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What Is QoS? How to Grasp a Tricky Measurement

This article was updated on July 6, 2021

What is QoS? Tied closely to cloud communications, video streaming, and other IP-based endeavors, quality of service goes far beyond the quality end users experience when they stream a movie or call a client via VoIP. While call quality and video service are functions of the metric, the service quality that a customer experiences is not the same as the quality of service measurements used to observe possible solutions.

What is QoS? It's the prioritization of data on the network, so your video conference won't lag or come in garbled.

Confused yet? You probably have some questions. How do you achieve QoS? When do you need to be concerned about it? What, exactly, is it? Here's a breakdown of the term to help you fully understand QoS.

What is QoS?

A streaming video buffers for an inordinate amount of time. A VoIP call comes through garbled. A video conference makes the person on the screen look like something out of a Dalí painting. These are all examples of what happens when a system fails to achieve QoS — and why you need QoS in the first place.

It's at this point that many people come up with a QoS definition that doesn't fully fit the mold. At a high level, the term covers a grouping of technologies, strategies, and quality metrics that improve the transmission of packets from one point to another. This is why network engineers and tech personnel fret about QoS, whether there are any end-user complaints or not. While QoS is all about providing good service, it achieves these means by monitoring and altering technical aspects users rarely consider, such as total network bandwidth or packet sequencing.

In other words, the end-user experience is only one of the factors that plays into the larger idea of QoS. Today's users have come to expect a baseline level of quality, so monitoring the factors that might affect service quality makes good business sense.

Essentially, good QoS makes real QoE possible. When you provide an elevated QoS and your users are happier for it, you're working toward good QoE.

Prioritization and the QoS Definition

It doesn't stop there, however. Prioritization, otherwise known as the sequence by which data packets — the bursts of data behind all network activity — also plays a role.

The modern network generally can't tell whether the data it's transmitting comes from a VoIP call or a website loading in a browser window, which can lead to trouble in a business environment. When your intern's fantasy football podcast loads with better quality than your important video conference simply because it "got there first" in terms of network resource usage, there's a clear need for change.

To put it another way, some packets are more important to businesses than others, which creates a natural need to shuffle them around. Organizations have leveraged a number of technologies to handle the issue over the years. A company may connect its main branch to its customer-facing locations via a private link, for example, then ensure certain critical data functions (like end-of-night sales reporting) only occur on that network. More recently, companies using data from multiple sources have turned to SD-WAN for UCaaS for help getting a handle on their QoS. In general, the latter technology provides two critical services to user organizations:

  1. It gives preferential treatment to communication data of the business's choosing.
  2. It shapes and sorts the resulting traffic over one or more data connections, effectively turning the organization's cell/broadband paths into a single, high-performance pipe for communication purposes.

With SD-WAN, a company's important training conference might be routed in tandem over its primary data connection and its backup 4G LTE line, all at the same time, without the trainer or trainees noticing. When the company's intern goes on YouTube on her lunch break, the same combined network automatically assigns that data to a proper spot in line … namely, near the back.

QoS vs. QoE

We can also learn what QoS is by discussing what it isn't. Technologies and activities that attempt to query, capture, or enhance the end user's overall satisfaction/enjoyment of a product fall under the quality of experience (QoE) banner.

QoS, by contrast, covers the technical aspects behind the experience. An engineer measuring the number of dropped packets or amount of available bandwidth during a high-traffic period is measuring QoS, not QoE. In car terms, it's the difference between saying, "This car has heated seats, a satellite radio, and a backup camera," and asking everyone who visits the lot what they thought after test-driving the car.

Essentially, good QoS makes real QoE possible. When you provide an elevated QoS and your users are happier for it, you're working toward good QoE. If your QoS leaves something to be desired, on the other hand, your QoE will suffer. Learning the difference is another key step in understanding what QoS is — a crucial lesson, considering just how big a role QoS tools play in improving the solutions professionals everywhere use to communicate.

Vonage Staff

Written by Vonage Staff

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