Information Technology Reference
In-Depth Information
11
CHAPTER
Troubleshooting DECnet
Digital Equipment Corporation (Digital) developed the DECnet protocol family to provide a
well-thought-out way for its computers to communicate with one another. The first version of DECnet,
released in 1975, allowed two directly attached PDP-11 minicomputers to communicate. In more recent
years, Digital has included support for nonproprietary protocols, but DECnet remains the most important
of Digital's network product offerings.
DECnet is currently in its fifth major product release (sometimes called
Phase V
and referred to as
DECnet/OSI in Digital literature). DECnet Phase V is a superset of the OSI protocol suite and supports
all OSI protocols as well as several other proprietary and standard protocols that were supported in
previous versions of DECnet. As with past changes to the protocol, DECnet Phase V is compatible with
the previous release (Phase IV, in this case).
Digital Network Architecture
Contrary to popular belief, DECnet is not a network architecture at all but is, rather, a series of products
conforming to Digital's Digital Network Architecture (DNA). Like most comprehensive network
architectures from large systems vendors, DNA supports a large set of both proprietary and standard
protocols. The list of DNA-supported technologies grows constantly as Digital implements new
protocols. Figure 11-1 illustrates an incomplete snapshot of DNA and the relationship of some of its
components to the OSI reference model.
