ETSI GR MEC 024 V2.1.1 (2019-11)

Multi-access Edge Computing (MEC); Support for network slicing

DGR/MEC-0024NWslicing

General Information

• Status: Published
• Publication Date: 27-Nov-2019
• Technical Committee: MEC - Multi-access Edge Computing
• Current Stage: 12 - Completion
• Due Date: 04-Dec-2019
• Completion Date: 28-Nov-2019

Standards Content (Sample)

ETSI GR MEC 024 V2.1.1 (2019-11)






GROUP REPORT
Multi-access Edge Computing (MEC);
Support for network slicing
Disclaimer
The present document has been produced and approved by the Multi-access Edge Computing (MEC) ETSI Industry
Specification Group (ISG) and represents the views of those members who participated in this ISG.
It does not necessarily represent the views of the entire ETSI membership.

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2 ETSI GR MEC 024 V2.1.1 (2019-11)



Reference
DGR/MEC-0024NWslicing
Keywords
MEC, slicing

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Contents
Intellectual Property Rights . 5
Foreword . 5
Modal verbs terminology . 5
1 Scope . 6
2 References . 6
2.1 Normative references . 6
2.2 Informative references . 6
3 Definition of terms, symbols and abbreviations . 7
3.1 Terms . 7
3.2 Symbols . 7
3.3 Abbreviations . 7
4 Overview . 8
4.1 Introduction . 8
4.2 NGMN . 8
4.3 ONF . 10
4.4 3GPP . 11
4.5 ETSI NFV . 13
5 Use cases . 15
5.1 Introduction . 15
5.2 Creation and termination of a Network Slice . 15
5.2.1 Description . 15
5.2.2 Use case recommendations . 16
5.2.3 Evaluation . 17
5.3 Instantiation of a Network Slice integrating MEC applications and using 3GPP elements . 17
5.3.1 Description . 17
5.3.2 Use case recommendations . 18
5.3.3 Evaluation . 18
5.4 MEC enables the network latency assurance for network slicing . 18
5.4.1 Description . 18
5.4.2 Use case recommendations . 19
5.4.3 Evaluation . 19
5.5 Dedicated instances of MEC components in a Network Slice . 20
5.5.1 Description . 20
5.5.2 Use case recommendations . 20
5.5.3 Evaluation . 20
5.6 Multiple tenants in a single Network Slice . 20
5.6.1 Description . 20
5.6.2 Use case recommendations . 21
5.6.3 Evaluation . 21
5.7 Efficient E2E multi-slice support for MEC-enabled 5G deployments . 21
5.7.1 Description . 21
5.7.2 Use case recommendations . 23
5.7.3 Evaluation . 23
6 Key issues and solutions. 24
6.1 Key issue 1: Slice-awareness of the MEAO . 24
6.1.1 Description . 24
6.1.2 Solution . 24
6.1.3 Gap analysis . 24
6.2 Key issue 2: Slice-awareness of a shared MEP . 24
6.2.1 Description . 24
6.2.2 Solution . 24
6.2.3 Gap analysis . 25
6.3 Key issue 3: Slice-awareness of a MEPM-V . 25
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4 ETSI GR MEC 024 V2.1.1 (2019-11)
6.3.1 Description . 25
6.3.2 Solution . 25
6.3.3 Gap analysis . 25
7 Conclusions and recommendations . 26
7.1 Prioritized concepts of network slicing . 26
7.2 Consolidated recommendations . 26
7.3 Recommendations for future work . 26
History . 28


ETSI

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Intellectual Property Rights
Essential patents
IPRs essential or potentially essential to normative deliverables may have been declared to ETSI. The information
pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found
in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in
respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web
server (https://ipr.etsi.org/).
Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee
can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web
server) which are, or may be, or may become, essential to the present document.
Trademarks
The present document may include trademarks and/or tradenames which are asserted and/or registered by their owners.
ETSI claims no ownership of these except for any which are indicated as being the property of ETSI, and conveys no
right to use or reproduce any trademark and/or tradename. Mention of those trademarks in the present document does
not constitute an endorsement by ETSI of products, services or organizations associated with those trademarks.
Foreword
This Group Report (GR) has been produced by ETSI Industry Specification Group (ISG) Multi-access Edge Computing
(MEC).
Modal verbs terminology
In the present document "should", "should not", "may", "need not", "will", "will not", "can" and "cannot" are to be
interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms for the expression of provisions).
"must" and "must not" are NOT allowed in ETSI deliverables except when used in direct citation.

ETSI

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1 Scope
The present document focuses on identifying the MEC functionalities to support network slicing. It first analyses the
relevant network slicing concepts as defined by external organizations. Next, it collects relevant use cases based on the
identified network slicing concepts when applied in the context of MEC and it evaluates the gaps from the defined MEC
functional elements. When necessary, the present document identifies new MEC functionalities or interfaces as well as
changes to existing MEC functional elements, interfaces and requirements. It will also recommend the necessary
normative work to close these gaps if identified.
2 References
2.1 Normative references
Normative references are not applicable in the present document.
2.2 Informative references
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
referenced document (including any amendments) applies.
NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long term validity.
The following referenced documents are not necessary for the application of the present document but they assist the
user with regard to a particular subject area.
[i.1] ETSI GS MEC 001: "Multi-access Edge Computing (MEC); Terminology".
[i.2] NGMN Alliance: "5G White Paper", February 2015.
[i.3] NGMN Alliance: "Description of Network Slicing Concept", January 2016.
[i.4] Open Networking Foundation: "Applying SDN Architecture to 5G slicing", ONF TR-526, April
2016.
[i.5] ETSI TS 123 501: "5G; System architecture for the 5G System (5GS) (3GPP TS 23.501)".
[i.6] 3GPP TR 28.801: "Telecommunication management; Study on management and orchestration of
network slicing for next generation network".
[i.7] ETSI TS 128 530: "5G; Management and orchestration; Concepts, use cases and requirements
(3GPP TS 28.530)".
[i.8] ETSI GS NFV-MAN 001: "Network Functions Virtualisation (NFV); Management and
Orchestration".
[i.9] ETSI GS NFV-IFA 013: "Network Function Virtualization (NFV); Management and
Orchestration; Os-Ma-Nfvo reference point - Interface and Information Model Specification".
[i.10] ETSI GR MEC 017: "Mobile Edge Computing (MEC); Deployment of Mobile Edge Computing in
an NFV environment".
[i.11] ETSI GS MEC 010-2: "Multi-access Edge Computing (MEC); MEC Management; Part 2:
Application lifecycle, rules and requirements management".
[i.12] ETSI GS MEC 003: "Multi-access Edge Computing (MEC); Framework and Reference
Architecture".
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7 ETSI GR MEC 024 V2.1.1 (2019-11)
[i.13] ETSI GS MEC 002: "Multi-access Edge Computing (MEC); Phase 2: Use Cases and
Requirements".
[i.14] ETSI GS MEC 010-1: "Mobile Edge Computing (MEC); Mobile Edge Management; Part 1:
System, host and platform management".
[i.15] ETSI White Paper No. 28: "MEC in 5G networks"; First edition - June 2018; ISBN No. 979-10-
92620-22-1.
[i.16] ETSI GR NFV-EVE 012: "Network Functions Virtualisation (NFV) Release 3; Evolution and
Ecosystem; Report on Network Slicing Support with ETSI NFV Architecture Framework".
[i.17] ETSI GR NFV 001: "Network Functions Virtualisation (NFV); Use Cases".
[i.18] ETSI GR NFV-IFA 028: "Network Functions Virtualisation (NFV) Release 3; Management and
Orchestration; Report on architecture options to support multiple administrative domains".
3 Definition of terms, symbols and abbreviations
3.1 Terms
For the purposes of the present document, the terms given in ETSI GS MEC 001 [i.1] apply.
3.2 Symbols
Void.
3.3 Abbreviations
For the purposes of the present document, the abbreviations given in ETSI GS MEC 001 [i.1] and the following apply:
rd
3GPP 3 Generation Partnership Project
5G Fifth Generation
5QI 5G QoS Class Identifier
AMF Access and Mobility Management Function
AN Access Network
API Application Programming Interface
CN Core Network
CSMF Communication Service Management Function
DN Data Network
E2E End-to-End
eMBB enhanced Mobile Broadband
IoT Internet of Things
MEAO Multi-access Edge Application Orchestrator
MEC Multi-access Edge Computing
MEP Multi-access Edge Platform
MEPM Multi-access Edge Platform Manager
MEPM-V Multi-access Edge Platform Manager - NFV
MIoT Massive Internet of Things
NF Network Function
NFV Network Function Virtualisation
NFVI NFV Infrastructure
NFVO NFV Orchestrator
NFV-SCF NFV-Slice Control Function
NGMN Next Generation Mobile Networks
NRF NF Repository Function
NS Network Service
NSD Network Service Descriptor
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NSI Network Slice Instance
NSMF Network Slice Management Function
NSSAI Network Slice Selection Assistance Information
NSSF Network Slice Selection Function
NSSI Network Slice Subnet Instance
NSSMF Network Slice Subnet Management Function
NSSP Network Slice Selection Policy
NST Network Slice Template
ONF Open Networking Foundation
OSS Operations Support System
PCC Policy & Charging Control
PCF Policy Control Function
PDB Packet Delay Budget
PDU Protocol Data Unit
PLMN Public Land Mobile Network
PNF Physical Network Function
QoS Quality of Service
RAN Radio Access Network
RAT Radio Access Technology
RNI Radio Network Information
RRC Radio Resource Connection
RTT Round Trip Time
SD Slice Differentiator
SDN Software Defined Networking
SDO Standards Development Organization
SI Service Instance
SLA Service Level Agreement
SMF Session Management Function
S-NSSAI Single NSSAI
SST Slice/Service Type
TN Transport Network
UE User Equipment
UPF User Plane Function
URLLC Ultra-Reliable Low Latency Communications
V2X Vehicle-to-everything
VIM Virtualised Infrastructure Manager
VNF Virtual Network Function
VNFFG VNF Forwarding Graph
VNFM VNF Manager
4 Overview
4.1 Introduction
The following clauses 4.2 to 4.5 provide an overview of network slicing concept as it has been defined in different
SDOs and Fora. In particular, the following clauses refer to the most relevant external body's documents which
introduce and define network slicing, and describe related specifications provided in NGMN, ONF, 3GPP and ETSI
ISG NFV.
4.2 NGMN
According to NGMN "5G White Paper" [i.2], a network slice (i.e. "5G slice") supports the communication service of a
particular connection type with a specific way of handling the C- and U-plane for this service. To this end, a 5G slice is
composed of a collection of 5G network functions and specific Radio Access Technology (RAT) settings that are
combined for the specific use case or business model while leveraging NFV and SDN concepts. Thus, a 5G slice can
span all domains of the network: software modules running on cloud nodes, specific configurations of the transport
network supporting flexible location of functions, a dedicated radio configuration or even a specific RAT, as well as
configuration of the 5G device.
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More specifically, the NGMN white paper "Description of Network Slicing Concept" [i.3] provides a detailed
description of terminology and network slicing related concepts that are organized according to a three-layer
architecture, as shown in Figure 4.2-1:
rd
• Service Instance Layer: the end-user or business services, provided by a network operator or a 3 party,
which should be supported by the slice. Each service is represented by a Service Instance (SI).
• Network Slice Instance Layer: Network Slice Instances are sets of functions, each forming a complete
instantiated logical network to meet certain network characteristics (e.g. ultra-low latency, ultra-reliability)
required by the Service Instance(s). They are created based on Network Slice Blueprints, which provide a
complete description of the network slice structure, lifecycle workflow and configuration options. A Network
Slice Instance can be shared among multiple Service Instances, at least when the Service Instances are
provided by network operators. Each Network Slice Instance may include one or more Sub-Network Instances
to form a set of Network Functions running in physical or logical resources.
• Resource Layer: Resources are distinguished in "physical resources" and "logical resources". A physical
resource is a physical asset for computation, storage or transport, including radio access. Logical resources are
partitions of physical resources or grouping of multiple physical resources dedicated to a Network Function or
shared between a group of Network Functions.

Figure 4.2-1: NGMN Network Slice Concept
(Figure 1 in NGMN White Paper "Description of Network Slicing Concept" [i.3])
The mapping between the NGMN layers and the ETSI NFV architectural framework is illustrated in Figure 4.2-2 and
can be summarized as follows:
• the Service Instance layer plays the role of an OSS functional block with regards to the NFVO;
• the Network Slice Instance layer maps to the collection of Network Services handled by NFV Management &
Orchestration functions. The network service can be described by a VNF Forwarding Graph (VNFFG),
typically defined by a Network Service Descriptor (NSD) using a specific deployment flavour;
• the Resource layer maps to the NFVI and the VIM(s).
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OSS
Service Instance
Slice Controller
Layer
NFVO(s)
VNF
VNF
VNF
NS /Sli ce
Network Slice
Instance Layer
VNF
VNF
VNF
VNFM(s)
NS /Sli ce
Resource Layer NFVI VIM(s)

Figure 4.2-2: Mapping of the NGMN layers onto the ETSI NFV architectural framework
Based on the NGMN white papers [i.2], [i.3], the NGMN focus is mainly given to communications services and to
traffic treatment into the 5G slice across both mobile and core networks while providing the network capacity when and
where needed and according to the use case requirements. Moreover, although cloud nodes are considered as possible
substrate to host the 5G network functions, not any reference is provided to the specific location of cloud resources used
to allocate the 5G slice, whether at the edge or in the centralized cloud. Finally, although the deployment of application
functions is considered as an option to address specific use cases (e.g. 5G slice for smartphone use), the on-boarding of
vertical application on a cloud node is not specifically addressed except in terms of just promoting the definition of
open interfaces.
4.3 ONF
The SDN architecture defined by ONF TR-526 [i.4] allows multiple client network instances to share the common
underlying infrastructure in a technology-independent fashion, thus enabling the orchestration of any type of resources,
such as storage, computing, and heterogeneous network resources (i.e. wired, wireless, and mobile) that may be
available at any location of the network including the edge. At that end, the ONF architecture comprises three main
components (see Figure 4.3-1), namely applications, SDN controller, and resources. A client-server relationship is
established through the interfaces between the applications and SDN controller and between the SDN controller and the
underlying resources.
The SDN controller is in charge of mapping the service requirements to the underlying resources according to policies
defined by the administrator of the network and of dynamically optimizing the use of such resources. The SDN
controller provides two types of resource views: one offered to the application on top, through a client context, which is
specific to a given client, and a second one enabling the interaction with the underlying resources, through a server
context, which is specific to a given group of underlying resources. The client context is created by the administrator
after a business agreement is reached between the client organization and the serving organization. Through
orchestration, the SDN controller dynamically handles the contention of multiple services for the resources of a
common infrastructure and it offers a homogeneous end-to-end handling of the underlying resources, even if belonging
to different technical and/or administrative domains. Through virtualisation instead, the SDN controller creates the
client context by allocating (part of) the underlying resources to that client. Additionally, the client context also includes
the actions by the client that are allowed over those resources. As part of the client context, resource groups determine
how virtual resources are exposed to the client.
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Figure 4.3-1: Core concepts of the SDN architecture
(Figure 1 in ONF TR-526 [i.4])
Since resource is understood in a generic sense, the virtual resources exposed to the client may, in turn, be seen as
underlying resources by that client and orchestrated and virtualised again to fulfil the service needs of the client of that
client. Therefore, recursion is supported by the architecture. In general, the slicing concept is initially seen from a
business perspective, in which clients request the provider to fulfil their specific service needs, including allocation of a
share of the underlying resources and a set of services to operate on them. Therefore, in the SDN architecture, the client
context can be directly mapped to a slice, since it offers the abstract set of resources requested by a service and the
supporting control service logic. Such slices can be instantiated on demand with per-service instance granularity and
tailored to the service needs, including their dynamic reconfiguration, and can span across multiple domains, including
the edge.
4.4 3GPP
The 3GPP approach is based on the NGMN slicing concept. According to NGMN, a slice instance is built over physical
or logical resources that are fully or partially isolated from other resources. The slice is built using the Network
Function that are processing functions of the Network Slice Instance (NSI) and correspond to ETSI virtual or physical
network functions (VNF and PNF, respectively). ETSI TS 123 501 [i.5] distinguishes between network slices and
Network Slice Instances. A network slice is considered as "a logical network that provides specific network capabilities
and network characteristics" [i.5]. These network capabilities and network characteristics are enabled specific through
Network Functions that communicate over a Service Based Architecture and corresponding Service Based Interfaces. A
Network Slice Instance is considered "a set of Network Function instances and the required resources (…) which form
a deployed Network Slice" [i.5]. Instances of the same Network Slice provide specific features based on their associated
Slice/Service Type (SST). A Slice Differentiator (SD) may be used to enable the deployment of Network Slice
Instances intended f
...