An introduction to quality of service

Quality of service (QoS) is like ‘life’ — a dictionary may define the word but it does not help us understand its meaning. This paper defines what is meant by QoS in the context of packet networks. It discusses the drivers that lead to the development of QoS for IP networks in the context of the history of packet communications. The paper then presents the basic packet QoS taxonomy using the simple analogy of the postal system. It also briefly looks at potential future developments, while discussing general QoS issues throughout.