A scheme for the quantification of congestion in communication services and systems

The characterization of congestion in communication systems is a pre-requisite for the definition of mechanisms that can be used in congestion control with the goal to minimize its effects on the performance of distributed applications. In order for those mechanisms to work properly, there is the need to quantify congestion of services and systems. This paper proposes a scheme that enables the quantification of the congestion of a particular communication service, the comparison of the congestion degree of two more services, and the quantification of the global system congestion, based on the definition of a set of system QoS parameters, of the their normal variation limits and of their degradation thresholds. The paper begins with the characterization of the congestion problem. Following, a congestion definition is presented and a congestion metric is proposed. The paper ends with an analysis of the quantification of congestion in communication systems when looked at as a set of several consecutive modules.