CA based quick consensus in distributed system through network partitioning

Eventually Byzantine Agreement on CDS-based mobile ad hoc network

The Mobile Ad-hoc Networks (MANET) are suffering from network partitioning when there is group mobility and thus cannot efficiently provide connectivity to all nodes in the network. Autonomous Mobile Mesh Network (AMMNET) is a new class of MANET which will overcome the weakness of MANET, especially from network partitioning. However, AMMNET is vulnerable to routing attacks such as Blackhole attack in which malicious node can make itself as intragroup, intergroup or intergroup bridge router and disrupt the network. In AMMNET, To maintain connectivity, network survivability is an important aspect of reliable communication. Maintaning security is a challenge in the self organising nature of the topology. To address this weakness proposed approach measured the performance of the impact of security enhancement on AMMNET with the basis of bait detection scheme. Modified bait approach that will prevent blackhole node entering into the network and helps to maintain the reliability of the network. The proposed scheme uses the idea of Wumpus World concept from Artificial Intelligence. Modified bait scheme will prevent the blackhole attack and secures network.

An optimal solution for byzantine agreement under a hierarchical cluster-oriented mobile ad hoc network

The fault-tolerance is an important research topic in the study of distributed systems. To cope with the influence from faulty processors, reaching a common agreement in the presence of faults before performing certain special tasks is essential. Therefore, the Byzantine Agreement (BA) problem has drawn more researcher attention as they explore deeper into the world of distributed systems. Traditionally, the BA problem is solved in a wired network. However, the mobile computers have become increasingly popular. This environment encourages distributed system design and practices that support mobile processors. A mobile ad-hoc network (MANET) is different from a wired network. The processors have high mobility. Therefore, to enhance fault-tolerance and MANET reliability, the BA problem in virtual subnet of MANET is revised in this paper. The proposed protocol uses a minimum number of message exchange rounds and can tolerate the maximum number of allowable faulty components and make each fault-free processor reach a common agreement in the virtual subnet of MANET

In this paper, we investigate the impact that human mobility and social interactions have on data replication schemes in mobile ad hoc networks (MANETs), and how they can be used to improve content availability. Since nodes in MANETs are free to move around, network partitions can result in disconnections between nodes which store content and those accessing it. In this work we investigate some of the metrics that are typically used to evaluate storage schemes. We discuss several different data storage and replication methods designed for MANETs, and under which circumstance one may be a better choice than another. We also investigate human mobility models and how social interactions are leveraged by the storage schemes might be leveraged to improve content availability in MANETs.

The opportunistic networking idea stems from the critical review of the research field on Mobile Ad hoc Networks (MANET). After more than ten years of research in the MANET field, this promising technology still has not massively entered the mass market. One of the main reasons of this is nowadays seen in the lack of a practical approach to the design of infrastructure-less multi-hop ad hoc networks [186, 185]. One of the main approaches of conventional MANET research is to design protocols that mask the features of mobile networks via the routing (and transport) layer, so as to expose to higher layers an Internet-like network abstraction. Wireless networks’ peculiarities, such as mobility of users, disconnection of nodes, network partitions, links’ instability, are seen—as in the legacy Internet—as exceptions. This often results in the design of MANET network stacks that are significantly complex and unstable [107].

A mobile ad hoc network (MANET) is a distinctive example of a decentralized, self-organizing, and self-managing wireless ad hoc network. MANET is utilized in several domains such as rescue operations, real-time information dissemination, interpersonal communication, information exchange, and network partitioning. MANET exhibits dynamic alterations in both its structure and nodes to facilitate rapid data transmission. The mobility of nodes presents numerous opportunities for routing design difficulties among them. A list of routing protocols exists, each with unique characteristics, developed for certain locations,, and compared based on various metrics. This study provides a comprehensive overview and comparison of several MANET routing strategies, along with their limitations in ad hoc routing networks.

In Mobile Adhoc networks (MANET) the mobility of nodes results in regular and random changes of network topology, which results in regular route changes, network partitions and possibly packet losses, making routing a challenging task in MANET network. The mostly used routing protocols in such networks are proactive and reactive routing protocols, but a reactive routing strategy is the most popular technique for wireless adhoc routing that provides a scalable solution to relatively large network topologies. However Hybrid GRP (Geographical Routing Protocol) are introduced comprises of both reactive and proactive routing properties to give high QoS parameter performance. This paper evaluates the performance of AODV- and DSR reactive routing protocols with hybrid GRP protocol in MANET network using QoS parameters like End-to-End Delay, Network Load, Throughput, Number of Hops/Route, PDR and NRL.

QoS-aware routing in mobile ad hoc networks (MANETs) is a major challenge due to node mobility and scarcity of resources. QoS-aware routing based on ant colony optimization (ACO) algorithms is a promising approach to overcome these problems. However, as compared to MANETs, vehicular ad hoc networks (VANETs) face additional challenges due to rapid topology change, making the estimation or prediction of QoS parameters difficult or stale. VANETs require time-critical message delivery, as late delivery may result in endangering lives. Currently existing routing protocols usually require the exchange of additional control message between neighbor nodes to compute QoS parameters. This makes the routing protocol too slow to react to fast topology change and also does not consider network congestion when forwarding a data packet. To reduce the overhead introduced to collect information from neighbor nodes and to obtain an accurate estimate of QoS parameters, we use the simple network management protocol to estimate these values locally. This paper describes a new approach for calculating QoS parameter locally and avoiding congestion during data transmission. The simulations are implemented using the network simulator ns-3, and the results show that our approach is scalable and performs well in high mobility. QoS-aware routing in mobile ad hoc networks (MANETs) is a major challenge due to node mobility and scarcity of resources. QoS-aware routing based on ant colony optimization (ACO) algorithms is a promising approach to overcome these problems. However, as compared to MANETs, vehicular ad hoc networks (VANETs) face additional challenges due to rapid topology change, making the estimation or prediction of QoS parameters difficult or stale. VANETs require time-critical message delivery, as late delivery may result in endangering lives. Currently existing routing protocols usually require the exchange of additional control message between neighbor nodes to compute QoS parameters. This makes the routing protocol too slow to react to fast topology change and also does not consider network congestion when forwarding a data packet. To reduce the overhead introduced to collect information from neighbor nodes and to obtain an accurate estimate of QoS parameters, we use the simple network management protocol to estimate these values locally. This paper describes a new approach for calculating QoS parameter locally and avoiding congestion during data transmission. The simulations are implemented using the network simulator ns-3, and the results show that our approach is scalable and performs well in high mobility.

Mobile ad hoc networks (MANETs) are infrastructureless and distributed communication systems that require sophisticated approaches to routing to cope with node mobility and heterogeneous application requirements. In the past few years, distributed hash table (DHT) has come forth as a useful additional technique to the design and specification of spontaneous and self-organized networks. Researchers have exploited its advantages by implementing it at the network layer and developing scalable routing protocols for MANETs. The implementation of DHT-based routing in a MANET requires different algorithms and specifications compared to routing in the Internet because a MANET has its unique characteristics, such as node mobility, spontaneous networking, decentralized architecture, limited transmission range, dynamic topology, and frequent network partitioning/merging. In this article, we present a comprehensive survey of research related to DHT-based routing that aims at enhancing the scalability of MANETs. We present a vivid taxonomy of DHT-based routing protocols and the guidelines to design such protocols for MANETs. We compare the features, strengths, and weaknesses of existing DHT-based routing protocols and highlight key research challenges that are vital to address. The outcome of the analysis serves as a guide for anyone willing to delve into research on DHT-based routing in MANETs.

Mobile ad hoc networks (MANETs) enable communication between moving nodes through multi-hop wireless routes. There are protocols with special features that handle both auto-configuration and routing in these networks. Nevertheless, many of these auto-configuration protocols have not been truly implemented and in consequence, only exist a few available solutions for MANETs conformation. This article presents a new solution for this issue, mainly in cases where only personal devices are available. The core of the proposal is a new auto-configuration protocol, which allows dynamic allocation of unique IP addresses and accomplishes effective answers in front of issues like mergers and partitions of networks, and others. Finally, the results of simulations in OMNET++ and of tests of a pilot version based on Android mobile phones are shown.

Transaction processing leads to new challenges in mobile ad-hoc networks, which, in comparison to fixed-wired networks, suffer from problems like node disconnection, message loss, and frequently appearing network partitioning. As the atomic commit protocol is that part of transaction processing in which failures can lead to the most serious data blocking, we have developed a robust and failure-tolerant distributed cross-layer atomic commit protocol called CLCP that uses multiple coordinators. In order to reduce the number of both, failures and messages, our protocol makes use of acknowledgement messages for piggybacking information. We have evaluated our protocol in mobile ad-hoc networks by using several mobility models (i.e. Random Waypoint, Manhattan, and Attraction Point), and compared CLCP with other atomic commit protocols, i.e. 2PC and Paxos Commit, each implemented in 3 versions, i.e. without sending message acknowledgements, with a Relay Routing technique, and with Nearest Forward Progress Routing. Special to our simulation environment is the use of the quasi-unit-disc model, which assumes a non-binary message reception probability that captures real-world behavior much better than the classical unit-disc-model, often used in theory. Using the quasi-unit-disc model, our evaluation shows the following results. CLCP and "2PC without acknowledgement messages" have a significantly lower energy consumption than the other protocols, and CLCP is able to commit significantly more distributed transactions than all the other atomic commit protocols for each of the mobility models.

Address allocation in Mobile Ad Hoc Network (MANET) receives significant importance recently, as a mobile device cannot participate in unicast communications until it is assigned with a conflict free IP address. All routing protocols assume nodes to be configured a priori with a unique IP address. Unlike infrastructure based networks, MANET supports autonomous and spontaneous networking and therefore, should be capable of self organization and configuration. We present a new address allocation protocol in MANET based on the concept of quadratic residue. Each node in the network is capable of assigning a unique IP address with low latency. Addresses are reclaimed automatically, as the quadratic residues lie in cycles. This saves lot of extra communication overhead and bandwidth. Our approach also has support for network merging and partitioning. The proposed scheme can be applied to large scale MANETs with low communication overhead, even distribution, and low latency.

A MANET is an autonomous collection of mobile nodes that communicate all the other nodes within their radio ranges. Where the nodes that are not in the direct communication range use intermediate node to communicate with each other. In MANET each mobile node has mobility and move according to the specified locations in the network. Therefore the verification of node locations is an important issue in mobile adhoc networks, and it becomes particularly challenging in the presence of adversaries aiming at harming the system. In this research work proposed a protocol called Neighbor position verification (NPV), in order to verify the position of its communication neighbors and detect the adversaries in the mobile adhoc network, This protocol is used to exchanges the messages and verifies the position of communicating nodes in the network. The first scheme is deals with the identification of nodes with which a communication link can be established or that are within a given distance. This distance calculation is based on message exchange between the verifier and its communicated neighbors. After the distances are calculated verifier verifies the position of communicating nodes in networks by following three tests that to be done, they are: 1) Direct symmetry test 2) Cross symmetry test 3) The Multilateration Test. This protocol is implemented over the MANET network and simulated using Network Simulator (NS2). This research work carry out QOS based forwarding node selection scheme to reduce the delay and achieve the high throughput. Performance of the proposed system evaluated based on the parameters such as delay and throughput.

ABSTRACTThis article investigates the tracking control problem for a class of uncertain nonlinear systems with time‐varying asymmetric state constraints of arbitrary time period. State constraints of arbitrary time period refer to the system states that are constrained during arbitrary finite time and are free for the other time (i.e., unconstrained), it is more common. This article addresses this issue for the first time. A novel shifting function is defined which moves any states or tracking errors out of the constraint area to the desired positions. Then, a barrier Lyapunov function is designed for the tracking error after shifting transformation, which ensures the satisfaction of state constraints. Dynamic surface control is used to avoid the high‐order derivation of functions which solves the complexity problem caused by item explosion in backstepping design. Lastly, a simulation illustration is given to verify the effectiveness and outstanding features of the proposed method. It demonstrates that state constraints of arbitrary time period are satisfied, all signals in the closed‐loop system are ultimately bounded, and the tracking error converges to an adjustable neighborhood of origin.