How it Works
The SMF maintains the cache data in a cache pod. It uses the cache pod to share the NF discovery cache across multiple instances of SBI pods. The SBI pod periodically updates the cache pod on receiving an NF discovery response. All SBI pods refresh its cache data periodically with the help of the cache pod.
If a message is sent to an NF that meets a specific criterion, the SMF looks up the cache data for further processing. During a cache lookup:
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On a cache hit without an expired entry, the selected cached NF response sends a message for an endpoint selection.
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On a cache hit with an expired entry, the SMF sends NF discovery requests to the NRF to fetch a new list of NF discovery responses.
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If there is a cache miss, the SMF sends NF discovery request to the NRF to retrieve a new list of NF discovery responses.