What is NRF?
The NRF is the 5G Core’s service registry and discovery function — essentially the directory service for the entire 5GC. Every Network Function instance registers its profile with the NRF when it starts, and other NFs discover available services by querying the NRF. It is what makes the Service-Based Architecture (SBA) dynamic and cloud-native.
How Does NRF Work?
NF instances call Nnrf_NFManagement (registration/update/deregistration) when they start, change state, or stop. When an NF needs to communicate with another NF type, it calls Nnrf_NFDiscovery with filtering criteria (NF type, location, slice, capacity) to get a list of available NF instances and their endpoints. This replaces static configuration between NFs.
Use Cases
Enabling dynamic NF discovery in cloud-native 5GC on Kubernetes, supporting NF auto-scaling (new instances auto-register), NF load balancing, facilitating network slice-specific NF selection.
3GPP / Standards Reference
3GPP TS 29.510 (NRF Services — Nnrf API)
Related Terms
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This glossary entry is part of the 5GWorldPro Complete 5G Glossary. To go deeper into 5G architecture and technology, explore our 5G Training courses.
