First and foremost, let’s try and understand what SNMP Monitoring is — Simple Network Management Protocol is a protocol for managing and monitoring our network devices. SNMP provides the ability to monitor the performance and health of the devices on a network by collecting data from them. SNMP consists of two main components -: the SNMP Agent and the SNMP Manager. The SNMP Agent is a software module installed on each networking device that requires to be monitored. The SNMP manager is the tool used to collect, analyze, and display the data collected by the SNMP agents. SNMP Monitoring allows us to monitor a wide range of network devices, including routers, switches, firewalls, servers, printers, and other devices that are SNMP enabled. This tool provides real-time monitoring, alerting, and reporting on the status, health, performance, and other metrics required to monitor our networking environments.
SNMP Architecture
The Simple Network Management Protocol includes four fundamental layers that must be understood.
SNMP Network Managers
The SNMP Network Manager is a tool that can collect data, analyze, and generate reports from the network devices we would like to monitor. We can look at this component as the tool that collects and curates all the data we want to collect from the network devices we want to monitor.
Master Agents
The Master Agent is a simple software program that interfaces between the Network Manager and subagents within our monitoring environment.
Subagents
A subagent is a software program installed within a network device and provides information to the SNMP Network Manager.
Managed components
A Managed Component is a hardware device or software with a subagent installed to provide information based on the metrics monitored within the device. For example, a router, server, or switch with an SNMP agent installed within it can be called a Managed Component.
Below is an architectural diagram that breaks down the above components to help visually understand how SNMP Managers, Master Agents, Subagents, and Managed Components work together in an environment.
Basic SNMP Messages
SNMP uses a set of messaging protocols to communicate between the SNMP Manager and the SNMP Agents installed on network devices. The SNMP Manager uses a set of commands to get the desired output from the SNMP Agents. Likewise, the SNMP Agents also use commands to send device information to SNMP Managers. Below are some of the basic commands used between SNMP Managers and Agents to monitor network devices -
Get
The Get PDU (Protocol Data Unit) is the query sent out by the SNMP Manager to retrieve data from an SNMP agent represented by an object ID.
Response
The Response is the message sent by an SNMP agent upon a request from the Manager.
GetNext
This command can efficiently get data from the SNMP agent until there is no more data to be fetched. We can use GetNext to query the next available object ID until there isn’t one to fetch.
GetBulk
This message was added in SNMP Version 2, which is an optimized version of GetNextRequest. The Response will contain as much data as allowed by the request. Essentially, this is a way to do several GetNextRequests at once, which enables users to create a list of all available data and parameters.
Trap
Traps are alerts that can be pre-configured to ensure the SNMP Manager is notified of an event. For example — we may want to be immediately alerted if our CPU utilization is above 80%. This can be set up using a trap instead of waiting for the Manager to collect all the data to identify whether this event has occurred.
Inform
Inform is the SNMP Managers version of a Response as discussed above. Inform is used to acknowledge when the Manager has received a trap. Until acknowledged, the SNMP agent will keep resending its Trap message.
Set
The Set message is used by the SNMP Manager as an instruction to alter a device’s setting monitored by an agent.
How can we use SNMP Monitoring?
Now that we understand what SNMP Monitoring is and the different components required to set up SNMP monitoring for a network environment, let’s look at how we could use SNMP Monitoring for our network environment.
Choosing an SNMP Manager
The most critical step of SNMP monitoring is choosing our desired SNMP Manager. To understand the best-suited SNMP Manager, we must understand our requirements clearly. Based on our requirements, we can choose from various tools that provide all we need to set up SNMP monitoring with our network devices. Here are some of the widely used SNMP Monitoring tools -
DataDog Network Device Monitoring
SolarWinds Network Performance Monitor
New Relic SNMP Monitoring
Atera
ManageEngine OpManager
Configuring the SNMP Agents on our Network Devices
Once we have decided on the SNMP Monitoring tool, we need to configure and install the SNMP agents onto all the network devices we want to monitor. The SNMP agent is how the device will communicate with the SNMP manager and send the requested data.
Add network devices to the SNMP Manager.
We need to add the network devices to the SNMP manager to ensure the SNMP manager collects data from the network devices we want to monitor. Usually, this involves configuring the IP address of the network device onto the SNMP Manager.
Monitor network devices
Once we have completed the above steps, we can start monitoring our network devices. Using our best-suited SNMP monitoring tool; we can set up alerts and notifications based on critical thresholds and generate data-driven reports on network health and performance.
Analyse data
Finally, we can analyze all the data collected from our network devices to identify trends, anomalies, and patterns that could help us identify potential issues and proactively resolve them.
That’s all for now on this topic. I hope this article helped you understand the basic principles of SNMP monitoring, and the tools you can explore to get started with it.
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