Saturday, 6 February 2021

Simple Network Management Protocol (SNMP)

What is Simple Network Management Protocol (SNMP)?

A Simple Network Management Protocol (SNMP) is an internet standard protocol or application layer protocol. It collects and manipulates valuable network information and it receives BASELINE - a report delimiting the operation traits of a healthy network and therefore this protocol stands as a watchdog (AGENTS) and agents send an alert called a TRAP to the management and it uses User Datagram Protocol (UDP) port number 161/162. However, the network devices that support SNMP include switches, router, printers, cable modems, workstations, routers, servers, etc,.

The Versions of Simple Network Management Protocol (SNMP) are SNMPv1 is the original version of the protocol, SNMPv2, and SNMPv3. SNMP is also called “simple” because of the uncomplicated nature of the protocol's architecture.

Benefits of SNMP

  • SNMP Open Protocol
  • Alerts with SNMP Traps
  • Fault Management

Components of SNMP

In the client-server architecture protocols it has three components they are

  • SNMP Agent
  • SNMP Manager
  • Management Information Base (MIB)

SNMP Agent

It is a network management software module which installed and run on the managed devices like servers, switches, routers, printers, workstations, hubs, bridges, computer hosts, cable modems, etc,.

SNMP Manager

It is a software platform that functions as a centralized system to which agent feed information, it is used to monitor a network and it is also called Network Management Station (NMS) or Network Elements.

Management Information Base (MIB)

It is a text file (.mib) database that consists of objects instances that are essentially variable and each MIB item is assigns as an object identifier and the protocol also permits active management tasks, such as configuration changes, through remote modification of these variables and the variables accessible via SNMP are organize in hierarchies.

Note: In this client-server architecture, the SNMP Manager acts as a client, the SNMP Agent acts as a server and the Management Information Base (MIB) acts as a server database. When the SNMP Manager asks the Agent a question, the Agent uses the MIB to supply answers.

SNMP Protocols

All SNMP messages and commands are transported over User Datagram Protocol (UDP) or Transmission Control Protocol (TCP) or Internet Protocol (IP)are known as Protocol Data Units (PDU), however, the SNMP agent receives requests on UDP port 161. The following different variables or SNMP messages are

GetRequest - SNMP manager generates this message and sends it to an SNMP agent to obtain the value of the variable. Therefore in response to this, the SNMP agent responds with requested values through a response message.

SetRequest - SNMP manager sends this message to the SNMP agent to change the value of the variable.

Response - SNMP agent sends this message in response to the SNMP manager to returns variable bindings or acknowledgment for GetRequest, GetNextRequest, GetBulkRequest, and SetRequest.

GetNextRequest - SNMP manager sends this message to the SNMP agent to retrieve the next available value of the variable in the MIB, starting at OID 0.

GetBulkRequest - SNMP manager sends this message to the SNMP agent to retrieve the bulk value of a variable or a large amount of data, especially large tables.

Trap - SNMP agent sends asynchronous alerts to the SNMP manager when an error or failure has occurred.

InformRequest - Asynchronous alerts similar to a Trap but adds acknowledgment that Trap doesn’t provide and it used to identify if the Trap message received by the manager or not.

SNMPv3 Security Levels

There are three security levels in SNMPv3 are

  1. NoAuthNoPriv
  2. AuthNoPriv
  3. AuthPriv
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