IBM SG24-4576-00 manual Management Information Base MIB, Snmp Agent, Snmp Manager, Traps

SNMP provides a means of communicating between the network management stations and the agents in the network resources. This information can be status information, counters, identifiers, etc.

The SNMP manager continuously polls the agents for error and statistical data. The performance of the network will be dependent upon the setting of the polling interval.

1.9.2.1 Management Information Base (MIB)

The Management Information Base is a collection of information about physical and logical characteristics of network objects. The individual pieces of information that comprise a MIB are called MIB objects and they reside on the agent system. These MIB objects can be accessed and changed by the agent at the manager′s request.

The MIB is usually made up of two components:

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MIB II

This a standard definition which defines the data layout (length of fields, what the field is to contain, etc.) for the management data for the resource. An example would be the resource name and address.

MIB Extension

This incorporates unique information about a resource. It is defined by the manufacturer of the resource that is being managed. These are usually unique and proprietary in nature.

1.9.2.2 SNMP Agent

The SNMP agent is responsible for managed resources and keeps data about the resources in a MIB. The SNMP agent has two responsibilities:

1.To place error and statistical data into the MIB fields

2.To react to changes in certain fields made by the manager

1.9.2.3 SNMP Manager

An SNMP manager has the ability to issue the SNMP commands and be the end point for traps being sent by the agent. Commands are sent to the agent using the MIB as a communication vehicle.

1.9.2.4 Traps

In a network managed with SNMP, network events are called traps. A trap is generally a network condition detected by an SNMP agent that requires immediate attention by the system administrator. It is a message sent from an agent to a manager without a specific request for the manager.

SNMP defines six generic types of traps and allows definitions of

enterprise-specific traps. This trap structure provides the following information:

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The particular agent object that was affected Event description(including trap number) Time stamp

Optional enterprise-specific trap identification List of variables describing the trap

In summary, the following events describe the interactions that take place in an SNMP-managed network:

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