DECnet Digital Network Architecture Phase IV Ethernet Data Link Functional Specification

This document is the DECnet Digital Network Architecture Phase IV Ethernet Data Link Functional Specification, published by Digital Equipment Corporation in December 1983.

Its primary purpose is to define the structure, functions, interfaces, and protocols of the DNA Ethernet Data Link that extend beyond the standard Digital, Intel, Xerox Ethernet Specification (Version 2.0) to ensure compatibility with DECnet's layered Digital Network Architecture (DNA).

The specification details:

• The relationship of the DNA Ethernet Data Link to other DNA network layers and its position within the overall architecture.
• Its functional description, outlining two main service classes: user services (for transmitting and receiving frames, including filtering by system address and protocol type) and network management services (for controlling and observing the data link).
• Detailed interfaces for both user operations (e.g., opening "portals," enabling promiscuous/protocol/multicast modes, transmitting, receiving, and polling for completion) and network management (e.g., reading channel status, resetting channels, setting addresses, and querying counters and events).
• The operational logic for how the Data Link processes requests, handles frame transmission and reception, manages channel states (Off, Init, On, Broken), and deals with error conditions.
• Network management information, providing definitions for various counters (e.g., bytes/frames sent/received, collision statistics, failures) and events (e.g., initialization failures, send/receive errors) crucial for monitoring performance and diagnosing issues within the network.

The document is primarily aimed at implementers of DECnet systems and assumes an understanding of the underlying Ethernet specification.