Question: The Data Stream Interface is a session layer used to carry this protocol formerly known as what?
Context: 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.  In macOS, AFP is one of several file services supported, with others including Server Message Block (SMB), Network File System (NFS), File Transfer Protocol (FTP), and WebDAV.  AFP currently supports Unicode file names, POSIX and access control list permissions, resource forks, named extended attributes, and advanced file locking.  In Mac OS 9 and earlier, AFP was the primary protocol for file services. In computing, the SSH File Transfer Protocol (also Secure File Transfer Protocol, or SFTP) is a network protocol that provides file access, file transfer, and file management over any reliable data stream.  It was designed by the Internet Engineering Task Force (IETF) as an extension of the Secure Shell protocol (SSH) version 2.0 to provide secure file transfer capabilities.  The IETF Internet Draft states that, even though this protocol is described in the context of the SSH-2 protocol, it could be used in a number of different applications, such as secure file transfer over Transport Layer Security (TLS) and transfer of management information in VPN applications. Chunked transfer encoding is a streaming data transfer mechanism available in the Hypertext Transfer Protocol (HTTP), version 1.1 and higher.  In chunked transfer encoding, the data stream is divided into a series of non-overlapping "chunks".  The chunks are sent out and received independently of one another.  No knowledge of the data stream outside the currently-being-processed chunk is necessary for both the sender and the receiver at any given time. Keyword Protocol 2000, abbreviated KWP2000, is a communications protocol used for on-board vehicle diagnostics systems (OBD).  This protocol covers the application layer in the OSI model of computer networking.  The protocol is standardized by International Organization for Standardization as ISO 14230.  KWP2000 also covers the session layer in the OSI model, in terms of starting, maintaining and terminating a communications session. In computing, vectored I/O, also known as scatter/gather I/O, is a method of input and output by which a single procedure call sequentially reads data from multiple buffers and writes it to a single data stream, or reads data from a data stream and writes it to multiple buffers, as defined in a vector of buffers.  "Scatter/gather" refers to the process of gathering data from, or scattering data into, the given set of buffers.  Vectored I/O can operate synchronously or asynchronously.  The main reasons for using vectored I/O are efficiency and convenience. Intelligent Printer Data Stream (IPDS) is InfoPrint Solution Company's Systems Application Architecture host-to-printer data stream for Advanced Function Presentation subsystems.  It provides an attachment-independent interface for controlling and managing all points addressable (APA) printers that allows the presentation of pages containing an architecturally unlimited mixture of different data types, including text, image, graphics, bar code, and object container.  It is used by a variety of InfoPrint and OEM print servers that drive all points addressable (APA) page printers.  Generally these printers are at the medium to high end of the print speed and volume spectrum. Out of band data is a logically independent transmission channel between a pair of connected stream sockets.  In computer networking, out-of-band data is the data transferred through a stream that is independent from the main "in-band" data stream.  An out-of-band data mechanism provides a conceptually independent channel, which allows any data sent via that mechanism to be kept separate from in-band data.  The out-of-band data mechanism should be provided as an inherent characteristic of the data channel and transmission protocol, rather than requiring a separate channel and endpoints to be established.  The term "out-of-band data" probably derives from out-of-band signaling, as used in the telecommunications industry. The Open Data-Link Interface (ODI), developed by Apple and Novell, serves the same function as Microsoft and 3COM's Network Driver Interface Specification (NDIS).  Originally, ODI was written for NetWare and Macintosh environments.  Like NDIS, ODI provides rules that establish a vendor-neutral interface between the protocol stack and the adapter driver.  It resides in Layer 2, the Data Link layer, of the OSI model.  This interface also enables one or more network drivers to support one or more protocol stacks. The Transmission Control Protocol (TCP) is one of the main protocols of the Internet protocol suite.  It originated in the initial network implementation in which it complemented the Internet Protocol (IP).  Therefore, the entire suite is commonly referred to as TCP/IP.  TCP provides reliable, ordered, and error-checked delivery of a stream of octets between applications running on hosts communicating by an IP network.  Major Internet applications such as the World Wide Web, email, remote administration, and file transfer rely on TCP.  Applications that do not require reliable data stream service may use the User Datagram Protocol (UDP), which provides a connectionless datagram service that emphasizes reduced latency over reliability. The Data Stream Interface (DSI) is a session layer used to carry Apple Filing Protocol traffic over Transmission Control Protocol.
Answer: AppleTalk Filing Protocol