Fairness Guarantees and Achievable QoS in Differentiated Services

Achievable quality of service (QoS) among flows with disparate metrics in Differentiated Services (Diffserv) presents challenges for network edge traffic conditioners. A fair traffic conditioner was presented by M. El-Gendy and K. Shin in [1]. It provides fairness guarantees by inverting a form of the TCP rate equation as an edge conditioner. It achieves fairness by conditioning all flows regardless of the individual characteristics. We analyzed this conditioner in [2] for effectiveness and provided an enhancement in the area of packet loss rate estimation. We have continued our research and our new contributions are two fold. We present a trend factor in TCP loss rate dynamics and its effect on traffic conditioning. Here, we employed the Holt-Winters algorithm which integrates trend measurement in loss rate estimation. We also investigated the effect of the Time Sliding Window algorithm as a rate estimator on the trend factor and how it affects packet marking. We have analyzed the effectiveness of these two working in tandem in the achievement of fairness in Diffserv.