We present Tapestry, a peer-to-peer overlay routing infrastructure offering efficient, scalable, locationindependent routing of messages directly to nearby copies of an object or service using only localized resources. Tapestry supports a generic Decentralized Object Location and Routing (DOLR) API using a self-repairing, softstate based routing layer. This paper presents the Tapestry architecture, algorithms, and implementation. It explores the behavior of a Tapestry deployment on PlanetLab, a global testbed of approximately 100 machines. Experimental results show that Tapestry exhibits stable behavior and performance as an overlay, despite the instability of the underlying network layers. Several widely-distributed applications have been implemented on Tapestry, illustrating its utility as a deployment infrastructure.

Modern networking applications replicate data and services widely, leading to a need for location-independent routing---the ability to route queries to objects using names independent of the objects' physical locations. Two important properties of such a routing infrastructure are routing locality and rapid adaptation to arriving and departing nodes. We show how these two properties can be efficiently achieved for certain network topologies. To do this, we present a new distributed algorithm that can solve the nearest-neighbor problem for these networks. We describe our solution in the context of Tapestry, an overlay network infrastructure that employs techniques proposed by Plaxton et al. [24].

In this paper, we show that two peer-to-peer systems, Pastry [13] and Tapestry [17] can be made tolerant to certain classes of failures and a limited class of attacks. These systems are said to operate properly if they can find the closest node matching a requested ID.

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Network coordinates, which embed network distance measurements in a coordinate system, were introduced as a method for determining the proximity of nodes for routing table updates in overlay networks. Their power has far broader reach: due to their low overhead and automatic adaptation to changes in the network, network coordinates provide a new paradigm for managing dynamic overlay networks. We compare network coordinates to other proposals for network-aware overlays and show how they permit the lucid expression of a range of distributed systems problems in well-understood geometric terms. 1.

Abstract—Internet-based overlay networks are likely to demonstrate poor performance when deployed on the Internet without consideration of topological and link properties. We introduce a new method for tactical construction of unstructured overlay networks which exploits a minimal landmark infrastructure to align the overlay with the underlying network. Our framework results in well-connected overlays which can better meet the growing demands of current applications. We demonstrate, using simulation, that our approach yields reduced latency, better connectivity and higher availability of resources than conventional overlay systems and other landmark-based approaches, thereby providing a scalable and efficient approach for overlay construction. Index Terms — Localization, Overlay Networks, Topology Awareness, Unstructured Peer-to-Peer Abstract—Internet-based overlay networks are likely to demonstrate poor performance when deployed on the Internet without consideration of topological and link properties. We introduce a new method for tactical construction of unstructured overlay networks which exploits a minimal landmark infrastructure to align the overlay with the underlying network. Our framework results in well-connected overlays which can better meet the growing demands of current applications. We demonstrate, using simulation, that our approach yields reduced latency, better connectivity and higher availability of resources than conventional overlay systems and other landmark-based approaches, thereby providing a scalable and efficient approach for overlay construction.

by Yanbin Zhao

management,

Currently, a scalable real-time traffic information system does not exist. The OpenRoad project at UCLA aims to provide a grassroots system that allows vehicles driving on the freeway or any side street to be

We present several optimizations aimed at improving the object location performance of locality-aware structured peer-to-peer overlays. We present simulation results that demonstrate the effectiveness of these optimizations in Tapestry, and discuss their usage of the overall storage resources of the system.