Chapter 18 SNMP

SNMP itself is a simple request/response protocol based on the manager/agent model. The manager issues a request and the agent returns responses using the following protocol operations:

Table 38 SNMP Commands

COMMAND

DESCRIPTION

Get

Allows the manager to retrieve an object variable from the agent.

 

 

GetNext

Allows the manager to retrieve the next object variable from a table or list within an

 

agent. In SNMPv1, when a manager wants to retrieve all elements of a table from an

 

agent, it initiates a Get operation, followed by a series of GetNext operations.

 

 

Set

Allows the manager to set values for object variables within an agent.

 

 

Trap

Used by the agent to inform the manager of some events.

 

 

18.1.1 Supported MIBs

MIBs let administrators collect statistics and monitor status and performance.

The switch supports the following MIBs:

RFC 1213 SNMP MIB II

MIB II - System

MIB II - Interface

RFC 1398 MIB - Ether-like

RFC 2674 SNMPv2, SNMPv2c

RFC 2819 RMON

Group 1 (Statistics)

Group 2 (History)

Group 3 (Alarm)

Group 9 (Event)

18.1.2SNMP Traps

The switch sends traps to an SNMP manager when an event occurs. SNMP traps supported are outlined in the following table.

Table 39 SNMP Traps

OBJECT LABEL

OBJECT ID

DESCRIPTION

SNMPv1/SNMPv2 Trap/Inform Requests:

 

 

 

 

authenticationFailure

1.3.6.1.6.3.1.1.5.5

This trap is sent when an SNMP request comes from

 

 

non-authenticated hosts.

 

 

 

RFC2819 Traps (alarmEntry)

1.3.6.1.2.1.16.3.1.1

A RMON event has been triggered.

 

 

 

18.1.3 SNMP v3 and Authentication

SNMP v3 adds the concept of groups and users to enhance security for SNMP management. A user is an SNMP manager. A group is a group of SNMP managers that are assigned common access rights to MIBs. For example, one group of managers may only have access to agents with MIB II - System Group MIBs while another may have access to agents with the Ether- like MIB.

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ES-1552 User’s Guide