In today’s chaotic network, data and services are mobile and replicated widely for availability, durability, and locality. Components within this infrastructure interact in rich and complex ways, greatly stressing traditional approaches to name service and routing. This paper explores an alternative to traditional approaches called Tapestry. Tapestry is an overlay location and routing infrastructure that provides location-independent routing of messages directly to the closest copy of an object or service using only point-to-point links and without centralized resources. The routing and directory information within this infrastructure is purely soft state and easily repaired. Tapestry is self-administering, faulttolerant, and resilient under load. This paper presents the architecture and algorithms of Tapestry and explores their advantages through a number of experiments. 1

Abstract — Over the Internet today, computing and communications environments are significantly more complex and chaotic than classical distributed systems, lacking any centralized organization or hierarchical control. There has been much interest in emerging Peer-to-Peer (P2P) network overlays because they provide a good substrate for creating large-scale data sharing, content distribution and application-level multicast applications. These P2P networks try to provide a long list of features such as: selection of nearby peers, redundant storage, efficient search/location of data items, data permanence or guarantees, hierarchical naming, trust and authentication, and, anonymity. P2P networks potentially offer an efficient routing architecture that is self-organizing, massively scalable, and robust in the wide-area, combining fault tolerance, load balancing and explicit notion of locality. In this paper, we present a survey and comparison of various Structured and Unstructured P2P networks. We categorize the various schemes into these two groups in the design spectrum and discuss the application-level network performance of each group.

In the recent years, the evolution of a new wave of innovative network architectures labeled peer-to-peer (p2p) has been witnessed. Such architectures and systems are characterized by direct access between peer computers, rather than through a centralized server. P2p file sharing architectures can be classified by their degree of centralization , i.e. to what extent they rely to one or more servers to facilitate the interaction between peers. Three categories are identified: Purely decentralized, partially centralized and hybrid decentralized. Furthermore, highly dynamic p2p networks of peers with complex topology can be differentiated by the degree to which they contain some structure or are created adhoc. By structure we refer to the way in which the content of the network is located: Is there a way of directly knowing which peers contain some specific content, or does one need to randomly search the entire network to locate it? Three categories of systems are examined: Structured, loosely structured and unstructured. Various p2p architectures from these categories are examined with focus on the way they operate and how successfully they address issues such as scalability, network latency, security, privacy, anonymity and others. The shortcomings of these systems and the latest variations, developments and trends in p2p file sharing network design that aim at improving upon them, are discussed.

by Yanbin Zhao

In today's chaotic network, data and services are mobile and replicated widely for availability, durability, and locality. Components within this infrastructure interact in rich and complex ways, greatly stressing traditional approaches to name service and routing. This paper explores an alternative to traditional approaches called Tapestry. Tapestry is an overlay location and routing infrastructure that provides location-independent routing of messages directly to the closest copy of an object or service using only point-to-point links and without centralized resources. The routing and directory information within this infrastructure is purely soft state and easily repaired. Tapestry is self-administering, faulttolerant, and resilient under load. This paper presents the architecture and algorithms of Tapestry and explores their advantages through a number of experiments.