Efficient Search in Unbalanced, Randomized Peer-To-Peer Search Trees

Scalable mechanisms to support efficient key-based search in distributed systems are an important part of the infrastructure of peer-to-peer systems and global information systems. They received substantial attention both in information and communication systems research. A particularly important class of approaches is based on a principle of scalable distribution of binary search trees that has been introduced by Plaxton \cite{PLAXTON}. When adapting the shape of such a tree search structure to the data distribution in order to obtain load balancing, the search trees may become highly unbalanced. We show that for P-Grid, a Plaxton-like distributed search structure that we first introduced in \cite{PGRID1}, the expected communication cost for searches is strictly limited by $\log(n)$ where $n$ is the number of peers. This result is completely independent of the shape of the underlying tree. The approach exploits the randomization principle of the P-Grid structure by virtue of its decentralized and randomized construction process

DSTP-AN: A Distributed System for Transaction Processing Based on Data Resource Migration in ATM Networks

The dynamic migration of data resources has become a strong tool for transaction processing in broadband networks such as ATM. In this paper, a distributed system that takes advantage of data resource migration for transaction processing in ATM networks has been proposed. The proposed system provides mechanisms to select the transaction processing method, to migrate data resources in a way that reduces the time delay and message traffic in locating and accessing them. The first mechanism selects one of the two transaction processing methods: the traditional method that uses two phase commit protocol and other new method based on data resource migration. The second mechanism attempts to improve performance by making each site follow a local policy for directing requests to locate and access data resources as well as migrating them through the system. For this, a new scheme that focuses on reducing the time delay and message traffic needed to access the migratory data resources is proposed. The performance of the proposed scheme has also been evaluated and compared with one of the existing schemes by a simulation study under different system parameters such as frequency of access to the data resources, frequency of data resource migrations, scale of network, etc

A self-organizing access structure for P2P information systems

Peer-To-Peer systems are driving a major paradigm shift in the era of genuinely distributed computing. Gnutella is a good example of a Peer-To-Peer success story: a rather simple software enables Internet users to freely exchange files, such as MP3 music files. But it shows up also some of the limitations of current P2P information systems with respect to their ability to manage data efficiently. In this paper we introduce P-Grid, a scalable access structure that is specifically designed for Peer-To-Peer information systems. P-Grids are constructed and maintained by using randomized algorithms strictly based on local interactions, provide reliable data access even with unreliable peers, and scale gracefully both in storage and communication cost. Keywords: Peer-To-Peer computing, Distributed Indexing, Distributed Databases, Randomized Algorithms

PeerCredential: a support reputation-based trust framework for peer-to-peer applications

Peer-to-Peer and scientific networks, often require those that use the system (i.e. users) to utilize other nodes (i.e. resources) that are unknown. Users are unable to identify whether a resource will be honest, selfish, or malicious. In order for users to reduce the risk of using a malicious resource and to motivate nodes from being selfish, we propose an adaptive reputation-based trust framework for distributed system applications. In this framework, users are able to appraise a resource by using price and a quantifiable metric of trust that is gathered from its own view and the views of other peers (i.e. references) regarding the reputation of the resource. The appraisal process provides the user with a reliable metric that can be used in the process of resource scheduling and selection. In response, economic resources will compete with each other using a variety of strategies that attempt to maximize their profit. The simulation results show that the framework is user friendly by providing long-term high satisfaction, filters out malicious nodes, and encourages resources to provide reliable and high-quality service

Efficient Peer-to-Peer Namespace Searches

In this paper we describe new methods for efficient and exact search (keyword and full-text) in distributed namespaces. Our methods can be used in conjunction with existing distributed lookup schemes, such as Distributed Hash Tables, and distributed directories. We describe how indexes for implementing distributed searches can be efficiently created, located, and stored. We describe techniques for creating approximate indexes that can be used to bound the space requirement at individual hosts; such techniques are particularly useful for full-text searches that may require a very large number of individual indexes to be created and maintained. Our methods use a new distributed data structure called the view tree. View trees can be used to efficiently cache and locate results from prior queries. We describe how view trees are created, and maintained. We present experimental results, using large namespaces and realistic data, showing that the techniques introduced in this paper can reduce search overheads (both network and processing costs) by more than an order of magnitude. (UMIACS-TR-2004-13

Replication control in distributed B-trees

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1995.Includes bibliographical references (p. 140-142).by Paul Richard Cosway.M.S