Quality of Service (QoS) has been touted as a technological requirement for many different networks at many different times. However, very few (if any) schemes for providing it have ever been successful, despite a huge amount of research in the area of QoS provision. In this position paper we analyze some of the reasons why so many QoS mechanisms have failed to be widely deployed. We suggest two factors in this failure: the timeliness of QoS mechanisms (they rarely arrive when they are needed),

more »

... and the inherent contradiction of layering QoS mechanisms over a best-effort network. We also give some thoughts on how future QoS research might increase its chances of successful deployment by better positioning itself relative to other developments in networking.