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Network Traffic Congestion Causes & Internet Monitoring Apps

So, when you hear the word “Network Traffic Congestion”, what comes to mind? Our guess is that you thought about traffic congestion on the road. When there are too many cars on a particular stretch of the road faster than they can exit that road, we have a traffic jam/congestion. Traffic congestion can also be caused by factors like accidents, bad roads, small roads, etc.

Perse, the point is that congestion results in a restricted flow of traffic. The same is true of Network Congestion as we will discuss in this article, looking at the causes, effects, troubleshooting tips, software tools, and how to fix network congestion. Today’s business and working environment requires a fast, stable, and secure network infrastructure to connect all hubs.

Be that as it may, in this article, we are going to discuss what Network Congestion usually entails and how it affects your User Experience (UX) and their computing gadgets (like mobile phones, desktops, laptops, and the like) in general. We’ll also look into how causes such as over-subscription, faulty devices, and security attacks can result in network congestion.

Not forgetting, we’ll equally discuss the overall Network Congestion effects that can be a pain to many users. Including poor user experience, packet loss, timed-out connections, and much more. Last but not least, we’ll still discuss how to troubleshoot network congestion in any Internet connection — as we also highlight some things that can be done to fix these issues.

What A Network Traffic Congestion Entails For Internet Connection Users

Just like road traffic congestion, Network Traffic Congestion occurs when a network is not able to adequately handle the traffic flowing through it. Oftentimes, this congestion occurs when a network is overrun with more data packet traffic than it can cope with. This backup of data traffic occurs when too many communication and data requests are made at the same time.

In other words, network traffic congestion refers to a reduction in Quality Of Service (QOS) that causes packet loss, queueing delay, or the blocking of new connections. Typically, network congestion occurs in cases of traffic overloading when a link or network node is handling data in excess of its capacity. For instance, using 98/100% of the distributed network data.

It may happen over a network that doesn’t have enough bandwidth to carry it. In particular, that’s if they operate under multiple computing devices and huge volumes of traffic that flows through them. Optimal network performance and the best user experience require high uptime. Issues like severe network congestion can lead to poor user experience at large.

As a result, this may severely affect the overall business performance, which in turn could lead to a loss of sales revenue. Fortunately, network congestion is usually a temporary state of a network rather than a permanent feature. But, there are still some notable cases where a network is always congested signifying a larger issue is at hand as we’ll showcase below.

The Topmost Common Network Traffic Congestion Causes To Consider

First of all, as far as the end-user is concerned, network traffic congestion feels like slow response times or a “network slow down.” When the internet, the WiFi, or even the computer itself just “feels slow,” that is often the result of network congestion. Unneeded traffic such as streaming video on a work system is a very common cause of network congestion.

Other examples of unneeded traffic eating up bandwidth include junk VoIP phone calls or unsolicited traffic like advertisements. Luckily, you can use the network management console to identify unneeded traffic. By the same token, to avoid collapse and reduce the effects of congestion in the network, organizations use various practice methods.

More so, to achieve network traffic congestion avoidance with the help of a variety of network congestion control measures and other related software application tools. Usually, this mix helps to achieve optimal network data output processing.

The key elements include:
  • Transmission Control Protocol (TCP) or Internet Protocol (IP) window reduction
  • Fair queueing in network devices such as routers, switches, and other devices
  • Priority schemes that transmit higher priority packets ahead of other traffic
  • Explicit network resource allocation via admission controls toward specific flows

There’s still more to network congestion, or rather, the actual main causes than what meets the eye. This means, that the methods you’ll choose — to check network congestion and identify issues — highly depend on real cause results after detecting the effects of congestion in the network. In the next section (as pictured below), we’ll look at the topmost causes.

The Most Common Network Traffic Congestion Causes To Consider

As we mentioned, while network congestion is usually temporary, it can cause inconvenient network problems that can affect performance, especially, in a workplace. Such as high levels of jitterpacket loss, and latency, as well as a decrease in throughput. This means, that a continuously congested network can be a notable sign of a larger issue in your network system.

On that note, because of this, it’s important to have a few network performance monitoring tools in place — that can proactively detect network congestion in your own network, and outside of it. So, what happens when there is a company-wide meeting and all employees come into the office? You guessed right – Network congestion. Below are a few other key causes.

1. Internet Bandwidth & Latency 

When a network is inundated with requests, it causes what’s sometimes referred to as a broadcast storm. This could happen for example, on an unusually busy day for an eCommerce business, or a video going viral. And, as a result, this creates a situation where a network can’t process all the requests at once. The main culprits of such storms are bandwidth and latency.

Bandwidth is among the most common causes of network congestion. It refers to the maximum rate at that data can move along a path or the total capacity of that path. Network congestion happens when there’s just not enough bandwidth to handle the existing traffic. The same problem that a road built for 50 cars faces when 200 cars a day try to drive on it.

Latency, on the other side, is the time it takes a data packet to travel from point A to point B. It’s usually closely connected to other congestion issues such as bandwidth. Back on the road, it’s expressed by the way it takes you 20 minutes to travel from point A to point B on one day during certain conditions. And 60 minutes for the same trip under different conditions.

In this case, we can simply say that the slower time is latency — it’s a sign of the problem, rather than something that itself leads to network congestion. Thus, both bandwidth and latency may serve as a great place to start investigations.

2. Traffic Jitters & Packet Collisions

Jitter is a variation in delay in traffic patterns. Computers, like most humans on the road, prefer predictable, consistent traffic. When traffic is unpredictable or inconsistent, this produces jitter, or variability in delay, causing more network congestion. On the road, drivers access the highway randomly, which means there may be large bursts of cars trying to merge at any one time.

For networks, such a surge can come from a system user that sends the network large bursts of traffic, consuming excessive bandwidth. Jitter creates congestion because the computer changes its traffic patterns each time the network tries to adjust. To avoid network collisions, the system pauses sending packets and initiates a random back-off for a period of time.

This is usually measured in milliseconds. This increases congestion as other network transmitters wait before trying again in a cascading effect. Similarly, it’s often packet collisions on the network that trigger the back-off process, described in relation to jitters. Packet collisions can be caused by poor cabling or bad equipment, and can produce a serious situation.

For example, some packet collisions may start forcing all packets to stop and wait for a clear network to retransmit. This produces even greater congestion and delay, and like with a highway collision, traffic direction is often required.

3. System Traffic Over-Subscription

Have you ever experienced a case where your web browsing experience is consistently faster at certain times of the day than others? For example, there is a high probability that you will have a better browsing experience at night than during the day. This is because there are more users on the network during the day (peak period) than at night (off-peak period).

Over-Subscription is usually to blame when a web browsing experience is consistently slower or faster at some times of the day or night. During the day, the network’s peak period, there are more users making demands on network resources than there are at night, the off-peak period for the network. This is like working on peak times versus the middle of the day or night.

Perse, it’s also similar to getting on the train during rush hour versus when everyone is at work. Cases like this are usually the result of Over-Subscription where a system (e.g. a network) is handling more traffic than it was designed to handle per time. It is, therefore, important to note that over-subscription is usually done on purpose as it may result in cost savings.

For example, let’s consider a scenario where an organization has 100 users and it has been determined that a 100Mbps Internet link will be suitable for all these users. Now imagine that most of the staff of this organization work from home. In this case, it will be more cost-efficient to go for a lower link capacity, say 50Mbps, since only a handful of employees will be using it.

4. Misconfiguration & Packet Retransmissions  

A more serious cause of network congestion is poor design or device Misconfiguration. Take for example a broadcast storm, where a large volume of broadcast and/or multicast traffic is seen on the network within a short time, resulting in severe performance degradation. Since broadcasts are contained within subnets, the larger the subnet the more serious the storm.

Therefore, a network that has been designed with large subnets without giving proper consideration to broadcast storms can result in network congestion. Another case of broadcast storms is Layer 2 loops. In a layer 2 segment, broadcast messages are used to discover unknown MAC addresses. If there is a loop on the network, the same broadcast message can have glitches.

Such as being sent back and forth between the devices on the network resulting in broadcast storms and possible network congestion. Still, speaking of the need to retransmit packets, packet retransmissions can also cause congestion and are typically caused by other congestion issues. Packet transmissions that arrive damaged or don’t arrive at all must be resent.

Clearly, each time a single packet must be sent two or more times, traffic congestion increases without any incremental benefit. It would be like breaking up a successful carpool.

5. Network Connection Over-Utilization

Similarly, some devices can handle more traffic than others, by design. Devices such as load balancers, switches, routers, and firewalls are built for network throughput. Additionally, any device’s assigned capacity is theoretical; it may not accurately represent the real-world ability of the device in various scenarios. For this reason, over-utilization is also a frequent casue.

More so, as a result of pushing devices to their maximum reported capacity. Oftentimes, structures for using multiple devices are hierarchically designed, with higher-level devices serving lower-level devices. To ensure healthy traffic levels and prevent congestion, it’s critical to ensure within the hierarchy that each level is demanding and receiving appropriate support.

Incongruencies between firewalls, routers, switches, and other devices can lead to data bottlenecks. Devices such as routers, switches, and firewalls have been designed to handle certain network throughput. For example, the Juniper MX5 has a capacity of 20Gbps. A theoretical value fact is that the capacity in the production environment will be slightly lower.

Suffice it to say, this is also the maximum capacity. Therefore, constantly pushing ~20Gbps of traffic to the device means that it will be over-utilized and will likely result in high CPU utilization and packet drops. Whilst, leading to congestion on the network. Another issue related to over-utilized devices that can cause network congestion is Bottlenecks as well.

6. Faulty Internet Connection Utilities

For most hierarchical designs where multiple devices feed into a higher-level device, care must be taken. To ensure that the higher-level device is capable of handling all the traffic from the lower-level devices. If this is not the case, then the higher-level device can result in a bottleneck causing congestion on the network. It’s like a 4-lane highway merging into a 2-way.

We once performed a network performance assessment for an organization. They were buying 100Mbps link capacity from their ISP but the users on the network were struggling to connect to the Internet effectively. As a result, they complained that the network was always “slow” (users speak for network congestion) — even when few people were on the network.

Upon investigation, we discovered that while their ISP was truly giving the agreed-upon 100Mbps, the edge device was only providing 30Mbps to the network! Apart from the fact that this organization had wrongly terminated the link on a Fast Ethernet interface (with a theoretical speed of 100Mbps but a much lower practical speed), that interface was also faulty.

By moving the ISP link to another interface (using a Gigabit Ethernet interface instead), optimal performance was achieved. So, since poor design or device misconfiguration is a more serious cause,  each network must be designed to handle the right loads. And also, configured to meet the needs, connects all segments, and maximize performance across each of them.

7. Cloud Computing Security Attack

Last but not least, various security attacks can cause network congestion, including worms, viruses, and Denial of Service (DoS) attacks. Basically, an optimized network connects all segments while maximizing both security and performance across each of them. For instance, a broadcast storm can cause severe performance degradation — giving hackers leeway.

Specifically, when the network experiences a large mass of broadcast or multicast traffic in a short time. Broadcasts are contained inside subnets, so a broadcast storm can have more serious effects on larger subnets. Designing a network that has large subnets without giving proper consideration to broadcast storms can cause network congestion.

To avoid this problem, create subnets near where large amounts of data will be stored to allocate performance where it’s needed. In another organization we consulted for, a network of about 10 users had a poor browsing experience even with the 4Mbps link they were getting from their ISP. Ideally, it should have been enough because the users were not heavily browsing.

Otherwise, it was just emails, web searches, and normal user activities. But, it could still be a cyber attack loophole for viruses, worms, and Denial of Service (DoS). If the server is compromised, the attacker may use this server to host illicit content resulting in huge server traffic. By cleaning it up, the congested network is once again “free” for normal user traffic.

The Simple Steps To Troubleshoot Network Traffic Congestion

Overall, there are various effects of network traffic congestion that are worth mentioning. Mind you, everyone on a network generally “feels” the effects of network congestion. Perse, they may not be able to explain it in technical terms but will say things like “The connection is so slow”, “I can’t open web pages”, “The network is really bad, I can’t hear you,” and the like.

Too many hosts in a broadcast domain — applies to a network structure — can also have an effect. This could be the network within an enterprise, educational facility, or VLAN. A ‘host’ refers to each individual router or switch within the broadcast domain. Too many hosts in the structure can cause an overload, as too many devices are requesting network access at once.

The concept also applies to mobile networks and routers. Mobile networks and routers are the broadcast domain. While computers, tablets, or phones are the hosts. The maximum capacity for hosts in a broadcast domain is 200–254. Feeling the effects of network congestion is one thing, yes, but actually confirming that a network is congested is another.

The main effects of a congested network include:
  • Delay: Also known as Latency, Delay is the time it takes for a destination to receive the packet sent by the sender. For example, the time it takes for a webpage to load is a result of how long it takes for the packets from the web server to get to the client. Another evidence of delay is the buffering you experience when watching a video, say on YouTube.
  • Packet Loss: While packets may take a while to get to their destination (delay), packet loss is an even more negative effect of network congestion. This is especially troubling for applications like Voice over IP (VoIP) that do not deal well with delay and packet loss, resulting in dropped calls and Call Detail Records, lag, robotic voices, and so on.
  • Timeouts: Network congestion can also result in timeouts in various applications. Since most connections will not stay up indefinitely waiting for packets to arrive, this can result in lost connections.

With that in mind, in the next section, we will look at some activities that can be performed to confirm that there is indeed network traffic congestion in any of your Internet-based connection environments.

1. Monitor And Analyze Network Traffic (Ping)

The starting point for solving most network congestion issues, especially, for too many devices, over-utilized devices, or an insufficient network design, is monitoring and analyzing traffic. To help identify where congestion may exist. And then, highlight under-utilized regions that are ripe for re-allocation to improve performance. Start with deeper network traffic insights.

By doing so, it’s very possible to take intelligent steps toward reducing network congestion. Monitor during heavy traffic times to diagnose network congestion, especially during peak hours when many devices are connected, or during company-wide events. The right network discovery tool can help reveal the source of network congestion as you scan your cloud servers.

You’ll also be able to scan your VPNs (Virtual Private Networks) and all other wireless-connected devices with a network discovery program. So as to identify servers, devices, and even users eating up too much bandwidth. After identifying the issues with bandwidth usage, you can now update the network infrastructure to allocate it more effectively during peak times.

From a technical perspective, one of the fastest ways to check if a network is congested is to use Ping because not only can it detect packet loss, but it can also reveal delay in a network i.e. through the round-trip time (RTT). Using a tool like MTR (which combines ping and traceroute) can also reveal parts of the network where congestion is occurring.

2. LAN Performance Tests

Must be remembered, the number, type, and bandwidth usage of network devices affect the whole network’s data processing. In some cases, some network users might accidentally be incorrectly using devices. While still, other users could be using “legacy devices” that are not well-supported. Both older and inefficient device usage contribute to network congestion.

So, try to assess each device to reduce or even prevent network congestion. Business critical traffic can be a mix of typical business network traffic types. Including multicast traffic for real-time media streams, broadcast traffic for network operation, and unicast traffic. In that case, they help to support everyday voice, data transfer, and video functions.

Unfortunately, most network-enabled and other computing devices cannot just automatically distinguish which of these intermixed traffic should get a priority share of bandwidth. Not without special configuration to make things work as they should. If you recall, we mentioned that this is what drives the realms of Quality of service (QoS)) protocols.

A tool like iPerf can be very useful in determining performance issues on a network and measuring statistics like bandwidth, delay, jitter, and packet loss. This can help reveal bottlenecks on the network and also identify any faulty devices/interfaces. Ultimately, control processing speeds, access levels, and other network permissions to reduce the risk of network congestion.

3. Internet Data Bandwidth Monitoring

Generally, speaking, network congestion is less likely when the network connection can transmit more data. Making increasing bandwidth is an obvious solution. However, a network, like a chain, is only as strong as the weakest — or in this case the slowest component. Quality of Service allows the same network traffic share, but not classified and forwarded the same.

Meaning, that the QoS is not classified and forwarded in an unequal way based on preset rules. You can think of a QoS as a police escort — that helps real-time applications and business-critical traffic through network congestion. During the investigation of the compromised server we mentioned above, we used a tool called ntopng to discover “Top Talkers.”

Eventually, which revealed that the server was using up all the bandwidth on the network. In the same way, tools that monitor bandwidth can reveal network congestion especially during a security attack or if a particular host is using up all the bandwidth. You can read this article for more information about performing a network performance assessment.

4. Segmenting, Prioritizing & Decongesting

For your information, traffic monitoring produces an additional benefit: the capacity to design or re-design a bespoke, optimized network for any business. To do that, segment the network into smaller sub-networks to create space for practical priorities and increase efficiency. In most cases, this permits more accurate monitoring as it produces a more viable network.

While, at the same time, increasing or reducing data traffic as needed to impact the areas most affected by network congestion. Prioritization means placing appropriate emphasis or priority on key network processes over less- or non-essential traffic to reduce network congestion. But, prioritizing must be done carefully to avoid the wrong design or configuration.

Effectively, this is something that can exacerbate the problem it is meant to resolve. For example, a large company is more likely to deploy a “client/server” network architecture than a “peer-to-peer” network. And this can provide too much access and bandwidth to users. Instead, allocate access according to needs-based, specific “tiers” for all users.

The fix for a congested network will depend on the cause:
  • For oversubscribed links, you may need to purchase more bandwidth from your service provider. Some service providers also allow you to temporarily boost your bandwidth for a small fee. You may also want to implement Quality of Service (QoS) features which will ensure that even in the event of congestion, critical applications can still function.
  • Layer 2 loops can be prevented by using loop prevention protocols such as Spanning Tree Protocol (STP). A poor network design can be more difficult to fix since the network is probably in use. For such cases, incremental changes can be made to improve the network and remove congestion.
  • Over-Utilized devices may need to be swapped out. Alternatively, the capacity of the system can be increased by implementing high-availability features such as clustering and stacking.
  • Faulty devices definitely need to be replaced. In some cases (like the example I gave above about the 100Mbps link reduced to 30Mbps), only a part of the device (e.g. an interface) needs to be replaced.
  • Security attacks need to be combated as soon as they are discovered. In the case of the compromised server, the first thing we did was to remove that server from the network completely. Since this is not always a feasible solution (e.g. the compromised device is a critical server), other temporary measures such as applying access control lists to deny the offending traffic may need to be implemented.

In layman’s language, your network architecture should be built to provide each user with the appropriate network bandwidth. Whilst, keeping in mind, that the wrong network architecture can cause network congestion.

5. Optimizing Network Data Bandwidth

Another high-impact area for optimizing data accessibility and movement is the critical link and transit path between storage and cloud computing. Traffic clogs here are disastrous. High-bandwidth and low-latency networking like InfiniBand is crucial to enabling training at scale. It’s especially important for large language models (LLM) deep learning.

Especially, where performance is often limited by network communication. When harnessing multiple GPU-accelerated servers to cooperate on large AI workloads, communications patterns between GPUs can be categorized as point-to-point or collective communications. Many point-to-point communications may happen simultaneously in an entire system.

More so, between sender and receiver and it helps if data can travel fast on a “superhighway” and avoid congestion. Collective communications, generally speaking, are patterns where a group of processes participates, such as in a broadcast or a reduction operation.  It’s important to note that high-volume collective operations are found in most AI algorithms.

The other key areas to help optimize your network connection:
  • Optimize the TCP/IP settings to balance the packet send/request speed
  • Use choke packets to prevent network congestion by reducing the sender device output
  • You can also use a Content Delivery Network (CDN) that will place more requests on edge servers to optimize resources
  • Try multi-hop routing for traffic so that whenever the default route starts queueing traffic will be over a different path
  • Assess security attacks and attack attempts in your internet connection logs and elsewhere
  • Use a VPN to bypass congestion or try using redundancy models
  • Conduct LAN performance network congestion tests

Intelligent Communication Software must get data to many GPUs repeatedly during a collective operation by taking the fastest, shortest path and minimizing bandwidth. That’s the job of communication acceleration libraries like NCCL (NVIDIA).

And, this is usually found extensively in deep learning frameworks for efficient neural network training. High-Bandwidth Networking optimizes the network infrastructure to allow multi-node communications in one hop or less. And since many data analysis algorithms use collective operations, using in-network computing can double the network bandwidth efficiency.

As a rule of thumb, having a high-speed network adapter per GPU for your network infrastructure allows AI workloads. Moving on, the next step is to consider using network performance monitoring software in your workplace.

Using A Network Performance Monitoring Software Application Tool

According to Gartner, the Network Performance Monitoring (NPM) Market consists of tools that leverage a combination of data sources to provide a holistic view of how networks (including corporate on-premises, cloud, multi-cloud, hybrid, and other networks) are performing. Data sources include network-device-generated traffic and data raw network packets.

In addition to network-device-generated health metrics and events tracking. NPM tools provide diagnostic workflows and forensic data to identify the root causes of performance degradations — increasingly through the adoption of advanced technology. Such as cloud computing, Artificial Intelligence (AI), or rather, Machine Learning (ML), Algorithms, and the like.

Lastly, based on network-derived performance data, NPM tools provide insight into the quality of the end-user experience. As an example, we can consider Avi as a great tool — a comprehensive traffic monitoring platform that distributes network traffic across multiple servers to ensure no single server triggers network congestion as it bears too much demand.

By creating and distributing an even workload, application responsiveness, availability, and security all increase. Fortunately, there are other network performance monitoring software tools you can use for Internet connection tracking.

  1. Catchpoint
  2. ManageEngine
  3. Avi Networks
  4. Solarwinds NPM
  5. Paessler PRTG
  6. Nagios XI
  7. ExtraHop Reveal
  8. Netflow Analyzer
  9. Progress WhatsUp Gold
  10. Cisco Prime Infrastructure
  11. GigaVUE Visibility Appliances
  12. Observer Platform
  13. ThousandEyes
  14. LM Envision
  15. Azure Network Watcher
  16. Kentik
  17. CA Spectrum
  18. Progress Flowmon
  19. Auvik
  20. LiveNX

Bear in mind, that besides the above list of applications, there are still many other even better software tools that you can consider giving a try out there. You just need to search for them only to find the most suitable ones. The best way to achieve this is by reading what other consumers are saying about them on various online review websites to serve as a starting point.

Summary Thoughts:

Just as we aforementioned, a highway is congested when it is overloaded with traffic in the form of vehicles. Similarly, a network is congested when it is overloaded with data. And just as is true on the road, network congestion can be the result of temporary circumstances such as high traffic or an attack, or the sign of deeper, chronic problems such as outstanding repairs.

Or even misconfiguration — issues that demand more significant solutions. Generally, we can now clearly state that network traffic congestion occurs when a network connection experiences traffic that is too much for the system. Fortunately, as you can see, there are a few methods you can consider to establish the cause as well as tools to help you track the same.

That’s it! Everything that you needed to know about the main causes of Network Traffic Congestion, the best steps to decongest the traffic drags, plus the best Internet Performance Monitoring Tools that you can use. Be that as it may, if you think there is something else missing that we can include in this resource guideline, kindly let us know in our comments section.

Not forgetting, you can also Consult Us if you’ll need more support from our professional experts. Feel free to share this blog with other readers like you who might also find it useful. And now, until the next one, thanks for your time, and welcome back!

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