SNMP is based on a manager/agent architecture. The architecture of network management with SNMP includes the following elements:
The network management station is a workstation with one or more network management applications installed, to graphically show information about managed devices.
NMS features:
A managed device is any device that has SNMP installed on it. A managed device could be a host, router, bridge, hub, etc. NMS can monitor and communicate with managed devices.
The information between the NMS and the managed device is transferred through two types of agents: subagent and master agent.
The subagent gathers information about the managed device and passes the information to the master agent.
The master agent exchanges information between the various subagents and the NMS. The master agent runs on the same host machine as the subagents with which it communicates.
SNMP exchanges network information in the form of protocol data units (PDUs). PDUs contain information about variables stored on the managed device. These variables are known as managed objects and have values and titles that are reported to the NMS. All managed objects are defined in the Management Information Base (MIB). MIB is a virtual database with a tree-like hierarchy.
The basic functions of SNMP are listed in the following table.
For more information about SNMP, refer to the following Web sites: