5G Core Part 5 — Network Repository Function
Introduction to NRF
The 3GPP 5GS specifications have introduced a new 5G Network Function (NF) in the Service Base Architecture (SBA) Control Plane (CP) called the Network Repository Function (NRF) since the 3GPP 5GS Release 15 a few years ago. This article describes the networking challenges the NRF is designed to resolve and the operations of the NRF using a Wireshark trace.
In the earlier mobile networks such as the 4G LTE, static NF provisioning was used. For example, if you were adding an additional NF such as the Mobile Management Entity (MME) onto the 4G mobile network to support additional mobile traffic and/or improve network resilience, one would need to perform a lot of configuration changes to all the NFs connected to the MME such as the Service Gateway (SGW) and the Home Subscriber Server (HSS) etc… Also, exchanging proprietary NFs’ network status, loading, capability and service information for load-balancing and redundancy failover could quickly become a very daunting task for a large mobile network. This led to the development of networking features and products such as the Diameter Routing Agents (DRAs) and DNS SRV for service discovery etc... in the 4G mobile networks. Also, adding and removing NFs involved a lot of manual configuration changes. Not only that they were operational expensive, they were also error…
