5G/NR - Network Architecture - NSSF

 

 

 

NR CORE - NSSF

NSSF plays(Network Slice Selection Function) has relatively simple function and interact with only a few NF(Network Functions). Within a PLMN, it interact only with NRF and AMF and exchange information about Network Slice Selection.

Followings are the name of each network component.

    AMF     Access and Mobility Management Function ==> Equivalent to MME in 4G

    AUSF    Authentication Server Function

    DN       Data Network

    NEF      Network Exposure Function

    NRF      Network Repository Function

    NSSF    Network Slice Selection Function

    PCF      Policy Control Function ==> Equivalent to PCRF in 5G

    (R)AN   (Radio) Access Network

    SMF     Session Management Function

    UDM     Unified Data Management ==> Equivalent to HSS in 4G

    UPF      User Plane Function ==> Equivalent to PGW in 4G

    SMSF   SMS Function

    SEAF    SEcurity Anchor Function ==> part of AMF function

    ARPF    Authentication credential Repository and Processing Function

    SIDF    Subscription Identifier De-concealing Function

GET operation of NSSF

Since the main roles of NSSF is to provide Network Slice Information to AMF, the major operation should be GET operation. NSSF GET operation described in 29.531 is as follows.

 

The same operation (with different parameters) happens in a few different situationas listed below :

  • during the mobility procedure (29.531-5.2.2.2.2)
  • during the PDU session establishment procedure (29.531-5.2.2.2.3)
  • during UE configuration update procedure (29.531-5.2.2.2.4)

Network Selection Related Information

 

< 29.531 - Table 6.1.6.1-1: Nnssf_NSSelection specific Data Types >

 

< 29.531 - Table 6.1.6.2.2-1: Definition of type AuthorizedNetworkSliceInfo >

 

< 29.531 - Table 6.1.6.2.3-1: Definition of type SubscribedSnssai >

 

< 29.531 - Table 6.1.6.2.5-1: Definition of type AllowedSnssai >

 

< 29.531 - Table 6.1.6.2.6-1: Definition of type AllowedNssai >

 

< 29.531 - Table 6.1.6.2.7-1: Definition of type NsiInformation >

 

< 29.531 - Table 6.1.6.2.8-1: Definition of type MappingOfSnssai >

 

< 29.531 - Table 6.1.6.2.10-1: Definition of type SliceInfoForRegistration >

 

< 29.531 - Table 6.1.6.2.11-1: Definition of type SliceInfoForPDUSession >

 

< 29.531 - Table 6.1.6.2.12-1: Definition of type ConfiguredSNssai >

 

< 29.531 - Table 6.1.6.2.13-1: Definition of type SliceInfoForUEConfigurationUpdate >