org.snmp4j.mp
Provides classes and interfaces for the SNMP message processing.
The org.snmp4j.mp classes provide services to process SNMP
messages. The services provided are defined in the
MessageProcessingModel interface and include the following:
- Prepare data elements from an incoming SNMP message as described in
RFC3412 §7.2.
- Prepare a response message as defined in RFC3412 §7.1.
- Prepare an outgoing message as defined in RFC3412 §7.1.
This interface is implemented
by the message processing model classes for the SNMP versions 1, v2c, and v3:
MPv1 , MPv2c , and MPv3 .
The MessageDispatcherImpl chooses which message processing model
it uses to process an outgoing or incoming SNMP message based on the SNMP
version of the message. The SNMP version is either extracted from the message
header (incoming message) or from the Target instance associated
with the outgoing PDU (ougoing message).
To be able to match requests and responses SNMP uses request IDs. Since request
IDs are created by the command generator, the request IDs are unique within
such a command generator only. SNMP4J therefore has to abstract from request IDs
and uses PduHandle instances instead.
If a PDU is processed for sending by the SNMP4J
MessageDispatcherImpl and
the PDU's request ID is set to 0, then a SNMP4J application wide unique ID
is generated and set as request ID of the supplied PDU. In any case, the
PDU's request ID will be used as transaction ID of the outgoing message. The
transaction ID identifies a messages PduHandle .
If a PDU is received by the SNMP4J
MessageDispatcherImpl a unique transaction ID is generated so
that command responders as well as the message processing model can match
requests and responses.
The following UML class diagram shows the most important classes of the
org.snmp4j.mp package and their relationships
(relationships to other packages are not shown):
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