Distributed Name Service (DNS) Management Operations Manual

How to Define DNS Names
Building and Modifying the DNS Database
4–30 31258 Tandem Computers Incorporated
Defining Groups A group is the name for a set of related DNS object names whose members can be
aliases, composites, or other groups. Groups are most often used to define sets of
objects on which the same operation must be performed, or objects all of which are
affected by the same actions. For example, a group could contain the names of lines
from which a certain quality of service is required. Applications can monitor statistics
and events involving those lines.
As illustrated in Figure 4-15, an example of a group name for all ATMs in San
Francisco could be SF-ATMS, which includes ATM-36, ATM-44, and others.
Figure 4-15. Group of ATMs
ATM-36 ATM-37 ATM-44 ATM-n
SF-ATMs
S8121-028
It would be unnecessary to define a group of terminals controlled by one Pathway
TCP, because an operator or application can easily get that information from Pathway.
Group names are required where the criteria for group membership are not known to
any subsystem or where members of a set are controlled by multiple subsystems. For
instance, the group name DENVER_TERMINALS might actually refer to all terminals
in Denver: \DENVER.$TERM001, \DENVER.$TERM002, \DENVER.$TERM003, ...;
\MILEHI.$TERM001, \MILEHI.$TERM002, \MILEHI.$TERM003, ...; and so on.
A group and its members need not be defined on the same system within a network.
A group may contain members that are defined elsewhere and replicated to the
group’s definition node; however, the GROUPS attribute for the member at its
definition node does not record such remote group membership.
Be careful to notice the difference between composites and groups. As displayed in
Figure 4-15, the ATM is a composite controlled by three components, but ATM-44 can
be a member of many different groups, for example, SF-ATM.
When you add a group definition, you specify the following:
The group name
The names of the members
The names of any other groups to which the group belongs
Optionally, you can specify the domain of the group in the definition of the group.