Asynchronous message logging based rollback recovery in MANETs

Mobile Ad hoc networks (MANETs) have significantly enhanced the wireless networks as they eliminate the need for fixed infrastructure and are easily deployable. Apart from their application for communication purposes, these are increasingly being used for expanding the computing capabilities of existing cellular mobile systems and for the implementation of mobile computing grids. Therefore, a fault tolerance technique is crucial in order to effectively utilize the computing potential of the network. Rollback recovery has been widely used to achieve fault tolerance in distributed networks; yet its application is not trivial in a MANET due to limited availability of stable storage, node mobility and frequent network partitioning. The paper presents a rollback recovery protocol for MANETs which addresses these challenges by using opportunistic routing. Since all nodes may not have enough stable storage, the nodes with sufficient availability of stable storage are distinguished as Checkpoint Storage Nodes (CSNs). Opportunistic contacts between mobile nodes are used, firstly, for locating Checkpoint Storage Nodes in the network and subsequently, for retrieving the last saved checkpoint of a failed node from a CSN at the time of recovery. We calculate the recoverability, i.e., the probability that a process can recovery in a given time period.

Mobile Ad hoc Networks (MANET) comprises of self-organizing autonomous mobile nodes. MANETs are open and decentralized. Therefore they are vulnerable to malicious entities. MANETs are multi-hop wireless network where all nodes supportively maintain network connectivity without a centralized infrastructure. Since MANETs are infrastructure less and independent, the secure communication is the main issue. Therefore they are vulnerable to malicious entities. Here the location identity and traffic can be traced out by an outside observer. Anonymity means secure communications by hiding node identities and preventing traffic analysis attacks by outside observers. This paper proposes Position based Anonymous Routing Scheme in MANETs (PARS).Here the routing is based on Greedy Perimeter Stateless Routing Protocol. The objective is an anonymous routing protocol for the network. The proposed one is a zone based anonymous GPSR based protocol that can provide source, destination and route anonymity. Performance of the proposed system is compared with that of GPSR and AODV using Network Simulator. Index Terms: Anonymous routing, position-based routing, random forwarder, zone partition. I. Introduction Mobile Ad hoc Networks are collection of independent mobile nodes that can communicate by radio waves. It is an infrastructure less self-organizing network. The nodes that are in radio range can communicate by single hop or by multi hop with the help of intermediate nodes. The network is open and decentralized and fully distributed. So they are perfect choice for communication and information sharing. MANETs are susceptible to malicious entities that aim to alter and analyzed the traffic analysis by communication eaves dropping or attacking routing protocols. MANETs are characterized by their distributed operation, multi hop routing, dynamic topology and shared physical medium. Nodes in a MANET are independently free to move in any direction. Due to the lack of a centralized coordinator security is the major concern here. Wireless communication can endure interferences or malicious interceptions; whereas multi-hop communication assumes that each node will perform properly its functions to support network services. Further, self-organization increases the complexity of security management operations as access control, node authentication, secure routing and cryptographic key distribution. There is no fixed infrastructure and the topology is frequently changing due to node mobility or environmental changes. Therefore, it is very hard to maintain a stable and efficient end-to-end route in an ad-hoc network. Each node in MANET is energy constrained. There is verylimited physical security in MANET. The type of attacks can be Active attacks or Passive attacks. The common security issues are Passive attacks which include eaves dropping and information disclosure. Active attacks include Do Sand Data modification. There are other more specific problems with mobile ad hoc network such as vulnerability of channels and nodes, Byzantine black hole and Byzantine wormhole attack. The security issue also includes attacks that may inject erroneous routing information and diverting network traffic thus making routing inefficient. There are many methods to reduce the impact of these attacks, which include a secure routing using public and private key s to get a certification authority and use of digital signatures and prior it rust relationships. Routing is the process of communication from one node to the other host in a network. Routing is the process off or warding packet towards its destination using most efficient path. Routing efficiency is measured in terms of Number of hops, traffic, security, etc. Routing protocols in MANETs are divided as reactive proactive and hybrid. Reactive Protocol maintains the routes in on demand manner. In route discovery phase it floods the route request (RREQ) packets throughout the network. Dynamic source Routing (DSR), ad hoc on- demand distance vector routing (AODV) are some of the examples of reactive protocols. In proactive approach every node in the MANET continuously maintains the complete routing information of the entire network. This is accomplished by flooding network periodically with network status information. Global State Routing (GSR), Hierarchical State Routing (HSR) and Destination Sequenced Distance Vector Routing (DSDV) are some of the examples of proactive

Networks are being used in various areas and the demand of users nowadays has motivated the emergence of the Mobile Ad Hoc Network (MANET). MANET is a dynamic network without fixed infrastructure due to their wireless nature and can be deployed as multi-hop packet networks. It is a wireless network and has dynamic topology due to its node mobility. There are two types of MANET, homogeneous and heterogeneous MANET. An architecture has been designed in previous work to model these two types of MANET. Three scenarios have been defined from this architecture: scenario I (communication entirely within MANET, homogeneous MANET), scenario II (communication between MANET and wireless LAN, heterogeneous MANET) and scenario III (communication between MANET with wireless LAN and wired LAN, heterogeneous MANET). MANET has its own routing protocols which can compromised with frequent route exchange, dynamic topology, bandwidth constraint and multi-hop routing. Ad hoc On Demand Distance Vector (AODV) is one of the routing protocols in MANET. The aim of this research is to assess the effects of different packet size with the implementation of AODV routing protocols in homogeneous and heterogeneous MANET through the simulation method. The three scenarios above have been developed in the OMNeT++ network simulator. The results achieved from the test have been evaluated using the metrics assigned, throughput and packet delivery ratio (PDR). The tests show that the increase of throughput and PDR performance was parallel with the increase of packet size. From the test also, we can conclude that the performance due to the packet size effect in homogeneous MANET is better than in heterogeneous MANET.

The primary challenges in mobile ad hoc network (MANET) are presence of obstacles, mobility, energy efficiency and network in dynamic topology environment. Efficient routing with obstacles avoidance in dynamic topology is a critical issue in MANET. Many mobility patterns have been recommended for the movement of nodes in presence of obstacles in MANET terrain. Some obstacles avoiding routing techniques are also proposed by some popular researchers. In this paper, many related articles have been reviewed and briefly discussed. The paper outlines advantages and drawbacks of each approach to get possible research scope in route planning in dynamic MANET topology in presence of obstacles.

Mobile Ad hoc Networks (MANETs) are new wireless networks with a self-configuring and self-maintaining topology, also characterized as dynamic topology. The architecture in MANETs has been introduced few years ago and its main characteristic is that it does not rely on any fixed infrastructure. These features bring in security vulnerabilities and also make it difficult to ensure security services to MANETs. To counteract this problem major research has been done. This article will talk about the approaches that intend to develop security schemes to MANETs and to create a defense against various attacks at different layers. Routing is a very important function in MANETs. It can also be easily misused, leading to several types of attack. This article proposes a scheme to improve and support mutual authentication and encrypt communication between the nodes in the MANET. The authentication scheme proposed is seeking to solve the security and privacy issues between any two communicating nodes in the MANET.

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.

Wormhole attack is a severe attack in mobile ad hoc networks, which is particularly challenging to defend against. In this paper, a new method defined as time ruler using distance measurement for detecting wormhole attack is proposed including its hypothetical model, the concept of time ruler and the process of its establishment, storage and calibration. The feasibility of the method on theory, thus respectively deriving two discriminating inequalities with the use of sending time ruler and receiving time ruler are analyzed in detail. The performances of the method are also analyzed and its validity is evaluated with Omnet++ developing tools. Mobile Ad Hoc networks (MANETs) are self-organized, multi-hop wireless networks which are independent of fixed infrastructure, with the advantages of easy networking and not being limited with time and space. Unlike the conventional network, MANETs are characterized by numerous constraints such as lack of infrastructure, lack of resources on nodes, dynamic topology, no centralized management and control, and lack of pre-established trust relationships between nodes. Due to these, MANETs are very likely to often be run in untrusted environments and make themselves vulnerable to various security attacks, such as eavesdropping, tamper, replay, and denial-of-service. Wormhole attack is also called Tunnel attack. In MANETs, a malicious node records a packet, at one location in the network, tunnels the packet to another location, and replays it there. If the tunneled distance is longer than the normal wireless transmission range of a single hop, it takes less time or less hops to make the tunneled packet arrive sooner than other packets transmitted over a normal multi- hop route. In this case, it creates the illusion that two remote regions of a MANET are directly connected through nodes that appear to be neighbors. Since it costs less hops to travel through tunnel than by a normal route, for shortest path routing protocol, the malicious node increases its attraction to network flow, and thereby providing advantageous conditions for itself to launch further attack such as tamper or packet-loss.

In Mobile Ad-hoc Networks (MANETs), each node is free to move and connect with one another over a wireless connection, without the requirement for a centralized controller or base station. These features make MANET useful and functional in a variety of areas, including tactical situations, sensor networks, rescue operations, and students on campus. However, this type of network also has a range of issues such as security, Quality of Service, dynamic topology, scalability, the absence of central management, and energy consumption. Since MANET nodes have little battery life, the power usage is among the most important design considerations in wireless ad-hoc networks. Each node is responsible for forwarding the packets to its neighboring nodes. Since the MANET does not contain a hierarchy, some nodes may not participate in forwarding the packets and prefer to keep their remaining energy for themselves; these nodes are called selfish nodes. The presence of selfish nodes in the MANET greatly affects the efficiency and activity of the network. The process of detecting and isolating the selfish node does not constitute an easy task. It still requires further investigation and study. Therefore, this survey is intended to determine, study and analyze some new detection mechanisms used in detecting selfish nodes in MANETs. It also classifies them into three categories which are credit-based, reputation-based, and acknowledgment-based techniques. In addition, it highlights some critical issues in MANET according to selfish behavior, and points out the necessary requirements for better improvement as well as fields for future research.

An ad hoc network is composed of mobile nodes without the intervention of any fixed infrastructure or central administration. Multicasting is intended for group-oriented communication. A lot many applications depend on one-to-many or many-to-many dissemination of the information. However, in ad hoc environment, multicasting protocols are faced with the challenge of producing multihop routes under dynamic topology and bandwidth constraints. Due to the dynamic topology of MANETs it is very difficult to build optimal multicast trees and maintaining group membership, making even more challenging to implement scalable and robust multicast in Mobile Ad hoc Networks (MANET). A Scalable and Robust Location Aware Multicast Algorithm, called SRLAMA, for mobile ad hoc networks is presented in the paper that is based on creation of shared tree using the physical location of the nodes for the multicast sessions. It constructs a shared bi-directional multicast tree with an alternate root that avoids the network partitioning in case of primary root failurte, which results in better performance even than a shared tree. The algorithm uses the concept of small overlapped zones around each node for employing proactive routing with in the smaller zone. Protocol is based on the location information obtained employing relevant data structure, which effectively reduces the overheads for route searching and shared multicast tree maintenance. It employs a preventive route reconfiguration to avoid the latency in case of link breakages and to prevent the network from splitting.

With the increasing demand of ubiquitous computing, the interconnection of mobile ad hoc networks (MANETs) to Internet is also getting attractive, which is so-called hybrid or connected MANET. In MANET paradigm, routing is a challenging task due to mobility and the resulting inherent dynamic network topology. In many applications, multipath routing scheme is favorable than single-path routing due to many advantages. Security issues in hybrid MANET, however, is still challenging task. There are two critical issues for providing a secure multihop route discovery: Internet connectivity and ad hoc routing. In this paper, we present architecture framework for secure hybrid multipath MANET that can provide global connectivity. We provide security analysis by using BAN logic.

Heterogeneous networks provide an appealing way of expanding the computing capability of mobile networks by combining infrastructure-less mobile ad-hoc networks with the infrastructure-based cellular mobile networks. The nodes in such a network range from low-power nodes to macro base stations and thus, vary greatly in their capabilities such as computation power and battery power. The nodes are susceptible to different types of transient and permanent failures and therefore, the algorithms designed for such networks need to be fault-tolerant. The article presents a checkpointing algorithm for the rollback recovery of mobile hosts in a heterogeneous mobile network. Checkpointing is a well established approach to provide fault tolerance in static and cellular mobile distributed systems. However, the use of checkpointing for fault tolerance in a heterogeneous environment remains to be explored. The proposed protocol is based on the results of zigzag paths and zigzag cycles by Netzer–Xu. Considering the heterogeneity prevalent in the network, an uncoordinated checkpointing technique is employed. Yet, useless checkpoints are avoided without causing a high message overhead.

The Mobile Ad-hoc Network (MANET) is an emerging infrastructure-free network constructed by self-organized mobile devices. In order to manage MANET, with its dynamic topology, several network management protocols have been proposed, and Network Configuration Protocol (NETCONF) is representative one. Nonetheless, the performance of these network management protocols on MANET remains unresolved. In this paper, we leverage the Common Open Research Emulator (CORE), a network emulation tool, to conduct the quantitative performance evaluation of NETCONF in an emulated MANET environment. We design a framework that captures the key characteristics of MANET (i.e., distance, mobility, and disruption), and develop subsequent emulation scenarios to perform the evaluation. Our experimental data illustrates how NETCONF performance is affected by each individual characteristic, and the results can serve as a guideline for deploying NETCONF in MANET.

Security in mobile ad hoc networks (MANETs) has been an actively researched topic for the several years. As opposed to wired networks, MANETs have dynamic topology, limited resources, limited bandwidth and are usually deployed in emergency scenarios outside, where landscape plays important role. MANETs are susceptible to insider and outsider attacks and bring new security challenges which were not present in the wired networks. The most important difference is that every node in MANET acts as a router and routes traffic throughout the network. Compromising one node can hugely affect network performance. In this paper, we present our security architecture for MANETs which secures important aspects of the network. We bring trust model into the network and nodes are secured by different mechanisms tailored specifically for the use in distributed environment. We use Omnet++for network simulations. Simulations use delays measured on the real hardware and we analyze performance of the network during different data plane and control plane loads

Mobile ad hoc network (MANET) is an autonomous system of mobile nodes, which are connected each other through wireless links. A mobile ad hoc network (MANET) is a type of self configuring network and have dynamic topology. Since each node in MANET is free to move independently, they can change their links to other nodes frequently. Secure communication among nodes in mobile ad hoc networks is a major concern. Many key management (KM) schemes and protocols have been evolved in past years, but developing fundamentally secure key management scheme for dynamic MANET's is still an open research problem. In this paper, first we reviewed some significant existing KM schemes and compared based on various criterias and design parameters. Next, we have proposed a scheme for pairwise key agreement with updation of key pre-distribution shares while new nodes are getting added to the MANET. Further, we have given our simulation results and performed a comparative analysis based on different simulation's parameters. Future research issues are also discussed at the end of the paper.

At present, communication technology provides support for different varieties of mobile networks, and among them, mobile ad hoc network (MANET) is of prime importance and challenging. Topological change with time is the inherent characteristics in MANET. This occurs either to save the energy or mobility observed with nodes. Therefore, routing problem under MANET is also dynamic and can be formulated as a dynamic optimization problem. It is essential that the solution should have a high level of adaptability to define dynamic routing. In this paper, high level of adaptiveness has achieved by designing the different strategies under genetic algorithm like redefinition of solution population, small random perturbation, and sharing the gained knowledge to current solution. The proposed solution has achieved optimal routing in a very efficient way under dynamic topology.