Specifications

Introduction
Page
6
1 INTRODUCTION
Certain maintenance functions need to be performed remotely at
a
low
level in the overall network architecture. These
are functions that
cannot depend on hiqh level software being operational in
the
system
being maintained.
In the context of this specification, low level implies direct usage
of data link services. High level means such network functions as
routing and end-to-end, virtual circuit type protocols, both of which
are also users of data lin~ services. This specification assumes that
only a minimal level of dara link services are available to support
maintenance operations, and that these maintenance operations provide
a base on which any higher level functions can be built.
This document describes the structure, functions,
interfaces, and
protocols needed for low level maintenance. DNA is the model on which
DECnet implementations are based. A DECnet network is a family of
software modules, data bases, and hardware components used to tie
DIGITAL systems together for resource sharing, distributed computation
or remote system communication.
DNA is a layered structure. Modules in each layer perform distinct
functions. Modules within a single DNA layer (but typically in
different computer systems) communicate using specific protocols.
Modules in different layers (but typically in the same computer
system) interface using subroutine calls or a system-dependent method.
In this document interfaces are described in terms
of calls to
subrout ines.
This document assumes that the reader is familiar with computer
communications and DECnet. The primary audience consists of those who
implement DECnet systems or other systems under different
architectures, but requiring the same
functions. However, the
document may be useful to anyone interested in the details
of DECnet
structure. The other current DNA functional specifications are:
DNA
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DNA
-
DNA
-
DNA
-
DNA
-
DNA
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Data Access Protocol (DAP) Functional Specification, Version
5.6.0, Order No. AA-K177A-TK
Digital Data Communications Message Protocol (DDCMP)
Functional Specification, Version 4.1.0, Order No. AA-K175A-TK
Ethernet Data Link Functional Specification, Version 1.0.0,
Order NO.=Y!~~A-TK
Ethernet Node Product Architecture Specification, Version
1.0.0, Order No. AA-X440A-TK
Network Management Functional Specification, Version 4.0.0,
Order No. AA-X437A-TK
Network Services Protocol Functional Specification, Version
4.0.0, Order No. AA-X439A-TK