DECbridge 90 Owners Manual

This document is the Owner's Manual for the DECbridge 90, a network device developed by Digital Equipment Corporation (published 1991/1992).

The DECbridge 90 is a specialized Local Area Network (LAN) device designed to connect two Ethernet or IEEE 802.3 compliant LAN segments—a "backbone" and a "work group"—to form a single, extended network. Its primary purpose is to enhance network reliability and efficiency by allowing LANs to be partitioned, thereby isolating traffic and extending network range.

Key aspects covered in the manual include:

• Overview: Describes the DECbridge 90's features, such as its easy-to-use "plug-and-go" installation, activity LEDs for diagnosis, frame filtering and forwarding capabilities, and support for the Spanning Tree Algorithm to prevent network loops. It can operate as a standalone unit or be rack-mounted in a DEChub 90 backplane.
• Connectivity: The work group typically connects via ThinWire (10Base2), while the backbone can use either ThinWire (10Base2) or AUI (10Base5).
• Configuration: Details the rules and guidelines for setting up the DECbridge 90, including considerations for work group size (optimally under 200 stations for traffic isolation, otherwise it enters "flood mode"), and managing redundant connections.
• Installation: Provides step-by-step instructions for both standalone and DEChub 90 backplane installations, including power supply connections and cable termination requirements.
• Management: Explains how to manage the DECbridge 90 primarily through the Maintenance Operations Protocol (MOP) console carrier (accessible from VMS or ULTRIX systems). MOP allows users to examine bridge/port status, configure advanced features like protocol filtering (to control specific types of network traffic), define passwords, and enable/disable flood mode. It also briefly mentions support for Remote Bridge Management Software (RBMS).
• Troubleshooting: Offers guidance on diagnosing problems using the front panel indicator lights (LEDs) and provides tables of common issues with suggested corrective actions.
• Specifications: Includes technical details such as physical dimensions, environmental operating and shipping requirements, and power specifications, along with a parts list.

In summary, the DECbridge 90 Owner's Manual is a comprehensive guide for understanding, installing, configuring, operating, and troubleshooting the DECbridge 90, enabling users to effectively manage and segment their Ethernet/IEEE 802.3 networks.