SNMP Manager Programmer's Guide

Introduction to Manager Services
SNMP Manager Programmer’s Guide–134249
1-2
MIB Object Identification
Request messages are sent by managers to monitor and control resources. Requests
retrieve specific information about resources or change the attributes of specific
resources.
Agents and subagents occasionally send traps to managers. Traps are messages
containing important but unsolicited information about resources of concern to specific
managers.
Messages exchanged between manager and agent, referred to as packets, identify
specific resources by using descriptions of those resources contained in a Management
Information Base (MIB). Agents and subagents support MIBs that characterize the
resources they have access to. A MIB characterizes resources by using a subset of the
Abstract Notation One (ASN.1) coding conventions, the subset supported by SNMP as
described in RFC 1155. These conventions for referring to managed objects make it
possible for managers to identify specific objects, for agents to route request packets to
the proper entity, and for the responsible entity to identify the resources that are the
target of a particular request.
MIB Object Identification
The MIB description for an object provides a number by which the object can be
unambiguously identified.
The Host Resources Subagent that Tandem offers, for example, supports a MIB that
describes several objects characterizing the subagent process. The ASN.1 MIB
definition for this information assigns numbers by which each object can be identified:
internet OBJECT IDENTIFIER ::= { iso org(3) dod(6) 1}
private OBJECT IDENTIFIER ::= { internet 4 }
enterprises OBJECT IDENTIFIER ::= { private 1}
tandem OBJECT IDENTIFIER ::= { enterprises 169 }
nonstopsystems OBJECT IDENTIFIER ::= { tandem 3 }
zhrm OBJECT IDENTIFIER ::= { nonstopsystems 180 }
...
zhrmSaProcess OBJECT IDENTIFIER ::= { zhrm 4 }
...
zhrmSaProcCurrTime OBJECT-TYPE
SYNTAX DisplayString
ACCESS read-only
...
::= { zhrmSaProcess 1 }
...