Netscape NETSCAPE CONSOLE 6.0 - MANAGING SERVERS, Руководство пользователя

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SNMP Basics
Chapter 11 Using SNMP to Monitor Servers 213
Types of SNMP Messages
SNMP defines three types of messages: GET, SET, and trap. The network
management station uses GET messages to request data and SET messages to
change variable values in the MIB. The messages sent by a server to the network
management station are known as trap messages.
The following examples illustrate how a network management station, and the
servers it communicates with, use GET, SET, and trap messages.
Network Management Station-Initiated Communication
A network management station can request information from a server or change
the value of a variable stored in a server’s MIB. For example:
1.
The network management station sends a GET message to the Administration
Server master agent. The GET message is a request for the number of Directory
Server errors encountered since the server was last started.
2.
The master agent forwards the message to the Directory Server’s SNMP
subagent.
3.
The subagent retrieves the data.
4.
The subagent sends the data to the master agent. The master agent sends a trap
message containing the data to the network management station.
5.
The network management station displays the data through its network
management application.
Server-Initiated Communication
The server subagent sends a trap message to the network management station
when a significant event has occurred. For example:
1.
The Directory Server’s subagent informs the master agent that the server has
stopped.
2.
The master agent sends a trap message reporting the event to the network
management station.
3.
The network management station displays the information textually or
graphically through its network management application.