DECnet-Plus

This document, "DECnet-Plus Problem Solving" (November 1996), is a technical manual for network and system managers troubleshooting DECnet-Plus networks on OpenVMS (VAX and Alpha) and Digital UNIX environments.

The manual outlines a structured approach to problem-solving, starting with an overview of fault isolation, problem classification (reproducible, intermittent, transient), understanding the DECnet-Plus network model (OSI, DNA, TCP/IP interoperability), and component relationships.

Key areas covered include:

• Preparation for Problem Solving: Identifying network topology, node names, operating system versions, and circuit information using tools like decnet_migrate, NCL, and NCP.
• Network Reachability Tests: Detailed instructions for quick reachability tests, various loopback tests (node-level, circuit-level, LAN), dts/dtr tests (connect, data, disconnect, interrupt), and OSI Echo (ping) for Digital UNIX.
• Problem Solving by Network Layer/Component:
  • DECnet Over TCP/IP: Specific troubleshooting for issues related to DECnet applications running over TCP/IP transport services.
  • Application Problems: Guidance for File Transfer, Access and Management (FTAM), Virtual Terminal (VT), and OSI Applications Kernel (OSAK) applications, including symptom analysis, event logging, and tracing.
  • Session Control Problems: Addressing issues such as unknown applications, "application too busy," access control, resource problems, timeouts, and node name resolution, including the use of the DECnet-Plus Naming Cache.
  • Transport Problems: Correcting connection problems related to OSI Transport over Connectionless-mode Network Service (CLNS) and Connection-Oriented Network Service (CONS/X.25), and troubleshooting RFC 1006.
  • Network Layer Problems: Isolating and correcting configuration and connectivity issues for various routing circuit and data link entities (HDLC, DDCMP, CSMA-CD, FDDI, Token Ring).

The document emphasizes using specific DECnet-Plus tools like Network Control Language (NCL) and DECnet Phase IV tools like Network Control Program (NCP), along with diagnostic utilities and log file analysis, to effectively diagnose and resolve network issues.