V-SMF (Visited SMF) is the session management function responsible for the user sessions of the UE, while the UE is roaming in the visited network. It interacts with the Home SMF (H-SMF) in the home network of the UE, to ensure seamless session management and mobility support for the roaming subscriber.

The V-SMF needs to align the policies enforced in the visited network with the policies defined by the home network's policy control functions, such as the Home Policy Control Function (H-PCF).

In addition, the it needs to ensure accurate charging and billing for the roaming subscriber's data usage, which may involve interactions with the home network's charging functions.