HP SNMP/XL User's Guide (36922-90036)

Chapter 1 15
Introduction to HP SNMP/XL
Concepts and Definitions
Concepts and Definitions
Following is information on some concepts related to SNMP.
Community Name
Requests for information on an agent are accompanied by a community
name. A community name is similar to a password preventing
unauthorized network managers from accessing agent information
(MIB values). The community name sent with a request must match
the community name expected by the target SNMP node (agent) and is
case-sensitive. Some SNMP nodes support multiple levels of access
based on the community name (e.g., read-only versus read-write). Most
nodes support the community name “public,” generally considered the
default.
Traps
An agent can send information to the manager without a request from
the manager. Such an operation is called a trap (or an event). Traps
inform the manager of changes that occur on the agent system, such as
a reboot, without being asked. The agent knows which manager system
to send traps to via its trap destination. A trap destination identifies a
manager system that is to receive the agent’s traps.
Protocol Data Units (PDUs)
The Protocol Data Unit (PDU) is the format of data exchanged between
the SNMP manager and agent. This data object is exchanged by peers
and contains protocol control information and user data.
SMI
The Structure of Management Information (SMI) is a document where
the SNMP network management information structure and language
for organizing that information is defined.
MIB
The information on the agent that the manager requests resides in the
Management Information Base (MIB). The MIB is a virtual database of
managed objects contained within the SNMP agent. The MIB is not a
physically distinct database, but rather it is a concept that includes
configuration and status values normally available on the agent
system.
The MIB defines the set of objects to be managed by SNMP and defines
the syntax by which the data is represented. It allows you to get
statistics and tabular data relevant to an internet protocol layer such as