PREVENTING SELFISHNESS DATA ACCESS IN WIRELESS NETWORK

A mobile adhoc network (MANET) is a wireless network among mobile device. A mobile adhoc network (MANET)is a constantly self-configuring, infrastructure-less network of mobile devices connected wirelessly. Each device in aMANET is free to move independently in any direction, and will therefore modify its relations to further devices regularly.Selfish assign nodes from direct based on simulation result analysis on MANET. Mobile ad-hoc networks (MANETs) relyon collaboration of all contribute nodes. Thus they are vulnerable to self-interested nodes using the net without providingown resources, as well as hateful nodes attacking the network communications

Supporting disconnection operations through cooperative hoarding

Mobile clients often need to operate while disconnected from the network due to limited battery life and network coverage. Hoarding supports this by fetching frequently accessed data into clients' local caches prior to disconnection. Existing work on hoarding have focused on improving data accessibility for individual mobile clients. However, due to storage limitations, mobile clients may not be able to hoard every data object they need. This leads to cache misses and disruption to clients' operations. In this paper, a new concept called cooperative hoarding is introduced to reduce the risks of cache misses for mobile clients. Cooperative hoarding takes advantage of group mobility behaviour, combined with peer cooperation in ad-hoc mode, to improve hoard performance. Two cooperative hoarding approaches are proposed that take into account access frequency, connection probability, and cache size of mobile clients so that hoarding can be performed cooperatively. Simulation results show that the proposed methods significantly improve cache hit ratio and provides better support for disconnected operations compared to existing schemes

Improving the Performance of Mobile Ad Hoc Network Using a Combined Credit Risk and Collaborative Watchdog Method

In mobile ad hoc networks nodes can move freely and link node failures occur frequently This leads to frequent network partitions which may significantly degrade the performance of data access in ad hoc networks When the network partition occurs mobile nodes in one network are not able to access data hosted by nodes in other networks In mobile ad hoc network some nodes may selfishly decide only to cooperate partially or not at all with other nodes These selfish nodes could then reduce the overall data accessibility in the network In this work the impact of selfish nodes in a mobile ad hoc network from the perspective of replica allocation is examined We term this selfish replica allocation A combined credit risk method collaborative watchdog is proposed to detect the selfish node and also apply the SCF tree based replica allocation method to handle the selfish replica allocation appropriately The proposed method improves the data accessibility reduces communication cost and average query delay and also to reduce the detection time and to improve the accuracy of watchdogs in the collaborative metho

Consistency Management Among Replicas in Peer-to-Peer Mobile Ad Hoc Networks

Recent advances in wireless communication along with peer-to-peer (P2P) paradigm have led to increasing interest in P2P mobile ad hoc networks. In this paper, we assume an environment where each mobile peer accesses data items held by other peers which are connected by a mobile ad hoc network. Since peers\u27 mobility causes frequent network partitions, replicas of a data item may be inconsistent due to write operations performed by mobile peers. In such an environment, the global consistency of data items is not desirable by many applications. Thus, new consistency maintenance based on local conditions such as location and time need to be investigated. This paper attempts to classify different consistency levels according to requirements from applications and provides protocols to realize them. We report simulation results to investigate the characteristics of these consistency protocols in a P2P wireless ad hoc network environment and their relationship with the quorum sizes

SAMPCAN: A NOVEL CACHING TECHNIQUE FOR CLIENT-SERVER INTERACTION MODEL IN LARGE AD HOC NETWORKS USING RESAMPLING METHODS

ABSTRAC

Web Service Composition Framework using Petrinet and Web Service Data Cache in MANET

A Mobile Ad Hoc Network (MANET) is characterized by multi-hop wireless links and frequent node mobility. Every neighboring node in the MANET is likely to have similar task and interests, several nodes might need to access the similar web service at different times. So, by caching the repeatedly accessed web service data within MANET, it is possible to reduce the cost of accessing the same service details from the UDDI and also from the external providers. Composition of web services leads to a better alternative as, at times a candidate web service may not completely serve the need of the customer. An effective Data Cache Mechanism (DCM) has been proposed in [6] using the Distributed Spanning Tree (DST) as a communication structure in Mobile network to improve scalability and lessen network overload. As an enhancement, Ant Colony Optimization (ACO) technique has been applied on DST to cope with the fragile nature of the MANET and to improve the network fault tolerance [1]. In these perspectives, an efficient Web Service Cache Mechanism (WSCM) can be modeled to improve the performance of the web service operations in MANET. In this paper, a fine grained theoretical model has been formulated to assess the various performance factors such as Cooperative Cache and Mobility Handoff. In addition to these, the performance improvement of WSCM using DST and ACO optimized DST techniques in MANET has been proved experimentally using Precision and Data Reliability of the system using appropriate simulation