What is SNMP in industrial networking?


What is SNMP?

Simple Network Management Protocol (SNMP) is a protocol in the application layer to exchange management information between network devices. SNMP is a widely accepted protocol for managing and monitoring network elements.

It is part of the software suite of the Internet Protocol (IP). A network device can be monitored and controlled using SNMP. In addition, notification can be received from a network device. There are three components in an SNMP - managed system: SNMP agents, Managed Devices and Network Management systems.

Basic components of SNMP:

SNMP Manager or Network Management System (NMS):

It is an entity that is responsible for communicating with SNMP agents that are implemented on network devices. Generally in the form of a computer that is used to run one or more network management systems. SNMP Manager has the following main functions:

  • Query the agent.
  • Obtain (GET) the response from the agent.
  • Set (SET) variable in the agent.
  • acknowledge the asynchronous event from the agent.

Managed Devices:

Managed devices are network elements that will be monitored and managed such as routers, switches, server workstations, printers, UPS, etc.

SNMP Agent:

SNMP Agent, is a program that is packaged inside network elements so that it allows it to collect management information databases from local devices and make them available to SNMP Managers. SNMP agents perform the following main functions:

  • Collect management information about the local environment.
  • Store and retrieve management information defined in MIB.
  • Give an event signal to Manager.
  • Works as a proxy for several network nodes that do not support SNMP.

Management Information Base (MIB):

MIB is a shared database between Agents and SNMP Managers. MIB consists of a collection of variable variables that are shared between NMS and network elements. MIB is extensible, so hardware and software vendors can add new variables to MIB.

SNMP messages:

SNMP messages can be initiated either by the Network Management System (NMS) or by network elements.

SNMP TRAP, is a message initialized by network elements and sent to the NMS, for example, a router sends a message if one of its redundant power supplies fails to work or a printer can send a message when out of paper.

SNMP GET, is a message initialized by the NMS when it wants to receive some data from network elements, such as utilization of the Wide Area Network (WAN) path for network elements ie routers every 5 minutes.

SNMP SET, is a message initialized by the NMS when it wants to make changes to data on network elements