An Advanced Traffic Engineering Approach Based on the Approximate Invariance of Effective Bandwidths

Abstract

We present a novel shaping algorithm, called effective bandwidth shaper (EBS), which limits passing data streams' effective bandwidths to a pre-defined upper bound. The shaping algorithm is part of the proposed traffic engineering approach for providing quality of service guarantees to the network users. The traffic engineering approach relies on the property, that effective bandwidths do not change when passing a network node, the so called "invariance property" of effective bandwidths. The algorithm's functionality is verified by application to MPEG video traces. Furthermore, the shaping performance is investigated in different network scenarios with reactive TCP traffic. Our performance studies focus on the dependencies of delays and throughputs upon the number of competing connections, the choice of the space parameter, different TCP protocol variants, and buffer sizes. Moreover we show that the effective bandwidths' invariance when passing a switch, as proven for the case of the many limiting regime (infinitely many sources), holds already for a surprisingly small number of competing flows even in the presence of aggressive TCP traffic.