SNMP Reference Guide

Introduction 31
Access specifies whether persons with administrative privileges can read but not
modify the value of a variable (read only) or can both read and modify the value
of a variable (read-write).
Frequently Used Terms in Variable Names
The following terms are frequently used in the name of a MIB variable:
Capability refers to the actions an object can perform, or to actions that can
be taken by the object. Hot-pluggable is an example of a capability. If a card is
hot-pluggable, it can be replaced while a system is running. Capability settings
refer to the capabilities of the object that the user can select from and activate
if desired. Capability settings allow users of the server administrator to
predetermine how an object will behave under specific conditions.
Settings are the conditions of a manageable object that determine what
happens when a certain value is detected in a component. For example, a user
can set the upper critical threshold of a temperature probe to 75 degrees
Celsius. If the probe reaches that temperature, the setting causes an alert to
be sent to the management console. Some settings, when reached, can trigger
a system shutdown or other response to prevent damage to the system.
State refers to the condition of an object that has more than one condition.
For example, an object may be in a "not ready" or in an "enabled" state.
Status refers to the health of an object or how the object is functioning. For
example, the status of a temperature probe that is measuring acceptable
temperatures would be reported as normal. When the probe begins reading
temperatures that exceed limits set by the user, it reports a critical status.
Tables
This reference guide contains two types of tables: tables that are used to
organize and define variable values and tables that define MIB objects.
Readers must understand the difference between these two types of tables.
SNMP Tables
Most of the MIB objects defined in this reference guide are organized into
SNMP tables. SNMP tables organize data into two-dimensional structural
arrays. In SNMP, objects that have a relationship to other objects are called
columnar objects. Columnar objects are objects used to form lists and tables.
When a MIB group is divided into one or more discrete tables, the word