Systems Network Architecture

Systems Network Architecture Systems Network Architecture (SNA) is a proprietary network architecture developed by IBM in the 1970s. It was designed to provide a comprehensive framework for building computer networks that could support a wide range of applications and devices. SNA was widely used in the 1980s and 1990s, particularly in mainframe environments, and played a significant role in shaping the development of modern networking technologies. The architecture was influenced by earlier work on network topology and communication protocols.

Overview

SNA was designed to provide a flexible and scalable architecture for building computer networks. It was based on a hierarchical structure, with a central mainframe or host computer at the top of the hierarchy, and a series of peripheral devices and terminals connected to it. SNA supported a wide range of network devices, including printers, disk drives, and terminals, and provided a range of network services, including file transfer, electronic mail, and remote access. The development of SNA was influenced by the work of Bob Hemenway, an IBM researcher who played a key role in the design of the architecture.

Architecture and components

The SNA architecture consisted of several key components, including the Physical Unit (PU), the Logical Unit (LU), and the Transmission Service. The PU was responsible for managing the physical connection between devices on the network, while the LU provided a logical interface for applications to communicate with each other. The Transmission Service was responsible for routing data packets between devices on the network. SNA also supported a range of network protocols, including the Synchronous Data Link Control (SDLC) and the Binary Synchronous Communication (BSC) protocols. The architecture was designed to be compatible with a range of operating systems, including Multiple Virtual Storage (MVS) and Virtual Machine (VM).

Protocols and operation

SNA used a range of network protocols to manage communication between devices on the network. The Data Link Switching (DLSw) protocol was used to route data packets between devices, while the Network Services Protocol (NSP) provided a range of network services, including connection management and data transfer. SNA also supported a range of session management protocols, including the LU 6.2 protocol, which provided a range of session management services, including session establishment and session termination. The IBM 3705 and IBM 3704 were two of the key network devices that supported SNA.

Development and history

SNA was developed in the 1970s by a team of researchers at IBM, led by Bob Hemenway. The architecture was designed to provide a comprehensive framework for building computer networks, and was influenced by earlier work on network topology and communication protocols. SNA was first released in 1974, and quickly gained popularity in mainframe environments. Over the years, SNA has undergone several revisions and updates, including the introduction of SNA 7, which provided a range of network services, including file transfer and electronic mail. The development of SNA was also influenced by the work of Larry Landweber, a researcher at IBM who contributed to the design of the architecture.

Impact and legacy

SNA played a significant role in shaping the development of modern networking technologies. Its hierarchical structure and use of network protocols influenced the development of later network architectures, including the Open Systems Interconnection (OSI) model. SNA also influenced the development of network devices, including routers and switches, and provided a range of network services, including file transfer and electronic mail. Today, SNA is still used in some mainframe environments, and its legacy can be seen in a range of modern networking technologies, including TCP/IP and HTTP. The IBM SNA architecture has had a lasting impact on the development of computer networks, and its influence can be seen in the work of Vint Cerf and Bob Kahn, two of the key developers of the Internet Protocol (IP).

Category:Computer networks