Distributed Name Service (DNS) Management Operations Manual

The Need for Better Name Management
Introducing Distributed Name Service
31258 Tandem Computers Incorporated 1–3
To appreciate the need for a good naming system, consider the following situations.
The Guardian names of certain objects change fairly often. For instance, terminal
names change as new communications lines are added and existing terminals are
moved to these lines. Disk files are routinely moved from one physical volume to
another, again requiring new names. These changes occur as a normal part of
ongoing maintenance or performance tuning.
If you are a system manager, these changes often require you to determine what
object definitions to alter to reflect the new addresses, and to coordinate these
changes between systems and subsystems such as the Guardian 90 operating
system and the appropriate Pathway monitor. To accomplish these changes, you
need to determine the various names by which the different subsystems recognize
each object. Usually, this means you must find these names by comparing reports
generated by various subsystems such as SCF, CMI, Pathmon, PUP, or FUP, each
of which may refer to the same object by a different name.
It is necessary to determine which objects are interrupted during a component
failure. If a byte-synchronous controller for a communications line fails, you may
want to transfer the circuit to a backup line quickly. In this case, you must
determine what other objects (such as Pathway terminals) should be altered to
accommodate this change and what initialization cold-load files must be updated
before the next cold load. These objects and their names are not always easy to
determine.
Some names for network objects are unknown to any Tandem subsystem. For
example, a communications line may be known to the telephone company as
0004KDF0401A, and that may be the name that is needed to solve a problem
occurring on the line.
You sometimes need to define and refer to arbitrary groups of objects. Such a
group might consist of all Tandem systems in California or all terminals in
department 3460. In such cases, you need the convenience of referring to these
objects collectively by one common name.
Clearly, with larger and more sophisticated systems, you need convenient ways to
view your current configuration, to assign simple names to objects, and to use these
names to retrieve information about the objects. DNS provides ways to perform these
tasks. It lets you determine the subsystem-object names for any object, find other
objects that depend in various ways on a particular object, and group objects by a
collective name.