Quality of Service (QoS) is an issue of ever growing importance as the world becomes ever more reliant on networks controlled by computers. QoS is of maximum importance as network traffic rises and networks grow congested. With streaming media being delivered over networks, it is even more vital to maintain reliability and high quality in transmission. QoS issues can only grow larger in time.

Even when/where network connections and protocols are very reliable and of high quality, operating systems (OSs) can introduce delays and errors in transmission. Thus network operating systems (NOSs) must also maintain Quality of Service guarantees, so the overall network continues to run reliably.