How to Detect Network Congestion

Alyssa Lamberti
Alyssa Lamberti Last updated on Feb 21, 2022

How to Detect Network Congestion

In Summary

We’ve all been stuck in traffic congestion on the road at some point in our lives. Traffic congestion may happen when there’s too many cars on the road, when there’s an accident or a closed street. Network congestion isn’t too different from that - but instead of cars causing congestion, it’s network traffic. That’s why, in this article, we’re running you through how to detect network congestion with Network Monitoring tools.

Table of Contents
Table of Contents

What is Network Congestion?
What is Network Congestion?

Network Congestion, similar to road congestion, occurs when your network cannot adequately handle the traffic flowing through it. This can be caused by events such as faulty or over-used devices or even bad network configurations.

This means that network congestion can occur in your network, or even outside of your network in your network devices, or your ISP network or Internet.

While network congestion is usually temporary, it can cause annoying network problems that can affect performance, such as high levels of jitter, packet loss, a decrease in throughput, and can be a sign of a larger issue in your network.

Because of this, it’s important to have a tool that can proactively detect network congestion and perform a network congestion test in your own network, and even outside of your network so you can troubleshoot before it affects your end-users, or turns into a much bigger problem that your IT team will be stuck dealing with.

Step 1. Deploy End-to-End Network Monitoring
Step 1. Deploy End-to-End Network Monitoring

You may be able to experience signs of network congestion in networks, but how do you know what’s causing it? And how can you fix network congestion?

To know how to check network congestion, you need an end-to-end monitoring tool to help you proactively detect network congestion, and that’s where Obkio Network Performance Monitoring Software can help.

Obkio continuously monitors end-to-end network performance so you can monitor performance from your local network (LAN, VPN), as well as third-party networks (WAN, ISP, and Internet Peering).

Unlike traditional monitor solutions that may only monitor local network equipment, Obkio allows you to monitor performance from every end of your network, where you may not have any IT staff or equipment available.

Obkio does so with synthetic traffic using Network Monitoring Agents, which monitor all ends of your network to measure network metrics, identify network problems (like congestion) and collect the information to help you troubleshoot.

Use Obkio’s free trial to begin.

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Step 2. Identify Network Congestion with Core Network Metrics
Step 2. Identify Network Congestion with Core Network Metrics

It's easy to detect congestion when it's happening with your own network equipment, but you’re not always using your own equipment. Some businesses may be using their ISP’s or MSP’s network equipment, so they don't have direct access to the network equipment’s data.

Additionally, the network congestion may not be actually happening in your own network, but maybe in your ISP’s network, on the local loop of its connection or even on the Internet.

But, it's still possible to detect network congestion by monitoring other core network metrics! You can easily identify network congestion by measuring:

Luckily for you, Obkio continuously measures these core network metrics and displays them on Obkio’s Network Response Time Graph so you can easily view metrics in real-time.

Obkio will also automatically notify you of events like substantial packet loss or high levels of jitter, so you know as soon as it starts happening!

How Network Congestions Affects Performance
How Network Congestions Affects Performance

Network congestion can cause dropped packets (aka packet loss), and increased latency and jitter. That’s because, when network congestion occurs, data packets can accumulate (like cars in a traffic jam), leading to a huge buffer.

It then takes time to empty and refill the buffer, which increases latency and jitter. If the buffer is small, the latency won’t increase too much but more packets will be dropped. Depending on the network equipment, the buffer size can be adjustable or it can be fixed in the hardware.

Network Congestion Example
Network Congestion Example

If you want to perform a network congestion test, here is an example of what network congestion looks like:

Network Congestion Graphs

In this screenshot, you can see three graphs.

  • In the first graph, you can see there is network congestion and the buffer is very large. Therefore there is little packet loss but a lot of latency and jitter.

  • In the second graph, there is network congestion with a medium buffer, so the packet loss, latency and jitter are all moderate.

  • In the third graph, there is network congestion with a small buffer, so the latency and jitter don’t increase too much but there is more packet loss.

How to Measure Packet Loss

Learn how to measure packet loss using Obkio’s Network Monitoring software to proactively identify problems in your network & collect data to troubleshoot.

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Step 3. Monitor Network Devices
Step 3. Monitor Network Devices

Because network congestion can be caused by overused network equipment, you can use Network Device Monitoring to monitor your own network equipment, and measure the quantity of traffic going through your devices.

If you’re reaching your limit on the amount of traffic your devices or Internet connection can handle, then you’re sure to experience network congestion.

If you’re only monitoring your devices, you may not find the problem if it is located elsewhere, which is why it’s important to primary monitor the network metrics we mentioned above.

Network Congestion Dashboard

Step 4. Identify a Lack of Resources
Step 4. Identify a Lack of Resources

Network congestion commonly occurs when your network devices or Internet connection are lacking the resources available, such as bandwidth or CPU, to process traffic flowing through the network.

In the screenshot below, we can see an example of high CPU usage on SD-WAN Devices affecting all sessions (in the second column). This means that the network device does not have enough available resources to manage the throughput. Since it cannot process data packers properly, it will end up dropping them and causing packet loss.

Network Congestion Dashboard

How to Identify a Lack of Resources
How to Identify a Lack of Resources

In all these circumstances, you can set up Network Device Monitoring with SNMP monitoring.

They will poll interfaces and graphs for bandwidth usage (inbound / outbound traffic) and detect short bursts of traffic or CPU utilization that affect network performance.

Network Device Monitoring to Identify & Troubleshoot Performance Issues

Learn about Network Device Monitoring to easily monitor performance of firewalls, routers & switches to identify problems like high CPU & bandwidth usage.

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Step 5. How to Reduce Network Congestion
Step 5. How to Reduce Network Congestion

If you've performed your network performance test and realized that you’re experiencing network congestion due to a lack of resources, here are some suggestions:

Analyze Traffic Logs
Analyze Traffic Logs

Look into the traffic going through your devices. Understand if the traffic is legitimate or not by looking at the firewall logs. Illegitimate traffic might be a security breach (data exfiltration), or mass data backup during business hours.

Upgrade Bandwidth
Upgrade Bandwidth

Upgrade your Internet connection bandwidth with your ISP if you’re just running out of bandwidth. This will increase your resources availability.

Decrease Usage
Decrease Usage

If your network devices can't handle the traffic going through them, you can also simply decrease your usage. This can mean allocating times during the day where you minimize traffic.

Manage Priorities
Manage Priorities

Depending on the network, you can use QoS (Quality of Service) to prioritize some traffic on the network in order to reduce high bandwidth or CPU usage causing congestion. Learn more about how Obkio performs QoS Monitoring with DSCP Features.

QoS Monitoring with Obkio DSCP Features

Learn how to monitor QoS performance on your private network, including MPLS, SD-WAN, or VPN, using Obkio's DSCP features.

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Step 6. Troubleshoot Network Congestion
Step 6. Troubleshoot Network Congestion

Now that you know how to set up Obkio to monitor and detect network congestion, you need to know how to fix network congestion.

With Obkio you can also identify network problems and collect the information you’ll use to troubleshoot the network congestion.

Create your own Obkio dashboard with a summary of your network metric measurements and data you need to troubleshoot the network congestion, including:

  • What the problem is (network congestion or other network problems)
  • Where the network congestion is located (Use Obkio’s Traceroutes or Vision Visual Traceroute tool to help pinpoint the location of problems)
  • What caused the network congestion
  • When the network congestion happened
  • Who is responsible for the network segment (is it happening inside of your network or in your ISP/ MSP network?)
How to Troubleshoot Network Issues

Learn how to troubleshoot network issues by identifying where, what, why network problems occur with Network Troubleshooting tools.

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Start Detecting Network Congestion
Start Detecting Network Congestion

With this setup, you can now proactively detect and troubleshoot network congestion before it starts impacting your network performance and user experience! It’s like finding an alternative route to avoid road congestion.

Use Network Device Monitoring to easily detect network congestion caused by your network equipment.

But remember, if the network congestion is occurring outside of your network, or with your ISP’s network equipment, use Obkio to measure network metrics like packet loss, jitter and latency, which can spike when network congestion occurs.

Use Obkio's Free Trial to get started!

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