HIERARCHICAL PEER-TO-PEER SYSTEMS

2003 ◽  
Vol 13 (04) ◽  
pp. 643-657 ◽  
Author(s):  
L. GARCÉS-ERICE ◽  
E. W. BIERSACK ◽  
K. W. ROSS ◽  
P. A. FELBER ◽  
G. URVOY-KELLER

Structured peer-to-peer (P2P) lookup services organize peers into a flat overlay network and offer distributed hash table (DHT) functionality. Data is associated with keys and each peer is responsible for a subset of the keys. In hierarchical DHTs, peers are organized into groups, and each group has its autonomous intra-group overlay network and lookup service. Groups are organized in a top-level overlay network. To find a peer that is responsible for a key, the top-level overlay first determines the group responsible for the key; the responsible group then uses its intra-group overlay to determine the specific peer that is responsible for the key. We provide a general framework for hierarchical DHTs with scalable overlay management. We specifically study a two-tier hierarchy that uses Chord for the top level. Our analysis shows that by using the most reliable peers in the top level, the hierarchical design significantly reduces the expected number of hops. We also present a method to construct hierarchical DHTs that map well to the Internet topology and achieve short intra-group communication delay. The results demonstrate the feasibility of locality-based peer groups, which allow P2P systems to take full advantage of the hierarchical design.

Author(s):  
Zoltán Czirkos ◽  
Gábor Hosszú

In this chapter, the authors present a novel peer-to-peer based intrusion detection system called Komondor, more specifically, its internals regarding the utilized peer-to-peer transport layer. The novelty of our intrusion detection system is that it is composed of independent software instances running on different hosts and is organized into a peer-to-peer network. The maintenance of this overlay network does not require any user interaction. The applied P2P overlay network model enables the nodes to communicate evenly over an unstable network. The base of our Komondor NIDS is a P2P network similar to Kademlia. To achieve high reliability and availability, we had to modify the Kademlia overlay network in such a way so that it would be resistent to network failures and support broadcast messages. The main purpose of this chapter is to present our modifications and enhancements on Kademlia.


Author(s):  
Mayank Singh ◽  
Shashikala Tapaswi

Mutual exclusion is one of the well-studied fundamental primitives in distributed systems, and a number of vital solutions have been proposed to achieve the same. However, the emerging Peer to Peer systems bring forward several challenges to protect consistent and concurrent access to shared resources, as classical peer-to-peer systems, like Napster, Gnutella, et cetera, have been mainly used for sharing files with read only permission. In this chapter, the authors propose a quorum based mutual exclusion algorithm that can be used over any Peer to Peer Distributed Hash Table (DHT). The proposed approach can be seen as extension to traditional Sigma protocol for mutual exclusion in Peer to Peer systems. The basic idea is to reduce message overhead with use of smart nodes present in each quorum set and message passing between the current owners of resource with next resource requester nodes.


Author(s):  
SUBY MARIA JACOB

Load balancing is a critical issue for the efficient operation of peer-to- peer networks. With the notion of virtual servers, peers participating in a heterogeneous, structured peer-to-peer (P2P) network may host different numbers of virtual servers, and by migrating virtual servers, peers can balance their loads proportional to their capacities. Peers participating in a Distributed Hash Table (DHT) are often heterogeneous. The existing and decentralized load balance algorithms designed for the heterogeneous, structured P2P networks either explicitly construct auxiliary networks to manipulate global information or implicitly demand the P2P substrates organized in a hierarchical fashion. Without relying on any auxiliary networks and independent of the geometry of the P2P substrates, this paper present ,a novel efficient, proximity-aware load balancing algorithm by using the concept of common virtual servers, that is unique in that each participating peer is based on the partial knowledge of the system to estimate the probability distributions of the capacities of peers and the loads of virtual servers. The movement cost can be reduced by using common virtual server


Author(s):  
Ying Qiao ◽  
Shah Asaduzzaman ◽  
Gregor V. Bochmann

This chapter presents a clustered peer-to-peer system as a resource organization structure for web-service hosting platforms. Where service quality, such as response time and service availability, are provided with assurance. The peer-to-peer organization allows integration of autonomous resources into a single platform in a scalable manner. In clustered peer-to-peer systems, nodes are organized into clusters based on some proximity metric, and a distributed hash table overlay is created among the clusters. This organization enables lightweight techniques for load balancing among different clusters, which is found to be essential for providing response time guarantees. Service availability is provided by replicating a service instance in multiple nodes in a cluster. A decentralized load balancing technique called diffusive load balancing is presented in the context of clustered peer-to-peer systems and evaluated for effectiveness and performance.


2020 ◽  
Vol 12 (6) ◽  
pp. 65-81
Author(s):  
Abdelkader Guezzi ◽  
Abderrahmane Lakas ◽  
Ahmed Korichi ◽  
Sarra Cherbal

Distributed Hash Table (DHT) based structured peer-to-peer (P2P) systems provide an efficient method of disseminating information in a VANET environment owing to its high performance and properties (e.g., self-organization, decentralization, scalability, etc.). The topology of ad hoc vehicle networks (VANET) varies dynamically; its disconnections are frequent due to the high movement of vehicles. In such a topology, information availability is an ultimate problem for vehicles, in general, connect and disconnect frequently from the network. Data replication is an appropriate and adequate solution to this problem. In this contribution, to increase the accessibility of data, which also increases the success rate of the lookup, a method based on replication in the Vanet network is proposed named LAaR-Vanet. Also, this replication strategy is combined with a locality-awareness method to promote the same purpose and to avoid the problems of long paths. The performance of the proposed solution is assessed by a series of in-depth simulations in urban areas. The obtained results indicate the efficiency of the proposed approach, in terms of the following metrics: lookup success rate, the delay, and the number of the logical hop.


Author(s):  
Xianghan Zheng ◽  
Vladimir Oleshchuk

Today, Peer-to-Peer SIP based communication systems have attracted much attention from both the academia and industry. The decentralized nature of P2P might provide the distributed peer-to-peer communication system without help of the traditional SIP server. However, the decentralization features come to the cost of the reduced manageability and create new concerns. Until now, the main focus of research was on the availability of the network and systems, while few attempts are put on protecting privacy. In this chapter, we investigate on P2PSIP security issues and introduce two enhancement solutions: central based security and distributed trust security, both of which have their own advantages and disadvantages. After that, we study appropriate combination of these two approaches to get optimized protection. Our design is independent of the DHT (Distributed Hash Table) overlay technology. We take the Chord overlay as the example, and then, analyze the system in several aspects: security & privacy, number-of the hops, message flows, etc.


2020 ◽  
Vol 16 (3) ◽  
pp. 1-16
Author(s):  
Hong He

In recent years, peer-to-peer (P2P) systems have become a promising paradigm to provide efficient storage service in distributed environments. Although its effectiveness has been proven in many areas, the data consistency problem in P2P systems are still an opening issue. This article proposes a novel data consistence model, virtual peers-based data consistency (VPDC), which introduces a set of virtual peers to provide guaranteed data consistency in decentralized and unstructured P2P systems. The VPDC model can be easily implemented in any P2P system without introducing any interference to data retrieval. Theoretical analysis on VPDC is presented to analyze its effectiveness and efficiency, and massive experiments are conducted to evaluate the performance of a VPDC model in a real-world P2P system. The results indicate that it can significantly improve the data consistence of P2P systems and outperform many similar approaches in various experimental settings.


Electronics ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 1610 ◽  
Author(s):  
Li-Yuan Hou ◽  
Tsung-Yi Tang ◽  
Tyng-Yeu Liang

BitTorrent (BT) is the most popular peer-to-peer file-sharing system. According to official BT information, more than 100 million active users use BT for file transfers every month. However, BT mainly relies on either a central tracker (tracker) or distributed hash table (DHT) for locating file seeders while it runs a risk of a single point of failure or cyber-attacks such as Sybil and Eclipses. To attack this problem, we proposed a Peer-to-Peer (P2P) file-sharing system called IOTA-BT by integrating BitTorrent with IOTA in this paper. The advantages of IOTA over blockchain include scalability for high throughput, compatibility with Internet of Things (IoT) footprints, zero transaction fees, partition-tolerant, and quantum-resistant cryptography. The autopeering and neighbor selection of the Coordicide of IOTA is aimed at defending a Sybil or Eclipse attack. IOTA-BT inherits these advantages from IOTA. Moreover, our experimental results have shown that the cost of executing BT functions, such as releasing torrent files and retrieving seeder information on IOTA-BT, is acceptable for improving the security of BT. IOTA-BT can indeed efficiently provide users with a P2P file-sharing environment of higher security.


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