SNMP

 Simple Network Management Protocol provide a consistent and reliable way for different devices on a network to share information with one another. It allows devices to communicate even if the devices are different hardware and run different software..


Without a protocol like SNMP, there would be no way for network management tools to identify devices, monitor network performance, keep track of changes to the network, or determine the status of network devices in real time. .

SNMP architecture

SNMP has a simple architecture based on a client-server model. The servers, called managers, collect and process information about devices on the network.

The clients, called agents, are any type of device or device component connected to the network. 

SNMP data hierarchy

In turn, each node has a unique Object Identifier, or OID.Using the OID, a manager can query an agent to find information about a device on the network. For example, if the manager wants to know whether an interface is up, it would first query the interface MIB (called the IF-MIB), then check the OID value that reflects operational status to determine whether the interface is up.

Understanding the Management Information Base (MIB)

When an SNMP manager requests information from an SNMP agent, the SNMP agent retrieves the current value of the requested information from the Management Information Base (MIB). The MIB defines the managed objects that an SNMP manager monitors (or sometimes configures) on an SNMP agent.