Distributed Hash Table Research Articles

Improving Management Performance of P2PSIP for Mobile Sensing in Wireless Overlays

Future wireless communications are heading towards an all-Internet Protocol (all-IP) design, and will rely on the Session Initiation Protocol (SIP) to manage services, such as voice over IP (VoIP). The centralized architecture of traditional SIP has numerous disadvantages for mobile ad hoc services that may be possibly overcome by advanced peer-to-peer (P2P) technologies initially developed for the Internet. In the context of mobile sensing, P2PSIP protocols facilitate decentralized and fast communications with sensor-enabled terminals. Nevertheless, in order to make P2PSIP protocols feasible in mobile sensing networks, it is necessary to minimize overhead transmissions for signaling purposes, which reduces the battery lifetime. In this paper, we present a solution to improve the management of wireless overlay networks by defining an adaptive algorithm for the calculation of refresh time. The main advantage of the proposed algorithm is that it takes into account new parameters, such as the delay between nodes, and provides satisfactory performance and reliability levels at a much lower management overhead than previous approaches. The proposed solution can be applied to many structured P2P overlays or P2PSIP protocols. We evaluate it with Kademlia-based distributed hash tables (DHT) and dSIP

Exploiting 3D Structure for Scalable Routing in MANETs

Avoiding the mismatch between a physical network (PT) and a logical identifier structure (LIS) in a distributed hash table (DHT) based routing for mobile ad hoc networks (MANETs) would prevent the problems of long routes, high path-stretch ratio, and increased traffic overhead. To address this mismatch problem, the proposed scheme exploits a 3-dimensional (3D) logical identifier space (LS), where each node computes a consecutive logical identifier (LID) to route packets. The proposed scheme also utilizes 3D-logical identifier structure (3D-LIS) to maintain multi-paths by exploiting multihops at a node to the destination node. Simulation results show that the proposed protocol is better than existing DHT-based routing protocol.

A scalable approach for content based image retrieval in cloud datacenter

The emergence of cloud datacenters enhances the capability of online data storage. Since massive data is stored in datacenters, it is necessary to effectively locate and access interest data in such a distributed system. However, traditional search techniques only allow users to search images over exact-match keywords through a centralized index. These techniques cannot satisfy the requirements of content based image retrieval (CBIR). In this paper, we propose a scalable image retrieval framework which can efficiently support content similarity search and semantic search in the distributed environment. Its key idea is to integrate image feature vectors into distributed hash tables (DHTs) by exploiting the property of locality sensitive hashing (LSH). Thus, images with similar content are most likely gathered into the same node without the knowledge of any global information. For searching semantically close images, the relevance feedback is adopted in our system to overcome the gap between low-level features and high-level features. We show that our approach yields high recall rate with good load balance and only requires a few number of hops.

Collaborative Web service composition based on distributed Hash table

Centralized CBR(Case-Based Reasoning) is faced with problems such as massive data maintenance cost,high node load and central failure.To tackle these problems,COCO(Distributed Hash Table(DHT) based Collaborative Web Service Composition) was proposed.COCO mappped the workflow and QoS properties of a composite service into a one-dimensional key using Hash function and Space-Filling Curve(SFC).Keys were used for queries of the existing composite services that satisfied user request in a Peer-to-Peer(P2P) fashion in the underlying DHT Overlay.One successful query returned composite services satisfying both functional and non-functional requirements.The experimental results show that COCO has scalable performance on both query delay and query hit rate,indicating COCO's applicability in large-scale network computing environment.

An Efficient and Scalable Routing for MANETs

Recently, Distributed-Hash-Table (DHT)-based routing protocols have been proposed for large scale mobile ad hoc networks (MANETs). The motive behind using DHT is to avoid/reduce network wide flooding in MANETs in route discovery phase leading to achieve more scalable network. The challenge of deploying DHT at network layer for routing purpose in MANETs is to achieve more matching between logical and physical networks. The paper describes that existing DHT-based routing protocols for MANETs lack this feature. The paper presents a new DHT based scheme [called an efficient and scalable routing for MANETs (ESR)] which reduces the ill-matching between logical and physical networks. This is achieved be distributing the logical identifier (LID) space of DHT structure among the nodes such that the physical neighbors have consecutive LID space portions, i.e. all physical neighbors of a node are also the logical neighbors of the node. Therefore the logical ID space portion of a node may be non-contiguous. Based on this logical structure, a node builds up binary-search-tree (BST) using both logical ID space portion of itself and its neighbors. This BST at the node is traversed to find the next hop for a query/message. Through simulation, the paper shows the proposed approach (ESR) performs better than the existing one in term of routing overhead, average end-to-end delay, path-stretch values and false-negative ratio.

On the performance improvement of gossip protocols for content-based publish-subscribe through caching

Gossip protocols are a common solution for content-based publish-subscribe. However, in spite of the advantages that these protocols present in comparison to other approaches, such as distributed hash tables, they also have inherent scalability issues. In this paper, CCPS (Caching Content-based Publish-Subscribe) is presented as a publish-subscribe protocol designed to address these scalability issues. Through caching, CCPS exploits search query repetition to address load balancing problems. It has been designed having in mind its use in combination with existing publish-subscribe solutions so as to improve their performance. In the paper, the protocol description together with the implementation details of its fundamental operations are provided, while CCPS performance is evaluated against standard gossip protocols.

Granary: A sharing oriented distributed storage system

Up to now, more and more people use Internet storage services as a new way of sharing. File sharing by a distributed storage system is quite different from a specific sharing application like BitTorrent. And as large file sharing becomes popular, the data transmission rate takes the place of the response delay to be the major factor influencing user experience. We present the design and implementation of a distributed storage system named as Granary in this paper, which provides reliable data storage and sharing service to cyber users. Granary uses a specific DHT(Distributed Hash Table) layer to store file meta-data and employs a raw data storage scheme to scatter large data. We introduce its adaptive DHT recovery algorithm in this paper which assures the availability and consistency of meta-data with small bandwidth consumption and improved throughout. The replication strategies which are used to accelerate file sharing with low bandwidth consumptions are further discussed. Experimental results show that these methods offer a reliable and efficient data storage and sharing speed with network bandwidth costs less than conventional policies.

DS2: A DHT-based substrate for distributed services

DHT (Distributed Hash Table) algorithms are very efficient for distributed data management. As one kind of P2P overlay, DHT overlay also has the advantages of high reliability, high scalability and low cost. Because of these advantages, DHT has been proposed to form server farms such as DHT-based NoSQL databases, SIP server farms, IMS server farms, OpenFlow controller farms, etc. This paper presents DS2, a DHT-based substrate designed for the application server farms providing distributed services. DS2 facilitates the deployment of DHT-based distributed services in three aspects. First, DS2 offers a powerful data model to manage complex data. Second, DS2 provides application message routing function and workload migration function, which help application server farm to achieve load balance, failover and service continuity. Third, DS2 allows deploying application server farms across data centers. DS2 deploying across data centers is optimized to provide better performance and service continuity. We have implemented a DS2 prototype and used it in ZTE’s P2P CSCFprototype and service routing prototype to enable IMS services and service routing services successfully.

Dual Heap Overlay for Range Queries for Handling Hardware Resources

Grid resource discovery involves resolving various types of queries including exact match and range queries. Our recent effort resulted in Dual Heap Overlay Resource Discovery Protocol for a Mobile Grid (DEEPG) to resolve exact match queries. DEEPG attempted to reduce the search set for query resolution by rejecting nodes which do not satisfy the sum of the attributes specified in the query. In this paper, we propose DEEPG-R, a Dual Heap Overlay Resource Discovery Protocol for Range Queries in Grid. Distributed Hash Table (DHT) based resource discovery mechanism is common in the field and fails to handle few challenges. Hence, DEEPG-R employs the non-DHT based overlays of DEEPG and is tuned to handle range queries. The focus of the extended protocol is on reducing the number of comparisons further by comparing the resource attributes with the lower and upper bounds specified in the range query. Simulation results prove that the proposed protocol is efficient with reduced search time complexities and low maintenance overheads.

A DHT-Based Networking and Addressing Method in the TCP/IP Building Intercom System

In the TCP/IP building intercom system, broadcast addressing or query-list addressing are often used to obtain the IP address of the called party. However, these methods are limited by the function of the network equipment, intolerable resource costs, and high failure rate of querying. To solve such problems, this paper presents a networking and addressing method in the TCP/IP building intercom system which is based on Distributed Hash Table (DHT). Results from theoretical analysis and simulations show the feasibility and superiority of such a method.

비 자율적 노드 위치 결정을 통한 DHT 네트워크 ID 매핑 공격 방지

Kademlia와 같은 DHT(Distributed Hash Table) 네트워크는 참여노드들이 네트워크 토폴로지 상에서 자신의 위치를 자율적으로 결정하는 구조를 가지고 있으며 이를 악용한 ID 매핑 공격에 매우 취약하다. 그 결과 DHT 네트워크에서는 eclipse, DRDoS, 봇넷 은닉통신 등의 보안 문제가 지속적으로 발생되고 있다. 본 논문에서는 ID 매핑 공격을 방지하기 위한 비 자율적 노드 위치 결정 방법을 제안하고 NAT 호환성, 공격 저항성, 네트워크 다양성의 세 가지 측면의 분석을 통해 타 방어기법들과 비교를 수행하였다. 분석결과, 제안된 방법은 타 방어기법과 동등한 수준의 공격 저항성을 나타냄과 동시에 타 방어기법이 갖는 단점인 NAT 호환성과 네트워크 다양성 문제를 극복할 수 있음을 확인하였다. DHT(Distributed Hash Table) networks such as Kademlia are vulnerable to the ID mapping attack caused by the voluntary DHT mapping structure where the location of a node is solely determined by itself on the network topology. This causes security problems such as eclipse, DRDoS and botnet C&C on DHT networks. To prevent ID mapping attacks, we propose a non-voluntary DHT mapping scheme and perform analysis on NAT compatibility, attack resistance, and network dynamicity. Analysis results show that our approach may have an equivalent level of attack resistance comparing with other defense mechanisms and overcome their limitations including NAT compatibility and network dynamicity.

Design and implementation of a P2P communication infrastructure for WSN-based vehicular traffic control applications

Wireless Sensor Network (WSN) technology has recently started to be applied to Intelligent Transportation Systems (ITS). In this kind of network, sensor nodes are scattered over a sensor field and they transmit information to a sink node. In this paper, we first propose the design of a proxy functionality for the sink node, which will be responsible for exchanging information with other proxy nodes by means of a new Peer-to-Peer (P2P) communication infrastructure implemented using a Distributed Hash Table (DHT). This infrastructure will also facilitate the distributed processing of sensing data in order to perform path planning in a vehicular traffic control application. This approach will be able to distribute the computational tasks for route calculations over the different sink nodes in the network. This paper will present a detailed prototype of the proposed P2P communication infrastructure.

Distributed deterministic 1–2 skip list for peer-to-peer system

Data management in the peer-to-peer system is a challenging task due to the random distribution of data among several participating peers. Efficient data structures like distributed hash tables (DHT) and its variants are designed and implemented to reduce the complexity of data management in such environment. However, DHT has its limitations in supporting range queries and its variants like distributed segment trees often perform poorly when the number of peers is high. Further, distributed lists and distributed balanced trees require significant amount of time for stabilizing after a new peer joins or a peer leaves. In this paper, a new distributed data structure called deterministic 1–2 skip list is introduced as an alternate solution for data management in the peer-to-peer systems. A deterministic skip list can be viewed as an alternate of a balanced tree, where the semantic locality of each key is preserved. Thus it can support the range queries as well as the single shot queries. This paper proposes three main operations on this data structure - searching data based on keys, insertion when a new peer joins, and deletion when a peer leaves. The correctness of the proposed operations are analyzed using theoretical arguments and mathematical proofs. The proposed scheme is simulated using NS-2.34 network simulator, and the efficiency of the scheme has been compared with DHT, DST, distributed list and distributed tree based data management.

Internet of Things Resources Addressing the Technical Analysis and Research

This paper presents a certain universal applicability entity coding standards and improved distributed hash table based on the specification developed a resource addressing system for the Internet of Things.

Performance analysis of distributed mapping system in ID/locator separation architectures

An ID/locator separation architecture is one of the most recognized technologies that enable the Future Internet. In ID/locator separation architecture, an ID/locator mapping system is indispensable to provide location management in mobile environments. This paper conducts a comparative study on two different ID/locator mapping approaches: centralized and distributed ID/locator mapping systems. We develop analytical models on the signaling cost incurred in location update and location query procedures of the centralized and distributed ID/locator mapping systems. Numerical results demonstrate that the distributed ID/locator mapping system with enhanced distributed hash table (DHT) has comparable signaling cost to the centralized ID/locator mapping system while providing higher scalability and robustness.

Handling Nodes Mobility and Failure During Bootstrapping in Randomly Deployed Ring-based Wireless Sensor Networks

Distributed Hash Table (DHT)-based protocols are new approaches proposed to Wireless Sensor Networks (WSN). Their main advantage resides on the easy integration of DHT-based WSN into the Internet Of Things. However, these protocols face multiple challenges in their bootstrapping phase, especially at the case of randomly deployed WSN. We presented in a recent work a bootstrapping protocol for use in DHT-based protocols having the structure of ring in static WSN. However, in most cases, there are some nodes that may fail or move in the network. Bootstrapping should take into account such situations in order to achieve better performance. In this paper, we propose a distributed local recovery method for use in our bootstrapping protocol that allows it to handle efficiently nodes failure and mobility. Simulation results have shown that our proposed approach is able to ensure the local recovery in a timely and energy-efficient manner.

Applying Pebble-Rotating Game to Enhance the Robustness of DHTs

Distributed hash tables (DHTs) are usually used in the open networking environment, where they are vulnerable to Sybil attacks. Pebble-Rotating Game (PRG) mixes the nodes of the honest and the adversarial randomly, and can resist the Sybil attack efficiently. However, the adversary may have some tricks to corrupt the rule of PRG. This paper proposes a set of mechanisms to make the rule of PRG be obliged to obey. A new joining node must ask the Certificate Authority (CA) for its signature and certificate, which records the complete process on how a node joins the network and obtains the legitimacy of the node. Then, to prevent the adversary from accumulating identifiers, any node can make use of the latest certificate to judge whether one identifier is expired with the help of the replacement property of RPG. This paper analyzes in details the number of expired certificates which are needed to store in every node, and gives asymptotic solution of this problem. The analysis and simulations show that the mean number of the certificates stored in each node are , where n is the size of the network.

Improving playback quality of peer-to-peer live streaming systems by joint scheduling and distributed Hash table based compensation

In Peer-to-Peer (P2P) streaming systems, video data may be lost since peers can join and leave the overlay network randomly, thereby deteriorating the video playback quality. In this paper we propose a new hybrid mesh and Distributed Hash Table (DHT) based P2P streaming system, called HQMedia, to provide high playback quality to users by maintaining high data dissemination resilience with a low overhead. In HQMedia, peers are classified into Super Peers (SP) and Common Peers (CP) according to their online time. SPs and CPs form a mesh structure, while SPs alone form a new Streaming DHT (SDHT) structure. In this hybrid architecture, we propose a joint scheduling and compensation mechanism. If any frames cannot be obtained during the scheduling phase, an SDHT-based compensation mechanism is invoked for retrieving the missing frames near the playback point. We evaluate the performance of HQMedia by both theoretical analysis and intensive simulation experiments on large-scale networks to demonstrate the effectiveness and scalability of the proposed system. Numerical results show that HQMedia significantly outperforms existing mesh-based and treebased P2P live streaming systems by improving playback quality with only less than 1% extra maintenance overhead.

APRICOD

Content discovery is a major source of latency in peer-to-peer (P2P) media streaming systems, especially in the presence of noncontinuous user access, such as random seek in Video-on-Demand (VoD) streaming and teleportation in a Networked Virtual Environment (NVE). After the aforementioned user interactions, streaming systems often need to initiate the content discovery process to identify where to retrieve the requested media objects. Short content lookup latency is demanded to ensure smooth user experience. Existing content discovery systems based on either a Distributed Hash Table (DHT) or gossip mechanism cannot cope with noncontinuous access efficiently due to their long lookup latency. In this work, we propose an access-pattern-driven distributed caching middleware named APRICOD, which caters for fast and scalable content discovery in peer-to-peer media streaming systems, especially when user interactions are present. APRICOD exploits correlations among media objects accessed by users, and adapts to shift in the user access pattern automatically. We first present a general APRICOD design that can be used with any existing content discovery system. We then present an implementation of APRICOD on top of Pastry, which we use to evaluate APRICOD. Our evaluation in a 1024-node system, using a Second Life trace with 5,735 users and a VoD trace with 54 users, shows that APRICOD can effectively resolve all continuous access queries with a single hop deterministically with node failure as an exception, and resolve noncontinuous access queries with a single hop with high probability.

A Symmetric Load Balancing Algorithm with Performance Guarantees for Distributed Hash Tables

Peers participating in a distributed hash table (DHT) may host different numbers of virtual servers and are enabled to balance their loads in the reallocation of virtual servers. Most decentralized load balance algorithms designed for DHTs based on virtual servers require the participating peers to be asymmetric, where some serve as the rendezvous nodes to pair virtual servers and participating peers, thereby introducing another load imbalance problem. While state-of-the-art studies intend to present symmetric load balancing algorithms, they introduce significant algorithmic overheads and guarantee no rigorous performance metrics. In this paper, a novel symmetric load balancing algorithm for DHTs is presented by having the participating peers approximate the system state with histograms and cooperatively implement a global index. Each peer independently reallocates in our proposal its locally hosted virtual servers by publishing and inquiring the global index based on their histograms. Unlike competitive algorithms, our proposal exhibits analytical performance guarantees in terms of the load balance factor and the algorithmic convergence rate, and introduces no load imbalance problem due to the algorithmic workload. Through computer simulations, we show that our proposal clearly outperforms existing distributed algorithms in terms of load balance factor with a comparable movement cost.