SNMP Manager Programmer's Guide

Introduction to Manager Services
SNMP Manager Programmer’s Guide–134249
1-16
Defining Manager Logic
Here is some additional information about the logic components highlighted in
Figure 1-11:
Library
header files
You always include seven library header files. They contain the
definitions of structures and prototypes of functions the library
uses to process packets. Section 3 describes the header files.
Packet
structure
declarations
You declare library structures needed by library functions, such
as SNMP_PKT_T, the structure for unencoded packet
information. Section 3 provides information on important data
structures as well as on general-purpose data types and defines
available for your use.
User interface
logic
You write the logic for accepting user input or arguments
describing resource management requests.
MIB object
handling
You write the logic for resolving resource descriptions into
representations your manager needs to build packets. The MIB
compiler, described in Section 4, provides some assistance in this
area, primarily for managers that perform MIB browsing.
Packet
initialization
You use the library function SNMP_Create_Request() to
initialize request packets and SNMP_Create_Trap() to initialize
trap packets. Section 5 describes these functions in detail.
Binding
variable
bindings
Associating variable bindings with packets is a process known as
binding. You bind variable bindings to Get and GetNext request
packets using the library function SNMP_Bind_Null(). You bind
variable bindings to Set or Trap packets using the library function
that supports MIB variables of specific SNMP types. For
example, you use SNMP_Bind_Integer() to bind variable
bindings for MIB objects of type INTEGER. Section 5 describes
all the binding functions.
Setting up
buffer for
encoded
packet
Before encoding a request or trap packet for transmission to an
agent or manager, respectively, you initialize a buffer for holding
the encoded packet. Section 6 describes the library functions,
such as EBuffer_Setup(), that are used to set up and manage
encoded-packet buffers.
Encoding
packet
You encode the packet into the encoded-packet buffer in a format
that can be interpreted by the target agent or manager. The
library function SNMP_Encode_Packet encodes the packet using
BER encoding, whereas tdm_SNMP_Encode_Packet() can be
used to either BER-encode or IPC-encode the packet. Section 6
describes the two packet encoding functions.
Transmitting
and receiving
packet
When communicating with NonStop agents and managers and
sending and receiving IPC-encoded packets, you use file system
calls. When sending and receiving BER-encoded packets, you
use calls supporting the transport protocol by which the target
entity can be addressed. Section 7 provides some information on
this topic.