Fair bandwidth sharing and delay differentiation: Joint packet scheduling with buffer management

Packet delay and bandwidth are two important metrics for measuring quality of service (QoS) of Internet services. Traditionally, packet delay differentiation and fair bandwidth sharing are studied separately. In this paper, we first propose a generalized model for providing fair bandwidth sharing with delay differentiation, namely FBS-DD, at the same time. It essentially aims to provide multi-dimensional proportional differentiation with respect to both QoS metrics. We design size-based packet scheduling schemes that take both packet delay and packet size into scheduling considerations, without assuming admission control or policing. Furthermore, we propose a PID control-theoretic buffer management scheme. The packet scheduling with buffer management approach provides delay and bandwidth differentiation in an integrated way, while existing approaches consider delay and loss rate differentiation as orthogonal issues. It enhances the flexibility of network resource management and multi-dimensional QoS provisioning. It is capable of self-adapting to varying workloads from different classes, which automatically builds a firewall around aggressive clients and hence protects network resources from saturation. Extensive simulation results by the use of trace files demonstrate that the packet scheduling schemes can provide predictable fair bandwidth sharing with delay differentiation at various situations. The control-theoretic buffer management scheme further improves the controllability.