SNMP is a simple protocol that can be used on just about any networking device in use today. In some environments it’s used heavily, in others it’s scarce. Some view it as a security threat; others see it as a way to efficiently manage some of their key systems.
The SNMP protocol was designed to provide a "simple" method of centralizing the management of TCP/IP-based networks – plain and simple. If you want to manage devices from a central location, the SNMP protocol is what facilitates the transfer of data from the client portion of the equation (the device you are monitoring) to the server portion where the data is centralized in logs for centralized viewing and analysis.
SNMP design is pretty simple. There are two main players in SNMP. The manager and the agent. The manager is generally the ‘main’ station such as HP Openview.
The agent would be the SNMP software running on a client system you are trying to monitor.
The manager is usually a software program running on a workstation or larger computer that communicates with agent processes that run on each device being monitored. Agents can be found on switches, firewalls, servers, wireless access points, routers, hubs, and even users' workstations – the list goes on and on. As seen in the illustration, the manager polls the agents making requests for information, and the agents respond when asked with the information requested.
The types of data the agent and manager exchange are defined by a database called the management information base (MIB).The MIB is a virtual information store. It is a small database of information and it resides on the agent. Information collected by the agent is stored in the MIB. The MIB is precisely defined; the current Internet standard MIB contains more than a thousand objects. Each object in the MIB represents some specific entity on the managed device.