10 Causes of Network Congestion You Should Know About

Your network is slow and you would like to know what you can do about it.

Network speed is a huge concern for businesses. This is no longer just the concern of the network engineer. It also affects the DevOps team and business teams.

You only have 5 seconds to engage a customer online. As someone working on the network, you might say: “that is not my concern”. This should be a company-wide concern. The company needs to grow and convert visitors into customers to continue to operate.

This is why understanding what could be slowing your network connection is vital.

Here are 10 causes of network congestion you should know about.

Too many hosts in broadcast domain

Network overload is what happens when you place too many hosts in a broadcast domain. The term “broadcast domain” is abstract, but the concept applies to network structure.

The broadcast domain is the network. This could be the network in an enterprise, university, or a VLAN. A host is going to be each individual router or switch within the broadcast domain.

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.

Thus, too many hosts in a broadcast domain can create network congestion. The cause is network overload, as too many devices are requesting network access at once.

A safe number of hosts in a broadcast domain is 200–254.

Broadcast Storms

A broadcast storm is a situation where there are unexpectedly too many requests on a network. This creates a situation where a network does not have the ability to process all the requests at once.

A broadcast storm can be a busy day for eCommerce or Black Friday sales. Also, a video going viral can cause a similar situation.

Low Bandwidth

Bandwidth refers to the “size of the pipe” in which Internet data can travel through. If the pipe is not large enough for all the traffic to move through at once, there becomes congestion.

This occurs during peak TV streaming hours when Netflix is consuming 40% of the Internet. The result is congestion, as many people are trying to consume large file size streaming.

Adding Retransmitting Hubs

When building out a network, there needs to be the integration of hubs. Hubs retransmit data over a network.

In an enterprise network, a hub is what connects the network to the public Internet.

This connection point offers a prime location for potential congestion. Thus, consider how to integrate the hub within the network.

Multicasting

Multicasting is where a network allows many computers to speak to each other simultaneously. This is the opposite of Unicast. Unicast is sending traffic to a specific router associated with a specific server.

Multicasting is designed to end network congestion. The reality is it could be creating it. As with most things, there are unintended consequences.

In multicasting, two packets transferred at the same time can cause a collision. This collision causes network congestion.

Outdated Hardware

Data transmitted through outdated switches, routers, servers, and Internet exchanges can cause bottlenecks.

If the hardware is not optimal, this creates a bottleneck for the transmission of data. The result is network congestion.

Bad Configuration Management

Fat fingers and misconfiguration are two things that can cause network congestion. NetDevOps has the goal of eliminating this problem.

Repetitive and one off scripts leaves room for error. The result is a network engineer introducing a bug into the network. These bugs create bottlenecks that cause congestion.

The other aspect to configuration management is not performing it. This is not maintaining your network. This is like a car. When no maintenance is performed, there is a chance for a break-down.

With NetDevOps and introducing an element of automation, these instances are reduced.

Rogue Adapter Broadcasts

Rogue adapters are any foreign devices on your network. This can be as simple as a neighbor coming onto a residential WiFi connection. Or, as severe as a hacker breaking into an enterprise network.

What occurs is the rogue adapter finds an entry point, which is usually an error in the network. Then once on the network, they begin to access the Internet. Having an extra device on a network can cause unexpected slowdowns.

Besides slowing the network, the bigger problem is the security threat. Any foreign device on a network can become malicious in intent.

Border Gateway Protocol

Border Gateway Protocol (BGP) can be causing network congestion. BGP sends all traffic through the shortest logical path. There is no consideration for how much traffic is already going over that path.

No consideration for current data going can result in transit paths becoming overloaded. This overload will create slower speeds, which is network congestion.

Artificial Congestion

An Internet Service Provider (ISP) can determine how fast it sends traffic over its network. The opposite result of this is the ISP can also slow the rate at which data is moving over its network. This is artificial congestion. ISP’s do this for many reasons, which they claim as network management.

What is affecting this is the established peering agreements. Also, a content provider can be sending more traffic than the ISP would like. The larger implications of this is can be an infringement on net neutrality.

Network congestion can present itself in many forms. By addressing the causes of network congestion, you can begin to improve your network.

Article originally published on the Datapath.io Blog.