Compaq AAR04BCTE - Manual (Page 14)

Overview
1.1 SNMP Architecture
Figure 1–1 SNMP Architecture
Master Agent
SNMP/ASN.1
Library
eSNMP API
AgentX (TCP/IP V5.1)
Subagent 1 Subagent 2 Subagent n
TCP/IP Kernel
OpenVMS
VM-0704A-AI
The SNMP environment consists of the following elements:
• The master agent, a process that runs on the host and handles SNMP
requests from clients over the standard SNMP well-known port 161.
• One or more subagents, each of which provides access to the MIB data
specified in client requests. In the TCP/IP Services implementation, the
master agent contains two resident subagents, one that handles a subset of
MIB II variables, and another that handles the Host Resources MIB. These
MIBs are described in Chapter 2.
• The SNMP ASN.1 library, used by the master agent to interpret ASN.1
messages.
• The eSNMP API, the application programming interface that provides
routines for programming your own subagents. This API runs on the AgentX
routines, which are internal to the SNMP architecture.
• The TCP/IP kernel running on the OpenVMS operating system.
The master agent and subagents communicate by means of the AgentX
protocol, which is based on RFC 2741.
For information about configuring and managing the SNMP service, refer to the
Compaq TCP/IP Services for OpenVMS Management guide.
1.2 Request Handling
The eSNMP software manages network communication by having the master
agent listen for requests and then passes the requests to the appropriate
subagent.
Figure 1–2 illustrates communication between the master agent and subagents.
1–2 Overview