Compaq AAR04BCTE manual 1.3 TCP/IP Services Components for SNMP, Overview 1.2 Request Handling

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$ESNMP_SERVER.EXE TCPIP$OS_MIBS.EXE TCPIP$HR_MIB.EXE

SYS$SYSTEM	Master agent image.
SYS$SYSTEM	MIB II subagent image.
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)

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