Network Working Group L. Geng
Internet-Draft China Mobile
Intended status: Informational S. Kuklinski
Expires: March 29, 2018 Orange
L. Qiang
Huawei Technologies
S. Matsushima
Softbank
A. Galis
University College London
Luis. Contreras
Telefonica
September 25, 2017
Problem Statement of Supervised Heterogeneous Network Slicing
draft-geng-coms-problem-statement-00
Abstract
This document discusses the general requirements and problem
statement of supervised heterogeneous network slicing. The purpose
of this document is to identify the key network components that are
used to create a network slice instance. Base on this information, a
general network slice template can be visualized. Furthermore, the
requirement of a common information model is identified and
corresponding management consideration of heterogeneous network slice
instance is also discussed.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
2. The components for a network slice instance . . . . . . . . . 4
2.1. Connectivity of network slice instance . . . . . . . . . 5
2.2. Computing for network slice instance . . . . . . . . . . 5
2.3. Storage for network slice instance . . . . . . . . . . . 6
2.4. Pre-defined function block for network slice instance . . 6
3. The requirements of common information model for supervised
heterogeneous network slice . . . . . . . . . . . . . . . . . 7
3.1. Management of heterogeneous network slice . . . . . . . . 8
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
5. Security Considerations . . . . . . . . . . . . . . . . . . . 9
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 9
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 9
7.1. Normative References . . . . . . . . . . . . . . . . . . 9
7.2. Informative References . . . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10
1. Introduction
The concept of network slicing is not new but energized greatly under
5G work in 3GPP. It is expected that further 5G network should be
capable of providing dedicated private network for different
verticals according to their specific requirements, which are created
by diversity of new services such as high definition (HD) video,
virtual reality (VR) and V2X applications. Looking at the
development of future network, no matter the service is connected via
5G cellular RAN, FTTx optical access network or other dedicated
connections, this resource dedication has become a fundamental
technology for services requiring extreme quality of user experience.
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The best effort transport is not good enough as both subscribers and
application providers are looking for and willing to pay for certain
level of quality dedication. Therefore it is inevitable for service
providers (telecommunication infrastructure owners) to rethink the
means of management and operation of their networks, which should
support end-to-end slicing capabilities.
The requirements from different verticals may be extremely
diversified. Typical examples includes high bandwidth, low latency,
high level of isolation, specific security and encryption
requirements and etc. These requirements may also change dynamically
along time since the services of certain industry vertical changes
very fast, and sometime spontaneously (i.e. burst bandwidth/latency
requirement from on-line shopping provider on certain period). It is
expected that the configuration of certain network slice instances
are very dynamic in a case-by-case manner. Meanwhile, there are many
technology options to fulfil particular requirements depending on
considerations on many aspects including cost, TTM and etc. The
diversity of both requirements and technology options makes network
slices significantly heterogeneous.
In order to provide cost-effective and efficient network slice
configuration, service provider needs to understand specifically the
components it can make use to create a network slice instance and how
these components map with the customer requirements. These
components include both network resources and management entities.
1.1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119.
1.2. Terminology
Network Slice Instance - A network slice instance (NSI) is a managed
group of subsets of network resources, network functions and network
management entities, forming a complete instantiated logical/physical
network to meet certain network characteristics required by the
network slice tenant(s). A network slice instance may also be shared
across multiple services provided by the network slice tenant. It is
re-configurable and is managed by network slice provider.
Network Slice Provider - A network slicing provider (NSP), typically
a telecommunication service provider, is the owner or tenant of the
network infrastructures from which network slices are created. The
network slicing provider takes the responsibilities of managing and
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orchestrating corresponding resource and management components that
the network slicing consists of.
Network Slice End-point - A network slice end-point (NSE) is a
network-slice-aware terminal, typically subscribed to the service
which is hosted in a network slice instance. A network slice end-
point may be capable of subscribing to multiple services hosted
independently in different network slice instance simultaneously.
Network Slice Tenant - A network slice tenant (NST) is the user of
specific NSIs, in which specific services are hosted and can be
provided to NSEs. Network slice tenants can make requests of the
creation of new network slice instances. Certain level of management
capability should be exposed to network slice tenant from network
slice service provider by pre-allocated outsource management
entities.
End-to-end Network Slice - A cross-domain network slice which may
consist of access network (fixed or cellular), transport network,
(mobile) core network and etc. End-to-end network slice can be
customized according to the requirements of network slice tenants
Network Function (NF) - A processing function in a network. It
includes but is not limited to network nodes functionality, e.g.
session management, mobility management, switching, routing
functions, which has defined functional behaviour and interfaces.
Network functions can be implemented as a network node on a dedicated
hardware or as a virtualized software functions. Data, Control,
Management, Orchestration planes functions are Network Functions.
Virtual Network Function (VNF) - A network function whose functional
software is decoupled from hardware. One or more virtual machines
running different software and processes on top of industry-standard
high-volume servers, switches and storage, or cloud computing
infrastructure, and capable of implementing network functions
traditionally implemented via custom hardware appliances and middle-
boxes (e.g. router, NAT, firewall, load balancer, etc.)
2. The components for a network slice instance
Fundamentally, NSIs are created based on the shared network
infrastructures. One can not create or define an NSI with components
that are not available in the shared infrastructure. Hence, it is
extremely important, both for NST and NSP, to understand a clear
scope of the usable components for NSI construction. An NSP can
therefore refer to this general scope to decide how each component
can be orchestrated and provided as a packaged network slice service
to NSTs. Based on this information, NSP can also further outline and
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figure out the what capability each component can offer and how they
meet NST's demands. Overall, it is not possible to map the offered
capability of a network slice instance with the specific demands from
an NST if an NSP is not clear on what components and corresponding
characteristics can be provided.
Network slice instance consists of dedicated network resources which
are orchestrated using all the available components offered by a NSP
network. In general, the components that an NSP can use to create an
NSI include connectivity, computing, storage, and management entity.
2.1. Connectivity of network slice instance
Connectivity is one of the essential components for an NSI. It can
be as simple as a best effort point-to-point VPN or a dedicated
complex topology with other specific requirements including
bandwidth, latency and etc. The characteristics of the connectivity
component should include the following aspects.
o Connection topology - The description of connection topology of a
NSI. It should explicitly describe the connectivity relationship
between each access point of the NSI. An NSP should be able to
understand the overall connectivity requirement of an NSI from
this topology information.
o Bandwidth - The description of bandwidth requirements of specific
links within an NSI. The requirements includes exactly amounts of
assured bandwidth, maximum bandwidth and other bandwidth QoS-
specific requirements
o Latency - The description of link latency requirements within an
NSI. It should identify the exact amount of latency between a
link defined in connection topology.
o Determinism - The description of the determinism of a link
latency. This should be defined in addition to the latency, which
further specify the jitter of the latency for a given link.
o Isolation level - The description of isolation level of an NSI. A
NST may request logical isolation which can be mapped to
tunnelling technologies. It may also request explicitly a
dedicated lamda or even physical link for specific services.
2.2. Computing for network slice instance
If an NST would like to host virtualized functions in an NSI, it may
be interested in asking for specific computing resource including
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both bare metal common servers and virtual machines. This resource
should also be specified considering the following characteristics.
o CPU resources - The physical and virtual CPU specifications a NST
may request a NSP to provide.
o GPU resources - The GPU specifications a NST may request a NSP to
provide.
o RAM resources - The RAM size associated with the requested
computing resources in a NSI.
Instead of providing bare metal resources, NSP may also provide
ready-to-used virtual machines and containers as part of the NSI.
This virtual resources need also be specified with virtulization
technology options, CPU/Virtual CPU requirements and etc.
2.3. Storage for network slice instance
It is necessary for NSP to provide storage components in an NSI since
NSTs may want to host contents on dedicated resources. Meanwhile,
NSP may also prefer to use dedicated storage for specific service
policies,authentication information and other management profiles.
o General storage - The description of storage resource in a NSI.
This may include the location, type, size and usage of the storage
resource. The general storage requirements may closely related to
the connectivity topology as well.
o CDN service - If an NSP can provide a turn-key CDN solution for
the NST. It can also include CDN service withing an NSI
2.4. Pre-defined function block for network slice instance
Many dedicated network functions, either physical or virtual, may
requested by a NST. Typical example include common network functions
as DHCP server, DNS, NAT, Firewall, SDN controller. Application-
level functions may also exist in a NSI, such as session management,
mobility management and etc. NSP should be able to provide such pre-
defined function blocks according to NST's request.
o Physical network function blocks- The description of dedicated
physical network functions. Physical network functions are
network equipments with dedicated software and hardware, which are
strictly coupled for the purpose of a providing specific network
function.
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o Virtual network function blocks- The description of virtualized
network functions. VNFs are software entities which are normally
hosted within pre-allocated virtual machines (or containers). The
virtual resources which are required by the VNF should be also
specified in terms of computing resources as described previously.
3. The requirements of common information model for supervised
heterogeneous network slice
As NSTs are not expected to be "network experts", the requirements
injected to a NSP may be diversified in forms. NSP may have
different preferences for the network slice service model provided to
potential NSTs. However, there is a need for a common information
model which explicitly describes the components and parameters within
a NSI.
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Slice Tenant
|
+---------------v------------------+
| Slice Provider |
+---------------+------------------+
|
+---------------v------------------+
| Slice Manager |
| +------------------------+ |
| |Common Information Model| |
| +------------------------+ |
+----------------------------------+
| |
+------------|---------v-------------------------+
| | |
| +----------|---------------------------+ |
| | +--------v-------+ +--------------+ | |
| | | Mngt Agent | |IntraNS Mngt | +----+ |
| | +----------------+ +--------------+ | | |
| | +---------------------------------+ | | |
| | | Connectivity, Computing | | | |
| | | Storage, Pre-defined Functions | | | |
| | | | | | |
| | +---------------------------------+ | | |
| | NSI | | |
| +----+---------------------------------+ | |
| | NSI | |
| +--------------------------------------+ |
| Network Infrastructure |
+------------------------------------------------+
Figure 1: Supervised heterogeneous network slice
As seen in Figure 1. The common information model is used to
describe a NSI according to the service model provided by NSTs. It
is then further de-composited to models that are used by various
management domain within the NSP's network infrastructure.
3.1. Management of heterogeneous network slice
The network slice management include two levels. One is network-
slice level management which is maintained by NSP, the other is
intra-slice management which is maintained by NST but supervised by
NSP.
o Network slice management agent - This is the NS-level management
agent provided by NSP. Each created NSI should have a logical
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entity serving as a network slice management agent. It executes
the OAM messages received from the NSP network slice manager
including life-cycle management, monitoring and etc. A profile of
the created NSI should also be maintained within this agent, where
the status of each element can be managed.
o Intra-slice management - As per agreement between NST and NSP,
intra-slice management may be provide by NSP to oversee an given
NSI as a general private network. NST are authorized to use this
management capability to maintain the NSI. The NSI-level
information is transparent to intra-slice management, which means
the management system does not know the existence of network slice
instances. The exposed management capability should be supervised
by the NSP, so that the NSI will not violate NSI-level policies.
Meanwhile, intra-slice management
o
4. IANA Considerations
This document makes no request of IANA.
5. Security Considerations
Each layer of the system has its own security requirements.
6. Acknowledgements
7. References
7.1. Normative References
[I-D.finn-detnet-architecture]
Finn, N. and P. Thubert, "Deterministic Networking
Architecture", draft-finn-detnet-architecture-08 (work in
progress), August 2016.
[I-D.qin-netslices-use-cases]
Qin, J., kiran.makhijani@huawei.com, k., Dong, J., Qiang,
L., and S. Peng, "Network Slicing Use Cases: Network
Customization for Different Services", draft-qin-
netslices-use-cases-00 (work in progress), March 2017.
7.2. Informative References
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[NS_WP] China Mobile Communication Corporation, Huawei
Technologies Co. Deutsche Telekom AG,Volkswagen, "5G
Service-Guaranteed Network Slicing White Paper", 2016,
<http://labs.chinamobile.com/
pdf/5GService-GuaranteedNetworkSlicingWhitePaper.pdf>.
Authors' Addresses
Liang Geng
China Mobile
Beijing
China
Email: gengliang@chinamobile.com
Slawomir Kuklinski
Orange
Email: slawomir.kuklinski@orange.com
Li Qiang
Huawei Technologies
Huawei Campus, No. 156 Beiqing Rd.
Beijing 100095
Email: qiangli3@huawei.com
Satoru Matsushima
Softbank
Email: satoru.matsushima@g.softbank.co.jp
Alex Galis
University College London
Email: a.galis@ucl.ac.uk
Luis Miguel Contreras Murillo
Telefonica
Email: luismiguel.contrerasmurillo@telefonica.com
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