NSF techniques can be used
   to interact with a given service function.

   Traffic isolation may be needed for some services. Legacy tools can
   be used. I'm not sure if there is specific work specific to slicing
   other than making sure that appropriate flows are grafted to the
   appropriate slice and no data leaking between slices is to happen.

2.2.6 Problem NSC6: flexibility and efficiency trade-offs (*)

   Related Identified IETF Gap: "A detailed specification of Network
   Slicing Specification".

   Methods and policies to manage the trade-offs between flexibility and
   efficiency in slicing.

   Short explanation: Mechanisms SHOULD be in place to allow different
   levels of flexibility when providing network slices: from the ones
   that provided greater levels of flexibility in the provided resources
   and services that compound the slice, allowing to dynamically
   change/scale/migrate it over time within a negotiated range, to the
   ones that ensure the efficiency of the use of the resources at the
   cost of a smaller degree of flexibility.

2.2.7 Problem NSC7: Optimisation  (**)

   Related Identified IETF Gap: "non-overlay OAM solution".

   Methods for network resources automatic selection for NS; global
   resource view formed; global energy view formed; Network Slice
   deployed based on global resource and energy efficiency; Mapping
   protocols.

   Short explanation: NS optimization includes methods which enable that
   resources utilization is monitored and maximize, that infrastructure
   operational costs are minimized and that QoS are managed and



Galis, et al.           Expires January 3, 2018                [Page 12]


INTERNET DRAFT Network Slicing Revised Problem Statement       July 2017


   maximized at the time of creation of network slice instance and well
   as during NS operation.

2.2.8 Problem NSC8: Monitoring and Discovery (**)

   Related Identified IETF Gap: "Mechanisms for dynamic discovery of
   service with function instances and their capabilities".

   Monitoring status and behaviour of NS in a single and/or muti-domain
   environment; NS interconnection.

   Short explanation: A Network slice is a managed group of subsets of
   resources, network functions / network virtual functions at the data,
   control, management/orchestration planes and services at a given
   time. Monitoring of slices interacts with and it is part of the NS
   Lifecycle management to aiming at reporting the performance of the
   running NS. As input, the Monitoring Subsystem receives the detailed
   service monitoring requests with references to resource allocation
   and Network functions instances in a NS. The Monitoring Subsystem is
   responsible for the monitoring continuously the state all 4
   components of a NS (Service Instance component, Network Slice
   Instance component, Resources component). New protocols are needed
   for discovery and monitoring probes of all NS components and NS
   itself itself and for dynamic discovery of service with function
   instances and their capability.

2.2.9 Problem NSC9: Capability exposure and APIs (***)

   Related Identified IETF Gap: "A detailed specification of Network
   Slicing Specification".

   Capability exposure for NS; plus APIs for slices

   Short explanation: To exploit the flexibility offered by network
   slices their users (customers, overlying operators) would need to
   know the features offered by both individual resources and complete
   slices. This means that there must be interfaces to deliver such
   information to the entity that needs it, but that will be also
   transitively delivered to the following chains of the slicing
   structure towards the final users.

   To this sense, there are two specific interfaces that must be defined
   to address such function:
      * The bottom-up interface, offered by underlying resource
        providers to resource consumers (operators) of any layer.
      * The top-down interface, offered by overlying operators to lower
        level providers.




Galis, et al.           Expires January 3, 2018                [Page 13]


INTERNET DRAFT Network Slicing Revised Problem Statement       July 2017


   On the one hand, the first interface will, obviously, enable slice
   operators to access the slices owned by underlying providers and
   manage the resources they have been assigned in them. On the other
   hand, the second interface will enable lower layers to know details
   about the resources managed by overlying operators and the
   requirements they impose to the overlying network slices.

   In this respect, both interfaces will emphasize the relation among
   the original resources, as well as the links from them to the
   resulting resources. This forms the main key of their management
   operations.

2.2.10 Problem NSC10: Programmability of Operations of Network Slices
   (**)

   Related Identified IETF Gap: "Mechanisms for customized granularity
   OAM (Operations, Administration, and Maintenance)".

   Short explanation: Network slice operations consist of all operations
   related to life cycle management of a slice and its optimized
   operation. Slice instance lifecycle management includes all
   operations related to slice instance creation, activation, update and
   deactivation. All these operations are automated and driven by
   appropriate policies. A slice instance is created according to a
   slice template and related policies. A unique identifier is assigned
   to each slice after its creation and a list of active slice instances
   are stored in slice repository. Several slice types are predefined
   which describe their functions as access, core, transport, data
   center and edge cloud slices. As example to each slice instance a
   Slice Priority parameter is assigned which describe the way of
   handling of slice degradation in case of lack of resources that can
   be allocated to slices. The parameter is also used in emergency
   situations in which there is a need to release resources from
   existing slices and to allocate them to newly created slices that are
   used for emergency situation handling.

   The end-to-end slice can be a composition of per administrative or
   technological domain slices that are created according to their local
   templates. The process of slice creation can be recursive. The slice
   level are split between slice operator and slice tenant. The slice
   tenant obtains information about slices related KPIs and is
   expressing his reconfiguration wills as intents (high level
   policies), which are implemented in an automated manner by slice
   control and management planes. The slice operator is responsible for
   slice lifecycle and slice FCAPS handling. During operations of slice
   the slice resources are allocated in a dynamic way in order to
   provide required performance but in an economical way.




Galis, et al.           Expires January 3, 2018                [Page 14]


INTERNET DRAFT Network Slicing Revised Problem Statement       July 2017


   Each network slice exhibits following features: protection (note 2),
   elasticity (note 3), extensibility (note 4) and safety (note 5).

2.3 Network Slice Operations - Problems (NSO)

2.3.1 Problem NSO1: Slice life cycle management  (***)

   Related Identified IETF Gap: "non-overlay OAM solution".

   Slice life cycle management including creation, activation /
   deactivation, protection (note 2), elasticity (note 3), extensibility
   (note 4), safety (note 5), sizing and scalability of the slicing
   model per network and per network cloud: slices in access, core and
   transport networks; slices in data centres, slices in edge clouds.

   Short explanation: Network slicing enables the operator to create
   logically partitioned networks at a given time customized to provide
   optimized services for different market scenarios. These scenarios
   demand diverse requirements in terms of service characteristics,
   required customized network and virtual network functionality (at the
   data, control, management planes), required network resources,
   performance, isolation, elasticity and QoS issues. A network slice is
   created only with the necessary network functions and network
   resources at a given time. They are gathered from a complete set of
   resources and network /virtual network functions and orchestrated for
   the particular services and purposes.

   New protocols are needed for realising full Slice life cycle
   management at two distinct levels:
    (1) "network slice life-cycle management level" (i.e. the series of
        state of functional activities through which a network slice
        passes: creation, operation, deletion) and
    (2) "network slice instances level" (activated network slice
        level).

   Functions for creating and managing network slice instances and the
   functions instantiated in the network slice instance are mapped to
   respective framework level.


2.3.2 Problem NSO2: Autonomic slice management and operation (**)

   Related Identified IETF Gap: "non-overlay OAM solution".

   It incudes self-configuration, self-composition, self-monitoring,
   self-optimisation, self-elasticity are carried as part of the slice
   protocols.




Galis, et al.           Expires January 3, 2018                [Page 15]


INTERNET DRAFT Network Slicing Revised Problem Statement       July 2017


   Short explanation: Network slice is a dynamic entity which lifecycle
   and operations should be automated. There are 3 main reasons of this
   automation:
    (1) There is an expectation that the number of slice instances can
        be huge what rises the problem of management scalability if it
        is performed in a classical, manual way.
    (2) Network slice instances can be created on demand by the end-
        users or verticals. They may play a role of slice instance
        administrator (making some reconfigurations or monitoring slice
        performance. It is however not expected that such administrator
        will have required experience and tools related to slice
        instance management. They can express some high-level requests
        that has to be translated into low level operations
    (3) Multiple network slice instances have to share common resources
        in economical way but with preserving required performance
        indicators. The problem of allocation of resources between
        slices combined with real-time optimization of slice operations
        can be only solved by continuous monitoring of slice performance
        and making continuous adaptations of resources allocated to
        them.

   The mentioned reasons call for autonomic management which part should
   be autonomic management of each slice and autonomic management of
   resources that are allocated to slices. The autonomic operations at
   the slice instance level comprise of self-configuration, self-
   composition, efficient self-monitoring, self-healing and real-time
   optimization (self-optimisation) as a part of the autonomic
   management framework.

2.3.3 Problem NSO3 - Slice stitching / composition (***)

   Related Identified IETF Gap: "non-overlay OAM solution".

   Having enablers and methods for efficient stitching /composition/
   decomposition of slices:
      * vertically (service + management + control planes) and/or
      * horizontally (between different domains part of access, core,
        edge segments) and /or
      * vertically + horizontally.


   Short explanation: Slice stitching. The network slice has to provide
   end-to-end communication and services. In some cases such end-to-end
   network slice instance can be created directly but in multi-domain
   environment the end-to slice will be a composition of slices of
   different domains in the each network segments (i.e. access, core,
   edge, transport, etc.). In such a case the domain slices will be
   created and maintained using domain specific slice templates and use



Galis, et al.           Expires January 3, 2018                [Page 16]


INTERNET DRAFT Network Slicing Revised Problem Statement       July 2017


   domain specific operations and all the domain slicing will be
   stitched together horizontally. The operation is supported by
   appropriate descriptions of domain slices, exchange of slice related
   policies between domains. Slice stitching operations are supported by
   uniform slice descriptors and appropriate matching of them. Each
   slices has appropriate set of mechanisms (slice border control
   functions) that support horizontal stitching of slices.

   The vertical stitching of slices is an operation that modifies
   functionality of existing slice by adding and merging of functions of
   another slice (i.e. enhancing control plane properties be functions
   defined in another slice template). In general the vertical stitching
   of slices is used to enrich slice services.

   Slices will be recursively used as components in software
   architectures. This means that several slices will be able to be used
   together to build a "composite network service" that inherits the
   capabilities of the original slices. The recursive property means
   that both slices and derived composite services can be again "split"
   into pieces to form new slices. The straight result of this aspect is
   that complex services are highly simplified by "stitching" slices
   and/or part of them, achieving the actual complexity by exploiting
   layering, which is the de-facto standard composition capability
   typically mapped into network architectures, but also by exploiting
   the abstraction levels offered by network service composability.

   However, to hide such complexity and thus achieve the intended
   abstraction, the network architecture (and slicing reference model)
   must include, adopt, and promote the deployment of the necessary
   mechanisms and functions that support slice stitching and network
   service composability.

2.3.4 Problem NSO4: E2E Network Orchestration (***)

   Related Identified IETF Gap: "non-overlay OAM solution (Operations,
   Administration, and Maintenance) solution".

   End-to-end network segments orchestration of slices ([GUERZONI-2016],
   [KARL-2016]).

   Short explanation: Network service composition has demonstrated to be
   highly beneficial for both operators and final users [GRAMMATIKOU-
   2012]. It allows the formation of large number of different services,
   which will be specialized to the particular needs of a user or a
   specific situation. However, the current network architecture is far
   for being ideal to implement such function.

   One of the keys of network slicing is the flexibility it adds to the



Galis, et al.           Expires January 3, 2018                [Page 17]


INTERNET DRAFT Network Slicing Revised Problem Statement       July 2017


   network and the resulting "de-ossification" of network resources.
   Thus, this environment is much more optimal to allow the
   proliferation of network service composition, but it means that some
   sort of specific requirements must be pushed towards the architecture
   that supports the general slicing.

   First, a proper composable network service model needs network
   resources to be compatible, regardless of the domain to which they
   pertain. Then they must be homogeneously described, so a user can
   actually understand their individual capabilities and "draw" the
   service they want to build by combining them. Finally, the resources
   living among separated network slices must be "connectable" to each
   other. This means that they must cross the domain of their
   providers/owners in order to reach their destination.

   New protocols are needed for full end to end orchestration between
   the layers, from the IP layer and up.

2.3.5 Problem NSO5: Service Mapping in a single domain and Cross-Domain
   Coordination (***)

   Related Identified IETF Gap: "Companion YANG data model for network
   slicing - single domain and Cross-Domain Coordination".

   Having dynamic and Automatic Mapping of Services to slices; YANG
   models for slices.

   Short Description: The main goal of the service mapping framework is
   to enable on-demand processing anywhere in the physically distributed
   network, with dynamic and fine granular service (re-)provisioning,
   which can hide significant part of the resource management complexity
   from service providers and users, hence allowing them to focus on
   service and application innovation. It include a slice-aware YANG
   information model based on necessary connectivity, storage, compute
   resources, network functions, capabilities exposed and service
   elements in a single domain as well as Cross-Domain Coordination. As
   such the service mapping participates in management of the network
   slices.

2.3.6 Problem NSO6: Roles in Network Slicing (*)

   Related Identified IETF Gap: "Detailed specification of Network
   Slicing  Specification".

   Enablers and methods for the above mentioned capabilities and
   operations from different viewpoints on slices (note 6).

   Short explanation:  Several viewpoints emerge from the global and



Galis, et al.           Expires January 3, 2018                [Page 18]


INTERNET DRAFT Network Slicing Revised Problem Statement       July 2017


   wide interaction among the Network Infrastructure Owner (NIO),
   Network Slice Provider (NSP), and Network Slice Tenant(NST), and they
   must be treated by network slicing to ensure their use cases are
   correctly covered. They are:

      - NIO <=> NSP:
          + NIO offers the physical infrastructure to NSP, and NSP
            creates and manages the "slice" of network resources.
          + NSP interacts vertically to request and instantiate (embed)
            composite network services onto the underlying physical
            infrastructures.
          + NSP can possibly act as NIO.

      - NSP <=> NST:
          + NSP offers the individual objects/resources obtained after
            slicing the physical infrastructure to the NST.
          + NST requests to the NSP the necessary CRUD (Create,
            Retrieve, Update, Delete) operations on its own Network
            Slices.

      - NSP <=> NSP:
          + Allows inter-provider tasks (e.g. migration of resources or
            whole slices among providers.
          + Organizes the interoperability levels among Network Slices
            managed  by different providers.
          + Facilitates the recursive slicing, so a new NSP slices the
            resources offered by other NSP.

        - NIO <=> NIO:
          + Horizontal communication between owners to coordinate the
            required interactions among physical infrastructure
            resources, and/or the migration of whole slices among
            different NIOs.
          + It may be common for NIO to provide network infrastructures
            to NSP in an old-fashion way where no network slicing is
            concerned.

   However, a NIO may become a double role of NIO+NSP once it provides
   NSaaS.

   Any NSP can become a NST if it uses specific network slice instance
   for a particular service, or it purchase NSaaS from another NSP.

2.3.7 Problem NSO7: Efficient enablers and methods for integration (*)

   Related Identified IETF Gap: "non-overlay OAM solution".

   Efficient enablers and methods for integration of above capabilities



Galis, et al.           Expires January 3, 2018                [Page 19]


INTERNET DRAFT Network Slicing Revised Problem Statement       July 2017


   and operations.

   Short explanation: In order to enable the above required capabilities
   and operation for network slicing, well defined reference points
   among the involved actors and entities are required, as well as the
   proper interface definitions ensuring interoperability of all
   involved pieces. Some examples of the required reference
   points/interfaces include:

   Customer/Vertical (user of the slice) - Network Slice Provider. The
   user of the slice SHOULD be able to specify the characteristics of
   the slide and provide it in a suitable/understandable format to the
   NSP. A proper information model is needed to convey the customer
   slice requirements. And the model might need to support different
   levels of abstraction, to support different use cases.

   Network Slice Provider - Network Slice Provider / Network Slice
   Operator / Network Service Provider. The slice provider MUST be able
   to request resources to compose a slice to other slice providers,
   slice operator or service operators. The interface needs to support
   recursiveness and different levels of abstraction (the request might
   involve resources or services).

   Inter-domain interactions at different levels. Another way of
   composing a slice is by interaction of players at the same level
   (peering, instead of recursive), by delegating the request to other
   provides/operators. This type of interaction can take place at
   different levels (resource, network service, etc), and therefore
   would impose different requirements. In all cases, security issues
   are key due to the inter-operator nature.


2.4 Notes

      (1) Protection refers to the related mechanisms so that events
          within one slice, such as congestion, do not have a negative
          impact on another slice.

      (2) Elasticity refers to the mechanisms and triggers for the
          growth/shrinkage of network resources, and/or network and
          service functions.

      (3) Extensibility refers to the ability to expand a NS with
          additional functionality and/or characteristics, or through
          the modification of existing functionality/characteristics,
          while minimizing impact to existing functions.

      (4) Safety refers to the conditions of being protected against



Galis, et al.           Expires January 3, 2018                [Page 20]


INTERNET DRAFT Network Slicing Revised Problem Statement       July 2017


          different types and the consequences of failure, error harm or
          any other event, which could be considered non-desirable.

      (5) Multiple viewpoints on slices: I) viewpoint of the slice's
          owner towards user: from this viewpoint a slice is defined as
          a means to "split" physical or virtual infrastructure elements
          to "service" smaller portions. This action would be
          recursively done from the owner of the initial and physical
          infrastructure element to the users. II) viewpoint of from the
          user towards the physical infrastructure owner. From this
          viewpoint a slice is viewed just as a set of resources that
          must be managed (requests to a provider, listed, changed,
          returned to the provider, etc.). This viewpoint emphasizes
          those issues that would be used in the SLA definition of a
          slice.


3. OAM Operation with Customized Granularity

   In accordance with [RFC6291], OAM is used to denote the following:

      * Operations: refer to activities that are undertaken to keep the
        network and the services it deliver up and running. It includes
        monitoring the underlying resources and identifying problems.
      * Administration: refer to activities to keep track of resources
        within the network and how they are used.
      * Maintenance: refer to activities to facilitate repairs and
        upgrades. Maintenance also involves corrective and preventive
        measures to make the managed network run more effectively, e.g.,
        adjusting configuration and parameters.

   As per [RFC6291], NetSlices provisioning operations are not
   considered as part of OAM. Provisioning operations are discussed in
   other sections. Maintaining automatically-provisioned slices within a
   network raises the following requirements:

      * Ability to run OAM activities on a provider's customized
        granularity level. In other words, ability to run OAM activities
        at any level of granularity that a service provider see fit. In
        particular:
          - An operator must be able to execute OAM tasks on a per slice
            basis.
          - These tasks can cover the "whole" slice within a domain or
            portion of that slice (for troubleshooting purposes, for
            example).
          - For example, OAM tasks can consist in tracing resources that
            are bound to a given slice, tracing resources that are
            invoked when forwarding a given flow bound to a given



Galis, et al.           Expires January 3, 2018                [Page 21]


INTERNET DRAFT Network Slicing Revised Problem Statement       July 2017


            network slice, assessing whether flow isolation
            characteristics are in conformance with the NS Resource
            Specification, or assessing the compliance of the allocated
            slice resource against flow/customer requirements.
          - An operator must be able to enable differentiated failure
            detect and repair features for a specific/subset of network.
            For example, a given slice may require fast detect and
            repair mechanisms (e.g., as a function of the nature of the
            traffic (pattern) forwarded through the NS), while others
            may not be engineered with such means.
          - When a given slice is shared among multiple
            services/customers, an operator must be able to execute
            (per-slice) OAM tasks for a particular service or customer.
      * Ability to automatically discover the underlying service
          functions and the slices they are involved in or they belong
          to.
      * Ability to dynamically discover the set of NetSlices that are
          enabled within a network. Such dynamic discovery capability
          facilitates the detection of any mismatch between the view
          maintained by the control plane and the actual network
          configuration.  When mismatches are detected, corrective
          actions must be undertaken accordingly.


4 Summary

   The following is a summary of the selected higher priority problems
   based on previous analysis in this document:

   (I) Identified IETF Gap: "A detailed specification of Network Slicing
   Specification"; Requirement: Network Slicing Specification.

      * Problem GI1: Uniform Reference Model
      * Problem GI3: Slice Templates
      * Problem NSC9: Capability exposure and APIs

   (II) Identified IETF Gap: "A companion YANG data model for Network
   Slicing"; Requirement: Network Slicing Specification.

      * Problem NSO5: Service Mapping in a single domain and Cross-
        Domain Coordination.

   (III) Identified IETF Gap:  "Slicing specific extension on Isolation
   (Performance Guarantee and Isolation-PGI"; Requirement: Performance
   Guarantee and Isolation.

      * Problem NSC1: Guarantees for isolation.




Galis, et al.           Expires January 3, 2018                [Page 22]


INTERNET DRAFT Network Slicing Revised Problem Statement       July 2017


   (IV) Identified IETF Gap: "Mechanisms for dynamic discovery of
   service with function instances and their capabilities"; Requirement:
   Network Slicing OAM.

      * Problem NSC8: Monitoring and Discovery

   (V) Identified IETF Gap: "non-overlay OAM (Operations,
   Administration, and Maintenance) solution"; Requirement: Network
   Slicing OAM.

      * Problem NSO1: Slice life cycle management
      * Problem NSO4: E2E Network Orchestration

   (VI) Identified IETF Gap: "Mechanisms for customized granularity OAM
   (Operations, Administration, and Maintenance)"; Requirement: Network
   Slicing OAM.

      * Problem NSO2: Autonomic slice management and operation
      * Problem NSO3: Slice stitching / composition

5  Security Considerations

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


6  IANA Considerations

   This document requests no IANA actions.

7 Acknowledgements

   Thanks to Sheng Jiang (Huawei Technologies), Kevin Smith (Vodafone),
   Satoru Matsushima (SoftBank), Christian Jacquenet (Orange), Mohamed
   Boucadair (Orange) for reviewing this draft. Thanks to Stuart Clayman
   (UCL) for creating the nroff markup for this document.

8  References

7.1 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



Galis, et al.           Expires January 3, 2018                [Page 23]


INTERNET DRAFT Network Slicing Revised Problem Statement       July 2017


              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.,
              <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>.



Galis, et al.           Expires January 3, 2018                [Page 24]


INTERNET DRAFT Network Slicing Revised Problem Statement       July 2017


   [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>.

   [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



Galis, et al.           Expires January 3, 2018                [Page 25]


INTERNET DRAFT Network Slicing Revised Problem Statement       July 2017


              the IETF" - June 2011 https://tools.ietf.org/html/rfc6291


7.2  Informative References

   [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>.

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

   [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



Galis, et al.           Expires January 3, 2018                [Page 26]


INTERNET DRAFT Network Slicing Revised Problem Statement       July 2017


              Slicing Concept", NGMN Alliance NGS-3GPP-2016, January
              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





Galis, et al.           Expires January 3, 2018                [Page 27]


INTERNET DRAFT Network Slicing Revised Problem Statement       July 2017


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

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

   Jie Dong
   Huawei Technologies
   Email: jie.dong@huawei.com

   Liang Geng
   China Mobile
   Email: gengliang@chinamobile.com

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

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

   Ravi Ravindran
   Huawei Technologies
   Email: ravi.ravindran@huawei.com

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

   Stewart Bryant
   Huawei Technologies
   Email: stewart.bryant@gmail.com

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

   Susan Hares
   Huawei Technologies
   Email: shares@ndzh.com

   Carlos Jesus Bernardos Cano
   University Carlos III Madrid
   Email: cjbc@it.uc3m.es



Galis, et al.           Expires January 3, 2018                [Page 28]


INTERNET DRAFT Network Slicing Revised Problem Statement       July 2017





















































Galis, et al.           Expires January 3, 2018                [Page 29]


Html markup produced by rfcmarkup 1.129b, available from https://tools.ietf.org/tools/rfcmarkup/