Showing papers by "Peter Key published in 2004"

PIC: practical Internet coordinates for distance estimation

Abstract: We introduce PIC, a practical coordinate-based mechanism to estimate Internet network distance (i.e., round-trip delay or network hops). Network distance estimation is important in many applications; for example, network-aware overlay construction and server selection. There are several proposals for distance estimation in the Internet but they all suffer from problems that limit their benefit. Most rely on a small set of infrastructure nodes that are a single point of failure and limit scalability. Others use sets of peers to compute coordinates but these coordinates can be arbitrarily wrong if one of these peers is malicious. While it may be reasonable to secure a small set of infrastructure nodes, it is unreasonable to secure all peers. PIC addresses these problems: it does not rely on infrastructure nodes and it can compute accurate coordinates even when some peers are malicious. We present PIC's design, experimental evaluation, and an application to network-aware overlay construction and maintenance.

Methods and systems for alleviating network congestion

Abstract: Methods and systems for detecting and predicting congestion patterns from network feedback are described. In the inventive embodiments, network feedback in the form of binary feedback messages is received. The network feedback can comprise any suitable feedback messages and, in the illustrated and described embodiments comprise packet loss events or ECN marks, to name just a few. The inventive embodiment uses the network feedback to predict when congestion is likely to occur in the future. Based on these predictions, the behavior of end users within the system can be modified so that congestion is reduced. Specifically, the data packets that are typically transmitted by the end users can be delayed until such a time when the predicted congestion is mitigated. Thus, the inventive systems and methods take a predictive, proactive approach to addressing network congestion issues, rather than a reactive approach.

Emulating low-priority transport at the application layer: a background transfer service

Abstract: Low priority data transfer across the wide area is useful in several contexts, for example for the dissemination of large files such as OS updates, content distribution or prefetching. Although the design of such a service is reasonably easy when the underlying network supports service differentiation, it becomes more challenging without such network support. We describe an application level approach to designing a low priority service -- one that is 'lower than best-effort' in the context of the current Internet. We require neither network support nor changes to TCP. Instead, we use a receive window control to limit the transfer rate of the application, and the optimal rate is determined by detecting a change-point. We motivate this joint control-estimation problem by considering a fluid-based optimisation framework, and describe practical solutions, based on stochastic approximation and binary search techniques. Simulation results demonstrate the effectiveness of the approach.

Fair internet traffic integration: network flow models and analysis

Abstract: We use flow-level models to study the integration of two types of Internet traffic, elastic file transfers and streaming traffic. Previous studies have concentrated on just one type of traffic, such as the flow level models of Internet congestion control, where network capacity is dynamically shared between elastic file transfers, with a randomly varying number of such flows. We consider the addition of streaming traffic in two cases, under a fairness assumption that includestcp-friendliness as a special case, and under certain admission control schemes. We establish sufficient conditions for stability, using a fluid model of the system. We also assess the impact of each traffic type on the other: file transfers are seen by streaming traffic as reducing the available capacity, whereas for file transfers the presence of streaming traffic amounts to replacing sharp capacity constraints by relaxed constraints. Simulation results suggest that the integration of streaming traffic and file transfers has a stabilizing effect on the variability of the number of flows present in the system.

Band control program, method, and end system

Abstract: PROBLEM TO BE SOLVED: To improve service quality in an initial congestion state by adjusting real-time communications on a network. SOLUTION: The system detects the initial congestion of the network. It executes the feedback of a report regarding the initial congestion to the transmission side. A transmission rate is properly changed by using a control algorithm on the basis of the information. The control algorithm calculates the transmission rate after the change on the basis of the information from a weight parameter, a gain parameter, and the congestion report. The transmission rate after the change improves the use of the usable bandwidth on the transmission side and it maintains allowable service quality on the reception side. COPYRIGHT: (C)2004,JPO&NCIPI