Specifications

Introduction Page 9
. Algorithms, particularly those found in memory-only systems,
are processing and memory efficient. Communications
efficiency
is a secondary goal. In the specific case of
down-line load and UD-line dump, overall speed of operation is
an important goal.
. Extensible to accommodate newly developed functions or
modification of current functions.
. Operates independently of the underlying communication
mechanism (e.g.
DDCMP, Ethernet, etc.).
. No complex algorithms or data bases. Minimal state kept in
the smallest systems.
The maintenance operation design does not try to have the following
characteristics:
. Isolation of components that have failed in a failing system.
. System security in the low level maintenance functions.
2 MODELS
This section describes the relationship of the low level maintenance
operations to other network layers and modules. Although this
specification primarily relates the maintenance operations to DNA, the
same relationships can also be applied within other network
architectures, such as
the DIGITAL System Communication Architecture.
2.1 Relationship to DIGITAL Network Architecture
The maintenance operations reside in the
DNA Network Management Layer.
They are direct users
of the DNA Data Link Layer. The other DNA
layers are not required in the support of the low level maintenance
operations unless such services as remote file access are to be used.
The following diagram shows the overall layering of DNA. A later
diagram shows the simplified model that
is applicable to the low level
maintenance operations.