5G • Core Network
NRF
Network Repository Function
The central discovery and registration hub in 5GC that maintains NF profiles and enables microservices to dynamically discover each other.
Technical Explanation
The NRF acts as the service registry and discovery engine in the 5G Service-Based Architecture. When a Network Function (e.g. SMF, PCF, UPF) boots up, it registers its NF Profile (IP, FQDN, supported slices, capacities, supported services) with the NRF. When another NF (e.g. AMF) needs to find an SMF supporting a specific S-NSSAI and DNN, it queries the NRF. The NRF also monitors NF status via periodic heartbeats and supports load balancing.
Key Functions
- Registration, deregistration, and heartbeat management of NF instances
- Dynamic discovery of NF service instances matching query criteria
- Authorization of service access tokens (OAuth 2.0) between NFs
- Status notification to subscribed NFs when peer instances change state
Specifications
3GPP TS 23.501, TS 29.510
Interfaces
Nnrf (Service-Based Interface)
Related 5G Concepts
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