An SMS flow entry point can be either an Application Phone or a Start iSMS depending on the way that is initiated:

SMS Session

In both situations, Platform Server creates a session to keep context for the end-user; the session is stored for a pre-defined period of time.

The session consists of user MSISDN and the application phone number. Platform Server uses this pair to identify the end.-user.

See Also

iSMS Initiated by the End-user | iSMS Initiated in Another Flow