A proportional intra-class scheduling for differentiated services model

Abstract

Aggregation of flows into classes is used to avoid the scalability problems of IntServ model and this requires per-class scheduling decisions. There are number of issues associated with such approach e.g. what will be per-flow guarantee, which flows are to be aggregated together, how to determine service order among multiple classes and within a class etc. DiffServ model is a framework wherein class based QoS support is provided. In this paper we propose an algorithm for intra-class scheduling (including a small modification in buffer management) when number of flows are aggregated within a single class. The algorithm proposed, dynamically selects a disjoint subset of flows to form a class (subgroup) and aggregation mechanisim allows us to define QoS requirement of the subgroup with the use of {Max, Min} operation. We show that the algorithm performs substantially better even under heavy network condition.