Simple Network Management Protocol (SNMP)

[VelMurugan]

Simple Network Management Protocol (SNMP)

Background:

The Simple Network Management Protocol (SNMP) is an application layer protocol that facilitates the exchange of management information between network devices. It is part of the Transmission Control Protocol/Internet Protocol (TCP/IP) protocol suite. SNMP enables network administrators to manage network performance, find and solve network problems, and plan for network growth.

Two versions of SNMP exist:

SNMP version 1 (SNMPv1) and SNMP version 2 (SNMPv2). Both versions have a number of features in common, but SNMPv2 offers enhancements, such as additional protocol operations.
Standardization of yet another version of SNMP—SNMP Version 3 (SNMPv3)—is pending. This chapter provides descriptions of the SNMPv1 and SNMPv2 protocol operations.

SNMP COMPONENTS:

An SNMP-managed network consists of three key components:
Managed devices, agents, and network-management systems (NMSs). A managed device is a network node that contains an SNMP agent and that resides on a managed network. Managed devices collect and store management information and make this information available to NMSs using SNMP. Managed devices, sometimes called network elements, can be routers and access servers, switches and bridges, hubs, computer hosts, or printers. An agent is a network-management software module that resides in a managed device. An agent has local knowledge of management information and translates that information into a form compatible with SNMP.

An NMS executes applications that monitor and control managed devices. NMSs provide the bulk of the processing and memory resources required for network management. One or more NMSs must exist on any managed network.
   
SNMP Basic Commands:

Managed devices are monitored and controlled using four basic SNMP commands: read, write, trap,and traversal operations.

The read command is used by an NMS to monitor managed devices. The NMS examines different variables that are maintained by managed devices.

The write command is used by an NMS to control manageddevices.The NMS changes the values of variables stored within managed devices.

The trap command is used by managed devices to asynchronously report events to the NMS.

When certain types of events occur, a managed device sends a trap to the NMS.

Traversal operations are used by the NMS to determine which variables a managed device supports and to sequentially gather information in variable tables, such as a routing table.

Source : ExpertsForge