What the SMF does
The SMF manages PDU sessions. It allocates session-related information, selects and controls UPFs, installs forwarding rules and coordinates QoS and charging-related session behaviour.
How it relates to slicing
A PDU session is associated with an S-NSSAI and DNN. The SMF uses that context when selecting the data-network path, UPF and policy treatment.
Why it matters to enterprises
UPF selection and session policy determine whether traffic exits centrally, reaches a private data network or breaks out locally towards an edge application.
Standards note: this page is an explanatory summary. Precise procedures, services and information elements are defined in the applicable 3GPP specifications.