Internet DRAFT - draft-flinck-slicing-management
draft-flinck-slicing-management
Internet Engineering Task Force H. Flinck
Internet-Draft C. Sartori
Intended status: Informational A. Andrianov
Expires: January 4, 2018 C. Mannweiler
N. Sprecher
Nokia
July 3, 2017
Network Slicing Management and Orchestration
draft-flinck-slicing-management-00
Abstract
Network Slicing is worked in multiple SDOs from different view
points. As network slicing is an end-to-end topic, this draft
proposes that network slices architecture [NS-Framework] aligns with
the work done in NGMN, 3GPP and ETSI with relation to management and
orchestration. The key aspect that this draft makes is the rational
for role and need for Network Slice Management Function (NSMF) entity
that operates above Network Virtualization Function Orchestrator and
PNFs Management Functions. NSMF needs to support different
abstractions of resources and to offer access to different management
entities.
Status of This Memo
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This Internet-Draft will expire on January 4, 2018.
Copyright Notice
Copyright (c) 2017 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Acronyms and Abbreviations . . . . . . . . . . . . . . . 5
2. Different levels of Network Slice Control exposure . . . . . 5
3. Network Slice Management Function (NSMF) . . . . . . . . . . 6
4. IANA considerations . . . . . . . . . . . . . . . . . . . . . 8
5. Security considerations . . . . . . . . . . . . . . . . . . . 8
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8
7. Informative References . . . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9
1. Introduction
The purpose of this draft is to highlight the essential aspects of
network slice management from 3GPP, NGMN and ETSI relevant for the
network slices architecture as described in [NS-Framework] and to
propose a minimal alignment between these works to ensure
compatibility between them. NGMN documents
"161010_NGMN_Network_Slicing_framework_v1.0.8" [NGMN_NS] and "5G
Network and Service Management including Orchestration" [NGMN_NSMN]
define Network Slicing and how it relates to overall Service and
Network Management architecture. The NGMN documents define as well
the terminology adopted later by 3GPP and reflected in 3GPP
[TR28.801]. In this paper, for sake of simplicity, only an
"executive summary" of network slicing is given, while relying on
both terminology and complete descriptions on the above mentioned
documents.
Network Slicing provides multiple logical networks on top of a
partially shared network infrastructure as described in
[NS-Framework]. Each instance of a network slice represents an
independent end-to-end network that allows deployment of different
architectural flavors in parallel slices. These slices may be
deployed and/or operated by the slice provider, or by the tenant who
requested the slice.
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A network slice can span across different administrative domains.
NGMN Network slicing white paper [NS-Framework] defines various
forward-looking business models engaging multiple administrative
domains that may be envisioned in the industry. An administrative
domain refers to the scope of jurisdiction of a provider. A provider
may obtain services from 3rd parties (i.e. sub-providers) to enrich
the services it provides to its end customers. A provider could also
benefit from offering its spare capabilities or resources to other
providers becoming itself a sub-provider. A network service can be a
single user connectivity service, NaaS (Network as a Service) such as
a service instance, a network slice instance or a subnetwork slice
(note NGMN and 3GPP use a different terminology for what IETF
netslices drafts call for "network slice segment") instance offering
for a business vertical that utilizes forward-looking business
models, or IaaS (Infra structure as a Service).
Depending on the use cases and type of services for which the end-to-
end slice has been instantiated multiple levels of control may be
exposed to the tenants by the slice provider. On the lowest level of
the exposed control the network slice provider grants only access to
use the slice and means to monitor its performance. At second level
a control exposure is to allow tenants to change the configuration of
the network functions associated to the tenant's network slice. At
the highest level of control tenants can compose network slices and
manage them with their own management system. These different levels
of control exposure require that the network slice management must
work on multiple levels of abstractions where highest level is at the
Service Management & Orchestration (M&O) and lowest level at the
network functions. The slice provider must be able to isolate these
control functions of different tenants to match the "Slice Provider"
- "Slice Consumer" -relationship.
A network slice instance can contain virtualized network functions as
well as physical network functions. Virtualized network functions
(VNF) are decoupled from physical network equipment by a
virtualization layer. Both the lifecycle of the types of the network
functions can span beyond the lifecycle of a Network Slice and they
need their own life cycle management functions. The life cycle
management of these two types of network functions differ. The
environment in which VNFs are deployed is called Network Functions
Virtualisation Infrastructure (NFVI) and is managed by Virtualised
Infrastructure Manager (VIM) according to ETSI NFV-MANO [MANO]
reference architecture. VNFs are instantiated by requests of NFV
Orchestrator (NFVO). In the MANO architecture NFV Orchestrator
(NFVO) uses VNF Managers for the lifecycle management of VNF
instances and the VIM allocates the needed virtualized resources as
requested by the NFVO into the NFVI. However, the same approach
cannot be applied to network functions of dedicated hardware
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(Physical Network Functions, PNF) as their resources are not
controlled by NFVO nor VIMs. Network Functions (whether PNF or VNF)
require their function specific management, as well as their resource
management.
When adding support for the virtualized version of the PNFs their
management systems will evolve to either extend their capability with
an embedded VNF management functionality or will delegate their
virtual resource management to an external VNF manager. In either
case, the VNF management function interacts with the NFVO and the VIM
through the MANO defined interfaces and provides the cloud resource
FCAPS management for the network functions. Another key issue for
provisioning of network slices is the identification, design, and
management of network functions which can be shared by multiple end-
to-end slices [Rost].
For Network slice management function (NSMF), which is a slice-
dedicated function with slice-specific view on any FCAPS data and
management procedures, such sharing or common usage should be
transparent, i.e., the multiplexing of multiple network slices to a
commonly used function/element is done by EMS/NMS. NSMF operates
above NFVO and PNFs Management Functions in the Service M&O. In view
of 3GPP as well as ETSI NFV, NSMF belongs to OSS/BSS. When a network
slice contains PNFs the NSMF instructs the PNFs Management Functions
to configure the physical network components to deliver the required
slice characteristics.
This draft introduces the role of NSMF in the context of 3GPP
[TR28.801], [TS28.530] and ETSI [MANO] work and reflects that back to
netslices-architecture presented in [NS-Framework]. We argue that
the NSMF is at the Service M&O level, even at a tenant. This is
because of several reasons:
o Need for exposing different levels of network slice control to the
tenants.
o Different life cycle management approaches for PNFs and VNFs.
NSMF must have interfaces both to NFVO and to PNFs Management and
is therefore above of the NFVO and PNF management and it should
support service level abstractions.
Network slicing is end-to-end concept, thus including several network
components, (Network Slice Subnetwork Functions according to 3GPP
terminology). Often those components belong to different
administrative domains (e.g. RAN, Core Network, Transport) and
therefore the need for a higher level of abstraction. Transport
network [ACTN] is a subnetwork slice in the 3GPP model and recursion
can be applied to slices as well as to subnetwork slices.
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1.1. Acronyms and Abbreviations
This document uses the following acronyms:
3GPP 3rd Generation Partnership Project
BSS/OSS Business Support Systems/Operations Support Systems
EMS Element Management System
ETSI European Telecommunications Standards Institute
FCAPS Fault, Configuration, Accounting, Performance, Security
IaaS Infra structure as a Service
KPI Key Performance Indicator
MANO ETSI Management and Orchestration
LCM Life Cycle Management
MNO Mobile Network Operator
M&O Management & Orchestration
NaaS Network as a Service
NGMN Next Generation Mobile Networks
NMS Network Management System
NSMF Network Slice Subnet Management Functions
NSSMF Network Slice Management Function
NFVI Network Functions Virtualisation Infrastructure
NVFO Network Virtualization Function Orchestrator
PNF Physical Network Function
RAN Radio Access Network
SLA Service Level Agreement
VIM Virtualised Infrastructure Manager
VNF Virtualised Network Function
2. Different levels of Network Slice Control exposure
Depending on the "Slice Provider" - "Slice Consumer" -relationship
the Slice Provider can offer various levels of control to the Slice
Consumers. Roughly speaking levels of control can be categorized
onto follow cases:
1. Monitoring only. The Slice Provider offers only means to monitor
the slice KPIs as agreed in the contract. Network slice
configuration is chosen from a catalogue of readymade slice
templates. Accesses via dashboard-like web service and/or north
bound interfaces provided by the Slice Provider.
2. Limited control to Slice Consumer to perform design and
composition of network slice. Slice Consumer can change
configuration of deployed network functions and /or onboard own
certified network functions into Slice Provider's repository
using interfaces provided by the Slice Provider.
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3. Extended Control. In this case the Slice Consumer deploys and
operates the network slice using its own MANO stack and NMS. The
Slice consumer has tight control over its own network functions
and services while has limited control over MNO network
functions.
Because of these varying levels of network slice control, the NSMF
needs to support different abstractions of resources and to offer
access to different management entities (e.g. PNFs management
functions, NFV-MANO). Consequently, the logical place for NSMF
function in the network slice management architecture is at the
Service Management & Orchestration (M&O).
3. Network Slice Management Function (NSMF)
Network slicing concept of NGMN consists of 3 layers: Service
Instance Layer, Network Slice Instance Layer, and Resource layer
[NGMN_NS]. The Service Instance Layer is managed by service
orchestrator that is considered to be part of BSS/OSS according to
the 3GPP view [TR28.801]. Network Slicing Instance Layer is a
Business to Business service and may pass across multiple
administrative domains. Network Slice Management Function resides at
this layer and is consequently part of Service Orchestration and BSS/
OSS.
The end-to-end network slice management (NSMF) can use different
technology domains and their segments to create an end-to-end slice.
It has full visibility and control to the end-to-end slice and its
performance. It resides above the Network Slice Subnet Management
Functions (NSSMF). It monitors slice specific FCAPS to maintain and
to expose the overall SLAs of the end-to-end slices to the tenant.
NSMF interfaces domain specific Network Management and Element
Management Systems through Network Slice Subnet Management Functions
(NSSMF). In addition, NSMF also interfaces NFV-MANO to manage
virtualization aspects (through "OS-Ma-nfvo"-interface).
NSSMF manages Network Slice Subnet (3GPP defined management
abstraction) composed of Network Functions (virtualized or not) and
other Network Slice Subnets (recursion principle). NM/EM could play
the role of NSSMF. For management of virtualization aspects (such as
NS and VNF LCM) and TN, NSSMF interacts with NFV-MANO (through "Os-
Ma-nfvo"-interface). The 3GPP defined Network Slice Subnets
correspond to ETSI NFV defined NSs composed from either network
functions and/or nested network slices (recursion principle).
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+------------------------------------+
| BSS/OSS |
| +-----------------------+ |
| | Service M&O | |
| | | |
| | +-------------+ | |
| | | NSMF +--------------------------+
| | ++------------+ | | |
| +---|-------------------+ | |
+------------|-----------------------+ |
| |
| |
+----------|-----+ |
| NM/EM | | |
| +------+-----+ +-----+------+
| | | | |
| | | | NFV |
| | NSSMF +---------------------------+ MANO |
| | | | |
| | +------------+ | |
+---+------+-----+ | +-----+------+
| | |
| | |
+-----+-----+ | +----+------+
| | | | |
| PNFs | +---------------+ VNFs |
| | | |
+-----+-----+ +----+------+
| |
| |
| |
+---------+---------------------------------------+-------------+
| Slice with shared and dedicated network functions |
+---------------------------------------------------------------+
Network Slice Management functional architecture.
Figure 1
Based on the above reasoning we propose to replace the "Figure 2: E2E
Slice Orchestration"-figure of the section of Management and
Orchestration of Network Slicing in [NS-Framework] with the following
figure with the above stated reasoning.
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+ ------------------------------------------------+
| NSMF |
+-------------------------------------------------+
| | |
+-----------+ +-----------+ +----------+
| Network | | Network | | Network |
| Slice | | Slice | | Slice |
| Subnet | | Subnet | | Subnet |
| Management| | Management| |Management|
| Function |------| Function |------ ... -- |Function |
+----------+ +-----------+ +----------+
| | |
+-------------------------------------------------------------+
| P/VNF FCAPS Management / NFV-MANO: VNF LCM management |
+-------------------------------------------------------------+
| | | |
+--------+ : +--------+ : +--------+ : +--------+
| PNF 1 |----- | PNF n |----- | VNF 1 |----...-- | VNF n |
+--------+ : +--------+ : +--------+ : +--------+
Network Slice Management Function (Network Slice segment term
corresponds roughly to Network Slice subnetwork term used by 3GPP/
NGMN)
Figure 2
4. IANA considerations
This document makes no request of IANA.
5. Security considerations
Each element and their interface of the proposed management
architecture needs to address their security requirements.
6. Acknowledgements
7. Informative References
[ACTN] Ceccarelli, D. and Lee, Y., "Framework for Abstraction and
Control of Traffic Engineered Networks", draft-ietf-teas-
actn-framework-06 (work in progress), June 2017.
[MANO] ETSI, "ETSI GS NFV-MAN 001: Network Functions
Virtualization (NFV); Management and Orchestration", 2014.
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[NGMN_NS] NGMN Alliance, "Description of Network Slicing Concept",
https://www.ngmn.org/uploads/
media/161010_NGMN_Network_Slicing_framework_v1.0.8.pdf ,
2016.
[NGMN_NSMN]
NGMN Alliance, "5G Network and Service Management
including Orchestration",
https://www.ngmn.org/publications/all-downloads/
article/5g-network-and-service-management-including-
orchestration.html , 2017.
[NS-Framework]
Geng, L., Dong, J., Bryant, S., Makhijani, K., Galis, A.,
De Foy, X., and Kuklinsk, S., "Network Slicing
Architecture", draft-geng-netslices-architecture-01 (work
in progress), June 2017.
[Rost] Rost, P., Mannweiler, C., Diomidis, M., Sartori, C.,
Sciancalepore, V., Sastry, N., Holland, O., Tayade, S.,
Han, B, Bega, D., Aziz, D., Bakker, H., and IEEE
Communications Magazine, Volume: 55 Issue: 5,, "Network
Slicing to Enable Scalability and Flexibility in 5G Mobile
Networks", May 2017.
[TR28.801]
3GPP, "Study on management and orchestration of network
slicing for next generation network, Release 14)3GPP TR
28.801 V1.2.0",
https://portal.3gpp.org/desktopmodules/Specifications/
SpecificationDetails.aspx?specificationId=3091 , 2017.
[TS28.530]
3GPP, "Management of network slicing in mobile networks;
Concepts, use cases and requirements. Technical
specification. Release 15. 3GPP TR 28.530.",
https://portal.3gpp.org/desktopmodules/Specifications/
SpecificationDetails.aspx?specificationId=3091 , 2017.
Authors' Addresses
Hannu Flinck
Nokia
Espoo
FI
Phone: +358504839522
Email: hannu.flinck@nokia.com
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Cinzia Sartori
Nokia
Munich
DE
Phone: +491713008990
Email: cinzia.sartori@nokia-bell-labs.com
Anatoly Andriannov
Nokia
Arlington Heights, IL
US
Phone: +1-847-668-0394
Email: anatoly.andrianov@nokia.com
Christian Mannweiler
Nokia
Munich
DE
Phone: +491715581581
Email: christian.mannweiler@nokia-bell-labs.com
Nurit Sprecher
Nokia
Hod HaSharon
IL
Phone: +97297751229
Email: nurit.sprecher@nokia.com
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