Simple Network Management System

Simple Network Protocol is a network protocol developed by the IETF supposed to monitor and control all network components (Routers, Servers, Swicthes, Printers, hosts ect) from a central sation. It consists of a set of standards for network management, including an application layer protocol, a database schema, and a set of data objects. This protocol governs all communication between monitored devices and the monitoring station. SNMP describes the structure of the data packets to be sent off as well as the communication flow. In order to make this task possible, SNMP relies on:


- monitoring of IP network component
- remote control and remote configuration of network component
- error detection and notification


SNMP has by virtue of its simplicity, modularity and versatility established itself as the standard of choice to support both most of the management programmes and the hardware devices on the network.

In typical uses of SNMP one or more administrative computers, called managers, have the task of monitoring or managing a group of hosts or devices on a computer network. Each managed system executes, at all times, a software component called an agent which reports information via SNMP to the manager.

Another way of putting it is thinking of SNMP agents as snitches. Ongoing punks that rat out to the manager.

SNMP agents expose management data on the managed systems as variables. The protocol also permits active management tasks, such as modifying and applying a new configuration through remote modification of these variables, like the environment variables in windows policies which affect all users. The variables accessible via SNMP are organized in hierarchies. These hierarchies, and other metadata (such as type and description of the variable), are described by Management Information Bases (MIBs). It becomes soon obvious how MIBs dictate hierarchies in an attempt to keep the variables sorted in a neat manner. If the 5 S's were to be applied here, MIBs would be tools for 整頓 (Seiton or to sort things out).

 An SNMP-managed network consists of three key components:

    Managed device
    Agent — software which runs on managed devices
    Network management station (NMS) — software which runs on the manager

A managed device is a network node that implements an SNMP interface that allows unidirectional (read-only) or bidirectional (read and write) access to node-specific information. Managed devices exchange node-specific information with the NMSs. Sometimes called network elements, the managed devices can be any type of device, including, but not limited to, routers, access servers, switches, cable modems, bridges, hubs, IP telephones, IP video cameras, computer hosts, and printers.