Exploring 5G Network Slicing and read that NSSF is the function that controls the Network slicing in a 5g infrastructure. Pair of SMF and UPF, works for slicing.
But I am not clear about whether UPF supports only one slice or can support more. What are the information exchanged between UPF and SMF regarding network slicing.
Indeed, the User Plane Function (UPF) has the capability to support various Network Slices (NW slices). In order to achieve this, the Session Management Function (SMF) includes the S-NSSAI (Single Network Slice Selection Assistance Information Element) as an optional component in the PFCP (Packet Forwarding Control Protocol) establishment Request.
For more detailed information, I would recommend referring to specification 29.244, specifically section 7.5.2 titled "PFCP Session Establishment Request."