Proceedings of the Sixth International Workshop on Web Caching and Content Distribution

OVERVIEW The International Web Content Caching and Distribution Workshop (WCW) is a premiere technical meeting for researchers and practitioners interested in all aspects of content caching, distribution and delivery on the Internet. The 2001 WCW meeting was held on the Boston University Campus. Building on the successes of the five previous WCW meetings, WCW01 featured a strong technical program and record participation from leading researchers and practitioners in the field. This report includes all the technical papers presented at WCW'01. Note: Proceedings of WCW'01 are published by Elsevier. Hardcopies of these proceedings can be purchased through the workshop organizers. As a service to the community, electronic copies of all WCW'01 papers are accessible through Technical Report BUCS‐TR‐2001‐017, available from the Boston University Computer Science Technical Report Archives at http://www.cs.bu.edu/techreps. [Ed.note: URL outdated. Use http://www.bu.edu/cs/research/technical-reports/ or http://hdl.handle.net/2144/1455 in this repository to access the reports.]Cisco Systems; InfoLibria; Measurement Factory Inc; Voler

Optimal control of a class of real-time computational systems

In many computational systems, tasks comprising numerical or symbolic data arrive at a processor periodically. Processing of the i\sp{th} task has to stop before processing of the ($i$ + 1)\sp{th} task begins, causing a hard constraint on T\sb{p}(i): the time needed for complete processing of the i\sp{th} task. Failing to meet this constraint means the processing is aborted and the output is deemed totally inaccurate or useless. To improve the probability of making real time, T\sb{p}(i) may be reduced by approximating the data or the processing algorithms. Since approximation also reduces output accuracy, an overall objective function is constructed that merges the real-time constraint with the objective of accuracy, maximization of which yields the optimal level of approximation. An Object Recognizer is chosen as an example where image resolution is the method of approximation. The optimal policy for this example is discussed in detail with the help of a simulation

Controlling Alternate Routing in General-Mesh Packet Flow Networks

High-speed packet networks will begin to support services that need Quality-of-Service (QoS) guarantees. Guaranteeing QoS typically translates to reserving resources for the duration of a call. We propose a statedependent routing scheme that builds on any base stateindependent routing scheme, by routing flows which are blocked on their primary paths (as selected by the state-independent scheme) onto alternate paths in a manner that is guaranteed---under certain Poisson assumptions---to improve on the performance of the base state-independent scheme. Our scheme only requires each node to have state information of those links that are incident on it. Such a scheme is of value when either the base state-independent scheme is already in place and a complete overhaul of the routing algorithm is undesirable, or when the state (reserved flows) of a link changes fast enough that the timely update of state information is infeasible to all possible call-originators. The performance improvements ..

SPREAD: Scalable Platform for Reliable and Efficient Automated Distribution

We introduce SPREAD -- a new architecture for distributing and maintaining up-to-date Web content that simultaneously employs three different mechanisms: client validation, server invalidation, and replication. Proxies within SPREAD self-configure themselves to form scalable distribution hierarchies that connect the origin servers of content providers to clients. Each proxy autonomously decides on the best mechanism based on the object’s popularity and modification rates. Requests and subscriptions propagate from edge proxies to the origin server through a chain of intermediate proxies. Invalidations and replications travel in the opposite direction. SPREAD’s network of proxies automatically reconfigure when proxies go down or come up, or when new ones are added. The ability to spontaneously form hierarchies is based on a modified Transparent Proxying mechanism, called Translucent Proxying, that sanitizes Transparent Proxying. It allows proxies to be placed in an ad-hoc fashion anywhere in the network- not just at focal points within the network that are guaranteed to see all the packets of a TCP connection. In this paper we (1) describe the architecture of SPREAD, (2) discuss how proxies determine which mechanism to use based on local observations, and (3) use a trace-driven simulation to test SPREAD’s behavior in a realistic setting

CDN Brokering

Content distribution networks (CDNs) increase the capacity of individual Web sites and attempt to deliver content from caches that are located "closer" to end-users than the origin servers that provide the content. CDN brokering provides CDNs a way to interoperate by allowing one CDN to intelligently redirect clients dynamically to other CDNs. This paper describes the goals, architecture, and performance of a CDN brokerage system. Our system has been deployed on the Internet on a provisional basis, and our architectural ideas have helped advance the evolution of Internet standards for interoperating CDNs

India: the next superpower?

When Hillary Clinton visited India in 2009, the US Secretary of State's verdict was unequivocal: 'I consider India not just a regional power, but a global power.' Following the success of economic liberalisation in the 1990s, which generated growth rates in excess of 8% and a rising middle class, expectations have grown that India might become a superpower, particularly in a West that sees in India's democratic heritage the potential for strategic partnership. However, there remain deep and pervasive fault-lines within Indian society. Crony capitalism, the collapse of public health systems, a rising Maoist insurgency, and rampant environmental degradation all call into doubt India's superpower aspirations. Rather than seek to expand its influence abroad, India would do well to focus on the fissures within