The QoSbox: Quantitative service differentiation in BSD routers

Abstract

We describe the design and implementation of the QoSbox, a configurable IP router that provides per-hop service differentiation on loss, delays and throughput to classes of traffic. The novel aspects of the QoSbox are that (1) the QoSbox does not rely on any external component (e.g., no traffic shaping and no admission control) to provide the desired service differentiation, but instead, (2) dynamically adapts packet forwarding and dropping decisions as a function of the instantaneous traffic arrivals and allows for temporary relaxation of some service objectives; also, (3) the QoSbox can enforce both absolute and proportional service differentiation on queuing delays, loss rates, and throughput at the same time. We focus on a publicly available implementation of the QoSbox in BSD-based PC-routers. We evaluate our implementation in a testbed of BSD routers over a FastEthernet network, and we sketch how the QoSbox can be implemented in high speed architectures.