Bufferbloat is a phenomenon where excess buffers in the network cause high latency and jitter. As more and more interactive applications (e.g. voice over IP, real time video conferencing and financial transactions) run in the Internet, high latency and jitter degrade application performance. There is a pressing need to design intelligent queue management schemes that can control latency and jitter; and hence provide desirable quality of service to users. We present here a lightweight design, PIE (Proportional Integral controller Enhanced), that can effectively control the average queueing latency to a reference value. The design does not require per-packet extra processing, so it incurs very small overhead and is simple to implement in both hardware and software. In addition, the design parameters are self-tuning, and hence PIE is robust and optimized for various network scenarios. Simulation results, theoretical analysis and Linux testbed results show that PIE can ensure low latency and achieve high link utilization under various congestion situations.

Single-hop wavelength division multiplexing (WDM) ring networks operating in packet mode are a promising architecture for the design of innovate metropolitan area networks. They allow a cost-effective design, with a good combination of optical and electronic technologies, while supporting features like restoration and reconfiguration that are essential in any metropolitan scenario. In this article, we address the fairness problem in a slotted WDM optical network. We introduce the multi-fasnet fairness protocol, we discuss its limitations and we propose an extension, based on a dynamic strategy, that achieves high aggregate network throughput, throughput fairness, and bounded and fair access delays.

This paper presents Ring Optical Network (RingO), a wavelength-division-multiplexing (WDM), ring-based, optical packet network suitable for a high-capacity metro environment. We present three alternative architectural designs and elaborate on the effectiveness of optic with respect to electronic technologies, trying to identify an optimal mix. We present the design and prototyping of a simple but efficient access control protocol, based upon the equivalence of the proposed network architecture with input-buffering packet switches. We discuss the problem of node allocation to WDM channels, which can be viewed as a particular optical network design problem. We, finally, briefly illustrate the fault protection properties of the RingO architecture. The main contribution of this paper is the identification and experimental validation of an innovative optical network architecture, which is feasible and cost effective with technologies available today, and can be a valid alternative to more consolidated solutions in metro applications.