Distributed Hash Table Protocol Research Articles

A Distributed and Flexible Architecture for Internet of Things

Abstract The great breakthrough in technological devices has lead to the migration of actual Internet to the Internet of Things. There are merely trillions of smart dynamic objects that will be connected to the Internet and that interact and collaborate together independently from any physical location. This progress necessitates the proposal of an adequate architecture and routing process. In this paper, we propose a novel design and overlay architecture that fulfills the Internet of Things requirements. This approach is mainly based on Distributed Hash Table protocols to afford the required flexiblity and to handle efficiently mobility and churn cases. We present also a formal study that proves the efficiency of our proposed architecture.

Routing Protocols of Distributed Hash Table Based Peer to Peer Networks

Distributed hash tables (DHTs) is an extremely attractive study theme during the part of P2P networks; such networks be fetching especially admired in functions similar to file sharing. The idea of the Distributed Hash Table is given that the technique to explore the resources (especially files) within a P2P network. A DHT protocol usually affords a solitary task to the P2P function: afford a key and find out the node (or may be nodes) which is responsible for such key [1][3]. Each and every one function (such as really recover the resource or storing the resource on the node afford for it) is offered by superior levels of the P2P function. In such article our objective is to discover the security measures and determine them on accessible routing procedures of such networks. The Chord [4] (a DHT protocol) is selected as the objective approach for a variety of reasons it resolve be enclosed in this paper.

一种基于多维DHT 空间映射的P2P 安全拓扑方案

Distributed search and routing algorithms based on the DHT (distributed Hash table) protocol have attracted considerable attention in structured P2P (peer-to-peer) research as a result of favorable properties such as distribution, self-organization, and high scalability. Compared with a traditional C/S (client/server) network, the probability of peers initiating malicious behavior increases dramatically because of their self-governing and dynamic characteristics, which also make it harder to satisfy the peers’ security required by DHT. In this paper, we propose a new secure DHT protocol based on a multidimensional mapping mechanism. This mechanism maps peers to a multidimensional space by dividing the identifiers into groups. Moreover, a series of secure methods and routing algorithms are provided to achieve secure DHT in smaller spaces. Compared with state-of-the-art approaches, the theoretical analysis and experimental results show that the multidimensional mapping mechanism can effectively improve the average success rate of a resource search by inhibiting malicious behavior.

Secure P2P topology based on a multidimensional DHT space mapping

Distributed search and routing algorithms based on the DHT (distributed hash table) protocol have attracted considerable attention in structured P2P (peer-to-peer) research as a result of favorable properties such as distribution, self-organization, and high scalability. Compared with a traditional C/S (client/server) network, the probability of peers initiating malicious behavior increases dramatically because of their self-governing and dynamic characteristics, which also make it harder to satisfy the peers’ security required by DHT. In this paper, we propose a new secure DHT protocol based on a multidimensional mapping mechanism. This mechanism maps peers to a multidimensional space by dividing the identifiers into groups. Moreover, a series of secure methods and routing algorithms are provided to achieve secure DHT in smaller spaces. Compared with state-of-the-art approaches, the theoretical analysis and experimental results show that the multidimensional mapping mechanism can effectively improve the average success rate of a resource search by inhibiting malicious behavior.

A Scalable and Robust DHT Protocol for Structured P2P Network

Distributed Hash Tables (DHTs) were originated from the design of structured peer-to-peer (P2P) systems. A DHT provides a key-based lookup service similar to a hash table. In this paper, we present the detailed design of a new DHT protocol, Tambour. The novelty of the protocol is that it uses parallel lookup to reduce retrive latency and bounds communication overhead to a dynamically adjusted routing table. Tambour estimates the probabilities of routing entries' liveness based on statistics of node lifetime history and evicts dead entries after lookup failures. When the network is unstable, more routing entries will be evicted in a given period of time, and the routing tables will be getting smaller which minimize the number of timeouts for later lookup requests. An experimental prototype of Tambour has been simulated and compared against two popular DHT protocols. Results show that Tambour outperforms the compared systems in terms of bandwith cost, lookup latency and the overall efficiency.

An enhanced reactive Chord for mobile networks

Chord is a peer-to-peer look up algorithm based on a distributed hash table protocol in wired IP networks, exploiting the advantage of scalability for large-scale of distributed applications. However, deploying Chord into mobile networks should be inherently accompanied with supplementary network traffics to maintain the hash key mapping rules because of a high rate of joining and leaving nodes. This paper proposes an enhanced reactive Chord for mobile networks, which can reduce network traffics and achieve fast lookup services. For this purpose, a conventional Chord is modified to act reactively, and then the table activity checking feature is devised into it, called enhanced reactive Chord. Simulation results show that the proposed Chord can decrease network traffics by an average of 41.3% maintaining same setup latency, compared with conventional Chord in mobile networks.

A Global Reputation Model for Grid Computing

Trust and reputation are important decision-making factors in large-scale distributed systems. The Constellation Model is one of our previous works about grid resource management. Since local feedback plays an important role in aggregating global reputation, a new local feedback metric is introduced to reflect the dynamic feature of trust. This paper introduces our recent effort of combining reputation into the Constelltaion Model. We propose a novel global reputation model for grid systems such as Constellation Model. We model the relationship between global reputation and the nodes' feedback credibility. A node's feedback credibility which is calculated by similarity measurement will impact on its reputation in a direct way. In our model, to promote a node's reputation, there exist two possible ways: the first one is to provide high-quality services to others. The second way is to provide authentic feedbacks towards others. In addition, to evaluate a node's local feedback trustiness, approach based on similarity measurement is employed. If local feedback trustiness is too low, compensation calculated by exponential smoothing is applied. This design is employed to combat malicious collectives and slandering in large-scale communities. The computational framework of EigenTrust which is proposed by S. D. Kamvar at Stanford University is used to compute global reputations of all the nodes in the Constellation Model. In the Constellation Model, nodes (stars) in a solar system can be organized using a Peer-to-Peer way. Distributed Hash Table protocol such as Chord which is proposed by I. Stoica, et al. at University of California, Berkeley can be used to implement the distributed ranking mechanism. We have implemented a prototype of Constellation Model. Experimental results show that, our model can reflect dynamic characteristics of trust better. Our model can also improve the evaluation accuracy of global reputation by leveraging feedback credibility. In Comparison with EigenTrust, our model shows an improved robustness with the presence of malicious behaviors in the Constellation Model.

UnoHop: Efficient Distributed Hash Table with O(1) Lookup Performance

Distributed Hash Tables (DHTs) with O(1) lookup performance strive to minimize the maintenance traffic required for disseminating membership changes information (events). These events dissemination allows each node in the peertopeer network maintains accurate routing tables with complete membership information. We present UnoHop, a novel DHT protocol with O(1) lookup performance. The protocol uses an efficient mechanism to distribute events through a dissemination tree that is constructed dynamically rooted at the node that detects the events. Our protocol produces symmetric bandwidth usage at all nodes while decreasing the events propagation delay.

Double Indirect Access: Efficient Peer-to-Peer Object Lookup Protocol in Location-Aware Mobile Ad Hoc Networks

Geographic distributed hash table (DHT) protocols are considered to be efficient for P2P object sharing in mobile ad-hoc networks. These protocols assume that the set of (key, value) pairs, called indexes, should be distributed among nodes according to the following hashing mapping rule: A key hashes into a geographic coordinate, and the corresponding index is stored at the node closest to the key's hash value. Therefore, when a node changes its position, some indexes have to be redistributed to other nodes in order to keep the hashing mapping rule consistent. The overhead of index redistribution may be high enough to impact the normal lookup operation if each node contains a large number of indexes. In this paper, we propose an efficient lookup protocol, called Double Indirect Access, that dispenses with index redistribution to improve lookup performance. The main idea is to determine the mapping from an index to a node not by the node's position, but by the node's static identifier that is obtained by hashing its MAC address into a geographic coordinate. However, a key lookup request will be routed to some node based on the key's hash value, resulting in failure of locating the index. In Double Indirect Access, the node to which a key lookup request has been routed is named as an indirection server, and it is responsible for relaying the lookup request to the node storing the corresponding index. In order for the indirection server to find out the correct destination node for the lookup request, it maintains a list of nodes' static identifiers whose values (i.e., geographic coordinates) are close to the location of the indirection server. Simulation results show that, when the average number of objects per node is more than 256, our approach is able to reduce the number of packet transmissions by about a half compared to the conventional geographical DHT protocol. It is also shown that, even when the average number of objects per node is about 9-16, the overhead of our approach is comparable with the conventional protocol.

A Hybrid Peer-to-Peer Lookup Service Algorithm on Distributed Hash Table

An application using a distributed hash table (DHT) with N nodes must choose a DHT protocol from the spectrum between O(1) lookup protocols and O(logN). However, various applications under different network churns require that an idea DHT would be adaptive in according with the churn rates. ROAD (routing on active and demand), a new lookup algorithm, adjusts itself to provide the best performance across a range of lookup delay and churn rates. The key challenges in the design of ROAD are the algorithms that construct the routing table’s size and decrease the delay. It will speed up the lookup process and reduce the service delay with the expressed routing table and power sorting multicast algorithm. Simulations show that ROAD maintains an efficient lookup delay versus churn rate tradeoff than the existing DHTs. ROAD should be expanded into a mechanism that provides some kinds of lookup services with a range of qualities of service through super-peers choosing methods.