Novell NETWARE 6-DOCUMENTATION Manual page 2053

NMS-Initiated Communication
Managed-Device-Initiated Communication
124 Getting Results with Novell Web Services
NMS-initiated communication is the most common type of communication
between an NMS and a managed device. In this type of communication, the
NMS either requests information from the managed device or changes the
value of a variable stored on the managed device.
The following steps make up an NMS-initiated SNMP session:
1. The NMS searches the server's MIB to determine which managed
devices and objects need to be monitored.
2. The NMS sends a PDU to the managed device's subagent through the
master agent. This PDU either requests information from the managed
device or tells the subagent to change the values for variables stored on
the managed device.
3. The subagent for the managed device receives the PDU from the master
agent.
4. If the PDU from the NMS is a request for information about variables, the
subagent gives information to the master agent and the master agent sends
it back to the NMS in the form of another PDU. The NMS then displays
the information textually or graphically.
If the PDU from the NMS requests that the subagent set variable values,
the subagent sets these values.
This type of communication occurs when the managed device needs to inform
the NMS of an event that has occurred. A managed device such as a terminal
would initiate communication with an NMS to inform the NMS of a shutdown
or startup. Communication initiated by a managed device is also known as a
trap.
The following steps make up a managed-device-initiated SNMP session:
1. An event occurs on the managed device.
2. The subagent informs the master agent of the event.
3. The master agent sends a PDU to the NMS to inform the NMS of the
event.
4. The NMS displays the information textually or graphically.