Network Slice Identification and Instances

3GPP 28.541 shows relationships between Network Slice, Service Profile, Network Slice Subnet, Slice Profile and Network Service. This is replicated from the same spec as below.

As per Section 6 of 28.541, the properties for the requirement of a Network Slice Instance are specified in the Service Profile. And the properties for the requirement of a Network Slice Subnet Instance are specified in the Slice Profile.

The template for a Service Profile specifies the requirement for a Network Slice identified by the S-NSSAI (Single Network Slice Selection Assitance Information).

As mentioned above, a Service Profile instantiated from the Service Profile template is the requirement of the Network Slice Instance.
A Slice Profile instantiated from the Slice Profile template is the requirement of the Network Slice Subnet Instance.

These requirements have to be met by finding a suitable NST and NSST to create the Network Slice Instance and Network Slice Subnet Instance.

As per 3GPP 28.801 the Network Slice is described by the Network Slice Template (NST). The Network Slice Instance(NSI) is created using the NST and instance-specific information.

In this context, the Network Slice reperesents a logical network with a particular set of characteristics such as service type, QoS along with security requirements. The Network Slice is identified by the S-NSSAI. It is assigned to NSI when NSI is created from NST of Network Slice.

Because of this relationship, a Network Slice Instance (NSI) can be related to one or more S-NSSAIs. And a single S-NSSAI can be related to one or more Network Slice Instances.

Where there are two slices with the same S-NSSAI then the NSI-id is used. It is returned by the NSSF (3GPP core function) for specific S-NSSAI.

The next topic covers creation of S-NSSAIs and use of the same.