When a Fifth Generation (5G) Network Repository Function (NRF) deployed in a Third Generation Partnership Project (3GPP) hierarchical model architecture receives a Network Function (NF) Discovery or Subscription or Access Token request, the NRF may not have the required information to serve the request on account of the information being divided among multiple NRF instances in the network. In such cases, the NRF instance that receives the request from a consumer NF may choose to forward or redirect the request to another NRF instance in the hierarchy. The conditions and policies to decide when to redirect or forward the request to another NRF are not defined by 3GPP. Further, the procedures and policies for selecting the next hop NRF are left to implementation. This is a major gap in 3GPP standards as an NRF at each hierarchical level needs rules to determine whether it can serve a request locally or needs to forward/redirect the request to another NRF instance in the hierarchy. This proposal involves defining a granular, flexible and policy-driven system for NRF selection and message routing between hierarchical NRFs to minimize latency and signaling overhead
