What Router QoS Does and When It Is Worth Turning On
An Engadget explainer published on October 10 describes how router Quality of Service prioritizes traffic, when it can help slower connections, and why it is often redundant on gigabit plans.
All data arriving from the internet is delivered as packets, and most of them are not mission-critical. Without prioritization, a router treats email, Netflix streams and smart home automations with the same urgency. QoS inspects incoming packets and decides what goes first, with priority most often given to streaming media, including voice and video calls, and to online games such as Big Walk or PUBG: Battlegrounds. That distinction matters in games, where an extra 20 milliseconds can decide whether a player lands a shot or takes one. Some routers allow users to assign priorities themselves, for example so that a video editor can get large project downloads from clients finished.
Where a router offers no QoS option, users may instead find SQM, short for Smart Queue Management, an evolution of the concept. SQM goes beyond QoS to handle bufferbloat, the lag created when packets are essentially waiting their turn to be processed, by implementing advanced scheduling and traffic shaping rather than simply moving selected items to the front of the queue. The catch is processing power: sorting and shaping traffic in a flash requires specifications some routers do not have. Outside Eero mesh systems, the report suggests looking for the feature on gaming routers, which are built with prioritization in mind, and checking official product pages to confirm whether QoS or SQM is supported.
QoS is likely to matter when an internet plan delivers less than 500 megabits per second and the home is full of demanding devices or users. Recommended minimums for 4K HDR video run from 15 to 25 Mbps, PC game downloads can measure in the dozens or hundreds of gigabytes, and routine app and operating system updates add further load, all of which can crowd out critical traffic.
On faster connections, however, QoS and SQM can be redundant. A gigabit plan carries enough bandwidth that no device is likely to be starved of it. The features can also backfire if they prioritize the wrong traffic at the wrong times or overwhelm a router's processor, and standard QoS does not address bufferbloat at all.
Engadget's advice is that households on limited speeds that are hitting genuine performance barriers should try QoS if it is not already enabled, since it may be a quick fix. Where everything is running relatively smoothly, the report says, switching it on will not suddenly make the internet experience markedly better.