SNMP Configuration and Management Manual

The NonStop SNMP Environment
SNMP Configuration and Management Manual—424777-006
1-8
Response PDU
The three request PDUs are:
•
GetRequest PDU. This PDU performs a Get operation. The Get operation
retrieves a value of a MIB object.
•
GetNextRequest PDU. This PDU performs a GetNext operation. The GetNext
operation retrieves the value of the object instance that is next in lexicographic
order.
•
SetRequest PDU. This PDU performs a Set operation. The Set operation alters
the value of a MIB object.
Response PDU
The function performed by a GetResponse PDU is referred to as an SNMP Response
operation. The Response operation returns a response to the originator of a Get,
GetNext, or Set operation. The response operation contains a request-id that
associates it with a request PDU. The response PDU provides such information as
error indications and values of MIB objects. Error-status values are described in
Appendix C, Unsolicited SNMP Agent Messages.
Trap PDU
The function performed by a Trap PDU is referred to as an SNMP Trap operation. The
Trap operation issues an unsolicited message to an SNMP manager to signal an
important event. The enterprise field provides the SNMP agent object identifier or
subagent object identifier; the object identifier for the SNMP agent is
1.3.6.1.4.1.169.3.155.1. (Object identifiers are described under Information Protocol on
page 1-9 The agent-address field is the Internet address of the device on which the
agent forwarding the trap is installed. The generic-trap and specific-trap fields
characterize the trap as a particular kind of trap. Values for traps that originate from the
SNMP agent are described in Appendix C, Unsolicited SNMP Agent Messages. Values
for traps from subagents are described in Section 9, EMS Trap Subagent.
Transmitting and Receiving SNMP Packets
SNMP managers convert user requests into SNMP messages, or packets, as
illustrated in Figure 1-3 on page 1-7. The manager then encodes these SNMP packets
into a format that can be transported to and decoded by the target agent.
IPC-Encoded and BER-Encoded SNMP Packets
The SNMP agent can process SNMP packets encoded using the HP IPC format. The
IPC format provides the best encoding and decoding performance on NonStop Kernel
systems.