Oracle SNMP Support Reference Guide

How SNMP Works

SNMP (Simple Network Management Protocol) is a standard internet protocol enabling certain nodes in a network, the management stations or managing nodes, to query other network components or applications for information concerning their status and activities. Such a query is known as an SNMP poll. The items that can be so polled are called managed elements. Traditionally, managed elements were limited to network components such as bridges and routers, but recently the definition has been extended to include mission-critical applications such as databases.

The software used by a management station is called a management framework or management platform. The management framework uses the SNMP protocol to request information from agents on the nodes being managed, and those agents send back the appropriate responses. The agents can also, independently of the framework, transmit messages called traps to well-known addresses in response to specific events. This is done to enable quick and possibly automatic reactions to the specific conditions that the traps indicate.

All requests sent to a given network node are handled by the same master agent. This agent redirects the requests to the appropriate managed elements on the node, in some cases using subagents. The protocol used for this is not yet standardized and is not SNMP. The information that SNMP can obtain is described in a structure called a Management Information Base (MIB), which is located on the node of the managed element.

Figure 1 - 1 shows the components of a management station and of a sample managed node.

Figure 1 - 1. Basic Components of Oracle SNMP Support