Distributed Name Service (DNS) Management Operations Manual

Selecting a Naming Strategy
Building and Modifying the DNS Database
4–2 31258 Tandem Computers Incorporated
When processing an update command, DNS always accesses the definition node for all
names involved in the command. This rule prevents the problems that would
otherwise occur if persons at two different nodes simultaneously tried to update their
local copies of the DNS database. See “How DNS Avoids Name Duplication and
Incompatibility” and “Distribution Strategy of Network Control Nodes” in Section 5
for information about name-distribution strategy.
It is also recommended that you select aliases that describe or otherwise suggest the
meaning of the objects to which they refer. For instance, ATM60 refers to an ATM,
and LP3 refers to a line printer. The same guideline applies to group names. For
example, CHICAGO-ATM is a descriptive name for a group of ATMs in Chicago, and
FASTPRINT for a group of high-speed line printers.
Traditionally, computer users establish names based on criteria such as geography
(DENVER-RUN for an application on a system in Denver), function (PAYCHECK for
an application that processes payroll checks), or business organization (ACCOUNTS1
for an application normally run by an Accounting department). These are all
reasonable criteria for aliases, composite, and group names. You should not, however,
assign aliases on the basis of network location; subsystem-object names already serve
that purpose. Aliases are intended to augment, not replace, subsystem-object names.
Another consideration is hierarchical nesting of aliases. Although DNS does not
directly provide this kind of nesting, you can indirectly achieve this effect by careful
arrangement of groups and their members. In addition to simple and composite
objects, groups can be members of other groups. Thus, you can effectively nest up to
four levels of names by associating these names with group names. DNS lets you do
this without imposing the many rules and complexities that normally accompany
hierarchical structures.
Figure 4-1 displays an example of a hierarchical structure where the group
OREGON_ATMS includes four subordinate groups: PORTLAND_ATMS,
MEDFORD_ATMS, SALEM_ATMS, and EUGENE_ATMS. Each of these groups, in
turn, might include its own set of groups. For instance, PORTLAND_ATMS might
contain as members PORT_NORTHWEST_ATMS, PORT_NORTHEAST_ATMS, and
so forth. Finally, PORT_NORTHWEST_ATMS might include the objects named
PNE_ATM1, PNE_ATM2, and PNE_ATM3. Details about nesting groups appears
under “Defining Groups” later in this section.