What Does 'QoS (Quality of Service)' Mean?

Quality of Service (QoS) refers to the capability of a network to provide better service to selected network traffic over various technologies. It enables network administrators to prioritize important network traffic, such as real-time audio and video, and delay less important traffic, like file downloads.

QoS can also be used to ensure a certain level of performance for a specific application or user. This can be accomplished by a combination of techniques, for example, traffic shaping, packet prioritization, and bandwidth allocation.

Usability

QoS is used to manage network resources and ensure that critical applications and services receive the bandwidth and performance they require to operate effectively. It can be used to guarantee a certain level of performance for specific network traffic, such as ensuring minimal delay for real-time voice and video traffic. This can be done by allocating bandwidth to these types of traffic and by using a variety of techniques, including traffic shaping, packet prioritization, and congestion management.

In addition to providing better performance for critical applications, QoS can also be used to improve network security by limiting the amount of bandwidth available to potentially malicious traffic and by implementing policies that prioritize legitimate network traffic.

Implementation

QoS can be implemented at different layers of the OSI model, with the most common being the Data Link Layer and Network Layer. At the “Data Link Layer,” QoS is implemented using tools such as “Link Aggregation” and “VLAN tagging,” while at the “Network Layer,” it is typically implemented using tools like “Differentiated Services (DiffServ)” and “Integrated Services (IntServ).”

More information

It’s important to keep in mind that, while QoS can help improve network performance, it can also add complexity to network management and be difficult to configure correctly. Moreover, QoS alone doesn’t guarantee that the network will always meet its performance objectives; other factors such as network congestion, traffic patterns, and general network design must be considered too.