Page 77 - ITU-T Focus Group IMT-2020 Deliverables

ITU-T Focus Group IMT-2020 Deliverables 3

Network Function: In this TR, Network function is a 3GPP adopted or 3GPP defined processing function in a
network, which has defined functional behaviour and 3GPP defined interfaces.
NOTE – A network function can be implemented either as a network element on a dedicated hardware, or as
a software instance running on a dedicated hardware, or as a virtualised function instantiated on an
appropriate platform, e.g. on a cloud infrastructure.

Network Slice Template (NST): is a logical representation of the Network Function(s) and corresponding
resource requirements necessary to provide the required telecommunication services and network
capabilities.

Network Slice Instance (NSI): is an instance created from a Network Slice Template (NST).
Network Slice: is a concept describing a system behaviour which is implemented via Network Slice
Instance(s).
NextGen Core Network: A core network specified in the present document that connects to a NextGen access
network.
NextGen Access Network (NG AN): It refers to a NextGen RAN or a Non-3GPP access network and interfaces
with the next generation core.

NextGen System (NG System): It refers to NextGen system including NextGen Access Network (NG AN) and
NextGen Core.

6.1.1.2 Key issues and solutions

6.1.1.2.1 Key issue: Support of network slicing
Network slicing is studied to provide operators flexibility to create networks customised according to diverse
requirements from the perspectives of functionality, performance, isolation, etc. They refer to the definitions
and terminologies on Network Slicing from 3GPP SA1 and NGMN while they still open to other industry
organisations for more inputs.
Among others, discussion through several meeting includes sharing of network functions among different
network slices, selection of network slice of a UE, how to enable a UE to simultaneously access multiple
network slices, etc. Please refer to Clauses 5.1 and 6.1 in NextGen TR 23.799 for the detailed non-exhaustive
list of solutions for this key issue.

Table 6.1.1-1 – Work tasks for network slicing

Work Task Work Task(s) Work Task Description
ID

NS_WT_#1 Network Slice 1) Initial network slice instance selection to support UE’s service establishment
Instance and re-selection to support UE mobility and other scenarios that are TBD,
Selection and NOTE – More scenarios beyond the mobility need to be identified that may trigger
Association network slice instance re-selection.
2) Network slice instance identification,
3) authorization for UE association with network slice instance
4) Network assistance information support for UE network slice instance
association with corresponding PLMN
NS_WT_#2 Network 1) Security isolation
Slicing 2) Resource isolation
Isolation 3) OAM support isolation (e.g., Usage and Fault isolation etc.)
NOTE – Whether all items listed here are within the scope of SA2 is FOR FURTHER
STUDY.

71