  The area of quality of service (QoS) in communications networks has been the
target of research for already several decades with tens of thousands of
published journal and conference papers. However, the practical introduction of
QoS systems in commercial networks has been limited (with a preference for
simple overprovisioning). Despite this dissonance, most influential QoS papers
do not discuss this lack of penetration or challenge any of the common
assumptions used to argue for QoS systems. So far, the few critical QoS papers
have had only a minor effect on QoS research and standardization. Therefore,
there is a serious risk that QoS will remain an academic research topic without
significant practical relevance. To help elucidate these issues, in this work,
we first perform a comprehensive review of QoS including a general overview and
an analysis of both influential and critical work from the past 30 years. We
examine properties such as citations, keywords, and author traits to show that
QoS has passed through several distinct phases with different topics while
maintaining the overall attitude towards the role and objective of QoS systems.
We then discuss QoS as a social phenomenon and in the context of current
networking standards. Finally, we propose a QoS scheme based on incentives that
avoids some of the problems identified in critical work, and we provide simple
recommendations for network operators. Overall, we hope to spark the community
to take a fresh look at QoS.
