Page 20 - ITU-T Focus Group IMT-2020 Deliverables

2 ITU-T Focus Group IMT-2020 Deliverables

3.2 Terms defined in this Recommendation

This Recommendation defines the following terms:
3.2.1 back haul: The network path connecting the base station site and the network controller or gateway
site
3.2.2 front haul: The intra-base station transport, in which a part of the base station function is moved to
the remote antenna site
3.2.3 evolved IMT-advanced RATs: The enhanced version of IMT-advanced RATs and they will be
supported by IMT-2020 network.
3.2.4 network slice: A Network slice is a managed group of infrastructure resources, network functions
and services. Network slice is programmable and has the ability to expose its capabilities. The behaviour of
the network slice realized via network slice instance(s).
NOTE 1 – Network slice enables the operator to create networks customized to provide flexible solutions for
different market scenarios, which have diverse requirements, with respect to the functionality, performance
and resource separation.

NOTE 2 – Infrastructure resources include any kind of resources (e.g., physical, logical, virtual resource).

3.2.5 network slice instance: An activated network slice. It is created based on network slice blueprint (or
template).

NOTE – A set of managed run-time network functions, and resources to run these network functions, forming
a complete instantiated logical network to meet certain network characteristics required by the service
instance(s). It provides the network characteristics which are required by a service instance. A network slice
instance may also be shared across multiple service instances provided by the network operator. The network
slice instance may be composed by none, one or more sub-network instances, which may be shared by
another network slice instance.
3.2.6 network softwarization: An overall transformation trend for designing, implementing, deploying,
managing and maintaining network equipment and/or network components by software programming,
exploiting the natures of software such as flexibility and rapidity all along the lifecycle of network equipment
/ components, for the sake of creating conditions enabling the re-design of network and services
architectures, optimizing costs and processes, enabling self-management and bringing added values in
network infrastructures.
3.2.7 orchestration: An automated arrangement, coordination of complex network systems and functions
including middleware for both physical and virtual infrastructures. It is often discussed as having an inherent
intelligence or even implicitly autonomic control. Orchestration results in automation with control network
systems.

3.2.8 orchestrator: An entity that fulfils orchestration functions.
NOTE – An entity that manages network service lifecycle and coordinates the management of network
service life cycle, network function lifecycle and network function infra resources to ensure optimized
allocation of the necessary resources and connectivity. It builds and operates each slice suitable for the
service requirements. It is also tightly connected to OSS/BSS for service management.
3.2.9 physical resource: A physical asset for computation, storage and transport (e.g. switch, router,
antenna, etc.).
NOTE – Network functions are not regarded as resources.

3.2.11 slice: As a concept describing system behaviour, slice is a logically isolated set of programmable
infrastructure resources (i.e., physical and/or logical resources) to enable functions and services of IMT-2020
network. Slice is created and deleted by order from the orchestrator.

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