6.2.6 LI support at NRF

33.1273GPPLawful Interception (LI) architecture and functionsRelease 18TS

6.2.6.1 Architecture

In 5G, network functions that support SBA register with the NRF after instantiation. The NRF thus provides the network repository functions and is aware of all the NFs that have been instantiated. The present document refers to this as system information.

The SIRF present in the NRF provides the system information to LIPF present in the ADMF, in order for the LIPF to establish which NFs (and therefore POIs) are applicable to a specific target user’s services. LI function service discovery is described in clause 5.5.

An architecture diagram depicting this LI at NRF is shown in figure 6.2-6 below.

Figure 6.2-6: LI Architecture depicting NRF as an SIRF

Figure 6.2-6 shows the architecture illustrating the SIRF functions within the NRF.

The LIPF present in the ADMF interacts with the SIRF (over LI_SI) present in the NRF to obtain the system information.

6.2.6.2 LI_SI notifications

The SIRF present in the NRF shall generate notifications over LI_SI when the SIRF detects the following specific events or information:

– NF service registration.

– NF service update.

– NF service deregistration.

– NF service chain change.

The NF service chain change notification shall be generated whenever an NF is added to or removed from a service chain in response to NF discovery and selection events.

6.2.6.3 LI_SI parameters

The notifications reported over LI_SI by the SIRF shall include the following information elements:

– Event type (as defined in clause 6.2.6.2).

– NF details, including appropriate information elements defined in TS 23.501 [2] clause 6.2.6.