S8 Home Routing Call Flow

This section describes the S8 Home Routing call flow.

For the preparation phase, see 3GPP TS 23502, Release 15.4.0, section 4.11.1.2.2.2-1—EPS to 5GS (4G to 5G) handover using N26 interface.

The home-routed roaming scenarios support the following functionalities:

  • H-PLMN supports the following nodes:

    • PGW-C and SMF

    • UPF and PGW-U

  • AMF selects a default vSMF per PDU session, and invokes the Nsmf_PDUSession_CreateSMContext service operation with the following:

    • UE PDN connection contexts

    • AMF ID

    • SMF

    • PGW-C address

    • S-NSSAI

  • The S-NSSAI is configured for interworking and is associated with default vSMF.

  • The default vSMF puts S-NSSAI in the N2 SM information container.

  • AMF selects PGW-C and SMF through NRF from S8 FQDN (obtained from the MME).