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3 tcp/ip services components for snmp, Table 1–1 snmp component files – Compaq AAR04BCTE User Manual

Page 16

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Overview
1.2 Request Handling

The network management station sends an SNMP request to the master
agent running on the host, using port 161. An SNMP request is made using
one of the following commands:

Get

GetNext

GetBulk

Set

Note

TCP/IP Services does not support the standard SNMP

Inform

command.

The request specifies the object identifer (OID) of the data to be accessed.
For information about formatting

get

and

set

requests, refer to Section 5.2.

Request formats are specified in RFC 1905.

2.

The master agent sends the request to the subagent that registered the
subtree containing the OID.

The subagent receives communications from the master agent over the socket
that was assigned when the subagent registered the subtree.

3.

The appropriate subagent processes the request.

4.

The subagent sends the response message to the master agent using the port
that was assigned when the subagent registered the MIB.

When they are idle, subagents periodically send a message to port 705 to ensure
that the master agent is still running. In Figure 1–2, subagent 1 is sending the

esnmp_are_you_there

message.

A

trap

is generated by the subagent and sent to the client. In Figure 1–2,

subagent n is generating a trap for the trap client on NMS 2.

The

trap

and

esnmp_are_you_there

routines are described in Section 5.1.

1.3 TCP/IP Services Components for SNMP

Table 1–1 lists the components of SNMP and the command procedures for
managing SNMP that are supplied with TCP/IP Services.

Table 1–1 SNMP Component Files

File

Location

Function

TCPIP$ESNMP_SERVER.EXE

SYS$SYSTEM

Master agent image.

TCPIP$OS_MIBS.EXE

SYS$SYSTEM

MIB II subagent image.

TCPIP$HR_MIB.EXE

SYS$SYSTEM

Host Resources MIB
subagent image.

TCPIP$SNMP_REQUEST.EXE

SYS$SYSTEM

Simple MIB browser.

TCPIP$SNMP_TRAPSND.EXE

SYS$SYSTEM

Utility for sending trap
messages.

(continued on next page)

1–4 Overview