Feedback control of QoS-aware servers has recently gained much popularity due to its robustness in the face of uncertainty and modeling errors. Performance of servers is characterized by the behavior of queues, which constitute the main elements of the control loop. The central role of queues in the loop motivates understanding their behavior in the context of feedback control schemes. A popula...

Class-based traffic treatment frameworks such as Differentiated Service (DiffServ) have been proposed to resolve the poor scalability problem in the flow-based approach. Although the performance is differentiated in a class-based basis, the performance seen by individual flows in the same class may differ from that seen by the class and has not been well understood. We investigate this issue by...

Wireless channels are characterized by more serious bursty and location-dependent errors. Many packet scheduling algorithms have been proposed for wireless networks to guarantee fairness and delay bounds. However, most existing schemes do not consider the difference of traffic natures among packet flows. This will cause the delay-weight coupling problem. In particular, serious queuing delays ma...

In this paper, the problem of fair scheduling in a wireless network is formulated as an assignment problem and an Optimal Radio Channel Allocation (ORCA) strategy is proposed for fair bandwidth allocation in a centralized manner. Simulation results show that the performance improvement due to ORCA can be significant compared to other wireless fairqueuing mechanisms proposed in the literature su...

Consider a wireless ad hoc network with random access channel. We present a model that takes into account topology, routing, random access in MAC layer and forwarding probability. We propose a new approach (based on cycle of transmissions) to derive throughput of multi-hop routes and stability of forwarding queues. With this cycle approach, we correct the analytical expressions derived in [2] a...

We develop a simple theory of flows to study the flow of data in real-time computing networks. Flow Theory is based on discrete and nondeterministic mathematics, rather than the customary continuous or probabilistic mathematics. The theory features two types of flows: smooth and uniform, and eight types of flow operators. We prove that, if the input flow to any of these operators is smooth or u...

We consider the problem of scheduling a group of heterogeneous, distributed processes, with different relative priorities and service preferences, to a group of heterogeneous virtual machines. Assuming linearly elastic IT resource needs, we extend prior results on proportional fair and max-min fair scheduling to a constrained multiresource case for a fam- ily of fairness criteria (including our...

With Weighted Fair Queuing, the link’s bandwidth is distributed among competing flows proportionally to their weights. In this paper we propose an extension of the DCF function of IEEE 802.11 to provide weighted fair queuing in Wireless LAN. Simulation results show that the proposed scheme is able to provide the desired bandwidth distribution independent of the flows aggressiveness and their wi...

We describe an eecient fair queuing scheme, Leap Forward Virtual Clock, that provides end-to-end delay bounds similar to WFQ, along with throughput fairness. Our scheme can be implemented with a worst-case time O(loglog N) per packet (inclusive of sorting costs), which improves upon all previously known schemes that guarantee delay and throughput fairness similar to WFQ. Interestingly, both the...

The transport of real-time data flows over wireless channels can be optimized by cross-layer schedulers which serve the different users dependent on their traffic load and channel state. This paper investigates the delay performance of a two-stage cross-layer scheduler which has been designed to meet the above requirements. The well-known Weighted Fair Queuing Scheduler can tramsmit packets wit...