Network Congestion: Guide on How to Detect and Fix It

Alexander Abgaryan
CEO, Senior DevOps
DevOps Implementation: Benefits, Use Cases, and ten-Step Plan to Undergo
Since more people get connected to the internet daily, the network gets overloaded. That leads to network congestion, a phenomenon that occurs when the network cannot handle the traffic going through it.
It is like the road in the peak period. When there is too much traffic, there’s no possibility for the transport to work at the usual speed.
Still, there are cases when network congestion turns into a permanent issue that causes big trouble for businesses.

To avoid this, you should know the answers to the following questions:

  • What is network congestion?
  • What are the causes of network congestion?
  • What are the effects of network congestion?
  • How to run a network congestion test properly?
  • What are the best network congestion solutions?

Let’s start with explaining the phenomenon of congestion and moving towards resolving the issue.

What is Network Congestion?

Network congestion is a drop in the network capacity to pass traffic. To an end-user, it looks like a slowdown, although it can fire up more serious issues. Packet loss and high ping are just a few to name.
What is Network Congestion: Diagram
Network Congestion

Increased collaboration

From causes to effects, network congestion is similar to a traffic jam. It is brought up either by
  • a hog (a faulty device or a broken car)
  • a heavy traffic (too many users)
  • or a bad road (poor network)
It leads to transportation delays or slow connections. No matter wired or wireless the system is, the network congestion occurs when the demand is greater than the ability of the network to cover it.

If network congestion isn’t connected to serious issues like a security attack or network failures, it can be solved by itself. In other cases, you may need expert support to fix it.

Luckily, there are numerous companies like IT-Magic succeeding in the development of effective methods of congestion fix.

Suspecting your network gets congested?

Don’t hesitate to contact IT-Magic for a consultation! Our company can help you to establish and eliminate the causes of congestion in your network and select effective network congestion solutions to set your network up and running.

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If traffic congestion problems are not a pressing issue yet, let’s move on to a detailed breakdown of the negative effects of network congestion.

Negative Effects of Network Congestion

As mentioned above, network congestion occurs when the whole network or a node is carrying more traffic than it was designed for. It can flow into several issues. They are latency, packet loss, bandwidth issues, jitter, collisions, and connection timeouts.
Negative Effects of Network Congestion
Effects of Network Congestion

  1. Bandwidth Issues

Bandwidth is the maximum amount of data that can travel along a path. As for transportation, bandwidth is an ability of a road to pass 1,000 cars per hour, for example. If you push 3,000 cars down the road. The traffic will be blocked.

In case of network congestion, too much data flow down a certain path, causing interruptions in the system work. Congestion-related bandwidth issues started occurring more often once more people shifted to work from home.

The symptoms of bandwidth issues are usual: an application starts working slowly or gets unusable, a video gets interrupted or slow to refresh, the sound gets distorted.

Classification of Network Congestion State
Classification of Network Congestion State

2. High Latency

Latency is the delay in data transmission.
It is analogical to the speed limit on a highway. Imagine you drive a car at a certain speed. If there are too many other cars, you have to slow down to avoid collisions.

So do other cars behind you. Generally, the whole system speed falls down. That is latency, one of the immediate effects of network congestion.

3. Jitter

That’s another sort of delay, yet, a more unpredictable one.
Every computer user wants to know how the network will work. When suddenly one of the computers in the network starts sending large bursts of data, most of the bandwidth gets assigned to this computer.

The network tries to adjust and to avoid collisions, your computer will pause sending packets of data. Usually, it takes milliseconds, but receiving no signal from this computer, other transmitters on the network will wait or stop receiving data from other ports. This way, network congestion acquires a cascading effect.

4. Packet Loss

The issues mentioned above mess up data packets transfer. If a packet can’t reach the destination, it should be resent. Sometimes it happens several times. If you send one and the same data packet two, three, or more times, that’s packet retransition, one of the nasty effects of network congestion.

It is like your family goes on a family trip, but returns several times to pick up something forgotten.

During packet retransmission, some data packets get lost, which negatively affects the quality of your business operations.

5. Collisions

Collision is a situation when several devices in a network send data at the same time. To avoid collisions, the network uses the CSMA/CD method, which makes every computer in the network wait for its turn to send data.

Yet, if some piece of hardware doesn’t work according to this method, two and more devices can start sending data at the same time. Then all packets have to wait for the network to clear. Different stations, aka computers, stop sending signals for a random interval of time for the network to clear. The more collisions appear, the longer the halt is.

The main reason for this network congestion effect is bad equipment, which makes other nods in the system break their schedule of packet transmission. Similarly, a traffic hog or road repairment causes all traffic on this road to stop.
One of the best network congestion solutions, in this case, will be removing the cause, which is a broken piece of equipment.

6. Connection Timeouts

For services to run smoothly, data packets should arrive in time. In case of a delay, many services will time out instead of waiting for data to retransmit.

Here’s an analogy: a shop has a schedule for product delivery. Yet, a delivery truck can’t reach the destination because of a traffic hog. In that case, a shop won’t open today.

That’s actually how network congestion breaks service performance.

Main 5 Reasons of Network Congestion

Network congestion causes are various. They may be over-subscription, poor network design, or security attacks. Proper diagnostics of causes is vital for finding effective network congestion solutions.
Key Causes of Network Congestion
Key Causes of Network Congestion

  1. Over-Subscription

There are hours when the network works faster than usual. That is because a little number of people are using it. Usually, it happens in the middle of the night.

During the working day or peak periods like Black Friday, you can face slow connection, which is an effect of the network overload. That’s because more people are using the network at the same time. It’s called over-subscription, one of the main causes of congestion in a network.

2. Poor Network Design

Unlike over-subscription, poor network design is one of the least pleasant network congestion causes. Say, your network has to broadcast a large volume of traffic within a short time. That’s called the broadcast storm.

The data are broadcast within subnets. If the subnets are large, the issue of network congestion is a matter of time. That should be taken into account when designing the network.

Another important consideration to fend off network congestion is giving special treatment to network-specific traffic. It is like clearing a lane for a presidential escort.

3. Over-Used Devices

A typical network has a maximum capacity. That means that routers, switches, and firewalls can pass through 20 GB per second, for example. Using the network at its maximum, that is pushing 20 Gbps daily will inescapably lead to network congestion. In practice, it will result in packet drops.

Another scenario for over-utilized devices is bottlenecks. They appear in hierarchical designs where several devices send data to one higher-level device. The latter is the one to get over-utilized. It is like a four-lane road that flows into a two-lane one.

To avoid network congestion, you have to ensure that a high-level device is capable of handling traffic from subsidiaries.

4. Faulty Devices

A faulty device can lead to network congestion even if the network itself works well.
A use case: a network started working sow. An ISP check proved that the network was passing 100 Mbps but the real user experience was far from those digits. The further check showed that the edge device was giving only 30 Mbps.

This way, one faulty device was a cause of network congestion. So by fixing that nod, a company avoided poor internet congestion further and boosted productivity.

5. Security Attack

Security attacks are the frequent causes of congestion in the network. For example, if a low-loaded network serving several users which do not do anything heavier than sending e-mails starts working slowly, it is likely to be compromised.

Attackers may secretly use the servers of that network to host a large amount of illicit content that takes a lot of traffic.

Another security-related issue is the denial-of-service or DoS attacks. In the result of DoS attack, users are not able to access services or devices because network or host is blogged with tons of traffic, and they finally crash.

When a network gets attacked by multiple machines, it is called a distributed denial-of-service attack or DDoS. DDoS attackers usually use a group of interrelated devices to target one victim. This is a large-scale attack compared to DoS and it is more difficult to find it source, and therefore, apply a solution.

One of the best network congestion solutions, in this case, will be server cleaning.
Other attacks influencing network congestion may be worms, viruses, denial of service, or DoS attacks.

Contact IT-Magic for free consultation and support!

Establishing proper causes of network congestion is critical for effective network congestion solutions. Therefore, you might need a skilled professional for a network congestion test. IT-Magic is providing network support services to numerous clients around the globe.

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Network Congestion Solutions: How to Fix It

Once you’ve diagnosed the causes of congestion in a network, you can switch to the next important step: finding out how to fix network congestion.
Your variants are multiple: running LAN performance testing, bandwidth monitoring, decongesting a network, segmenting, and prioritizing your traffic.

1. Ping

Ping is the best way to detect packet loss. It’s also one of the fastest network congestion solutions. This method helps to reveal network delays. If you use tools like MTR, you can easily disclose parts of the network where traffic congestion problems occur.

2. LAN Performance Tests

One of the most frequently used network congestion solutions is LAN performance testing. It gives statistics on bandwidth, jitter, delays, or packet loss. Using these data, you reveal faulty devices.

3. Bandwidth Monitoring

Bandwidth monitoring is one of the most helpful network congestion solutions.
In case of bandwidth issues, it is important to establish what users report first. These may be difficulties with IP or video conferencing, slowing down in application performance, etc.

Knowing which issues are making trouble will prompt which part of the network is damaged. For example, format errors may be caused by QoS classes dropping packets. Then you will know you have to change the QoS configuration to solve issues.

Also, there are numerous tools to monitor your network performance. They will prompt you where to look further to prevent network congestion from the start.

4. Decongesting a network

After testing, decongesting is the next in your list of network congestion solutions.
Every cause of a congested network has its own decongestion routine.

Over-subscription requires a purchase of bandwidth or using temporal solutions like a bandwidth boost - an ability to use more bandwidth for a limited amount of time. It’s like adding an extra lane to a four-lane road for peak periods.

Over-utilized devices need reinforcement or at least implement high-availability features like stacking or clustering.

5. Segment and Prioritize your Traffic

Your network runs different sorts of traffic, like broadcast traffic for network operation, multi-cast traffic supporting streaming of real-time media, or unicast traffic supporting voice and video transfer of the conference and communication services.
Steps to Fix Network Congestions
Steps to Fix Network Congestions
Any of these types can be business-critical, depending on the type of business, you run. For example, voice traffic will be critical for a conference service. Other types of data may be of low priority or unneeded.

For proper network design, it is vital to assign high-priority subnets to important traffic. This way, your business will run smoothly in peak periods.

Network Congestion: To Sum Things Up

We hope the tips described above have brought you to an understanding of how to fix network congestion effectively.

Let’s sum up the main points of this article:

  • You can avoid congestion collapse if you detect the symptoms early. The main effects of network congestion are bandwidth issues, packet loss, connection timeouts, collisions, latency.
  • Upon detecting network congestion signals, you have to establish the causes properly. The most frequent network congestion causes are over-subscription, poor network design, over-used or faulty devices, a security attack.
  • Depending on the causes of congestion in a network, you pick up the solutions. These are LAN performance testing, bandwidth monitoring, decongesting a network, segmenting, and prioritizing traffic.

Naturally, you’ll need a skilled service provider to implement network congestion solutions effectively. It will be wise to select a provider, that can offer you effective ways to improve your network without blowing up your budget.
Flow of Network Troubleshooting
Flow of Network Troubleshooting

Contact IT-Magic for a consultation on the best and most effective network congestion solutions for your business! We specialize in network solutions and provide IT solutions and infrastructure set up to sustain your business during sale seasons and Black Fridays.

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