SNMP is short for Simple Network Management Protocol. Its predecessor is SGMP (which is short for Simple Gateway Management Protocol). It is an “Internet-standard” protocol developed to manage devices (such as routers, servers, switches, printers and so on) on IP networks. It is widely used by network administrators to monitor the health and welfare of network-attached devices in network management systems.
The first versions of SNMP were developed in the early 80s, and SNMPv3 is the most recent standard approved by the Internet Engineering Task Force (IETF).
SNMP is one of the members of Internet Protocol Suit in the Application Layer. It is a protocol on top of UDP protocol. Like UDP, it also needs two ends, i.e., server and client. Should you manage any system over the network, you need a server running on it. In SNMP terms, server is called as Agent. Any PC also can have a SNMP agent running. In this case, you can manage that PC from anywhere in the world.
3 Basic components
As can be seen from the figure above that, the entire management system includes 3 key components: the managed device (contains an SNMP agent, collects and stores management information), the SNMP network management system (which is to collect and retrieve data from the monitored device) and the SNMP agent (which is running on the managed device to retrieve data from the device and store them into MIB). MIB (Management Information Base) is used to define the available information; it describes the structure of the management data of a device subsystem.