SMF Design Overview
 
UPF-Adapter
As UPF may not support connections from multiple SMF instances with same Node-Id, UPF-Adapter layer has been introduced.
- UPF-Adapter acts like Mux-Demux for PFCP messages between multiple SMF instances and UPF. 
- SMF sends custom PFCP msg to UPF-Adapter if UPF-Adapter is deployed. 
- The UPF-Adapter intercepts and modifies certain fields before sending PFCP msg to actual UPF. 
- Similar handling is done for the response from UPF towards SMF.