Page 47 - ITU-T Focus Group IMT-2020 Deliverables

ITU-T Focus Group IMT-2020 Deliverables 2

PGW Packet data network GateWay

QoS Quality of Service
QSCF QoS Control Function

RAT Radio Access Technology
SDN Software Defined Network

SGW Serving GateWay
SIDB Subscriber Information DataBase
SMCF Session Management Control Function

TUPF Terminating User Plane Function
UACF Unified Authentication Control Function

UE User Equipment
UPGW User Plane GateWay function
UP User Plane

VPN Virtual Private Network

5 Overview of IMT-2020 network architecture framework

5.1 General framework and architectural principles
IMT-2020 shall provide converged network-computing capabilities to enable variety of services including
eMBB, massive IoT, autonomous vehicles, tactile Internet, etc. The scope of the IMT-2020 includes not only
mobile technologies but also fixed communication, cloud, and services. Further, IMT-2020 will allow the
provisioning of both existing and new services independently of the network and the access type used.
It is expected that network systems will consist of distributed multiple physical and/or virtual network
functions that may be deployed on-demand basis over the infrastructure in the operator's network, and be
able to support diverse service requirements.

By virtue of softwarization and pervasive deployment of computing infrastructure with connectivity and
storage, network function instances can be distributed on an on-demand basis. This brings to the IMT-2020
network architecture a shift in networking paradigms: a transition from deployment of network entities with
fixed functionalities (e.g., PGW, SGW, etc.) to deployment of network functions as necessary.
IMT-2020 network shall provide network services demanding diverse requirements, by using network
functions instantiated at right place. IMT-2020 infrastructure will provide required infrastructure resources
to instantiate the network functions. Network operators can provision and operate many different network
slices according to their business strategies.

Network slicing enables the operator to create logically partitioned networks customised to provide
optimized solutions for different market scenarios. These scenarios demand diverse requirements in terms
of service characteristics, required functionality, performance and isolation issues.
The functional architecture of IMT-2020 network shall provide a complete set of network functions required
to support all IMT-2020 services. On the other hand, a network slice is comprised only of the necessary
network functions. They are collected from a complete set of network functions in the IMT-2020 network
functional architecture, and orchestrated for the particular services and purposes.
The general framework of IMT-2020 can be represented by two separate architecture levels, i.e. the ‘IMT-
2020 network slice life-cycle management’ level and the ‘network slice instances’ level as shown in Figure 5-
1. Functions for creating and managing network slice instances and the functions instantiated in the network
slice instance are mapped to respective architecture level.

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