14.3.11 VAL services over 5GS supporting EPS interworking

23.4343GPPFunctional architecture and information flowsRelease 18Service Enabler Architecture Layer for Verticals (SEAL)TS

The VAL server consumes the network resource management services from the NRM server. As specified in 3GPP TS 23.501 [10], a dedicated user plane anchor point, i.e. UPF + PGW-U function, is defined for interworking between 5GS and EPS. This enables that the network can directly handle PDU sessions (in 5GS) and PDN connections (in EPS) associated to VAL service sessions of a VAL UE during inter-system mobility.

The inter-system mobility of a VAL UE will be transparent to the NRM server and VAL server. The NRM server will continue interacting with the same control plane functions, e.g. PCF, and the VAL server will continue interacting with the same user plane function, e.g. UPF + PGW-U.

NOTE: For the case that seamless session continuity is required for VAL services, EPS interworking with N26 (interface between AMF in 5GC and MME in EPC) is required for inter-system change, as described in 3GPP TS 23.501 [10].