Network Congestion

Network Congestion Definition

Network congestion is defined as a decline in quality of service (QOS) that results in packet loss, queueing delays, or the blocking of new connections. Network congestion is typically caused by traffic overload, which happens when a link or network node handles data that exceeds its capacity.

Organizations utilize a variety of congestion avoidance and control approaches to prevent network collapse and mitigate the consequences of congestion. This includes:

• TCP/IP Window Reduction
• Fair queueing in network equipment including routers, switches, and other devices.
• Priority schemes transmit higher priority packets ahead of other traffic.
• Explicit network resource allocation using admission controls to specific flows

What is Network Congestion?

A highway becomes congested when it is overburdened with car traffic. Similarly, a network becomes congested when it is overburdened with data. And, just like on the road, network congestion can be caused by short circumstances such as heavy traffic or an attack, or it can be a symptom of deeper, chronic problems such as pending repairs or misconfiguration—issues that necessitate more major resolutions.

End-users perceive network congestion as delayed response times or a “network slow down.” When the internet, WiFi, or even the computer “feels slow,” it is usually due to network congestion. However, network traffic congestion encompasses more than just this.

How to assess network congestion and identify difficulties depends on recognizing the consequences of congestion in the network.

Bandwidth Usage

Bandwidth is one of the most common reasons of network congestion. Bandwidth is the maximum pace at which data may move down a path, often known as the path’s total capacity. Network congestion occurs when there is insufficient bandwidth to accommodate the current volume of traffic. This is the same issue that a road designed for 50 automobiles encounters when 200 cars per day try to drive on it.

Latency

Latency is the time it takes for a data packet to move from point A to point B. Latency is generally linked to other congestion issues like bandwidth. Back on the road, latency is demonstrated by the fact that it takes 20 minutes to go from point A to point B in one day under some conditions and 60 minutes under different conditions. The slower time is due to latency, which is a symptom rather than a cause of network congestion.

Jitter

Jitter is a variation in delay in traffic patterns. Computers, like most people on the road, enjoy predictable and consistent traffic. When traffic is unpredictable or inconsistent, it causes jitter, or fluctuation in delay, resulting in increased network congestion.

On the road, drivers approach the highway at random, therefore there may be large groups of cars attempting to merge at any given time. For networks, a surge can occur when a system user sends huge bursts of traffic to the network, consuming excessive capacity.

Jitter causes congestion because the computer alters its traffic patterns every time the network attempts to compensate. To avoid network collisions, the system pauses sending packets and conducts a millisecond-long random back-off. This causes congestion as other network transmitters wait before attempting again, resulting in a cascading effect.

Packet retransmissions

Regarding the requirement to retransmit packets, packet retransmissions can generate congestion and are frequently triggered by other congestion issues. Packets that arrive damaged or not at all must be re-sent. Clearly, every time a single packet must be sent twice or more, traffic congestion worsens without providing any additional value. It’d be like breaking up a successful carpool.

Collisions

Often, packet collisions on the network initiate the back-off process, as discussed above in regard to jitter. Packet collisions can be caused by faulty cabling or malfunctioning equipment, resulting in a serious situation in which all packets must pause and wait for a clear network to retransmit. This causes even more congestion and delays, and, as with a highway incident, traffic direction is frequently required.

What Are the Reasons for Congestion in a Network?

In general, network congestion happens when a network receives more traffic than it can handle. That being stated, there are five major sources of network congestion:

Overused Devices

Some devices are designed to manage greater traffic than others. Load balancers, switches, routers, and firewalls are designed to maximize network throughput. Furthermore, any device’s designated capacity is theoretical; it may not precisely reflect the device’s real-world capability in a variety of settings. Over-utilization is a common effect of pushing devices to their maximum declared capacity.

Structures for employing numerous devices are frequently organized hierarchically, with higher-level devices serving lower-level devices. To maintain healthy traffic levels and avoid congestion, it is vital to guarantee that each level in the hierarchy demands and receives adequate assistance. Inconsistencies between firewalls, routers, switches, and other devices can cause data bottlenecks.

Back on the road, this type of difficulty may appear to be a freeway transition that was incapable of combining multi-lane roadways into fewer lanes. Constant use of such device with high volumes of traffic will result in over-consumption, packet losses, and high CPU utilization. This, in turn, causes network congestion.

Over-Subscription

Over-subscription is typically to fault when a web browsing experience is consistently slower or faster at certain times of day or night. This is due to the fact that there are more users placing demands on network resources during the day, the network’s peak time, than there are at night, when the network is off-peak. This is similar to commuting to work on a highway or by rail during rush hour or peak times vs the middle of the day or night when everyone is already at work or home.

Oversubscription is often done on purpose to save money, which is why it is a prevalent cause of network congestion. For example, a company with 1,000 in-house employees typically need a 1,000Mbps Internet connection. If they’ve primarily shifted to working from home, they may only require 500Mbps—until a company-wide event strains the system and causes network congestion.

Unneeded Traffic

Unwanted traffic, such as streaming movie on a work computer, is another major source of network congestion. Other instances of unwanted traffic that consumes bandwidth include garbage VoIP phone calls and uninvited traffic such as ads. Use the network management console to detect unnecessary traffic.

Antiquated hardware and defective devices

As the demands of the business evolve, hardware, devices, and the ethernet cables and wire connections between them may all need to be updated or replaced. The data speed and other parameters for each network segment should be evaluated as part of a network performance assessment for network congestion.

Security Attack

Worms, viruses, and Denial of Service (DoS) assaults are all potential sources of network congestion.

Defective Design or Misconfiguration

Poor design or device misconfiguration is a more serious source of network congestion. Each network must be built to carry the appropriate loads and configured to suit the organization’s requirements. An efficient network connects all segments while maximizing performance in each.

A broadcast storm is an excellent example of this topic. When the network is subjected to a huge volume of broadcast or multicast traffic in a short period of time, this problem causes significant performance degradation. Broadcasts are contained within subnets, so a broadcast storm might have a greater impact on bigger subnets. Designing a network with huge subnets without sufficient consideration for broadcast storms might result in network congestion. To circumvent this issue, construct subnets near where big volumes of data will be stored so that performance can be allocated where it is required.

How to Solve Network Congestion Issues?

Monitor and analyze network traffic.

Monitoring and analyzing network traffic is the first step in resolving most network congestion issues, particularly those caused by an excessive number of devices, over-utilized devices, or an insufficient network design. This will aid in identifying potential congestion points as well as highlighting underutilized zones that are ready for re-allocation to improve performance. Deeper insights into network traffic enable smarter approaches toward minimizing network congestion.

Monitor during high traffic periods to diagnose network congestion, particularly during peak hours when many devices are connected or during company-wide events. The correct network discovery tool can help you identify the source of network congestion. A network discovery application can be used to scan cloud servers, virtual networks, and all other wireless devices and networks in order to detect servers, devices, and even users that are consuming excessive bandwidth.

After identifying the problems with bandwidth utilization, change the network infrastructure to better allocate it during peak hours.

Bandwidth

In terms of bandwidth, increasing bandwidth is an apparent option because it reduces the likelihood of network congestion. A network, like a chain, is only as strong as its weakest (or in this case, slowest) component.

Segmenting and prioritizing

Traffic monitoring provides an additional benefit: the ability to construct or re-design a customized, optimal network for any business. To accomplish this, divide the network into smaller sub-networks to make room for practical priorities while increasing efficiency. This allows for more precise monitoring since it creates a more viable network, boosting or decreasing data traffic as necessary to impact the areas most affected by network congestion.

Prioritization refers to giving proper attention or priority to vital network activities over less-or non-essential traffic in order to alleviate network congestion. Prioritizing must be done carefully to prevent creating an incorrect design or configuration, which can compound the problem it is intended to solve.

Business critical traffic can be a combination of common business network traffic types, such as multicast traffic for real-time media streams, broadcast traffic for network management, and unicast traffic for phone, data transfer, and video activities. Without special settings, network devices cannot automatically determine which of the intermixed traffic should be prioritized for bandwidth allocation. This is the domain of Quality of Service (QoS) protocols.

Quality of Service allows traffic to use the same network but is classified and forwarded in an unequal manner based on predefined rules. QoS functions as a police escort, guiding real-time applications and business vital traffic past network congestion.

Assess Your Devices

The quantity, type, and bandwidth of network devices have an impact on data processing across the entire network. In certain circumstances, network users may be utilizing devices incorrectly by accident, while others may be using “legacy devices” that are no longer supported. Older and inefficient device utilization both contribute to network congestion; therefore, evaluate each device to reduce or even prevent network congestion.

Evaluate Your Network Architecture.

Network architecture should be designed to give each user with sufficient network bandwidth. The improper network architecture might lead to network congestion.

For example, a major firm is more likely to utilize a “client/server” network architecture rather than a “peer-to-peer” network, which can give customers with excessive access and bandwidth. Instead, assign access to all users based on their needs, creating “tiers” of access. IT or the C-suite can eventually regulate processing speeds, access levels, and other network rights, lowering the danger of congestion.

• Other areas to examine while deciding how to lessen network congestion include:
• Optimize the TCP/IP parameters to balance the packet send and request speed.
• To optimize resources, use a CDN (Content Delivery Network) that routes more requests to edge servers.
• To mitigate network congestion, use choke packets to reduce sender device output.
• Select multi-hop routing for traffic so that when the default route starts queueing, traffic will be sent over an alternate path.
• Evaluate security threats and attempts in your internet connection logs and elsewhere.
• Use a VPN to bypass the congestion.
• Using redundant models
• Run LAN performance and network congestion testing.

Reference

• What is Network Congestion? | Avi …
• What is Network Congestion? Common Causes and How …
• What Is Network Congestion? – IT Glossary