A Survey on Investigating the Need for Intelligent Power-Aware Load Balanced Routing Protocols for Handling Critical Links in MANETs
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paper_title: Review: A survey on coverage and connectivity issues in wireless sensor networks

paper_content:

A wireless sensor network (WSN) is composed of a group of small power-constrained nodes with functions of sensing and communication, which can be scattered over a vast region for the purpose of detecting or monitoring some special events. The first challenge encountered in WSNs is how to cover a monitoring region perfectly. Coverage and connectivity are two of the most fundamental issues in WSNs, which have a great impact on the performance of WSNs. Optimized deployment strategy, sleep scheduling mechanism, and coverage radius cannot only reduce cost, but also extend the network lifetime. In this paper, we classify the coverage problem from different angles, describe the evaluation metrics of coverage control algorithms, analyze the relationship between coverage and connectivity, compare typical simulation tools, and discuss research challenges and existing problems in this area.
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paper_title: Identification of Critical Node for the Efficient Performance in Manet

paper_content:

This paper considers a network where nodes are connected randomly and can fail at random times. The critical- node test detects nodes, whose failures are malicious behavior, disconnects or significantly degrades the performance of the network. The critical node is an element, position or control entity whose disruption, is immediately degrades the ability of a force to command, control or effectively conducts combat operations. If a node is critical node, then more attention must be paid to it to avoid its failure or removal of a network. So how to confirm critical nodes in the ad hoc network is the premise to predict the network partition. A critical node is the most important node within the entity of a network. This paper suggests methods that find the critical nodes of a network based on residual battery power, reliability, bandwidth, availability and service traffic type. The metrics for evaluation has been considered as packet delivery ratio, end-to-end delay and throughput. Nodes in Mobile Ad hoc Networks (MANETs) are battery powered and hence have limited lifetime. Due to excessive utilization a node may die which can result in energy depletion problem and thereby affect overall network performance. Local rate of energy consumption based on application can be monitored. Thus early detection and avoidance of energy depletion problem is possible based on monitoring of power and remaining battery lifetime. As and when the rate of consumption based on the application returns to efficient levels, the mobile relay is released so that it can be made available for other critical nodes. This technique can be applied to any protocol used in MANETs such as DSDV, DSR, AODV, TORA etc. In this work, we focus on maximizing avoidance of network partition, rather than after the network partition, then taking some remedial measures. We describe the critical nodes compensation approach to increase the network connectivity and improve packet delivery rate. First, we detect the critical nodes which may lead to the network partitioning. Secondly, propose the compensation algorithm to avoid the network partitioning. This approach described in this paper is built around the notion of a critical node in an ad hoc network. Our definition of a critical node is a node, whose failure or malicious behavior disconnects or significantly degrades the performance of the network. Once identified, a critical node can be monitored in terms of resource. If a node is not considered critical, this metric can be used to decide if the application or the risk environment warrant the expenditure of the additional resources required to monitor, diagnose, and alert other nodes about the problem. Determining the global network topology in a MANET gives the time delays of the diagnostic packets and the mobility of the nodes makes this task futile, but determining an approximation of this topology or subset of this topology, within a certain time frame may be useful. An approximation of the network topology can still provide useful information about network the density, network mobility, critical paths, and critical nodes. Even with the uncertainty associated with correctly reconstructing the network topology for a given time period, this additional information can help to reduce the resources consumed to monitor all nodes in the absence of this information.
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paper_title: QoS-aware MAC protocols for wireless sensor networks: A survey

paper_content:

The adoption of wireless sensor networks by applications that require complex operations, ranging from health care to industrial monitoring, has brought forward a new challenge of fulfilling the quality of service (QoS) requirements of these applications. However, providing QoS support is a challenging issue due to highly resource constrained nature of sensor nodes, unreliable wireless links and harsh operation environments. In this paper, we focus on the QoS support at the MAC layer which forms the basis of communication stack and has the ability to tune key QoS-specific parameters, such as duty cycle of the sensor devices. We explore QoS challenges and perspectives for wireless sensor networks, survey the QoS mechanisms and classify the state of the art QoS-aware MAC protocols together with discussing their advantages and disadvantages. According to this survey, we observe that instead of providing deterministic QoS guarantees, majority of the protocols follow a service differentiation approach by classifying the data packets according to their type (or classes) and packets from different classes are treated according to their requirements by tuning the associated network parameters at the MAC layer. Design tradeoffs and open research issues are also investigated to point out the further possible research directions in the field of QoS provisioning in wireless sensor networks at the MAC layer.
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paper_title: Design, Modeling, and Capacity Planning for Micro-solar Power Sensor Networks

paper_content:

This paper describes a systematic approach to building micro-solar power subsystems for wireless sensor network nodes. Our approach composes models of the basic pieces - solar panels, regulators, energy storage elements, and application loads - to appropriately select and size the components. We demonstrate our approach in the context of a microclimate monitoring project through the design of the node, micro-solar subsystem, and network, which is deployed in a challenging, deep forest setting. We evaluate our deployment by analyzing the effects of the range of solar profiles experienced across the network.
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paper_title: A distributed transmission power control protocol for mobile ad hoc networks

paper_content:

In this paper, we propose a comprehensive solution for power control in mobile ad hoc networks (MANETs). Our solution emphasizes the interplay between the MAC and network layers, whereby the MAC layer indirectly influences the selection of the next-hop by properly adjusting the power of route request packets. This is done while maintaining network connectivity. Channel-gain information obtained mainly from overheard RTS and CTS packets is used to dynamically construct the network topology. Unlike the IEEE 802.11 approach and previously proposed schemes, ours does not use the RTS/CTS packets to silence the neighboring nodes. Instead, collision avoidance information is inserted in the CTS packets and sent over an out-of-band control channel. This information is used to dynamically bound the transmission power of potentially interfering nodes in the vicinity of a receiver. By properly estimating the required transmission power for data packets, our protocol allows for interference-limited simultaneous transmissions to take place in the neighborhood of a receiving node. Simulation results indicate that, compared to the IEEE 802.11 approach, the proposed protocol achieves a significant increase in the channel utilization and end-to-end network throughput and a significant decrease in the total energy consumption.
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paper_title: An energy-efficient QoS-aware media access control protocol for wireless sensor networks

paper_content:

We present an innovative MAC protocol (Q-MAC) that minimizes the energy consumption in multi-hop wireless sensor networks (WSNs) and provides quality of service (QoS) by differentiating network services based on priority levels. The priority levels reflect application priority and the state of system resources, namely residual energy and queue occupancies. The Q-MAC utilizes both intra-node and inter-node arbitration. The intra-node packet scheduling is a multiple queuing architecture with packet classification and weighted arbitration. We also introduce the power conservation MACAW (PC-MACAW) - a power-aware scheduling mechanism that, together with the loosely prioritized random access (LPRA) algorithm, govern the inter-node scheduling. Performance evaluation are conducted between Q-MAC and S-MAC with respect to two performance metrics: energy consumption and average latency. Simulation results indicate that the performance of the Q-MAC is comparable to that of the S-MAC in non-prioritized traffic scenarios; when packets with different priorities are present, Q-MAC supiors in average latency differentiation between the classes of service, while maintaining the same energy level as that of S-MAC
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paper_title: QoS-aware MAC protocols for wireless sensor networks: A survey

paper_content:

The adoption of wireless sensor networks by applications that require complex operations, ranging from health care to industrial monitoring, has brought forward a new challenge of fulfilling the quality of service (QoS) requirements of these applications. However, providing QoS support is a challenging issue due to highly resource constrained nature of sensor nodes, unreliable wireless links and harsh operation environments. In this paper, we focus on the QoS support at the MAC layer which forms the basis of communication stack and has the ability to tune key QoS-specific parameters, such as duty cycle of the sensor devices. We explore QoS challenges and perspectives for wireless sensor networks, survey the QoS mechanisms and classify the state of the art QoS-aware MAC protocols together with discussing their advantages and disadvantages. According to this survey, we observe that instead of providing deterministic QoS guarantees, majority of the protocols follow a service differentiation approach by classifying the data packets according to their type (or classes) and packets from different classes are treated according to their requirements by tuning the associated network parameters at the MAC layer. Design tradeoffs and open research issues are also investigated to point out the further possible research directions in the field of QoS provisioning in wireless sensor networks at the MAC layer.
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paper_title: PR-MAC A Priority Reservation MAC Protocol For Wireless Sensor Networks

paper_content:

Wireless sensor networks are very application specific and have to be developed according to the requirements of a particular problem. They are usually deployed in harsh and mobile environments, with tasks ranging from just collecting environment readings to highly crucial tasks like tracking an enemy vehicle. This means the sensor networks can monitor or sense a very wide range of parameters and tasks. However, all these measurements and events that are read by the sensors are never of equal importance. So we propose PR-MAC, which provides a scheme in which we prioritize the events that are being recognized. Our aim is to design a MAC layer protocol which would reduce the delay of transmitting high priority tasks or measurements.
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paper_title: An implicit prioritized access protocol for wireless sensor networks

paper_content:

Recent advances in wireless technology have brought us closer to the vision of pervasive computing where sensors/actuators can be connected through a wireless network. Due to cost constraints and the dynamic nature of sensor networks, it is undesirable to assume the existence of base stations connected by a wired backbone. In this paper, we present a network architecture suitable for sensor networks along with a medium access control protocol based on earliest deadline first.
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paper_title: Service Differentiation in Sensor Networks

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Abstract Recent technological advances have made it possible to havelarge wireless ad-hoc networks of small devices. The primepurpose of such sensor networks is to disseminate informationabout the environmentthey sense. We observethat informationprovidedmayhavedifferent levelsof importanceandarguethatthe sensor networks should be willing to spend more resourcesin disseminating packets carrying more important information.In this paper, weintroducethe conceptof servicedifferenti-ationasapplicabletosensornetworks,highlightitsfundamentaldifferences with normal data networks and deﬁne the relevantmetrics. Variousmechanismswhichmay provideservicescom-patible with the packet priority levels are proposed. We evalu-ate one of the proposedmethod , Adaptive Forwarding Scheme(AFS) and show that our scheme provides the desired levels ofservice. Keywords SensorNetworks,ServiceDifferentiation, AdaptiveForwardingScheme 1. Introduction Technologicaladvanceshavemade it feasible to havesmall de-vices with computation, communication and sensing capabili-ties [1, 2, 3]. These devices run on batteries and thus their ca-pabilities are limited by the available energy. A sensornetworkconsistingofalargenumberofsuchnodescanbeusefulinkeep-ing track of various activities in a givenregion. However, oper-ations performed in such a sensor network have to be energy-efﬁcient becauseof the energy constraints of its nodes.In a sensor network, sensors would sensesome data, pack-etize it and send the packet to a monitor node along a path con-sisting of multiple wireless hops. Researchers have come upwith schemes to provide the functionality required to performthese operations efﬁciently. For routing the data to the moni-tor node, schemeslike Directed Diffusion [4] and Power-awarerouting [5] have been proposed. Clustering schemes [6, 7, 8]group the nodesinto clusters for network management[7]. Lo-cation dissemination schemes [9, 10] provide the sensors withinformation about their locations. Simple and efﬁcient operat-ing system like tinyOS [3] have been designed for these smallnodes. All these works focus on cutting down on the energyrequirements of a sensor network, while providing the minimalfunctionality for the network to operate.We observe that in sensor networks different data packetsmight have different importance.For example, if a temperaturesensorinaforest,senses60Fonanormalspringday,thevalueis
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paper_title: A hybrid MAC with prioritization for wireless sensor networks

paper_content:

This paper introduces I-MAC, a new medium access control protocol for wireless sensor networks. I-MAC targets at improving both channel utilisation and energy efficiency while taking into account traffic load for each sensor node according to its role in the network. I-MAC reaches its objectives through prioritized and adaptive access to the channel. I-MAC performances obtained through simulations for different network topologies, scenarios and traffic loads show significant improvements in energy efficiency, channel utilization, loss ratio and delay compared to existing protocols.
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paper_title: A Prioritized MAC Protocol for Multihop, Event-driven Wireless Sensor Networks

paper_content:

This paper presents a new prioritized medium access control protocol (PSIFT) that improves the performance of event-driven wireless sensor networks by suppressing the redundant reports of sensor nodes in proximity. This suppression of similar reports results in low collision probability, shorter delay and accurate detection of events by the sink. PSIFT is a CSMA-based MAC protocol that provides traffic differentiation by varying the inter frame space and contention window size for each traffic class. We also introduce the new report suppression mechanism based on the broadcast nature of wireless transmission in PSIFT. This mechanism works very efficiently in large-scale, event-driven wireless sensor networks. Simulation results show that the new PSIFT MAC protocol can bring significant improvement in delay performance of the networks. When the sensing range grows up to transmission range, PSIFT can reduce the latency as much as three times in delivering reports as compared to the existing IEEE802.11 MAC protocol.
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paper_title: A medium access control protocol for UWB sensor networks with QoS support

paper_content:

Ultra-wideband (UWB) is a physical (PHY) layer technology that promises high transmission rates, as well as high resistance to noise and multipath effects. However, the impulse-based nature of UWB, coupled with its low transmission power, makes it difficult to enable efficient detection of the signals. Consequently, conventional carrier-sensing based MAC protocols cannot be used with a UWB PHY. In this paper, we propose SASW-CR - a slotted Aloha MAC protocol for UWB networks with sliding contention window and cooperative retransmissions, which provides QoS support without the use of carrier sensing. SASW-CR utilizes the slotted-Aloha technique to avoid carrier sensing and reduce packet collisions. In addition, it makes use of differentiated contention windows to provide varying classes of QoS for different traffic classes. A cooperative retransmission technique is also introduced to improve the overall traffic throughput and reduce end-to-end delay. The efficacy of our protocol is demonstrated through simulations.
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paper_title: Dynamic duty cycle and adaptive contention window based QoS-MAC protocol for wireless multimedia sensor networks

paper_content:

Rapid penetration of small, customized wireless devices and enormous growth of wireless communication technologies has already set the stage for large-scale deployment of wireless sensor networks. While the need to minimize the energy consumption has driven significant researches in wireless sensor networks, offering some precise quality of service (QoS) for multimedia transmission over sensor networks has not received significant attention. However, the emerging new applications like video surveillance, telemedicine and traffic monitoring needs transmission of wireless multimedia over sensor networks. Naturally, offering some better QoS for wireless multimedia over sensor networks raises significant challenges. The network needs to cope up with battery-constraints, while providing improved QoS (end-to-end delay and bandwidth requirement). This calls for a suitable sensory MAC protocol capable of achieving application-specific QoS. In this paper, we have proposed a new QoS-based sensory MAC protocol, which not only adapts to application-oriented QoS, but also attempts to conserve energy without violating QoS-constraints. Performance modeling, analysis and simulation results demonstrate that the proposed protocol is capable of providing lower delay and better throughput, at the cost of reasonable energy consumption, in comparison to other existing sensory MAC protocols.
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paper_title: Traffic Engineering Dynamic Routing Based on Bandwidth and Hops

paper_content:

With development of network scale and hardware,router solution project based on Traffic Engineering has been more and more poprlar.And in the Traffic Engineering solution project,Traffic Engineering dynamic routing is an important part.So,we have analysed the current situation,and presented TE dynamic routing math model,which takes bandwidth and hops into account and presents routing rules.In the end,by the computer simulation,we validate the feasibility of the routing and advantage of the current shortest path priority routing.
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paper_title: Localized algorithms for detection of critical nodes and links for connectivity in ad hoc networks

paper_content:

Ad hoc network normally has critical connectivity properties before partitioning. The timely recognition is important in order to perform some data or service replication. Several existing centralized or globalized algorithms declare an edge or a node as critical if their removal will separate the network into several components. We introduce several localized definitions of critical nodes and critical links, using topological or positional information. A node is critical if the subgraph of k-hop neighbours of node (without the node itself) is disconnected. We propose three definitions of critical links, based on verifying common k-hop neighbours, loop length, and critical status of link endpoints, respectively. The experiments with random unit graph model of ad hoc networks show high correspondence of local and global decisions. For instance, in experiments with 500 nodes in connected random unit graphs, over half of locally estimated critical nodes and links were indeed globally critical even for k=1 (the accuracy increases to over 70% for k=2 and over 80% for k=3), for average number of neighbours ranging from 3 to 15. The errors mostly occur when alternative routes exist but are relatively long, and therefore may not provide satisfactory service in applications. Therefore our localized protocols provide faster and often more reliable partition warnings for possible timely replication decisions.
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paper_title: A heuristic adaptive genetic algorithm for load balancing in MPLS networks

paper_content:

A heuristic adaptive genetic algorithm for load balancing in MPLS networks is proposed in this article. It introduces the natural number coding method, adaptive probabilities of crossover and mutation, and furthermore, makes use of heuristic information to improve search efficiency effectively. The simulation results show the given algorithm is effective, in which it dramatically improves the unbalanced traffic distribution condition brought about by traditional SPF routing policy.
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paper_title: Detecting critical nodes in sparse graphs

paper_content:

Identifying critical nodes in a graph is important to understand the structural characteristics and the connectivity properties of the network. In this paper, we focus on detecting critical nodes, or nodes whose deletion results in the minimum pair-wise connectivity among the remaining nodes. This problem, known as the critical node problem has applications in several fields including biomedicine, telecommunications, and military strategic planning. We show that the recognition version of the problem is NP-complete and derive a mathematical formulation based on integer linear programming. In addition, we propose a heuristic for the problem which exploits the combinatorial structure of the graph. The heuristic is then enhanced by the application of a local improvement method. A computational study is presented in which we apply the integer programming formulation and the heuristic to real and randomly generated data sets. For all instances tested, the heuristic is able to efficiently provide optimal solutions in a fraction of the time required by a commercial software package.
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paper_title: Internet Routing Optimization Control Algorithm with Multiple Objectives

paper_content:

Internet routing control by link weights optimization with traffic engineering objectives is studied.It is modeled as a mathematical programming problem with the objectives of network congestion minimization and delay minimization.It is a NP hard problem,and a chaotic group search algorithm based on local search is proposed,which makes use of chaos variable to find initial solutions with favorable distribution,and applies extended greedy principle to local search process to increase global search ability.Simulation results manifest that it improves network performance with decreased congestion probability caused by unbalanced traffic distribution,and restricted extra path hops.
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paper_title: Enhanced fault tolerant routing algorithms using a concept of balanced ring

paper_content:

Fault rings can be used to guide messages bypass faulty nodes/links in a fault tolerant interconnection network. However, nodes on the fault ring become hot spots, thus causing uneven distribution of the traffic loads. To avoid such traffic congestion, a concept of the balanced ring is proposed in this paper. The proposed balanced ring, defined as concentric rings of a given fault ring, can be applied to the fault tolerant routing algorithms for mesh and torus topologies. By properly guiding messages to route on the balanced ring and the fault ring, more balanced link utilization and greatly reduced traffic congestion can be achieved on a fault tolerant network. Methods of applying the balanced ring concept to some published fault tolerant routing algorithms are discussed. Proof of deadlock and livelock freedom is also presented. The use of balanced ring does not need to add new virtual channels. The performance of two routing algorithms with and without the balanced ring is simulated and evaluated. The results indicate that routing algorithms with the balanced rings constantly yield larger throughput and smaller latency than those without.
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paper_title: Ad-hoc on-demand distance vector routing

paper_content:

An ad-hoc network is the cooperative engagement of a collection of mobile nodes without the required intervention of any centralized access point or existing infrastructure. We present Ad-hoc On Demand Distance Vector Routing (AODV), a novel algorithm for the operation of such ad-hoc networks. Each mobile host operates as a specialized router, and routes are obtained as needed (i.e., on-demand) with little or no reliance on periodic advertisements. Our new routing algorithm is quite suitable for a dynamic self starting network, as required by users wishing to utilize ad-hoc networks. AODV provides loop-free routes even while repairing broken links. Because the protocol does not require global periodic routing advertisements, the demand on the overall bandwidth available to the mobile nodes is substantially less than in those protocols that do necessitate such advertisements. Nevertheless we can still maintain most of the advantages of basic distance vector routing mechanisms. We show that our algorithm scales to large populations of mobile nodes wishing to form ad-hoc networks. We also include an evaluation methodology and simulation results to verify the operation of our algorithm.
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paper_title: Optimized link state routing protocol for ad hoc networks

paper_content:

In this paper we propose and discuss an optimized link state routing protocol, named OLSR, for mobile wireless networks. The protocol is based on the link state algorithm and it is proactive (or table-driven) in nature. It employs periodic exchange of messages to maintain topology information of the network at each node. OLSR is an optimization over a pure link state protocol as it compacts the size of information sent in the messages, and furthermore, reduces the number of retransmissions to flood these messages in an entire network. For this purpose, the protocol uses the multipoint relaying technique to efficiently and economically flood its control messages. It provides optimal routes in terms of number of hops, which are immediately available when needed. The proposed protocol is best suitable for large and dense ad hoc networks.
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paper_title: Comparative analysis of link quality metrics and routing protocols for optimal route construction in wireless mesh networks

paper_content:

We provide a comparative analysis of various routing strategies that affect the end-to-end performance in wireless mesh networks. We first improve well-known link quality metrics and routing algorithms to enhance performance in wireless mesh environments. We then investigate the route optimality, i.e., whether the best end-to-end route with respect to a given link quality metric is established, and its impact on the network performance. Network topologies, number of concurrent flows, and interference types are varied in our evaluation and we find that a non-optimal route is often established because of the routing protocol's misbehavior, inaccurate link metric design, interflow interference, and their interplay. Through extensive simulation analysis, we present insights on how to design wireless link metrics and routing algorithms to enhance the network capacity and provide reliable connectivity.
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paper_title: ExOR: opportunistic multi-hop routing for wireless networks

paper_content:

This paper describes ExOR,an integrated routing and MAC protocol that increases the throughput of large unicast transfers in multi-hop wireless networks. ExOR chooses each hop of a packet's route after the transmission for that hop, so that the choice can reflect which intermediate nodes actually received the transmission. This deferred choice gives each transmission multiple opportunities to make progress. As a result ExOR can use long radio links with high loss rates, which would be avoided by traditional routing. ExOR increases a connection's throughput while using no more network capacity than traditional routine.ExOR's design faces the following challenges. The nodes that receive each packet must agree on their identities and choose one forwarder.The agreement protocol must have low overhead, but must also be robust enough that it rarely forwards a packet zero times or more than once. Finally, ExOR must choose the forwarder with the lowest remaining cost to the ultimate destination.Measurements of an implementation on a 38-node 802.11b test-bed show that ExOR increases throughput for most node pairs when compared with traditional routing. For pairs between which traditional routing uses one or two hops, ExOR's robust acknowledgments prevent unnecessary retransmissions,increasing throughput by nearly 35%. For more distant pairs, ExOR takes advantage of the choice of forwarders to provide throughput gains of a factor of two to four.
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paper_title: A high-throughput path metric for multi-hop wireless routing

paper_content:

This paper presents the expected transmission count metric (ETX), which finds high-throughput paths on multi-hop wireless networks. ETX minimizes the expected total number of packet transmissions (including retransmissions) required to successfully deliver a packet to the ultimate destination. The ETX metric incorporates the effects of link loss ratios, asymmetry in the loss ratios between the two directions of each link, and interference among the successive links of a path. In contrast, the minimum hop-count metric chooses arbitrarily among the different paths of the same minimum length, regardless of the often large differences in throughput among those paths, and ignoring the possibility that a longer path might offer higher throughput.This paper describes the design and implementation of ETX as a metric for the DSDV and DSR routing protocols, as well as modifications to DSDV and DSR which allow them to use ETX. Measurements taken from a 29-node 802.11b test-bed demonstrate the poor performance of minimum hop-count, illustrate the causes of that poor performance, and confirm that ETX improves performance. For long paths the throughput improvement is often a factor of two or more, suggesting that ETX will become more useful as networks grow larger and paths become longer.
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paper_title: Comparative analysis of link quality metrics and routing protocols for optimal route construction in wireless mesh networks

paper_content:

We provide a comparative analysis of various routing strategies that affect the end-to-end performance in wireless mesh networks. We first improve well-known link quality metrics and routing algorithms to enhance performance in wireless mesh environments. We then investigate the route optimality, i.e., whether the best end-to-end route with respect to a given link quality metric is established, and its impact on the network performance. Network topologies, number of concurrent flows, and interference types are varied in our evaluation and we find that a non-optimal route is often established because of the routing protocol's misbehavior, inaccurate link metric design, interflow interference, and their interplay. Through extensive simulation analysis, we present insights on how to design wireless link metrics and routing algorithms to enhance the network capacity and provide reliable connectivity.
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paper_title: Trading structure for randomness in wireless opportunistic routing

paper_content:

Opportunistic routing is a recent technique that achieves high throughput in the face of lossy wireless links. The current opportunistic routing protocol, ExOR, ties the MAC with routing, imposing a strict schedule on routers' access to the medium. Although the scheduler delivers opportunistic gains, it misses some of the inherent features of the 802.11 MAC. For example, it prevents spatial reuse and thus may underutilize the wireless medium. It also eliminates the layering abstraction, making the protocol less amenable to extensions to alternate traffic types such as multicast. This paper presents MORE, a MAC-independent opportunistic routing protocol. MORE randomly mixes packets before forwarding them. This randomness ensures that routers that hear the same transmission do not forward the same packets. Thus, MORE needs no special scheduler to coordinate routers and can run directly on top of 802.11. Experimental results from a 20-node wireless testbed show that MORE's median unicast throughput is 22% higher than ExOR, and the gains rise to 45% over ExOR when there is a chance of spatial reuse. For multicast, MORE's gains increase with the number of destinations, and are 35-200% greater than ExOR.
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paper_title: Ad-hoc on-demand distance vector routing

paper_content:

An ad-hoc network is the cooperative engagement of a collection of mobile nodes without the required intervention of any centralized access point or existing infrastructure. We present Ad-hoc On Demand Distance Vector Routing (AODV), a novel algorithm for the operation of such ad-hoc networks. Each mobile host operates as a specialized router, and routes are obtained as needed (i.e., on-demand) with little or no reliance on periodic advertisements. Our new routing algorithm is quite suitable for a dynamic self starting network, as required by users wishing to utilize ad-hoc networks. AODV provides loop-free routes even while repairing broken links. Because the protocol does not require global periodic routing advertisements, the demand on the overall bandwidth available to the mobile nodes is substantially less than in those protocols that do necessitate such advertisements. Nevertheless we can still maintain most of the advantages of basic distance vector routing mechanisms. We show that our algorithm scales to large populations of mobile nodes wishing to form ad-hoc networks. We also include an evaluation methodology and simulation results to verify the operation of our algorithm.
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paper_title: Multi-point Relaying Techniques with OSPF on Ad Hoc Networks

paper_content:

Incorporating multi-hop ad hoc wireless networks in theIP infrastructure is an effort to which a growing communityparticipates. One instance of such activity is theextension of the most widely deployed interior gatewayrouting protocol on the Internet, OSPF (Open Shortest PathFirst), for operation on Mobile Ad hoc Networks (MANETs).Such extension allows OSPF to work on heterogeneousnetworks encompassing both wired and wireless routers,which may self-organize as multi-hop wireless subnetworks,and be mobile. Three solutions have been proposed for thisextension, among which two based on techniques derivedfrom multi-point relaying (MPR). This paper analyzes thesetwo approaches and identifies some fundamental discussionitems that pertain to adapting OSPF mechanisms to multihopwireless networking, before concluding with a proposalfor a unique, merged solution based on this analysis.
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paper_title: Optimized link state routing protocol for ad hoc networks

paper_content:

In this paper we propose and discuss an optimized link state routing protocol, named OLSR, for mobile wireless networks. The protocol is based on the link state algorithm and it is proactive (or table-driven) in nature. It employs periodic exchange of messages to maintain topology information of the network at each node. OLSR is an optimization over a pure link state protocol as it compacts the size of information sent in the messages, and furthermore, reduces the number of retransmissions to flood these messages in an entire network. For this purpose, the protocol uses the multipoint relaying technique to efficiently and economically flood its control messages. It provides optimal routes in terms of number of hops, which are immediately available when needed. The proposed protocol is best suitable for large and dense ad hoc networks.
---
paper_title: Comparative analysis of link quality metrics and routing protocols for optimal route construction in wireless mesh networks

paper_content:

We provide a comparative analysis of various routing strategies that affect the end-to-end performance in wireless mesh networks. We first improve well-known link quality metrics and routing algorithms to enhance performance in wireless mesh environments. We then investigate the route optimality, i.e., whether the best end-to-end route with respect to a given link quality metric is established, and its impact on the network performance. Network topologies, number of concurrent flows, and interference types are varied in our evaluation and we find that a non-optimal route is often established because of the routing protocol's misbehavior, inaccurate link metric design, interflow interference, and their interplay. Through extensive simulation analysis, we present insights on how to design wireless link metrics and routing algorithms to enhance the network capacity and provide reliable connectivity.
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paper_title: Comparison studies of OSPF-MDR, OLSR and Composite Routing

paper_content:

In this paper, we investigate the benefits and tradeoffs among various routing strategies used in Mobile Ad Hoc Networks (MANET). In particular, we compare the performance of OSPF-MDR, OLSR, and Composite Routing. Our composite routing implementation is based on further extensions of OSPF-MDR that employs OLSR as the sub-IP MANET routing protocol. The performance evaluation was conducted on an emulation test-bed that utilizes the light-weight Linux network stack virtualization, namely network namespaces. The performance results show that OLSR outperforms OSPF-MDR. As a result, composite routing can leverage OLSR to achieve better network performance than OSPF-MDR with less overhead. Furthermore, composite routing can significantly reduce routing updates to legacy networks due to MANET dynamics (by about 95% under high mobility).
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paper_title: IP multicast fault recovery in PIM over OSPF

paper_content:

Little attention has been given to understanding the fault recovery characteristics and performance tuning of native IP multicast networks. This paper focuses on the interactions of the component protocols to understand their behavior in network failure and recovery scenarios. We consider a multicast environment based on the Protocol Independent Multicast (PIM) routing protocol, the Internet Group Management Protocol (IGMP) and the Open Shortest Path First (OSPF) protocol. Analytical models are presented to describe the interplay of all of these protocols in various multicast channel recovery scenarios. Quantitative results for the recovery time of IP multicast channels are given as references for network configurations, and protocol development. Simulation models are developed using the OPNET simulation tool to measure the fault recovery time and the associated protocol control overhead, and study the influence of important protocol parameters. A testbed with five Cisco routers is configured with PIM, OSPF, and IGMP to measure the multicast channel failure and recovery times for a variety of different link and router failures. In general, the failure recovery is found to be lightweight in term of control overhead and recovery time. Failure recovery time in a WAN is found to be dominated by the unicast protocol recovery process. Failure recovery in a LAN is more complex, and strongly influenced by protocol interaction and implementation specifics. Suggestion for improvement of the failure recovery time via protocol enhancements, parameter tuning, and network configuration are provided.
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paper_title: Three load metrics for routing in ad hoc networks

paper_content:

Most existing routing protocols for mobile ad hoc networks are designed to search for the shortest path with minimum hop counts. However, the shortest routes do not always provide the best performance, especially when there are congested nodes along these routes. We investigate a load-aware routing protocol using three load metrics for route selection, which include MAC layer channel contention information, the number of packets in the interface queue, and the traditional hop count. Among these metrics, MAC layer contention information provides an accurate estimation of neighbor node activities, and queue length provides a measure of traffic load at the mobile node itself. Combined with the number of hops, this load-aware routing protocol can effectively balance the traffic and improve throughput within the ad hoc network. The impact of these three load metrics on the routing performance are studied, and simulations are conducted to validate our conclusions.
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paper_title: Load Balanced Routing Mechanisms for Mobile Ad Hoc Networks

paper_content:

Properties of mobile ad hoc networks (MANET) like dynamic topology and decentralized connectivity make routing a challenging task. Moreover, overloaded nodes may deplete their energy in forwarding others pack-ets resulting in unstable network and performance degradation. In this paper we propose load-balancing schemes that distribute the traffic on the basis of three important metrics -residual battery capacity, average interface queue length and hop count along with the associated weight values. It helps to achieve load bal-ancing and to extend the entire network lifetime. Simulation results show that the proposed load-balancing schemes significantly enhance the network performance and outperform one of the most prominent ad hoc routing protocols AODV and previously proposed load balanced ad hoc routing protocols including DLAR and LARA in terms of average delay, packet delivery fraction and jitter.
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paper_title: Load-balanced routing through virtual paths: highly adaptive and efficient routing scheme for ad hoc wireless networks

paper_content:

Routing protocols for ad hoc wireless networks consider the path with the minimum number of hops as the optimal path to any given destination. However, this strategy does not balance the traffic load over the network, and may create congested areas. These congested areas greatly degrade the performance of the routing protocols. In this paper, we propose a routing scheme that balances the load over the network by selecting a path based on traffic sizes. We present a simulation study to demonstrate the effectiveness of the proposed scheme.
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paper_title: Dynamic load-aware routing in ad hoc networks

paper_content:

Ad hoc networks are deployed in situations where no base station is available and a network has to be built impromptu. Since there is no wired backbone, each host is a router and a packet forwarder. Each node may be mobile, and topology changes frequently and unpredictably. Routing protocol development has received much attention because mobility management and efficient bandwidth and power usage are critical in ad hoc networks. No existing protocol however, considers the load as the main route selection criteria. This routing philosophy can lead to network congestion and create bottlenecks. We present dynamic load-aware routing (DLAR) protocol that considers intermediate node routing loads as the primary route selection metric. The protocol also monitors the congestion status of active routes and reconstructs the path when nodes of the route have their interface queue overloaded. We describe three DLAR algorithms and show their effectiveness by presenting and comparing simulation results with an ad hoc routing protocol that uses the shortest paths.
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paper_title: Load balanced routing in mobile ad hoc networks

paper_content:

We present a new protocol called Load Aware Routing in Ad hoc (LARA) networks protocol for efficient data transmission in mobile ad hoc networks. We also define a new metric for routing called traffic density to represent the degree of contention at the medium access control layer. During the route setup, this metric is used to select the route with the minimum traffic load. We have carried out extensive simulation studies to evaluate the performance of our proposed protocol vis-a-vis the existing protocols. Performance results show that our LARA protocol outperforms existing routing protocols in terms of end-to-end delay, throughput, packet delivery fraction, and battery power consumption at the nodes.
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paper_title: Efficient Load Balancing in MANETS to Improve Network Performance

paper_content:

It is expected that future ITS (Intelligent Transport System) network will involve a lot of mobile equipments and form a complex network. Maintaining the good performance of this complex network is a complicated task, and efficient load balancing plays an important role. In this paper, a new load balancing solution is proposed. In this solution, the load balancing is performed by the source node based on the probe packets sent by the destination node. Doing so will reduce the number of probe packets to half. A new formula for available bandwidth estimation of 802.11 ad hoc network is also presented. The simulation results show that the proposed solution has improved the connection throughput significantly.
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paper_title: Load balanced routing protocols for ad hoc mobile wireless networks

paper_content:

Mobile ad hoc networks are collections of mobile nodes that can dynamically form temporary networks without the need for pre-existing network infrastructure or centralized administration. These nodes can be arbitrarily located and can move freely at any given time. Hence, the network topology can change rapidly and unpredictably. Because wireless link capacities are usually limited, congestion is possible in MANETs. Hence, balancing the load in a MANET is important since nodes with high loads will deplete their batteries quickly, thereby increasing the probability of disconnecting or partitioning the network. This article discusses the various load metrics and summarizes the principles behind several existing load balanced ad hoc routing protocols. Finally, a qualitative comparison of the various load metrics and load balanced routing protocols is presented.
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paper_title: A Load-Balancing Routing Considering Power Conservation in Wireless Ad Hoc Networks

paper_content:

Of existing ad-hoc protocols, on-demand routing protocol is suitable to wireless networks that have frequent mobility of nodes. Besides, when network is stable, data is transmitted after choosing shortest path without any consideration of any particular node's traffic, and then traffic is concentrated on a particular node, which raises the problem of delay of transmission and huge energy consuming. In this paper, load-balancing routing method, which considers power conversation, is suggested. The proposed method improves (complements) the function of router discovery by adding energy factor to the existing DSR (dynamic source routing)
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paper_title: Virtual paths routing: a highly dynamic routing protocol for ad hoc wireless networks

paper_content:

We introduce the virtual paths routing (VPR) protocol for ad hoc wireless networks. VPR provides highly dynamic, correct, and efficient paths creation and maintenance between nodes. Innovatively, the protocol utilizes a technique to monitor the mobility of the nodes, and factorizes it in its operations. VPR is a distributed, on-demand, and adaptive protocol that comprises two phases. The first phase is path discovery, in which VPR discovers and creates a virtual path between source and destination nodes. The second phase is path maintenance, in which the protocol monitors the usability of all active paths.
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paper_title: A Correlated Load Aware Routing Protocol in Mobile Ad Hoc Networks

paper_content:

In this paper, we investigate the load distribution in ad hoc networks for reducing the possibility of power depletion and queuing delay at a node with heavy load environments. We examine the efficiency of dominant ad hoc routing protocols from a point of load balancing. Based on the results from various simulations, we design a new Correlated Load-Aware Routing (CLAR) protocol that considers the traffic load, through and around neighboring nodes, as the primary route selection metric. Simulation results show that CLAR outperforms other popular protocols and is better suited for the heady load networks with low mobility.
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paper_title: Associativity-Based Routing For Ad-Hoc Mobile Networks

paper_content:

This paper presents a new, simple and bandwidth-efficient distributed routing protocol to support mobile computing in a conference size ad-hoc mobile network environment. Unlike the conventional approaches such as link-state and distance-vector distributed routing algorithms, our protocol does not attempt to consistently maintain routing information in every node. In an ad-hoc mobile network where mobile hosts (MHs) are acting as routers and where routes are made inconsistent by MHs‘ movement, we employ an associativity-based routing scheme where a route is selected based on nodes having associativity states that imply periods of stability. In this manner, the routes selected are likely to be long-lived and hence there is no need to restart frequently, resulting in higher attainable throughput. Route requests are broadcast on a per need basis. The association property also allows the integration of ad-hoc routing into a BS-oriented Wireless LAN (WLAN) environment, providing the fault tolerance in times of base stations (BSs) failures. To discover shorter routes and to shorten the route recovery time when the association property is violated, the localised-query and quick-abort mechanisms are respectively incorporated into the protocol. To further increase cell capacity and lower transmission power requirements, a dynamic cell size adjustment scheme is introduced. The protocol is free from loops, deadlock and packet duplicates and has scalable memory requirements. Simulation results obtained reveal that shorter and better routes can be discovered during route re-constructions.
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paper_title: On the impact of alternate path routing for load balancing in mobile ad hoc networks

paper_content:

Alternate path routing (APR) can provide load balancing and route failure protection by distributing traffic among a set of diverse paths. These benefits make APR appear to be an ideal candidate for the bandwidth limited and mobile ad-hoc networks. However, we find that APR's potential is not fully realized in ad-hoc networks because of route coupling resulting from the geographic proximity of candidate paths between common endpoints. In multiple channel networks, coupling occurs when paths share common intermediate nodes. The coupling problem is much more serious in single channel networks, where coupling also occurs where one path crosses the radio coverage area of another path. The network's inherent route coupling is further aggravated by the routing protocol, which may provide an incomplete view of current network connectivity.Through analysis and simulation, we demonstrate the impact of route coupling on APR's delay performance in ad-hoc networks. In multiple channel environments, APR is able to provide a 20% reduction in end-to-end delay for bursty data streams. Though these gains are appreciable, they are about half what we would expect from APR with independently operating routes. Route coupling is so severe in single channel networks that APR provides only negligible improvements in quality of service.
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paper_title: A load balanced aware routing protocol for wireless ad hoc networks

paper_content:

Nodes in ad hoc networks can be unfairly burdened to support many packet-relaying functions, resulting in excessive loads on these hot spots. This load on nodes appears in two major aspects: traffic and power consumption. Unbalanced traffic may lead to more delay, packet dropping, and decreasing packet delivery ratio (PDR). Unbalanced energy consumption leads to node failure, network partitioning and decreases network lifetime and route reliability. Existing approaches try to improve the performance of routing protocols with respect to traffic balancing or energy consumption balancing, but most lead to drawbacks such as more delay, blocking, or dependence on global information from all nodes. In this paper we improve the well known Dynamic Source Routing (DSR) protocol to the so called Load Balanced DSR (LBDSR) protocol. We modify the RREQ (Route Request) and RREP (Route Reply) messages in DSR in order to maintain the remaining energy of intermediate nodes which forward RREQ and RREP. Route structure, available in the nodes cache, is modified so that the remaining energy of nodes can be calculated. LBDSR shows better traffic balancing and energy consumption balancing, end-to-end delay and route reliability metrics than DSR. Furthermore, LBDSR can also be customized to achieve better performance with respect to each of these metrics instead of being a trade-off between them.
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paper_title: Load-balancing in MANET shortest-path routing protocols

paper_content:

Mobile ad hoc networks (MANET) are infrastructure-less networks, dynamically formed by an independent system of mobile nodes that are connected via wireless links. Because routing is performed by nodes with limited resources, load should be efficiently distributed through the network. Otherwise, heavily-loaded nodes may make up a bottleneck that lowers the network performances by congestion and larger delays. Regrettably, load-balancing is a critical deficiency in MANET shortest-path routing protocols, as nodes at the center of the network are much heavily-loaded than the others. Thus, we propose, in this paper, load-balancing mechanisms that push the traffic further from the center of the network. Basically, we provide novel routing metrics that take into account nodes degree of centrality, for both proactive and reactive routing protocols. Simulations show that the proposed mechanisms improve the load distribution and significantly enhance the network performances in terms of average delay and reliability.
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paper_title: A workload-based adaptive load-balancing technique for mobile ad hoc networks

paper_content:

A novel load-balancing technique for ad hoc on-demand routing protocols is presented. Currently, ad hoc routing protocols lack load-balancing capabilities, and thus, they often fail to provide good performance especially in the presence of a large volume of traffic. We present a simple but very effective method to achieve load balance and congestion alleviation. The new scheme is motivated by the observation that ad hoc on-demand routing protocols flood route request (RREQ) messages to acquire routes, and only nodes that respond to those messages have a potential to serve as intermediate forwarding nodes. If a node ignores RREQ messages within a specific period, it can completely be excluded from the additional communications that might have occurred for that period otherwise. Thus, a node can decide not to serve a traffic flow by dropping the RREQ for that flow. In the new scheme, RREQ messages are forwarded selectively according to the load status of each node so that overloaded nodes can be excluded from the requested paths. Each node begins to allow additional traffic flows again whenever its overloaded status is dissolved. The new scheme utilizes interface queue occupancy and workload to control RREQ messages adaptively. The enhanced versions of protocols with this scheme are compared to the base protocols. Simulation results reveal that the new scheme greatly reduces packet latency as well as routing overhead without adversely affecting the network throughput, and it successfully balances the network load among nodes.
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paper_title: Routing with load balancing in wireless Ad hoc networks

paper_content:

An ad hoc wireless mobile network is an infrastructure-less mobile network that has no fixed routers; instead, all nodes are capable of movement and can be connected dynamically in an arbitrary manner. In order to facilitate communication of mobile nodes that may not be within the wireless range of each other, an efficient routing protocol is used to discover routes between nodes so that messages may be delivered in a timely manner. In this paper, we present a novel Load-Balanced Ad hoc Routing (LBAR) protocol for communication in wireless ad hoc networks. LBAR defines a new metric for routing known as the degree of nodal activity to represent the load on a mobile node. In LBAR routing information on all paths from source to destination are forwarded through setup messages to the destination. Setup messages include nodal activity information of all nodes on the traversed path. After collecting information on all possible paths, the destination then makes a selection of the path with the best-cost value and sends an acknowledgement to the source node. LBAR also provides efficient path maintenance to patch up broken links by detouring traffic to the destination. A comprehensive simulation study was conducted to evaluate the performance of the proposed scheme. Performance results show that LBAR outperforms existing ad hoc routing protocols in terms of packet delivery and average end-to-end delay.
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paper_title: Load-aware on-demand routing (LAOR) protocol for mobile ad hoc networks

paper_content:

Most current routing protocols for mobile ad hoc networks consider the shortest path with minimum hop counts at the optimal route. However, the minimum end-to-end delay from source to destination may not always be achieved through this shortest path. In this paper, we propose an efficient delay-based load-aware on-demand routing (D-LAOR) protocol, which determines the optimal path based on the estimated total path delay and the hop count. We demonstrate the effectiveness of D-LAOR by integrating it with the ad hoc on-demand distance vector (AODV) routing protocol. Simulation results obtained suing the ns-2 network simulation platform, show that D-LAOR scheme increases packet delivery fraction and decreases end-to-end delay by more than 10% in a moderate network scenario when compared with the original AODV ad the other LAOR protocols.
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paper_title: Adaptive load balancing in mobile ad hoc networks

paper_content:

In this paper, we propose a prediction based adaptive load balancing mechanism for mobile ad hoc networks. This mechanism can cooperate with any kind of multipath source routing protocol. It distributes traffic load among multiple disjoint paths based on the measurement and prediction of network traffic. In order to predict network traffic accurately, we first analyze the traffic data collected in our mobile ad hoc network testbed and find out that ad hoc networks traffic is self-similar. Then, we propose a traffic predictor based on wavelet analysis. The simulation results show that our loading balancing approach can distribute traffic properly and lead to a decrease of traffic load imbalance of multiple paths and network congestion. As a result, it reduces the end-to-end packet delay and packet dropping probability and balances the energy consumption of the network.
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paper_title: Relieving critical nodes and designing of fault tolerant data networks

paper_content:

The communication networks having different types of nodes, links and other resources cause uneven distribution of the traffic loads. Also the chances of failure increase with the growth of the network size. To avoid such uneven traffic distribution and failure, and to continue with the usual traffic load, some precautions must be taken. This paper as a remedy, introduces a concept of critical nodes (CN) and the formation of critical rings (CR) around CN to relive the networks from such unequal traffic distribution and failure. In brief, a node is termed as critical node that establishes maximum source-terminal paths and a critical ring is defined as the nearest ring around a CN by considering the nodes directly connected to the CN, which may require inserting one or more links. The merits of this CR are that it can bypass some of the routes of the CN and convert it into non- critical node, and can tolerate fault(s) occurring on or around CN, thus make the network fault-tolerant. The proposed concepts have been applied to a sample network of 11 nodes and above mentioned remedies have been achieved.
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paper_title: Critical node lifetimes in random networks via the chen-stein method

paper_content:

This correspondence considers networks where nodes are connected randomly and can fail at random times. It provides scaling laws that allow to find the critical time at which isolated nodes begin to appear in the system as its size tends to infinity. Applications are in the areas of sensor and ad-hoc networks where nodes are subject to battery drainage and 'blind spots' formation becomes a primary concern. The techniques adopted are based on the Chen-Stein method of Poisson approximation, which allows to obtain elegant derivations that are shown to improve upon and simplify previous related results that appeared in the literature. Since blind spots are strongly related to full connectivity, we also obtain some scaling results about the latter.
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paper_title: Detecting critical nodes for MANET intrusion detection systems

paper_content:

Ad hoc routing protocols have been designed to efficiently reroute traffic when confronted with network congestion, faulty nodes, and dynamically changing topologies. The common design goal of reactive, proactive, and hybrid ad hoc routing protocols is to faithfully route packets from a source node to a destination node while maintaining a satisfactory level of service in a resource-constrained environment. Detecting malicious nodes in an open ad hoc network in which participating nodes have no previous security associations presents a number of challenges not faced by traditional wired networks. Traffic monitoring in wired networks is usually performed at switches, routers and gateways, but an ad hoc network does not have these types of network elements where the intrusion detection system (IDS) can collect and analyze audit data for the entire network. A number of neighbor-monitoring, trust-building, and cluster-based voting schemes have been proposed in the research to enable the detection and reporting of malicious activity in ad hoc networks. The resources consumed by ad hoc network member nodes to monitor, detect, report, and diagnose malicious activity, however, may be greater than simply rerouting packets through a different available path. This paper presents a method for determining conditions under which critical nodes should be monitored, describes the details of a critical node test implementation, presents experimental results, and offers a new approach for conserving the limited resources of an ad hoc network IDS.
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paper_title: Identification of Critical Node for the Efficient Performance in Manet

paper_content:

This paper considers a network where nodes are connected randomly and can fail at random times. The critical- node test detects nodes, whose failures are malicious behavior, disconnects or significantly degrades the performance of the network. The critical node is an element, position or control entity whose disruption, is immediately degrades the ability of a force to command, control or effectively conducts combat operations. If a node is critical node, then more attention must be paid to it to avoid its failure or removal of a network. So how to confirm critical nodes in the ad hoc network is the premise to predict the network partition. A critical node is the most important node within the entity of a network. This paper suggests methods that find the critical nodes of a network based on residual battery power, reliability, bandwidth, availability and service traffic type. The metrics for evaluation has been considered as packet delivery ratio, end-to-end delay and throughput. Nodes in Mobile Ad hoc Networks (MANETs) are battery powered and hence have limited lifetime. Due to excessive utilization a node may die which can result in energy depletion problem and thereby affect overall network performance. Local rate of energy consumption based on application can be monitored. Thus early detection and avoidance of energy depletion problem is possible based on monitoring of power and remaining battery lifetime. As and when the rate of consumption based on the application returns to efficient levels, the mobile relay is released so that it can be made available for other critical nodes. This technique can be applied to any protocol used in MANETs such as DSDV, DSR, AODV, TORA etc. In this work, we focus on maximizing avoidance of network partition, rather than after the network partition, then taking some remedial measures. We describe the critical nodes compensation approach to increase the network connectivity and improve packet delivery rate. First, we detect the critical nodes which may lead to the network partitioning. Secondly, propose the compensation algorithm to avoid the network partitioning. This approach described in this paper is built around the notion of a critical node in an ad hoc network. Our definition of a critical node is a node, whose failure or malicious behavior disconnects or significantly degrades the performance of the network. Once identified, a critical node can be monitored in terms of resource. If a node is not considered critical, this metric can be used to decide if the application or the risk environment warrant the expenditure of the additional resources required to monitor, diagnose, and alert other nodes about the problem. Determining the global network topology in a MANET gives the time delays of the diagnostic packets and the mobility of the nodes makes this task futile, but determining an approximation of this topology or subset of this topology, within a certain time frame may be useful. An approximation of the network topology can still provide useful information about network the density, network mobility, critical paths, and critical nodes. Even with the uncertainty associated with correctly reconstructing the network topology for a given time period, this additional information can help to reduce the resources consumed to monitor all nodes in the absence of this information.
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paper_title: Minimum augmentation of local edge-connectivity between vertices and vertex subsets in undirected graphs

paper_content:

Given an undirected multigraph G = (V, E), a family W of sets W ⊆ V of vertices (areas), and a requirement function r : W → Z+ (where Z+ is the set of nonnegative integers) we consider the problem of augmenting G by the smallest number of new edges so that the resulting graph has at least r(W) edge-disjoint paths between v and W for every pair of a vertex v ∈ V and an area W ∈ W. So far this problem was shown to be NP-hard in the uniform case of r(W) = 1 for each W ∈ W, and polynomially solvable in the uniform case of r(W) = r ≥ 2 for each W ∈ W. In this paper, we show that the problem can be solved in O(m + pn4(r* + logn)) time, even if r(W) ≥ 2 holds for each W ∈ W, where n = |V|, m = |{{u, v}|(u, v) ∈ E}|, p = |W|, and r* = max{r(W)|W ∈ W}.
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paper_title: Hardness of Approximation for Vertex-Connectivity Network-Design Problems

paper_content:

In the survivable network design problem SNDP, the goal is to find a minimum-cost subgraph satisfying certain connectivity requirements. We study the vertex-connectivity variant of SNDP in which the input specifies, for each pair of vertices, a required number of vertexdisjoint paths connecting them.We give the first lower bound on the approximability of SNDP, showing that the problem admits no efficient 2log1-?n ratio approximation for any fixed ? > 0 unless NP ? DTIME(npolylog(n)>). We also show hardness of approximation results for several important special cases of SNDP, including constant factor hardness for the k-vertex connected spanning subgraph problem (k-VCSS) and for the vertex-connectivity augmentation problem, even when the edge costs are severely restricted.
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paper_title: Design Method of Robust Networks against Performance Deterioration during Failures

paper_content:

When a link or node failure occurs in a network, flows are detoured and therefore the hop counts of the flows increase. This increase could drastically deteriorate the quality of a network. The flow hop length stability as well as network connectivity is important for network reliability. We investigate a network design method that improves stability and connectivity of a network during a failure with a limited investment cost. We formalize a network design problem, prove that this problem is NP-complete, and propose an approximation algorithm. In addition, we evaluate the performance of the algorithm by using publicly available data for 39 backbone networks of commercial ISPs and networks generated by two well-known models. The results show that the proposed algorithm provides effective solutions from a practical viewpoint in sufficiently small computation time.
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paper_title: Augmenting graphs to meet edge-connectivity requirements

paper_content:

The problem of determining the minimum number gamma of edges to be added to a graph G so that in the resulting graph the edge-connectivity between every pair (u,v) of nodes is at least a prescribed value r(u,v) is treated. A min-max formula for gamma is derived, and a polynomial-time algorithm for computing gamma is described. The directed counterpart of the problem is also solved for the case in which r(u,v)=k>or=1. The approach used makes it possible to solve a degree-constrained version of the problem. The minimum-cost augmentation problem can also be solved in polynomial time provided that the edge costs arise from node costs. >
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paper_title: Augmenting Forests to Meet Odd Diameter Requirements

paper_content:

Given a graph G = (V,E) and an integer D > 1, we consider the problem of augmenting G by the smallest number of new edges so that the diameter becomes at most D. It is known that no constant approximation algorithms to this problem with an arbitrary graph G can be obtained unless P = NP. For a forest G and an odd D > 3, it was open whether the problem is approximable within a constant factor. In this paper, we give the first constant factor approximation algorithm to the problem with a forest G and an odd D; our algorithm delivers an 8-approximate solution in O(|V| 3 ) time. We also show that a 4-approximate solution to the problem with a forest G and an odd D can be obtained in linear time if an augmented graph is additionally required to be biconnected.
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paper_title: Connectivity and Stability at Failures in ISP Backbone Networks

paper_content:

When a link or node failure occurs, flows are detoured around the failed portion, so the hop count of flows could change dramatically as a result of a failure. It is therefore important to evaluate the reliability of backbone networks from the viewpoint of flow hop length stability as well as network connectivity. In this paper, we analyze the possible primary causes of the degradation of reliability of the backbone networks of 36 commercial ISPs and present guidelines for making effective investments in link addition.
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paper_title: Critical Links Detection to Maintain Small Diameter Against Link Failures

paper_content:

The critical links whose failures significantly deteriorate the performance in a network must be protected not to fail or to be rapidly switched to their backup links. The number of these links should be small to restrict the investment cost of facilities and the operational cost for Internet service providers. Therefore, it is important to find the smallest number of links to be protected such that the diameter of the resulting graph by the failures of non-protected links is less than or equal to a given value. In this paper, we formulate this new link protection problem and prove that the problem is NP-hard. In addition, we propose a polynomial-time algorithm to solve the problem that the number of the simultaneous link failures is restricted to one. As about 70% of unintentional failures, excluding ones caused by maintenance, are single link failures, our algorithm for the restricted problem is not only theoretically important but also actually useful.
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paper_title: Comparative analysis of link quality metrics and routing protocols for optimal route construction in wireless mesh networks

paper_content:

We provide a comparative analysis of various routing strategies that affect the end-to-end performance in wireless mesh networks. We first improve well-known link quality metrics and routing algorithms to enhance performance in wireless mesh environments. We then investigate the route optimality, i.e., whether the best end-to-end route with respect to a given link quality metric is established, and its impact on the network performance. Network topologies, number of concurrent flows, and interference types are varied in our evaluation and we find that a non-optimal route is often established because of the routing protocol's misbehavior, inaccurate link metric design, interflow interference, and their interplay. Through extensive simulation analysis, we present insights on how to design wireless link metrics and routing algorithms to enhance the network capacity and provide reliable connectivity.
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paper_title: An energy aware fuzzy approach to unequal clustering in wireless sensor networks

paper_content:

In order to gather information more efficiently in terms of energy consumption, wireless sensor networks (WSNs) are partitioned into clusters. In clustered WSNs, each sensor node sends its collected data to the head of the cluster that it belongs to. The cluster-heads are responsible for aggregating the collected data and forwarding it to the base station through other cluster-heads in the network. This leads to a situation known as the hot spots problem where cluster-heads that are closer to the base station tend to die earlier because of the heavy traffic they relay. In order to solve this problem, unequal clustering algorithms generate clusters of different sizes. In WSNs that are clustered with unequal clustering, the clusters close to the base station have smaller sizes than clusters far from the base station. In this paper, a fuzzy energy-aware unequal clustering algorithm (EAUCF), that addresses the hot spots problem, is introduced. EAUCF aims to decrease the intra-cluster work of the cluster-heads that are either close to the base station or have low remaining battery power. A fuzzy logic approach is adopted in order to handle uncertainties in cluster-head radius estimation. The proposed algorithm is compared with some popular clustering algorithms in the literature, namely Low Energy Adaptive Clustering Hierarchy, Cluster-Head Election Mechanism using Fuzzy Logic and Energy-Efficient Unequal Clustering. The experiment results show that EAUCF performs better than the other algorithms in terms of first node dies, half of the nodes alive and energy-efficiency metrics in all scenarios. Therefore, EAUCF is a stable and energy-efficient clustering algorithm to be utilized in any WSN application.
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paper_title: Identification of Critical Node for the Efficient Performance in Manet

paper_content:

This paper considers a network where nodes are connected randomly and can fail at random times. The critical- node test detects nodes, whose failures are malicious behavior, disconnects or significantly degrades the performance of the network. The critical node is an element, position or control entity whose disruption, is immediately degrades the ability of a force to command, control or effectively conducts combat operations. If a node is critical node, then more attention must be paid to it to avoid its failure or removal of a network. So how to confirm critical nodes in the ad hoc network is the premise to predict the network partition. A critical node is the most important node within the entity of a network. This paper suggests methods that find the critical nodes of a network based on residual battery power, reliability, bandwidth, availability and service traffic type. The metrics for evaluation has been considered as packet delivery ratio, end-to-end delay and throughput. Nodes in Mobile Ad hoc Networks (MANETs) are battery powered and hence have limited lifetime. Due to excessive utilization a node may die which can result in energy depletion problem and thereby affect overall network performance. Local rate of energy consumption based on application can be monitored. Thus early detection and avoidance of energy depletion problem is possible based on monitoring of power and remaining battery lifetime. As and when the rate of consumption based on the application returns to efficient levels, the mobile relay is released so that it can be made available for other critical nodes. This technique can be applied to any protocol used in MANETs such as DSDV, DSR, AODV, TORA etc. In this work, we focus on maximizing avoidance of network partition, rather than after the network partition, then taking some remedial measures. We describe the critical nodes compensation approach to increase the network connectivity and improve packet delivery rate. First, we detect the critical nodes which may lead to the network partitioning. Secondly, propose the compensation algorithm to avoid the network partitioning. This approach described in this paper is built around the notion of a critical node in an ad hoc network. Our definition of a critical node is a node, whose failure or malicious behavior disconnects or significantly degrades the performance of the network. Once identified, a critical node can be monitored in terms of resource. If a node is not considered critical, this metric can be used to decide if the application or the risk environment warrant the expenditure of the additional resources required to monitor, diagnose, and alert other nodes about the problem. Determining the global network topology in a MANET gives the time delays of the diagnostic packets and the mobility of the nodes makes this task futile, but determining an approximation of this topology or subset of this topology, within a certain time frame may be useful. An approximation of the network topology can still provide useful information about network the density, network mobility, critical paths, and critical nodes. Even with the uncertainty associated with correctly reconstructing the network topology for a given time period, this additional information can help to reduce the resources consumed to monitor all nodes in the absence of this information.
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Title: A Survey on Investigating the Need for Intelligent Power-Aware Load Balanced Routing Protocols for Handling Critical Links in MANETs

Section 1: Introduction
Description 1: Introduce the concept of MANETs, their challenges with energy utilization, connectivity, reliability, and the importance of critical link management.

Section 2: QoS Requirements and Challenges
Description 2: Discuss QoS provisions, resource constraints, node deployment, topology changes, and unbalanced traffic issues in MANETs.

Section 3: QoS Performance Metrics
Description 3: Outline the key performance metrics for QoS in MANETs, including latency, reliability, energy consumption, parallel transmission handling, and change management.

Section 4: Power Control
Description 4: Explain the strategies for adjusting transmission power to control energy consumption and network connectivity in MANETs.

Section 5: Clustering
Description 5: Describe the importance and mechanisms of clustering nodes to improve connectivity, load balancing, and power management.

Section 6: Service Differentiation
Description 6: Detail the methods for differentiating and prioritizing network traffic to manage resource sharing and fulfill application requirements.

Section 7: The Critical Node Problem
Description 7: Illustrate the significance of detecting and managing critical nodes to maintain network efficiency and prevent communication breakdowns.

Section 8: Routing Protocols in MANETs
Description 8: Review various routing protocols, including AODV, OLSR, and others, discussing their approach to handling critical links and load balancing.

Section 9: Protocols for Load Balancing in MANETs
Description 9: Survey different load balancing protocols in MANETs that cater to delay, traffic, and energy considerations.

Section 10: Protocols for Critical Node Detection
Description 10: Present the algorithms and strategies for detecting critical nodes to prevent network failures and maintain optimal traffic distribution.

Section 11: Open Challenges
Description 11: Discuss the open challenges in MANETs, such as bandwidth constraints and the need for robust protocols to handle critical nodes and links.

Section 12: Conclusion
Description 12: Summarize the need for early detection of critical links, load balancing, and the use of machine learning algorithms for improving network performance.