Lookup Success Rate Research Articles

Peer to Peer Approach based Replica and Locality Awareness to Manage and Disseminate Data in Vehicular Ad Hoc Networks

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.

Local P2P group (LPG) communication in structured mobile P2P networks

With the onset of the digital era and the availability of the internet, the need for digital data in a huge manner can be fulfilled by peer-to-peer (P2P) network instead of a traditional client server-based solution. Generally, mobile communication is based on cellular networks or multi-hop wireless networks. Cellular networks have adequate fixed infrastructure whereas multi-hop wireless networks have limited infrastructure and hence there are many limitations. The P2P systems are mainly designed for wired networks and the routing is based on IP infrastructure. Chord based protocols are widely deployed in the structured P2P networks but it can not perform well when implemented for mobile P2P networks due to the mobility of the users. Mobility pattern of mobile users plays an important role in locating users and delivering data packets seamlessly. Today, many of the mobile users follow a fixed mobility pattern in urban cities and mobility pattern of the mobile users can be utilized to reduce table update cost and increase Lookup Success Rate (LSR). We have proposed Local P2P Group (LPG) based communication scheme for structured mobile P2P networks. We are focussed on the mobility pattern of the mobile users in urban cities. We have analytically evaluated the proposed scheme using fluid-flow and RWP (Random Waypoint) mobility models and found that the proposed scheme performs better than the existing schemes like MR-Chord and MobiStore. Our proposed scheme has up to 40% higher Lookup Success Rate and 81% less table update cost than existing schemes, MR-Chord and MobiStore.

A Novel Clustering Tree-based Video lookup Strategy for Supporting VCR-like Operations in MANETs

Mobile Peer-to-Peer (MP2P) network is a promising avenue for large-scale deployment of Video-on-Demand (VoD) applications over mobile ad-hoc networks (MANETs). In P2P VoD systems, fast search for resources is key determinants for improving the Quality of Service (QoS) due to the low delay of seeking resources caused by streaming interactivity. In this paper, we propose a novel Clustering Tree-based Video Lookup strategy for supporting VCR-like operations in MANETs (CTVL) CTVL selects the chunks with the high popularity as overlay router chunks to build the virtual with other chunks in terms of the popularities and external connection of video chunks. CTVL designs a new clustering strategy to group nodes in P2P networks and a maintenance mechanism of cluster structure, which achieves the high system scalability and fast resource search performance. Thorough simulation results also show how CTVL achieves higher average lookup success rate, lower maintenance cost, lower average end-to-end delay and lower packet loss ratio (PLR) in comparison with other state of the art solutions.

IPersea: Towards improving the Sybil-resilience of social DHT

P2P systems are highly susceptible to Sybil attacks, in which an attacker creates a large number of identities and uses them to control a substantial fraction of the system. Persea is the most recent approach towards designing a social network based Sybil-resistant DHT. Unlike prior Sybil-resistant P2P systems based on social networks, Persea does not rely on two key assumptions: (i) that the social network is fast mixing, and (ii) that there is a small ratio of attack edges to honest peers. Both assumptions have been shown to be unreliable in real social networks. The hierarchical distribution of node IDs in Persea confines a large attacker botnet to a considerably smaller region of the ID space than in a normal P2P system and its replication mechanism lets a peer to retrieve the desired results even if a given region is occupied by attackers. However, Persea system suffers from certain limitations, since it cannot handle the scenario, where the malicious target returns an incorrect result instead of just ignoring the lookup request. In this paper, we address this major limitation of Persea through a Sybil detection mechanism built on top of Persea system, which accommodates inspection lookup, a specially designed lookup scheme to detect the Sybil nodes based on their responses to the lookup query. We design a scheme to filter those detected Sybils to ensure the participation of honest nodes on the lookup path during regular DHT lookup. Since the malicious nodes are opt-out from the lookup path in our system, they cannot return any incorrect result during regular lookup. We evaluate our system in simulations with social network datasets and the results show that catster, the largest network in our simulation with 149,700 nodes and 5,449,275 edges, gains 100% lookup success rate, even when the number of attack edges is equal to the number of benign peers in the network.

MobiStore: A system for efficient mobile P2P data sharing

MobiStore is a P2P data store for decentralized mobile computing, designed to achieve high availability and load balance. As P2P platforms, mobile devices connected to the Internet through WiFi or cellular networks are different from wired devices in two main aspects: (1) higher churn due to mobility, weak wireless signals, or battery constraints, and (2) significant variability in bandwidth and latency based on the point of attachment. These problems affect the stored content availability and skew the content serving load over the peers. MobiStore structures the mobile P2P network into clusters of redundant peers. The topology uses both algorithmically-defined and random edges among the peers of different clusters. The routing information is updated using a gossip-based protocol. Thus, MobiStore achieves, with high probability, O(1) lookup operations despite high churn and link variability. Inside the clusters, all peers replicate the content, which improves the content availability. Furthermore, based on the current load, MobiStore dynamically changes the number of peers inside the clusters and routes content request to randomly selected peers. These two dynamic techniques along with using consistent hashing to map content to peers balance the load over the peers. While some of these techniques are well known, the main contribution is on the novel ways of applying them to design and implement an efficient mobile P2P data store. Simulation results show MobiStore achieves an availability, i.e., lookup success rate, between 12–48 % higher than two baseline systems built over the MR-Chord and Chord P2P protocols; and it reduces the latency up to 9 times compared to these protocols. Finally, the results show MobiStore adapts to churn and workload to evenly distribute the requests across clusters and peers better than both baseline solutions.

A Novel Energy-Efficiency Social-Inspired Video Sharing Solution in Wireless Networks

Mobile multimedia streaming services provide rich-content visual resources for the mobile users via ubiquitous access to Internet. The video resource sharing focuses on the matching of appropriate resource supplier for the resource requesters and is a key issue for P2P-based video system scalability and user quality of experience. In this context, leveraging social-driven interaction between mobile users enables the discovery of common interests to improve video content sharing efficiency. In this paper, we propose a novel energy-efficiency social-inspired video sharing solution in wireless networks (ESVS). By the analysis of historical request behaviors of users, ESVS designs an estimation method of relationship between videos and groups the videos into a chain-based tree structure. Based on the constructed video tree, ESVS designs a hybrid resource lookup algorithm including push and pull and a communication quality-aware selection strategy of video suppliers, which improves the communication capacities between requesters and suppliers and reduces the network bandwidth consumption. Simulation results also show how ESVS achieves higher resource lookup success rate, lower startup delay, less packet loss rate, and lower maintenance cost than another state-of-the-art solution.

MR-Chord: Improved Chord Lookup Performance in Structured Mobile P2P Networks

Peer-to-peer (P2P) networks are becoming very popular since various applications such as media streaming and voice over IP use these networks in different environment settings without the need for a client-server structure. P2P protocols have been originally designed for traditional wired networks, and when deployed in wireless network environments, several challenges are encountered. For instance, P2P clients may depart or join the network frequently, raising the issue of identification and retrieval of data items in an efficient manner. In this scenario, the routing information in P2P clients may become overdue, leading to lookup failures. This paper continues the investigation of our recently proposed solution for Chord lookup in mobile P2P networks [so-called mobile robust Chord (MR-Chord)]. MR-Chord was designed to maintain and update the finger table using a modified distributed hash table-based protocol, so that the necessary lookup services in the network are provided. Our contribution consists in studying the effects of node mobility on the performance of MR-Chord. Simulation results show that in the presence of node mobility, MR-Chord outperforms the original Chord protocol in terms of lookup success rate, overlay consistency, lookup delay time, lookup hot count, and total network load, chosen as performance metrics.

Adaptive Lookup Protocol for Two-Tier VANET/P2P Information Retrieval Services

Intelligent transportation system (ITS) services have attracted significant attention in recent years. To support ITS services, architecture is required to retrieve information and data from moving vehicles and roadside facilities in an efficient manner. A two-tier system that integrates low-tier vehicular ad hoc networks (VANETs) and a high-tier infrastructure-based peer-to-peer (P2P) overlay, which can achieve a high lookup success rate and low lookup latency for information retrieval, has been developed. However, conventional information lookups in the two-tier VANET/P2P system may introduce extra lookup messages and latencies because the lookup queries are simultaneously performed over the VANET/P2P networks. This paper proposes an adaptive lookup protocol for the two-tier VANET/P2P system to improve the efficiency of information retrieval. The proposed protocol uses a Bloom filter, which is a space-efficient data structure, to collect reachability information of road segments; therefore, adaptive routing of queries between low- and high-tier networks according to reachability probability can be employed. Simulations based on the SUMO traffic simulator and QualNet network simulator demonstrate that compared with the conventional two-tier lookup mechanism, the adaptive lookup protocol can reduce the lookup latency by 12%, reduce the P2P lookup overhead by 20%-33%, and achieve a high success rate in information lookups.

Virtual community-based video resource sharing solution in MANETs

The virtual community has emerged as a state-of-the-art technology, grouping the user with the common interest and providing a feasible solution for large-scale deployment of resource sharing services. Efficient sharing for video resources and low maintenance cost of overlay topology are key factors in MP2P video on demand systems. In this paper, a novel virtual community-based video resource sharing (VCVRS) solution in MANETs is proposed. VCVRS design a virtual community construction strategy to group the nodes with the common playback behavior and a flexible community maintenance mechanism so as to obtain the fast supplier discovery and low maintenance overhead. Simulation results show how VCVRS achieves higher lookup success rate, lower server stress, lower node load and less overlay maintenance overhead, in comparison with another state of the art solution.

QoE-Driven User-Centric VoD Services in Urban Multihomed P2P-Based Vehicular Networks

Recently, many cities around the world have witnessed large-scale deployment of terrestrial broadcasting mobile television (TV) to vehicles. This service is similar to the cable or satellite TV already in the home, and user-centric interactive mobile Video-on-Demand (VoD) over urban vehicular networks is in fact expected. However, providing this new service with focus on user Quality of Experience (QoE) constitutes a significant challenge. This paper introduces a QoE-driven User-centric solution for VoD services in urban vehicular network environments (QUVoD). QUVoD relies on a multihomed hierarchical peer-to-peer (P2P) and vehicular ad-hoc network (VANET) architecture. Vehicles construct a low-layer VANET via Wireless Access in the Vehicular Environment interfaces; they also form an upper layer P2P Chord overlay on top of a cellular network via Fourth-Generation (4G) interfaces. A novel grouping-based storage strategy that uniformly distributes the video segments along the Chord overlay is proposed, reducing segment seeking traffic while also enabling load balancing. A novel segment seeking and multipath delivery scheme that achieves high lookup success rate and very good video data delivery efficiency is also introduced, which achieves high lookup success rate and very good video data delivery efficiency. Furthermore, a new speculation-based prefetching strategy is proposed, which analyses users' interactive viewing behavior and, by estimating video segment playback order, employs prefetching of the expected segments, smoothening the video playback. Simulation results show how QUVoD is a highly efficient user-centric mobile VoD solution in urban vehicular networks in comparison with existing state-of-the-art solutions.

Design and evaluation of a two-tier peer-to-peer traffic information system

Decentralized traffic information systems realize real-time traffic information services without the need for a server infrastructure. However, existing systems rely on either the vehicular ad hoc network or application-layer peer-to-peer protocols over a broadband wireless network suffering from low lookup success rate, high lookup latency, and maintenance overhead of the P2P network. This article proposes a two-tier VANET/P2P architecture that exploits both VANET and P2P technology. In the low tier, vehicles form a VANET via intervehicle communication to exchange traffic information. On top of the VANET, a portion of the vehicles further establish a P2P overlay through a broadband wireless infrastructure to mitigate the disconnectivity problems of the VANET. Simulation results demonstrate that the two-tier architecture can significantly improve the lookup success rate compared to the single-tier VANET systems while reducing lookup latency and maintenance overhead compared to the single-tier P2P systems.