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Snmp manager functions, Snmp agent functions – IBM 12.1(22)EA6 User Manual

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21-3

Cisco Systems Intelligent Gigabit Ethernet Switch Modules for the IBM BladeCenter, Software Configuration Guide

24R9746

Chapter 21 Configuring SNMP

Understanding SNMP

Table 21-1

identifies the characteristics of the different combinations of security models and levels.

You must configure the SNMP agent to use the SNMP version supported by the management station.
Because an agent can communicate with multiple managers, you can configure the software to support
communications using SNMPv1, SNMPv2C, or SNMPv3.

SNMP Manager Functions

The SNMP manager uses information in the MIB to perform the operations described in

Table 21-2

.

SNMP Agent Functions

The SNMP agent responds to SNMP manager requests as follows:

Get a MIB variable—The SNMP agent begins this function in response to a request from the NMS.
The agent retrieves the value of the requested MIB variable and responds to the NMS with that
value.

Set a MIB variable—The SNMP agent begins this function in response to a message from the NMS.
The SNMP agent changes the value of the MIB variable to the value requested by the NMS.

Table 21-1

SNMP Security Models and Levels

Model

Level

Authentication

Encryption

Result

SNMPv1

noAuthNoPriv

Community string

No

Uses a community string match for authentication.

SNMPv2C

noAuthNoPriv

Community string

No

Uses a community string match for authentication.

SNMPv3

noAuthNoPriv

Username

No

Uses a username match for authentication.

SNMPv3

authNoPriv

MD5 or SHA

No

Provides authentication based on the HMAC-MD5
or HMAC-SHA algorithms.

Table 21-2

SNMP Operations

Operation

Description

get-request

Retrieves a value from a specific variable.

get-next-request

Retrieves a value from a variable within a table.

1

1.

With this operation, an SNMP manager does not need to know the exact variable name. A sequential search is performed to
find the needed variable from within a table.

get-bulk-request

2

2.

The get-bulk command only works with SNMPv2 or later.

Retrieves large blocks of data, such as multiple rows in a table, that would
otherwise require the transmission of many small blocks of data.

get-response

Replies to a get-request, get-next-request, and set-request sent by an NMS.

set-request

Stores a value in a specific variable.

trap

An unsolicited message sent by an SNMP agent to an SNMP manager when some
event has occurred.