Linux bandwidth monitoring: the 5 best tools in 2020

Wouldn't we all wish our networks had infinite bandwidth? However, the reality is that this is often a very limited resource. Add to that the fact that overuse of bandwidth can have a huge impact on network performance and we have a recipe for disaster.

The solution: set up a bandwidth monitoring system. Many of them are available. However, most of them work on Windows, and if your operating system is Linux, your options are a bit more limited. However, you still have a lot of options and we're about to bring you the best bandwidth monitoring tools in Linux.

We'll start by introducing bandwidth monitoring and explain what it is. Next, we'll cover the ins and outs of Simple Network Management Protocol, or SNMP, one of the most widely used monitoring technologies. Our next agenda will be to take a look at Linux as an operating system, but more specifically as a platform for monitoring tools. And finally, we'll briefly review some of the best Linux bandwidth monitoring tools and describe their best features.

About bandwidth monitoring

Network bandwidth monitoring is a very specific type of monitoring. It measures the amount of traffic passing through one or more specific locations on a network. Typically, measurement points are router or switch interfaces, but it is not uncommon to monitor the bandwidth usage of a server's LAN interface. The important thing here is to understand that all we are measuring is the amount of traffic. Monitoring the bandwidth will not give you any information on the nature of this traffic, on its volume.

There are several reasons for wanting to monitor network bandwidth usage. First, it can help you identify areas of conflict. As the use of a network circuit increases, its performance begins to degrade. Unfortunately, there is nothing we can do about it. The closer you get to maximum capacity, the greater the impact on performance. By allowing you to monitor network usage, Bandwidth Monitoring tools give you the ability to detect high usage - and remedy it - before users notice it.

Another important benefit of network monitoring tools is capacity planning. Network circuits, especially long distance WAN connections, are expensive and often only have the bandwidth that was initially required when they were first installed. While this amount of bandwidth may have been fair at the time, it will eventually need to be increased. By monitoring the progress of the bandwidth usage of your network circuits, you can see which ones need to be updated and when.

Bandwidth monitoring tools can also be useful in troubleshooting application performance issues. When a user complains that a remote application is slowing down, looking at their network's bandwidth usage can give them a pretty good idea of ​​whether or not the problem is due to network congestion. If you notice low network usage, chances are you can focus your troubleshooting efforts elsewhere.

Overview of SNMP (Simple Network Management Protocol)

Many (if not all) network bandwidth monitoring tools rely on Simple Network Management Protocol (SNMP) to do their magic. This is because most network equipment has built-in SNMP capability and can be polled by monitoring tools at regular intervals. However, despite its name which might lead you to think otherwise, SNMP is actually quite complex. But don't worry, you don't have to be an expert and know everything to use it. It's like you don't have to be a mechanic to drive a car. However, it's best to at least have a feel for how it works, so let's take a look at that.

Basically, SNMP is a communication protocol that specifies how an SNMP management system can read and write operational parameters to remote devices. The parameters are called object identifiers or OIDs. Some of the interesting OIDs from a monitoring standpoint are those that contain the main metrics of the device, such as CPU and memory load or disk usage, for example. But when monitoring network bandwidth usage, two OIDs are of particular interest. These are the output bytes and the counter bytes associated with each interface. Network devices automatically increment them as data is sent or entered.

From a time when IT security was not an issue, SNMP has only had minimal security. An SNMP manager connecting to an SNMP compatible device will transmit a "community string" with your request. If the string matches the one configured on the device, the request will be made. Devices typically have two community strings configured, one for read-only OIDs and one for writable OIDs. Communication is not encrypted and anyone intercepting it will see the community strings in clear text. This is why SNMP is only used on private and secure networks.

How it works in real life

This is how most monitoring systems use SNMP to monitor bandwidth usage. They periodically read the input and output byte counters of the interfaces of a network device at known intervals. Five minutes is a typical interval value, but shorter times can be used for finer resolution. Then they store the queried values ​​in some sort of database or file.

The rest of the process is just mathematical calculations. The monitoring system subtracts the previous counter value from the current value to obtain the number of bytes transmitted or received during the polling interval. Then you can multiply that number by eight to get the number of bits and divide it by the number of seconds in the interval to get the number of bits per second. This information is generally plotted on a graph which shows its evolution over time and is stored in a database.

It's important to note that what you get is an estimate of the average usage during the polling interval, not the actual bandwidth usage. Suppose, for example, that a circuit is used at full capacity for half of the polling interval and carries no traffic for the other half. It seems to be used at 50% of its capacity despite its maximum for an extended period of time. Shorter polling intervals will reduce this distortion, but it's important to note that these systems only give you average values.

Use Linux as a monitoring platform

As an operating system, Linux is functionally no different from others like Windows or Mac OS. The main difference between Linux and other popular operating systems is that Linux is an open source effort and most distributions are available for free. Many people tend to confuse free and open source. It is true that open source software is generally free, but that is not necessarily the case. For example, the Red Hat Enterprise Linux operating system is not free. To add to the confusion, those in the open source movement often refer to open source software as free software in which free implies freedom rather than cost.

Over the years, Linux, once a fringe operating system installed by nerds and computer students, I remember spending weeks downloading SLS Linux one floppy image at a time over a dial-up connection. 1200 baud; I was definitely one of those nerds; it has become a popular choice as a server operating system. Some recent distributions are also making great strides as a viable alternative to Windows as a personal computer operating system, although that is an entirely different debate.

While Linux is a popular operating system for servers of all kinds, it is even more so when it comes to running specific tools. There are several free and open source network bandwidth monitoring tools that will only work on Linux. And if the tool you choose can run on Windows or Linux, wouldn't it be more cost effective to use a free operating system instead of spending money on an expensive system?

While some people still don't trust free and open source software and operating systems for mission-critical applications and, for example, don't put their valuable business data on a MySQL server running Linux, a lot of between them usually do not. make. they have so many objections to using the platform to run network management tools. One of the main advantages of using Linux as the underlying platform for network monitoring tools is that it is easy to set up a Linux server with only the necessary packages. While it can be done with Windows, it is much more complicated.

Best tools to monitor bandwidth in Linux

We have searched the web for some of the best bandwidth monitoring tools that can work in Linux. What we have come up with are commercial products and free and open source products. Some products on our list can be installed on Linux or Windows, while others are for Linux only. They all offer SNMP bandwidth monitoring and all have a centralized console where you can configure the tool and view monitoring results. While there are command line-only tools, we've excluded them from our list.

1. ManageEngineOpManager

Le ManageEngineOpManager is a powerful all-in-one network tool for capacities of surveillance offers a full network monitoring. It can help you monitor network bandwidth usage, detect network failures in real time, troubleshoot errors, and avoid downtime. The tool supports multiple multi-vendor environments and can be scaled to fit your network of any size. It can run on Linux or Windows and will allow you to monitor your devices and network and give you visibility into your entire network infrastructure. Installation and configuration of this product is quick and easy. You can get it up and running in under two minutes.It does not require any complex installation procedure and comes with built-in web servers and databases.

> The> ManageEngineOpManager Continuously monitors the performance of network devices in real time and displays them on its dashboards and live graphs. In addition to bandwidth, it looks at various critical operational metrics like packet loss, errors and rejects, etc.