SNMP Stands for Simple Network Management Protocol.
It is a framework for managing devices in an internet using the TCP/IP protocol suite.
It is an Application Level Protocol.
It provides a set of fundamental operations for monitoring and maintaining an internet.
SNMP uses the concept of manager and agent.
That is, a manager, usually a host, controls and monitors a set of agents, usually routers.
I) SNMP Manager:
A manager or management system is a separate entity that is responsible to communicate with the SNMP agent implemented network devices.
This is typically a computer that is used to run one or more network management systems.
SNMP Manager’s key functions:
a. Queries agents.
b. Gets responses from agents.
c. Sets variables in agents.
d. Acknowledges asynchronous events from agents.
II) Managed Devices:
A managed device or the network element is a part of the network that requires some form of monitoring and management
Example: Routers, Switches, Servers, Workstations, Printers, UPSs, etc.
III) SNMP Agent:
The agent is a program that is packaged within the network element.
It makes information available to the SNMP manager, when it is queried for.
These agents could be standard (e.g. Net-SNMP) or specific to a vendor (e.g. HP insight agent)
SNMP agent’s key functions:
a. Collects management information about its local environment.
b. Stores and retrieves management information as defined in the MIB.
c. Signals an event to the manager.
d. Acts as a proxy for some non–SNMP manageable network node.
IV) Management Information Base (MIB):
Every SNMP agent maintains an information database describing the managed device parameters.
The SNMP manager uses this database to request the agent for specific information and further translates the information as needed for the Network Management System (NMS).
This commonly shared database between the Agent and the Manager is called Management Information Base (MIB).
MIB contains standard set of statistical and control values defined for hardware nodes on a network.
MIB files are the set of questions that a SNMP Manager can ask the agent.
Agent collects these data locally and stores it, as defined in the MIB.