5GC Service‐Based Interfaces and Protocols
Zhu Fenqin · Wiley 5G Ref · 2021
Abstract The service‐based interface is used for the message interaction among the 5GC NFs. It is clarified what is the NF service, NF service operation, system procedure, and the relation among them. How to define the NF service in a suitable granularity is discussed. The protocol of the service‐based interface (SBI) is explained. For the interaction between the NF service consumer and NF service producer, it can be either request/response semantics service operation or subscribe/notify semantics service operation. The general behavior of these two types of service operation is described. Service Framework is the basic functionality supported by each by each 5GC NF. It includes service registration/discovery/authorization. Service status subscription is another import functionality even it is not belonged to the service framework. How to structure the NRF in the network is another important issue when considering the big network. To support the priority service, e.g. emergency service, Message priority header is introduced. It does have some impact on the NF service consumer, proxy, NF service producer. Load/Overload control can keep the network in the stable state. This requires some design considerations at the SBI interface. Security includes the service access authorization, the transferring of the signaling communication. It is always possible that a NF/NF service instance is failure and restart. To minimize the service interruption, it should be possible to detect this failure and restart of the NF instance or NF service instance. After that failure and restart detection, the NF service instance or NF instance can be reselected.