The Data Stream Interface is a session layer used to carry this protocol formerly known as what?
Data Stream Interface: The Data Stream Interface (DSI) is a session layer used to carry Apple Filing Protocol traffic over Transmission Control Protocol. Apple Filing Protocol: The Apple Filing Protocol (AFP), formerly AppleTalk Filing Protocol, is a proprietary network protocol, and part of the Apple File Service (AFS), that offers file services for macOS and the classic Mac OS.
AppleTalk Filing Protocol