Introduction

Over the last decade, the development of wireless networking has accelerated the rapid expansion of computer networks. Networks that were used to connect a few computers are now interconnecting thousands of devices across different locations. The complexities of networks of routers, servers, and switches require advanced tools and protocols that can manage this complexity. This is where SNMP comes into action.

SNMP in computer networks was developed to meet the expanding need for a standard way of monitoring and controlling IP-based devices. SNMP offers its users a “simple” set of functions, allowing for remote management of these devices.

This blog will mainly focus on the SNMP protocol, its history, components, and it’s working. Let’s begin!

What is SNMP in Computer Networks?

SNMP in Computer Networks stands for Simple Network Management Protocol. It is a widely accepted and standardized application layer protocol specifically designed to exchange device management information among network devices within a TCP/IP network.

The primary function of SNMP protocol involves the gathering of statistical and configuration data related to various network devices, including computers, hubs, switches, routers, and network printers. The statistical data includes metrics such as the number of packets or frames transmitted or received per second, the rate of errors occurring per second, and so on.

It is important to note that network administrators can use the statistical and configuration data provided by SNMP to monitor the availability and performance of SNMP network devices. Administrators can also monitor the status of different SNMP versions and see the complete network with the right SNMP monitoring tool.

History of Simple Network Management Protocol

SNMP Protocol was introduced in 1988 as a successor to SGMP (Simple Gateway Monitoring Protocol) and quickly became widely adopted due to its simplicity.

Due to its ease of use, SNMPv1 was widely adopted, but due to its insufficient security protections, there is a need for better options.

In order to address the concerns raised in SNMPv1, the SNMPv2 protocol was developed in the mid-1990s. However, its new party-based security paradigm was so complicated that its adoption failed.

The third version of SNMP, i.e., SNMPv3, which was standardized in 1998, is now the industry standard for managing networks.

How does SNMP in Computer Networks Work?

A network consists of a minimum of one computer or server and monitoring software for monitoring their activities. The managing entity is responsible for overseeing operations. The network will consist of various other devices, such as switches, workstations, routers, server racks, and printers, that require monitoring. These devices and well-known as managed devices.

SNMP messages are transmitted and received between entities commonly referred to as managers and agents. Typically, the SNMP manager is installed on the overseeing entity (managing entity) within the network, while the SNMP agents are installed on the devices being managed (managed devices).

The way messages are transferred in SNMP can be compared to the communication in the client-server model. SNMP message transfer provides both pull and push methods of data delivery.

Usually, the most common communication type uses a pull (or poll) mechanism, in which a client (such as the network management software on the managing entity) queries a server (or managed device) for information. When an event occurs, the controlled device may “speak” by sending out an SNMP message using push technology.

In terms of SNMP, a GET request originating from an SNMP manager, which acts as the client, complies with the pull model. On the other hand, an SNMP trap is “pushed out” by an SNMP agent, which functions as the server, without any preceding request.

SNMP specifies many operations for communicating between components. Below we have explained different SNMP operations in tabular form.

SNMP Versions: SNMPV1, SNMPV2c, or SNMPV3 -Which is Best?

There are basically three versions, namely – SNMPv1, SNMPv2c, and SNMPv3. Below, we have discussed different SNMP versions based on features.

Let’s see SNMP Versions in detail.

SNMPv1

This is the primary version of the protocol that is easily installed. This is described in RFCs 1155 and 1157. It is a Basic protocol with limited commands and make use of plain text community strings. 

SNMPv2c

SNMPv2c is an edited version that has improved transport mapping, protocol packet types, and MIB structure components, but it also uses the existing SNMPv1 management structure that is “community-based”, which is why this version is called SNMPv2c. It is published in RFC 1901, RFC 1905, and RFC 1906. SNMPv2c adds GetBulk and Inform commands and uses community strings for access control.

SNMPv3

It helps in the virtual configuration of SNMP structures. The addition of both authentication and encryption (used together or independently) makes SNMPv3 the most secure version. It is described in RFC 1905, RFC 1906, RFC 2571, RFC 2572, RFC 2574, and RFC 2575.

Note: SNMP Version 3 remains the gold standard for production environments today.

These are the three versions of SNMP in Computer Networks.

Components of SNMP Protocol

SNMP architecture mainly consists of four components. These are:

• SNMP Manager
• SNMP Agent
• Managed Devices
• MIB

SNMP Manager

SNMP Manager acts as a client and serves as the central system utilized for monitoring the SNMP network. The SNMP manager, also referred to as a network management station (NMS), is tasked with establishing communication with network devices that have implemented SNMP agents. The system operates on a host within the network.

The manager initiates inquiries with the agents, receives corresponding responses, sets variables within them, and acknowledges events communicated by them. In simple words, when the SNMP Manager initiates an inquiry, the SNMP Agent uses the Management Information Base (MIB) to send the corresponding response.

SNMP Agent

SNMP Agent acts as a server. It refers to a software process responsible for responding to SNMP queries to provide information regarding the status and statistics of a network node. The most crucial function of management is performed by SNMP agents. They are locally associated with networked devices and perform actions like collecting, storing, and transmitting monitoring data.

When queried, the designated SNMP manager receives transmitted data. SNMP software agents deployed on network devices and services establish communication with a network management system in order to transmit status information and configuration modifications.

Managed Devices

A managed device is a node in a network that supports the SNMP and provides either one-way (read-only) or two-way (read/write) access to data about that device.

MIB (Management Information Base)

MIB acts as a database. Information exchange in an SNMP system is governed by a structure called MIB. Each SNMP agent has its own information database that contains a description of the device’s parameters that it handles. An SNMP manager is a software system that utilizes SNMP to gather data associated with capacity planning, performance management, and fault management.

The MIB serves as a shared database between the agent and the manager. Object identifiers, often known as object IDs or OIDs, are the names given to the managed objects that are included inside a MIB. The collected data in SNMP managers is stored in a MIB, which serves as a shared database between the agent and the manager.

The Object Identifier (OID) is a unique identifier for each object managed within a MIB hierarchy. Its design allows for a considerable degree of flexibility, allowing even proprietary requirements.

SNMP Messages

These are the types of SNMP Messages –

• GetRequest – GetRequest helps to retrieve data through SNMP agents. In return, the SNMP agent replies with a message at the requested value.
• GetNextRequest – The administrator sends GetNextRequest messages to agents to obtain the value of a variable. In a table, the values of entries are recovered from this type of communication. If the administrator does not remember the indices of the entries the administrator is unable to view the values. The GetNextRequest message returns an object under certain conditions.
• SetRequest – The SNMP manager uses SetRequest to adjust the value of an Item instance on the SNMP agent.
• Response – When sending a response to Set message, it will include the most recently set value for verification that the value has been set.
• Trap – Traps are messages that are sent by the agent without the administrator’s permission. This is sent if any failure has occurred.
• InformRequest – InformRequest is like Trap but has an additional acceptance that Trap does not have. It was connected to SNMPv2c and checks if the administrator receives trap messages.

SNMP Commands

snmpget: Fetches single values from network devices.

Example: snmpget -v2c -c public 192.168.1.1 sysName.0 retrieves hostname

snmpset: Changes device settings.

Example: snmpset -v2c -c private 192.168.1.1 sysContact.0 s “[email protected]” updates contact information

snmpwalk: Scans entire MIB trees.

Example: snmpwalk -v2c -c public 192.168.1.1 ifDescr lists all interfaces

snmpbulkget: Grabs multiple values fast.

Example: snmpbulkget -v2c -c public 192.168.1.1 ifTable pulls interface data efficiently

snmptrap: Sends alerts when events occur.

Example: snmptrap -v2c -c public manager.local linkDown notifies link failure

Note: Each command uses community strings for authentication. Version 2c works for most networks today. 

SNMP Ports and Port numbers

SNMP port is an endpoint of SNMP communication that analyzes SNMP data sharing. To address commands and messages, both port 161 and port 162 are used by SNMP. With the help of specified SNMP ports, SNMP managers communicate with SNMP agents. SNMP messages are transmitted via the User Datagram Protocol (UDP) and Transport Layer Security (TLS) or Datagram Transport Layer Security (DTLS) protocols, which are rarely used.

Here is a list of port numbers that are used by each protocol for particular processes:

Advantages of SNMP in Computer Networks

• It is simple and easy to implement.
• It supports a wide range of devices and vendors.
• It allows centralized monitoring and control of network devices.
• It provides scalability and flexibility for network management.
• It reduces network traffic and bandwidth consumption by using efficient data encoding.

Limitations of SNMP in Computer Networks

• It can reduce the network bandwidth due to frequent polling and trap messages.
• It can pose security risks due to cleartext transmission and weak authentication in earlier versions.
• It can lose data packets due to unreliable UDP transport and lack of acknowledgment.
• It can generate a flood of traps in case of a major network failure or outage.

Use Cases of SNMP in Modern Computer Networks

SNMP is used for various reasons, such as:

• Network Monitoring: You can have complete overview of network health with SNMP.
• Device Management: With SNMP, you can manage and overlook various network devices at different locations.
• Traffic Analysis: You can analyze and optimize network traffic using SNMP Data.
• Performance Tracking: Teams measure device response times and bandwidth usage through SNMP metrics. This data shows which routers need upgrades. Organizations save money by replacing only the equipment that is stressed. 
• Security Monitoring: SNMP logs track configuration changes and access attempts. Security teams spot unusual patterns quickly. The protocol helps detect network intrusions before data breaches occur. 
• Automated Reporting: SNMP collects uptime statistics and availability data automatically. IT departments prove SLA compliance with these reports. Management gets clear visibility into network reliability trends. 

Future of SNMP Protocol

SNMP faces competition from modern protocols like gRPC and streaming telemetry. Yet it remains vital for legacy device management. Network engineers expect SNMPv3 adoption to grow as security concerns increase. The protocol will likely coexist with newer technologies rather than disappear.

Cloud environments drive demand for RESTful APIs over traditional SNMP polling. However, embedded systems and IoT devices still rely on SNMP’s lightweight design. Vendors continue supporting SNMP in enterprise equipment. Future versions might add encryption improvements and faster data collection methods.

The protocol’s simplicity ensures its survival. Organizations with mixed infrastructure need SNMP for complete visibility. Hybrid monitoring approaches combining SNMP with modern tools have become standard practice.

Frequently Asked Questions

Conclusion

SNMP in computer networks is critical for networking management and monitoring. Network administrators can retrieve device statistics, modify configurations, and receive automatic alerts when problems occur. This standardization means one management platform can control an entire network infrastructure. This blog has discussed SNMP, its working, architecture, advantages, and disadvantages. We have also covered the different operations that are carried out between the agent and the manager for a better understanding of the working of SNMP protocol. Learn more about SNMP in Computer Networks by joining a CCNA Course.