Overview
1.5 The eSNMP API
Interface routines handle the basic subagent operations, such as:
•
Subagent initialization and termination
•
Registration
•
Polling of the master agent
•
Trap sending
•
UNIX system time conversion
•
Adding and removing subagent capabilities registered with the master agent
The support routines allow the subagent to manipulate the data in the response
to the request, and include the following:
•
Basic protocol data unit (PDU) handling
•
Authentication handling
•
Octet string handling
•
Variable binding (
VARBIND
) handling
•
Object identifier (OID) handling
•
Buffer handling
Chapter 5 describes the API routines in more detail.
To create a subagent, the programmer must provide modules to implement the
method routines, as described in Chapter 3.
1.5.1 The SNMP Utilities
To provide quick access to information in the MIBs, and to test SNMP operation,
TCP/IP Services provides the following utilities:
•
TCPIP$SNMP_REQUEST.EXE, a MIB browser that allows you to retrieve
and update objects from the MIBs.
•
TCPIP$SNMP_TRPSND.EXE, a trap sender that generates traps (messages
that require no response).
•
TCPIP$SNMP_TRPRCV.EXE, a trap receiver (or ‘‘listener’’) that is used to
detect trap messages.
For information about using the SNMP utilities, see Chapter 4.
1.6 The MIB Compiler
The MIB compiler processes the statements in an ASN.1 file and generates
modules that are used by the developer to create subagent routines. For every
ASN.1 input file that is processed using the MIB compiler, two output files, a
subtree_TBL.H file and a subtree_TBL.C file, are generated, where subtree is the
name from the original MIB definition file (for example, chess). The output files
are described in more detail in Chapter 3.
The subtree_TBL.H file is a header file that contains the following:
•
A declaration of the subtree structure
•
Index definitions for each MIB variable in the subtree
•
Enumeration definitions for MIB variables with enumerated values
•
MIB group data structure definitions
Overview 1–7
