Sun Microsystems Netscape Enterprise Server, Руководство администратора

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Chapter 9, Using SNMP to Monitor Servers 201
SNMP Basics
For detailed information about Enterprise Server’s network management
variables, see “The Enterprise Server MIB” on page 202.
The Enterprise Server MIB
The Enterprise Server MIB is a file named
netscape-http.mib
.
This file lists each object identifier for all servers currently supported by
Netscape. It also defines the Enterprise Server object identifier as
netscape 1
(
http OBJECT IDENTIFIER : := { netscape 1 }
).
Types of SNMP Messages
GET and SET are two types of messages defined by SNMP. GET and SET
messages are sent by an NMS to a master agent. You can use one or the other,
or both with Enterprise Administration Server. SNMP exchanges network
information in the form of
protocol data units (PDUs) . PDUs contain
information about variables stored on the managed device. These variables,
also known as managed objects, have values and titles that are reported to the
NMS as necessary. PDUs sent by the server to the NMS are known as “traps.”
The following examples best illustrate the use of GET, SET, and “trap”
messages.
NMS-initiated communication. The NMS either requests information from
the server or changes the value of a variable store in the server’s MIB. For
example:
1.
The NMS sends a message to the Administration Server master agent.
The message might be a request for data (a GET message), or an
instruction to set a variable in the MIB (a SET message).
2.
The master agent forwards the message to the appropriate subagent.
3.
The subagent retrieves the data or changes the variable in the MIB.
4.
The subagent reports data or status to the master agent, and then the
master agent forwards the message back (a GET message) to the NMS.
5.
The NMS displays the data textually or graphically through its network
management application.