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Your guide to choosing SNMP monitoring devices

By Andrew Erickson

August 27, 2022

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SNMP monitoring is one of the most popular ways to monitor and manage your remote assets and infrastructure. Let's pick apart this standard protocol and many of the best practices that have grown up around it.

What is SNMP monitoring?

The phrase "SNMP monitoring" merely describes remote site monitoring in one specific way: using the industry-standard SNMP (Simple Network Management Protocol) to get the job done.

It can also imply one particular style of SNMP communication, as opposed to other more recent innovations. We'll get into that topic a bit later.

What equipment is required to monitor with SNMP?

Every network of equipment being monitored via SNMP falls has gear that falls into one of two categories:

  1. SNMP Agents are devices that emit SNMP messages (called "traps") when they have something to say. These can either be purpose-built monitoring devices like RTUs or "smart" devices that are capable of reporting their own statuses.
  2. SNMP Managers are the central collectors for SNMP traps. They sit at the top of your SNMP monitoring architecture. It will be the display screen of your SNMP manager that you look at to know what's going on in your network/operation.

Is there more than one architecture used for SNMP monitoring?

Traditionally, SNMP is "asynchronous". This means that the SNMP manager at the heart of your network management system will patiently wait for any SNMP trap sent by an SNMP agent.

While this is good for network traffic and monitoring latency, it can be a problem if a device goes offline. In this case, you have no way of knowing that you have a problem at all, because no trap message can be sent by an offline device.

The different SNMP versions released over time have offered mitigations to the problems of asynchronous monitoring. One of them, the "Inform" message typed released in SNMP v2c, includes a delivery confirmation sent by the manager back to the Agent. That way, a message that gets lost due a communications failure can be sent a second time.

Still, this doesn't help us in our first hypothetical. If your device goes offline, SNMP v2c Informs won't help alert you.

Over time, the community of SNMP users have developed a best practice to solve this problem. Instead of only using asynchronous communication, the SNMP Get message type is used by the manager to poll its managed devices.

This type of regular polling by the SNMP manager ensures that you can detect, in a reasonable period of time, if a device has failed in the field. At most, you'll have to wait one complete polling cycle (typically a few minutes or less) to detect an unresponsive device.

How much does this cost to set up?

SNMP monitoring tools, just like network monitoring tools more generally, come in a massive range of different price points. You can find $500,000 options, free trials of $50,000 software, and even open-source options that are free forever.

So what differences can you expect at different price points? While each of your possible choices supports SNMP, their monitoring capabilities are much different.

The most obvious difference will be capacity. While superior hardware can help, good software utilizes its available hardware resources much more effectively. You can do more with the same server. For hardware-software appliances, you'll have purchased a high-quality server as part of your overall buying transaction.

You'll also find better performance monitoring at higher price points. Conveniences like auto-discovery (automatic device discovery of SNMP-capable equipment on your LAN) are also much more common in high-dollar commercial SNMP managers than inexpensive software.

Prices are important so you can stay within your budget, but there are also many costs that get reduced if you make the right choice. How do you balance the costs and the benefits to help your bottom line as much as possible?

That's a question of choosing the right SNMP manager...

What SNMP management software should I choose?

There's no one correct answer here, because I don't (yet) know the parameters of your project. Even though DPS sells telco-grade SNMP managers like our T/Mon, I actually get quite a few calls from hobbyists and engineering students.

If you're not working on a commercial project for a telco, utility, railroad, or government entity, you have options. Considering you probably don't have a huge (or any) budget, I recommend open-source SNMP managers. These don't generally do much more than act as "email inboxes" for SNMP alarms, they'll get the job done to help you learn the fundamentals.

If you do work for a large-scale operation of some kind, you owe it to your customers, your coworkers, and even your own career to choose quality. In the grand scheme of things, there's almost no purchase here that can bankrupt you.

Your bigger risk in a serious business or government enterprise is to choose something inexpensive and ineffective. In the long run, reduced efficiency and expensive equipment damage are the price you pay for buying something cheap.

Equipment damage at a $1 million remote site absolutely dwarfs even $50,000 in extra spending on the SNMP manager you actually needed. Situational awareness is priceless, and the correct SNMP manager helps you maintain a nearly perfect understanding of every remote site.

Give me a call to discuss your SNMP monitoring project with an engineer

When you're just getting started, there's nothing "simple" about SNMP at all. Every SNMP device and interface is totally new to you. I know what that is like, because I was a beginner once, too.

When I was learning, I spoke with the engineers here at DPS who designed both our NetGuardian SNMP RTUs (agents) and our T/Mon SNMP manager. Even though you don't work down the hall from these engineers, they're still available to you.

To get started, just give me a call. I can answer quite a few SNMP questions on my own for you. If you exceed what I know, I can either do a bit of quick research (about a specific product, maybe) or connect you with one of our engineers.

Call me at 1-800-693-0351 or send me an email at sales@dpstele.com

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Andrew Erickson

Andrew Erickson

Andrew Erickson is an Application Engineer at DPS Telecom, a manufacturer of semi-custom remote alarm monitoring systems based in Fresno, California. Andrew brings more than 15 years of experience building site monitoring solutions, developing intuitive user interfaces and documentation, and opt...

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