SNMP-based Network Management
This section describes the main components in the network management framework, their relationships, and how they communicate.
SNMP-based network management includes the following four components:
- NMS
Generally, the network management station (NMS) is an independent device that runs the network management application. The network management application provides at least one human-machine interface (HMI) through which the network administrator manages the network.
- SNMP agent
The agent is the software installed on a managed node. It receives and handles request packets from the NMS, and returns responses to the NMS. In some urgent cases, the agent sends trap packets to the NMS.
- SNMP protocol
As an application layer protocol in the TCP/IP suite, SNMP exchanges management information between the NMS and a managed node.
- MIB
The management information base (MIB) is a set of managed objects (MOs). It acts as a communication bridge between the NMS and an agent. Each agent maintains a MIB whose object values can be read or set by the NMS.
Figure 1-1 shows the components and their relationships in the SNMP-based network. The communication between those components is described as follows:
- The NMS communicates with the agent using SNMP. The NMS monitors and manages the managed node where the agent resides by reading and modifying the objects in the MIB.
- SNMP is the carrier for the communication between the NMS and the agent. Data is encapsulated in the protocol data unit (PDU) defined by SNMP. SNMP does not transmit data. Instead, data exchange tasks are implemented by the transport layer protocols such as UDP.
- The agent is a process running on a managed node. The agent communicates with the NMS and maintains the MIB to manage and monitor modules in the managed node.
- The MIB stores information about each module in the managed node. The NMS maintains and monitors a managed node through read and write operations on the objects contained in the MIB.
