DECnet Open Networking

This document is a volume of the Digital Technical Journal from Winter 1993, focusing on "DECnet Open Networking" and detailing Digital Equipment Corporation's advanced networking technologies. It covers the evolution and implementation of DECnet Phase V, Digital's fifth-generation network architecture, designed for large, open, and standardized networks capable of supporting millions of nodes.

Key areas explored include:

• DECnet Phase V Overview: Describes the architecture's principles, layered structure, and goals to integrate industry standards (OSI, TCP/IP, X.25) while maintaining backward compatibility with previous DECnet versions.
• Operating System Implementations: Specific papers detail the DECnet/OSI implementations for OpenVMS Version 5.5 and ULTRIX, outlining their designs, network management, session control, transport layers, and configuration tools.
• High-Performance Networking: Highlights optimizations for TCP/IP and UDP/IP on DEC OSF/1 for Alpha AXP workstations to achieve full FDDI (100 Mb/s) bandwidth, addressing bottlenecks, optimizing data movement and checksums, and supporting features like large TCP windows.
• Routing Architecture: Discusses the IS-IS protocol for intra-domain routing, its self-stabilizing nature, hierarchical structure, efficient LAN utilization (pseudonodes), and mechanisms to handle database overload. It also covers Digital's multiprotocol routing software design, focusing on stability, performance, and the DECNIS 500/600 bridge/router.
• Frame Relay Networks: Explains frame relay as a high-speed packet-mode transmission service for bursty traffic, including its protocol, congestion avoidance mechanisms, and its support in Digital's DECNIS and WANrouter products.
• OSI Upper Layers and Applications: Describes the implementation of OSI session, presentation, and application layers, emphasizing File Transfer, Access, and Management (FTAM) and Virtual Terminal (VT) protocols, with a focus on performance, maintainability, and portability.
• Network Management: Introduces Digital's Enterprise Management Architecture (EMA) and the DECmcc Management Director, a platform designed for consistent, extensible, and integrated management of networks and systems across diverse hardware and software platforms, using concepts like entities, directors, agents, and the Common Management Information Protocol (CMIP).

The overarching theme is Digital's commitment to developing robust, scalable, high-performance, and easily manageable networking solutions that adapt to evolving industry standards and multivendor environments.