Page 78 - ITU-T Focus Group IMT-2020 Deliverables

3 ITU-T Focus Group IMT-2020 Deliverables

Table 6.1.1-1 – Work tasks for network slicing

Work Task Work Task(s) Work Task Description
ID
NS_WT_#3 Network 1) Identifying impacted network functions and interfaces to support one or more
Slicing network slice instances on top of a shared RAN and a shared infrastructure.
Architecture 2) Identifying the common functions (if any) that need to be available in the core
network and/or RAN to enable network slicing
3) Identifying the approach to enable UE to associate with multiple slices
simultaneously.
NS_WT_#4 Network 1) Determination what visiting and home Network Function(s) are required to
Slicing support roaming.
Roaming
support
NS_WT_#5 Network 1) If Network Slice Instance is agreed to apply E2E system, then, we should
Slicing consider new terminology for Access slice instance and Core slice instances.
terminology
& definitions

The following bullets are the current status of agreements on the network slicing (source: SA2 #118)
1) The network slice is a complete logical network (providing Telecommunication Services and Network
Capabilities) including AN and CN. Whether RAN is sliced is up to RAN WGs to determine.
a) AN can be common to multiple network slices.
b) Network slices may differ for features supported and Network Functions optimisations use
cases.
c) Networks may deploy multiple Network slice instances delivering exactly the same
optimisations and features as per but dedicated to different groups of UEs, e.g. as they deliver
a different committed service and/or because they may be dedicated to a customer.

2) A UE may provide network slice selection assistance information (NSSAI) consisting of a set of
parameters to the network to select the set of RAN and CN part of the network slice instances (NSIs)
for the UE.
a) The NSSAI can have standard values or PLMN specific values. The NSSAI (which is used to select
the CCNF) is a collection of SM-NSSAIs (see sub-bullet 2c for the SM-NSSAI definition), each
allowing the network to select a particular slice.

NOTE – whether a single value which is a representation of a collection of the SM-NSSAIs could also
be used as NSSAI is to be assessed in normative work.
b) The UE may store a Configured and/or Accepted NSSAI per PLMN.

The Configured NSSAI is a NSSAI configured by default in a UE to be used in a PLMN before any
interaction with the PLMN ever took place.

The Accepted NSSAI is the NSSAI used by the UE after the PLMN has accepted an Attach Request
from the UE. The Attach Accept message includes the Accepted NSSAI. The accepted NSSAI may
be updated by MM procedures (see below).

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