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CHAPTER 3

QoS AND SECURITY ISSUES IN MANET

3.1 QoS IN MANET

In Yi-Sheng Su et al., 2014, the authors considered the problem of joint

Topology Transparent Scheduling (TTS) and Quality of Service (QoS) routing in ad-

hoc networks and presented a joint scheme for the problem. Due to its ability to

guarantee single-hop QoS support, TTS has been chosen as the underlying Medium-

Access-Control (MAC) protocol. Being built on top of TTS, their paper first designs

methods for Bandwidth Estimation and Allocation (BWE and BWA, respectively) to

provide QoS support without the knowledge of slot status information, and then,

estimates and allocated non assigned eligible bandwidth for Best Effort (BE) flows.

With these bandwidth management methods, their paper proposed a QoS routing

protocol for a mixture of QoS and BE flows

In IPv6 based MANETs, the address configuration was done either with a

stateless mechanisms or with the help of server like Dynamic Host Configuration

Protocol version 6 (DHCPv6). The DHCPv6 server initially resides on the node which

acts as the Internet Gateway (IGW) in the network and later on, each of the

configured nodes would become a server. The node which enters the network would

request for an IP address and the server distributes a unique IP address and an address

pool. Formerly, the new node identifies the server using a random selection algorithm.

This method faces many QoS issues due to the usage of the random selection

algorithm. The proposed technique in Punitha et al.,2013 addressed the issues using a

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QoS enabled algorithm, which reduces delay in the address acquisition and packet

drops in the network, and thus enhancing the performance of the network.

Ad-hoc networks, as any other network, need to support both real time traffic

and normal data traffic. Multimedia applications demand stringent guarantees on

bandwidth, delay and jitter. In a best effort network, all users obtain the same level of

service depending on the network load. In other words, it cannot support the

sophisticated requirements of multimedia applications. Therefore, new mechanisms

have to be developed to support the desired QoS levels for the modern applications.

QoS provision at the medium access level was particularly important because it has a

direct effect on how and when data was transmitted. Some of these mechanisms were

based on dividing traffic into various traffic classes and assigning different back off

related values for each class. A few others were based on transmitting multiple frames

at a time to reduce the number of contention attempts and others discard frames with

expired deadlines. However many of these mechanisms dictate strict procedures for

assuring the desired QoS of the application. The proposed method in Narasimhan and

Deepa., 2013 was a simpler one based on the application of token rings to wireless

domain. It uses an election algorithm to find who should transmit data next. Unlike

token ring, the proposed system uses a distributed procedure for maintaining the

logical structure of the ring.

Shivashankar et al., 2013 presented a source based power-aware reactive

routing protocol for Mobile Ad-hoc Networks (MANETs). It considers the QoS

parameters namely delay, throughput, bandwidth and cost of each link. The QoS

routing in an ad-hoc network was difficult because the network topology may change

constantly and the available state information for routing was inherently imprecise.


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They proposed a new Efficient Power-Aware QoS Routing (QEPAR) protocol and

implemented it on the existing DSR protocol with residual battery power and

bandwidth (data rate), as the QoS requirement metric for ad-hoc networks to provide a

solution for energy consumption.

Achankunju et al.,2013 proposed a secure clustering algorithm using Multi-

Objective Particle Swarm Optimization technique (MOPSO). The algorithm uses

three objective functions based on nodes QoS parameters: trust value, life time and

available bandwidth. The main advantage of MOPSO was that it provides multiple

solutions at a time through optimal Pareto front. The proposed approach was

simulated with MATLAB and NS2.

The consideration of energy consumption in wireless ad-hoc networks

prevents the problem of the network exhausting batteries, thus partitioning the entire

network. Power-aware multicasting was proposed to reduce the power consumption.

An energy-efficient genetic algorithm mechanism was proposed to resolve QoS

multicast routing problem, which was NP-complete. In Ting Lu and Jie Zhu., 2013

authors proposed a genetic algorithm which depends on bounded end-to-end delay

and minimum energy cost of the multicast tree.

In order to support QoS in wireless ad-hoc networks, each node needs to

monitor the network status and determine whether the current network status satisfies

the requirements of an application or not. Since the network requirements on an

intermediate node were usually different from those on the end nodes, there was a

need to convert the application requirement into a hop-by-hop network requirement.

Byoungheon Shin et al., 2013 induced link validation formulas for each node to

determine if a link could satisfy the requirement of a specific application.


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The need for efficient routing protocols to allow the nodes to communicate

with some QoS guarantee has always been on the increase to achieve this, in Tekaya

et al.,2013 the authors worked on the AutoRegressive Moving Average (ARMA),

model which was used to forecasting resources to meet the QoS requirements in ad-

hoc networks. The authors applied this model in Ad-hoc On Demand Multipath

Distance Vector (AOMDV) protocol.

Vakilinia et al.,2013 presented a Multi-path Multi-Channel model for wireless

Ad-Hoc networks with a focus on voice calls for providing Quality of Service (QoS)

while addressing security and power consumption of such networks. The goal of their

paper was to provide a secure QoS aware optimum design which takes into account

cross layer relationships.

Maniscalco et al.,2013 considered Genetic Algorithms (GAs) for QoS routing

in MANETs. GAs could solve the NP search of QoS routes with multiple constraints,

and then address the UPC QoS requirements. The focus was on tree-based GAs,

which represented the set of paths from source to destination as a tree and encodes

them through the crossed junctions. They encode single paths in the chromosome.

They investigated the effects of binary encoding schema on tree-based GAs. To

achieve this purpose, the authors designed a GA with binary encoding that maps

classes of paths in single chromosomes. These classes were both collectively

exhaustive and mutually exclusive. The GA with binary encoding uses an adaptive

mutation probability for deeper exploration of the search space and local search on

classes of paths.

Gupta et al., 2013 presented QoS routing algorithm which found a optimal

path from source to destination as well as for other nodes in the network. Route


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discovery was initiated by a source node and routing path was selected based on

routing metric value, which has delay and bandwidth as constraints. The probability

updating rule was used to increase the probability of beam in the direction of

successful transmission and it reduces the routing overhead in retransmission.

Aljeri et al.,2013 proposed to evaluate the performance of a load balanced and

introduce a new QoS gateway discovery protocol (Collaged) that permits the

connection to heterogeneous wireless networks. The protocol guaranteed both

balancing the load at the gateways levels and the routing paths between gateways and

gateway requesters. It also permitted gateway requesters to choose and connect to the

gateways that satisfy the QoS required by the vehicles.

Sakeena et al.,2013 focused on improving route maintenance for QoS in

MANETs. The Ad-hoc On-demand Distance Vector (AODV) routing protocol was

modified to provide QoS in terms of end-to-end delay and also to minimize the

modifications to the protocol.

The main purpose of QoS routing was to find a feasible path that has sufficient

resources to satisfy the constraints. Considering the fact that more than 2 metrics were

involved, there are additional computational complexities and proves to be NP-

complete problem. Stochastic optimization techniques were better solutions for these

kinds of problems. A routing model could be chosen either as a proactive or a reactive

protocol while proactive protocols were not optimal for rapidly changing topologies,

purely reactive protocols were often inappropriate for relatively static networks. In

addition, reactive protocols also suffer from additional delay for real-time traffic. In

such scenarios, hybrid routing was proven to improve on purely reactive-routing, if

most traffic was localized. In order to achieve routing efficiency in such an


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environment, a hybrid routing strategy which combining the advantages of both

proactive and reactive mechanisms was proposed. In Nivetha et al., 2013, the authors

proposed a novel QoS routing strategy called Swarm-based Hybrid Routing Protocol

(SHRP) based on ant colony optimization to support the three metrics such as end-to-

end delay, bandwidth and hop count. The shortest path was decided according to

some other sub metrics. In wired networks these metrics could be more complex. In

Mobile Ad-hoc Networks (MANETs) simpler metrics were used such as hop count. In

Simsek and Dogan., 2013 the authors suggested a new routing metric for MANETs:

One-Way-Delay (OWD).

Thaalbi et al.,2013 addressed the quality aware routing issue in MANET:

Mobile Ad-hoc networks. The MANET network was based on dynamic radio links.

Their contribution was found to improve the multipath routing in Mobile Ad-hoc

networks based on the path quality, path stability and QoS awareness. Prediction

methods were used to estimate the path quality. The paths would be sorted and

weighted according to the application class. Route selection process was based on

multi-criteria selection method. Interactions between routing layer and MAC layer

were exploited to get the path quality. To take into account the application class in the

routing process, cross layer interactions between routing layer and upper layers were

needed.

Hosek et al., 2013 dealt with the characteristics of Mobile Ad-hoc Networks

and the issue of Quality of Service assurance in these networks. The work focuses

mainly on the routing protocol AODV and its ability to provide different processing

probabilities for different types of network traffic. Firstly, the development of the


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MANET simulation model and implementation of AODV protocol were described.

The Network Simulator 3 was used as the key software tool for this purpose.

Natkaniec et al., 2013 attempted to describe the Quality of Service (QoS)

mechanisms employed by Medium Access Control (MAC) protocols designed for ad-

hoc networks. Based on the presented survey, they observed that QoS provisioning,

was not only challenging but was also a significant contemporary research problem.

Ad-hoc wireless networks were considered to be the most suitable wireless

communication system in order to support various applications in mobility

environments. The following were certain requirements for providing real-time

applications in ad-hoc wireless networks, there were some requirements: i) the design

of routing algorithm with packet delivery reliability while maintaining the established

route for an arbitrary length of time (i.e., route duration); ii) the prompt transmission

of the packets communication pairs (i.e., the source and destination) while minimizing

packet delivery latency; iii) the minimization of the number of rebroadcasting nodes

in route discovery procedure in order to suppress redundant routing overhead. In Do-

hyeon Lee and Jeom-goo Kim.,2013 the authors analyzed and compared packet

forwarding approaches that were proposed to alleviate network overhead problems

and guarantee reliable and fast packet delivery to the destination in ad-hoc wireless

networks.

Xu Zhen and Xiao Juan., 2012 developed a energy-ware and delay-aware

routing approach for MANET. They based their approach on Dynamic Source

Routing (DSR) and it was found to both timeliness and energy efficiency by avoiding

low-power and busy intermediate node.


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MANETs with cooperative communications (CO-MANETs) were vulnerable

to attacks initiated on relays. Although encryption and authentication protocols might

prevent compromised data transmission when a selected relay was attacked, their cost

is high. Du Zheng et al.,2012 proposed a game theoretic approach to quantitatively

analyze the attack strategies of the attacker inorder to make rational decision on relay

selection and the adaption of authentication parameter to reach the trade-off between

security and Quality of Service (QoS) in CO-MANETs.

Bagwari et al., 2012 analyzed the performance of reactive routing protocol via

increasing number of nodes and observing its effect on Quality of Service (QoS) of

Mobile Adhoc Network. They observed the performance of Routing Protocol via

enhancing the network size on the basis of the following parameters: delay,

throughput, traffic sent, traffic received, data dropped and network load. Network

simulation tool used in simulation was OPNET Modeler (Ver. 14.0).

Abassi and Fatmi., 2012 used a delegation process in order to enhance the

QoS of Ad-hoc networks by allowing the perpetuity of routes without stopping the

packets transfer nor the re-calculation of a novel route. In view of the importance of

this issue, they proposed to base delegation on trust relations. Trust was a security

concept generally used to provide collaborating network entities with a mean to

counter their uncertainty.

Hengheng Xie et al., 2012 proposed, a novel contention window adjustment

QoS scheme, as a special case of QoS classification for achieving QoS-fairness on

Ad-hoc Networks. It applies dynamic automatic QoS assignment with low complexity

by considering the restriction among various terminal requirements.


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Cakan and Wieser., 2012 presented the application of directional antennas in

wireless MANET network and its contribution to enhancement of Quality of Service

(QoS) parameters. The model of wireless MANET network was created in NS-2

simulator with two types of antennas - omni-directional and directional.

Liu et al., 2012 described the Ad-hoc on-demand QoS routing based on

Bandwidth Prediction (AQBP). Differing from the existing QoS routing protocols,

AQBP takes node future bandwidth into consideration when selecting route.

Providing Quality-of-Service (QoS) support for Ad-hoc networks was a challenging

task due to dynamicity, lack of centralized control, constrained resources and

unreliable nature of radio channels and in Mobile Ad-hoc Networks. Finding a path

that remains valid for sufficiently longer period was also a critical task in MANET. In

Srinivasan and Kamalakkannan., 2012 the authors proposed a novel, stability and

energy-based QoS routing protocol, which was an extension of their route stability

and energy based routing (RSEA) to support applications with throughput and delay

constraints.

Yang Qin et al.,2012 proposed a flow admission control scheme at the routing

layer to mitigate the above problem by taking pre-emptive measures through

bandwidth and congestion estimation. The scheme could reduce unnecessary control

overhead for route maintenance and select a proper route for a flow, thus improving

the overall network performance quality. Moreover, established routes could be

protected from any changes in traffic load for the duration of the route lifetime.

Yuanfeng Wen et al.,2012 the authors developed an M/M+/1 model for the

service discovery on MANET nodes. This model was first applied to predict system

behaviors such as system throughput and then to find the value of a control variable. It


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was found that the calculated value was set at runtime, the system would provide the

optimal QoS.

Santhi et al.,2011 proposed a MANET routing protocol considering the QoS

(Quality of Service) parameters such as bandwidth efficiency, link stability and power

metric. The idea of learning the network status information to enhance network

routing was the key concept of their project. This helps to learn about the expiry of

links and choose the path with a longer time expiry.

Al-Soufy and Abbas.,2011 presented a routing protocol which identified

multiple node-disjoint paths between a given source and a destination. These multiple

node-disjoint paths were examined for satisfying QoS in terms of end-to-end delay.

They analyzed the end-to-end delay along the paths taking into account the IEEE

802.11 contention delays.

Ping Feng et al.,2011 designed a cognitive retransmission mechanism for the

communication scenarios based on the directional antenna. The mechanism could

increase the probability of successful retransmission on one hand; on the other hand, it

could dramatically reduce the route discovery time in ad-hoc networks. For factual

applications, they propose a QoS-constrained cognitive routing algorithm named as

QoS CRA for wireless ad-hoc networks. This algorithm adopts the strategy of

initiating the route discovery by the source node, but by deciding to choose the

destination node.

Heuristic algorithms should be developed for multi-path constraints QoS

routing. Also, the routing methods should be adaptive, flexible, and intelligent. In

Barolli et al., 2011 the authors used Genetic Algorithms (GAs) and Multi-objective


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Optimization for QoS routing in Ad-hoc Networks. In order to reduce the search

space of GA, they implemented a Search Space Reduction Algorithm (SSRA).

Ali et al., 2011 presented a new approach based on multipath routing

backbones for enhanced QoS in MANETs. Nodes in MANETs greatly differ with

each other in terms of communication and processing capabilities. In this approach,

multiple routing backbones were identified from source to destination using

intermediate nodes that contain better communication and processing capabilities to

take part in the mobile routing backbones and to efficiently participate in the routing

process.

Anzar et al., 2011 proposed a mechanism in which communication outside the

cluster was distributed through separate Cluster Head Gateways. The routing

reliability to outside the cluster was increased since routes to different clusters used

distinct Cluster Head Gateways.

Szu-Lin Su et al., 2011 designed a quality-of-service routing protocol,

containing efficient bandwidth estimations, admission control and node-disjoint

multipath establishment. While detecting link breaks, they used back-up routes to

avoid another wasteful route discovery. If a single route with sufficient bandwidth

cannot be discovered, they combine multiple routes to support QoS transmission.

Xiaon'an Feng., 2011 proposed a hybrid routing scheme based on a dynamic

clustering algorithm. The adaptive clustering algorithm deals with mobility, transmit

power conservation and improving system throughput. Routing algorithm proposed

was decoupled from the clustering algorithm, and tradeoff between proactive and

reactive routing, and tradeoff route optimality for routing overhead in a novel way.


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Moreover, the author describes how to gather three metrics, which were used to

support Qos aware route computation.

Many shortest path routing protocols have been proposed, neglecting the

effect of lower layers. In Dahal, Sanguankotchakorn., 2011 authors proposed a

modified Ad-hoc On Demand Distance Vector routing based on Bit Error Rate

(MAODV-BER) , where the route discovery of AODV was modified to achieve the

stable route by obtaining Bit Error Rate (BER) information from physical layer

through cross-layer approach.

Zheng Sihai et al.,2011 put forward a QoS-based multipath routing protocol

QMPSR. It took bandwidth and delay constraint into account and could find several

paths to provide QoS guarantee. Simulation showed that QMPSR protocol was better

than QoS-MSR. Further, the following could be observed: it had a higher packet

delivery ratio, lesser average delay and minimum increased routing overhead

Qabajeh et al.,2011 proposed a model that searches for QoS paths from a

single source to a set of destinations. The physical area was partitioned into equal size

hexagonal cells and a leader and backup leader nodes were selected to maintain up-to-

date information about the network topology. Efficient routing was performed based

on nodes positions to deliver data packets to all the receivers.

Kyung-Seop Shin et al.,2011, proposed a multi-channel MAC protocol that

provides QoS for ad-hoc networks based on the IEEE 802.11 DCF mode. The IEEE

802.11 standard gives methodologies and examples for contention-based distributed

coordination systems for only a single channel. To overcome this limited channel

usage, many studies on how it works in multi-channel environment have been

performed. The IEEE 802.11e proposed the priority schemes that operate on the


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single channel. They combine this concept supporting QoS with multi-channel MAC

protocol, thus achieving the advantage of multi-channel and provide QoS for real-time

users.

Jian Chen et al.,2011 proposed a route protocol called Qos-AOMDV which

takes into consideration, namely the balance of the route and power. Qos-AOMDV

was based on cross-layer design, which could cooperate in sharing network-status

information in different layers, while maintaining the layers separation to optimize

overall network performance. In the path selection phase, the destination nodes did

not reply to route request (RREQ) immediately. Route reply (RREP) was carried out

based on the general cost criterion. In the transmission phase the data was transmitted

in multiple paths one by one to balance the energy and the traffic loads in multiple

paths.

Hui Xia et al., 2011 introduced the concept of trust into multicast routing

problem which was made as another QoS constraint. Finally they propose a multicast

trusted routing algorithm with QoS multi-constraints based on a modified ant colony

algorithm. In this new algorithm, ants moved constantly on the network to find an

optimal constrained multicast security tree. Their algorithm could quickly find the

feasible solution to solve constrained multicast security routing issue when compared

to CSTMAN new algorithm showed improved the packet delivery ratio.

Nazhad et al., 2011 proposed a fully distributed MAC algorithm to support the

QoS in ad-hoc networks. This algorithm provided delay fairness and delay

differentiation for real-time flows. This algorithm also used the fixed and/or less

stationary nodes for the transmission of real-time flows by increasing the QoS of the

multimedia flows.


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Deepalakshmi and Radhakrishnan.,2011 introduced a Source initiated Mesh

and soft-state based QoS Probabilistic multicast routing protocol (SQMP) for

MANETs. SQMP drew its inspiration from the ant colony's route finding algorithm

through which an ant chooses the best path to its destination by cooperating with

others. Similar to the behaviour of the ant searching for food, SQMP introduces

Probabilistic forwarding and soft state for making forwarding decisions with QoS

satisfaction which were automatically adaptive to mobility of nodes in MANETs.

Otrok et al.,2011 considered the tradeoff between prolonging the ad-hoc

network lifetime and QoS assurance based on QOLSR routing protocol. They

proposed a novel clustering algorithm and a relay node selection based on different

combinations of metrics, such as connectivity, residual energy, and bandwidth. Four

cluster-based models were derived.

Oh Chan Kwon et al., 2011 presented an effective QoS routing algorithm

based on the IEEE 802.11 multi-rate for video streaming over mobile ad-hoc

networks. The proposed routing algorithm was designed to minimize the consumed

timeslots while guaranteeing the required timeslots at all the pairs of adjacent nodes

over the route and the contention neighbours of these nodes to support the route.

Furthermore, the proposed routing algorithm could distribute the network loads well

over the entire network.

Zafar et al., 2011 proposed a new capacity-constrained QoS-aware routing

scheme. The novel part of this scheme was a simple additional mechanism to estimate

the residual capacity in IEEE 802.11-based ad-hoc networks. The scheme proposed

the use of a `forgiveness factor' to weigh these previous measurements. It was shown


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through simulation-based evaluation to provide improved utilizations estimation and

better available capacity based admission control.

Jin Lu et al., 2011 proposed a protocol combining a new particle swarm

optimization algorithm and MAODV multicast routing discovery algorithm, which

divided the set of multicast trees into families. Family history optimal solution and

global optimal solution would determine the optimal choice for every iteration

process, until global convergence occurred. The Protocol not only met the QoS

requirements of ad-hoc, but also achieved global convergence quickly and found a

multicast routing tree with a minimal cost and a stable state.

Rong Geng., 2011 proposed a designed on cross layer QoS model in mobile

Ad-hoc network for mobile Ad-hoc networks. By considering path end-to-end

communication delay, path usable degree (PUD), hops and throughput ratio, the

required bandwidth of routing as access control restriction, the model analyzed and

made decisions on the routes between the source and destination node.

A QoS-aware routing (QAR) protocol and an admission control (AC) protocol

were two of the most important components of a system attempted to provide QoS

guarantees in the face of the above - mentioned difficulties. In Hanzo and Tafazolli.,

2011, proposed and evaluated new solutions for improving the performance of QAR

and AC protocols in the face of mobility, shadowing, and varying link SINR. It was

found that proactively maintaining backup routes for active sessions, adapting

transmission rates, and routing around temporarily low-SINR links could noticeably

improve the reliability of assured throughput services.

Bitam et al.,2010, introduced a new multipath quality of service (QoS) routing

protocol for mobile ad-hoc networks (MANETs) called QoSBeeManet. Based on the


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autonomic bee communication principle, the protocol guarantees, in addition to the

basic routing functionality, a set of measurable QoS metrics used for multimedia and

real time applications. To reduce the network congestion, QoSBeeManet used a

stochastic broadcasting of scouts as routing packets. Moreover, an evaluation of each

discovered path was executed and was taken into account by the source node in the

aim to transmit fairly data packets through the paths found.

Wai Yee Tai et al., 2010 presented an adaptive routing scheme that works with

IPv6 that provides QoS for real time applications transmission in such an

unpredictable ad-hoc network by exploiting the Flow label resided in the IPv6 packet

header.

Naeem et al., 2010 the author evaluated two secure routing protocols Ariadne

and SAODV in terms of performance than security under random way point and

Manhattan grid mobility models. They used and implement the extension of AODV

that was secure ad-hoc on-demand distance vector routing protocol (SAODV) and the

extension of DSR (i.e) Ariadne in the network simulator 2 (NS-2). In their study, they

compared these protocols on basis of following quality of service parameters such as

delay, jitter, routing overhead, route acquisition time, throughput, hop count, packet

delivery ratio using Manhattan grid and random waypoint mobility models. Their

main aim was to find out the payload a node has to pay to guarantee the good quality

of service.

Roy et al., 2010 focused on proposing a new route maintenance strategy with

multiple options that would lead to better performance during link failure on a route.

During route discovery and route reply procedures, delay & bandwidth were the two

different QoS parameters considered. The routes should be selected during route


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discovery process. The route maintenance strategy may be applied to both the routes

independently and simultaneously by the internal nodes where the link failure

occurred.

A constant change in the topologies of the Ad-hoc Network leads to routing

reconstruction. In order to reduce route reconstruction, Jin Lian and Xiao-yan Zhu.,

2010, presented a node-disjoint multi-path QoS routing algorithm based on entropy in

ad-hoc network. The algorithm adopted the entropy metric to measure the routing

stability and satisfied the bandwidth constraint. Therefore, it could obtain the node-

disjoint multipath QoS routing.

To exploit multiuser diversity and achieve QoS requirements in MIMO ad-hoc

networks, Jialing Zheng and Maode Ma., 2010 proposed an optimal scheduling policy

which utilizes stream control schemes. They also presented a medium access control

(MAC) protocol to implement the optimal scheduling policy.

A new Virtual Base Station (VBS) election technique was proposed in Fahmy

et al., 2010. The authors helped in QoS provisioning in the infrastructure-less Mobile

Ad-hoc Networks referred to as MANET. This VBS election technique was based on

the mobile node's Signal-to-Noise Ratio (SNR) and was applied on the MANET's

hybrid routing protocol: The Zone-based Routing Protocol. The developed routing

protocols were referred to as SNR-VBS ZRP. Based on the QoS adopted definitions

special to the MANETs, the performance evaluation metrics were redefined in the

paper.

Goudarzi et al., 2009, introduced a cross-layer technique which was based on

the packet loss information from the lower layers. Some optimal bandwidth was

assigned to the real-time applications which needed some levels of the maximum


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packet loss guaranties. As each real-time application needed a different level of

maximum packet loss guarantee, a weighted aggregate packet loss objective function

was introduced. The weights were found to be proportional to importance of the

packet loss mitigation for a specific application.

Manoj et al., 2009, analyzed the packet scheduling algorithm to find those that

improved performance in congested network. They presented a fuzzy based priority

scheduler for mobile ad-hoc networks to determine the priority of the packets using

Destination Sequenced Distance Vector (DSDVs) as the routing protocols. It was

found that the scheduler provided an overall improvement in the performance of the

system when evaluated under different load and mobility conditions.

Malany and Chandrasekaran., 2009, demonstrated how to design a network

according to the applications of mobile adhoc network experiments with different

workloads. The average end-to-end delay, throughput and average jitter were some of

the metrics used for quality of service requirements, which were evaluated in their

paper. The event analysis was also performed and they validated the scheme by

simulating under different speed utilization with IEEE 802.11 distributed coordination

function (DCF) adhoc mode.

Abdrabou and Weihua Zhuang., 2009, proposed a model-based quality-of-

service (QoS) routing scheme for IEEE 802.11 ad-hoc networks. Unlike most of QoS

routing schemes in literature, the proposed scheme provides stochastic end-to-end

delay guarantees, instead of average delay guarantees, to delay-sensitive busy traffic

sources. The scheme selects the routes based on a geographical on-demand ad-hoc

routing protocol via a cross-layer design approach and checks the availability of

network resources by using traffic source and link-layer channel modelling. It also


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took into consideration the IEEE 802.11 characteristics and node interactions. Their

scheme extended the well developed effective bandwidth theory and its dual effective

capacity concept to multihop IEEE 802.11 ad-hoc networks.

In order to satisfy the demand of rapid growth of multimedia applications in

mobile ad-hoc network (MANET), Gao Qian., 2009 proposed an improved QoS

routing algorithm based on AODV. It adopted the mechanism of intermediate request

returning, selected flooding, and local route recovery. The protocol was observed to

reduce control overhead and route searching time, and to provide the QoS routing

stability in dynamic mobile ad-hoc networks.

Calafate et al., 2009, proposed a novel QoS architecture which was able to

support applications with the bandwidth, delay, and jitter requirements in MANET

environments. The proposed architecture was modular, allowing the plugging in of

different protocols thus offering great flexibility. Despite its modularity, they

proposed optimizations based on interactions between the media access control

(MAC), routing, and admission control layers which offer significant performance

improvements. They validated their proposal in scenarios where different network

loads, node mobility degrees, and routing algorithms were tested in order to quantify

the benefits offered by their QoS proposal.

Ming Yu and Leung., 2009, a new secure routing protocol (SRP) with quality

of service (QoS) support, called trustworthiness-based quality of service (TQOS)

routing, which included secure route discovery, secure route setup, and

trustworthiness-based QoS routing metrics. The routing control messages were

secured by using both public and shared keys, which could be generated on-demand

and maintained dynamically. The message exchanging mechanism also provided a


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way to detect attacks against routing protocols, particularly the most difficult internal

attacks. The routing metrics were obtained by combing the requirements on the

trustworthiness of the nodes in the network and the QoS of the links along a route.

Caviglione et al.,2009 investigated the capabilities offered by a P2P overlay

for distributed bandwidth management in a controlled ad-hoc deployment, to support

specific requirements in service-oriented wireless networks. The proposed mechanism

allows complementing the core functionalities of the IEEE 802.11e protocol, and

enhancing them to handle local mobility and dynamic requests for bandwidth.

Yahaya et al.,2008 explored iREX's network load distribution by comparing

its performance to a lower bound for network congestion in two ways. They first

presented an analytical model of iREX in terms of an online algorithm and analyzed

its efficiency via competitive analysis. Their main results showed that the efficiency

loss of iREX with respect to monetary cost was upper-bounded by a factor of 8 K/2

K+1, where K s the number of deployments and provided affine linear price functions

were used. When the price functions were used to model congestion in the network,

this result implied upper bounds on the efficiency loss of iREX with respect to

network congestion. They then complemented the analytical model with a numerical

study using simulations, whole deriving optimal solutions derived from unsplittable

and splittable multi-commodity flow optimization models.

ZhengMing Shen and Thomas.,2008 proposed a mechanism for a distributed

dynamic management system which aims to maximize QoS and/or security while

maintaining a minimum user acceptable level of QoS and/or security even as network

resource availability change. In order to achieve this objective, authors proposed three


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basic frameworks: a policy based plug-in security framework, multi-layer QoS guided

routing and a proportional integral derivative (PID) controller.

Hang Su and Xi Zhang.,2008 proposed the cross-layer based opportunistic

multi-channel medium access control (MAC) protocols, which integrated the

spectrum sensing at physical (PHY) layer with the packet scheduling at MAC layer,

for the wireless ad-hoc networks. The MAC protocols in particular enabled the

secondary users to identify and utilize the leftover frequency spectrum in such a way

that constrains the level of interference to the primary users. In their proposed

protocols, each secondary user was equipped with two transceivers. One transceiver

was tuned to the dedicated control channel, while the other was designed specifically

as a cognitive radio that could periodically sense and dynamically use the identified

un-used channels. To obtain the channel state accurately, they proposed two

collaborative channel spectrum-sensing policies, namely, the random sensing policy

and the negotiation-based sensing policy to help the MAC protocols detect the

availability of leftover channels. Under the random sensing policy, each secondary

user just randomly selected one of the channels for sensing. On the other hand, under

the negotiation-based sensing policy, different secondary users attempted to select the

distinct channels to sense by overhearing the control packets over the control channel.

They developed the Markov chain model and the M/GY/1-based queueing model to

characterize the performance of their proposed multi-channel MAC protocols under

the two types of channel-sensing policies for the saturation network and the non-

saturation network scenarios, respectively.

The concept of cross-layer design is based on architecture where different

layers could exchange information in order to improve the overall network


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performance. Promising results were achieved by cross-layer optimizations which

initiated a significant research activity in this area. Qian Zhang and Ya-Qin

Zhang.,2008 aimed at reviewing the cross-layer paradigm for QoS support in

multihop wireless networks.

QoS qualifiers in the IP header were prone to attacks. Malicious modifications

might result in both theft and denial of services. Standard IPsec does not cover these

header fields, leaving them prone to attacks. Hegland and Winjum.,2008 proposed a

variant of the IPsec authentication header that includes protection of these fields. The

solution was designed for single-domain networks with planned origin, such as

military ad-hoc networks.

Qing Chen et al.,2008 considered an opportunistic scheduling that takes

advantage of a time-varying channel among different receivers to improve system

performance. Maximizing the overall throughput and satisfying the QoS requirements

for the transmission flows were the two important objectives that were considered.

They presented an optimal scheduling policy which maximized the overall network

performance while satisfying the QoS requirements of the individual flow. They also

proposed a distributed cooperative and opportunistic scheduling algorithm that

modifies the IEEE 802.11 protocol to implement the optimal scheduling policy.

Yue Rong and Hua.,2008 addressed the proportional fair (PF) and quality-of-

service (QoS) issues of the STPS scheme, which were important for those networks

with asymmetric topology and/or asymmetric traffic demands. Both slow fading

channels and fast fading channels were considered. They demonstrated that the PF-

STPS scheme provided a very attractive tradeoff between the sum capacity and rate

distribution for asymmetric links. They also demonstrated that the QoS-STPS scheme


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has a much higher power-and-spectral efficiency when compared to the previously

existing QoS based scheme that do not exploit the temporal freedom.

Bo Yang and Hurson.,2007 proposed a semantic-aware image caching (SAIC)

scheme. Their proposed scheme could efficiently utilize the cache space and

significantly reduce the cost of image retrieval. The proposed SAIC scheme was

based on several innovative ideas: 1) multilevel representation of the semantic

contents, 2) association-based and Bayesian probability-based content prediction, 3)

constraint-based representation method showing the semantic similarity between

images, 4) nonflooding query processing, and 5) adaptive cache consistency

maintenance. The proposed model was introduced, and through extensive simulation,

its behaviour was compared against two state-of-the-art ad-hoc caching schemes.

Carrascal Frias., 2007 described a MM-DSR (Multipath Multimedia Dynamic

Source Routing) which was a multipath routing protocol DSR-based merged with a

cross-layer algorithm to provide QoS for multiple sources of video over IEEE

802.11b Ad-hoc networks. The weaknesses of the system with plain DSR and IEEE

802.11b were analysed and work was done in order to improve the throughput and the

final user quality. The performance of video-streaming applications was improved

under high traffic load conditions over mobile Ad-hoc networks.

Vergados et al.,2006, illustrated a method for invoking this algorithm to

achieve efficient end-to-end QoS provisioning and concluded by demonstrating the

superiority of the proposed algorithm over the other recently proposed TDMA

scheduling algorithms.

Hui Cheng et al., 2006, examined the problem of quality-of-service group

communications in a heterogeneous network which consisted of multiple mobile ad-


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hoc networks attached to the backbone Internet. A heuristic multicast algorithm

named delay and delay variation multicast algorithm (DDVMA) was proposed. It

could find a multicast tree satisfying the multicast end-to-end delay constraint and

minimize the multicast delay variation. Two concepts were proposed, namely, 1) the

proprietary second shortest path and 2) the partially proprietary second shortest path

could help the DDVMA achieve better performance in terms of multicast delay

variation than the delay and delay variation constraint algorithm be the most efficient

so far. An analysis was given to show the correctness of DDVMA, and simulations

were conducted to demonstrate the performance improvement of DDVMA in terms of

multicast delay variation.

In Lent., 2006 the author addressed two scalability problems related to the

cognitive map of packets in ad-hoc cognitive packet networks and proposed a

solution. Previous works included latency as part of the routing goal of smart packets,

which required packets to collect their arrival time at each node in a path. Such a

requirement resulted in a packet overhead proportional to the path length. The second

problem was that the multiplicative form of path availability, which was employed to

measure resources, loses accuracy in long paths.

Abdrabou and Weihua Zhuang.,2006 presented a position-based quality-of-

service (QoS) routing scheme for UWB mobile ad-hoc networks. The scheme applies

call admission control and temporary bandwidth reservation for discovered routes,

taking into consideration the medium access control interactions. Via cross-layer

design, it exploited UWB advantages at the network layer by using the position

information in routing and bandwidth reservation and by supporting the multirate

capability.


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Qingwen Liu et al., 2006 proposed a scheduling algorithm at the medium

access control (MAC) layer for multiple connections with diverse QoS requirements,

where each connection employs adaptive modulation and coding (AMC) scheme at

the physical (PHY) layer over wireless fading channels. Each connection was

assigned a priority, which was updated dynamically based on its channel and service

status; the connection with the highest priority was scheduled each time. The authors'

scheduler provided diverse QoS guarantees, used the wireless bandwidth efficiently,

and enjoys flexibility, scalability, and low implementation complexity

Yang Xiao and Yi Pan., 2005 have studied and enhanced distributed medium

access techniques for real-time transmissions in IEEE 802.11 single-hop ad-hoc

wireless networks. In the IEEE 802.11 MAC, error control adopted positive

acknowledgement and retransmission to improve transmission reliability in the

wireless medium (WM). They have addressed several MAC issues and QoS issues

for delay-sensitive real-time traffic in their study. First, a priority scheme was

proposed to differentiate the delay sensitive real-time traffic from the best-effort

traffic. In the proposed priority scheme, retransmission was not used for the real-time

traffic, and a smaller backoff window size was adopted. Second, they proposed

several schemes to guarantee QoS requirements. While the first scheme was to

guarantee frame-dropping probability for the real-time traffic, the second was to

guarantee throughput and delay. The last scheme was to guarantee throughput, delay,

and frame-dropping probability simultaneously.

A typical communication shelter was composed of unencrypted LANs

connected to a packet-encrypted backbone network. Elmasry et al.,2005 presented a


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partitioned QoS approach, focusing on QoS management at the unencrypted LAN that

complemented QoS management done at the encrypted backbone.

3.2 SECURITY ISSUES IN MANET

Kukreja et al.,2014 proposed a novel method for securing Mobile Ad-hoc

Networks. They used Dynamic Source Routing (DSR) as the principal protocol and

presented a method which selects the most trustworthy path between the source and

destination that was free from malicious nodes. The proposed method identified and

punished the malicious nodes inducing a variety of attacks like: malicious topology

change behaviour, dropping data packets, dropping control packets and packet

modification.

Using recent advances in mean field game theory. Yanwei Wang.,2014,

proposed a novel game theoretic approach with multiple players for security in

MANETs. The proposed scheme could enable an individual node in MANETs to

make strategic security defence decisions without the need for a centralized

administration. In addition, since security defence mechanisms consume precious

system resources (e.g., energy), the proposed scheme considered not only the security

requirement of MANETs, but also the system resources. Moreover, each node in the

proposed scheme needs to know just its own state information and the aggregate

effect of the other nodes in the MANET.

The distinctive features of mobile ad-hoc networks (MANETs), including

dynamic topology and open wireless medium, may result in making MANETs prove

to many security vulnerabilities. To overcome this issue Wei et al., 2014, proposed a

trust management scheme and the trust model has two components: trust from direct

observation and trust from indirect observation. Dempster-Shafer theory was another


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type of uncertain reasoning where the proposition of interest could be derived by an

indirect method. Combining these two components in the trust model, they obtained a

more accurate trust values of the observed nodes in MANETs. They then evaluated

their scheme under the scenario of MANET routing. Extensive simulation results

showed the effectiveness of the proposed scheme. Specifically, throughput and packet

delivery ratio could be significantly improved with a slightly increased average end-

to-end delay and overhead of messages.

Khatri., 2014 work proposed a composite identity and trust based model

(CIDT) which was dependent on public key, physical identity, and trust of a node

which enabled secure data transfer over wireless channels. CIDT was a modified DSR

routing protocol for achieving security. Experience based trust factor (TF) of a node

was used to decide the authenticity of a node. A valid certificate was generated for

authentic node to carry out the communication in the network. The proposed method

was found to work well for self certification scheme of a node in the network.

Ben Chehida et al., 2013 proposed a novel reputation-based clustering

mechanism to locate malicious nodes and isolate them. In order to reduce network

overhead and to handle network topology dynamicity, the proposed mechanism was

based on a specific clustering environment. The complexity of clustering maintenance

was for its part reduced by the use of a reputation based delegation process, thus

allowing the cluster-head to delegate its privileges to a chosen cluster member in case

of displacement or lack of energy.

Though there were various Routing protocols in Mobile Ad-hoc network, the

ad-hoc on demand distance vector (AODV) is one of the most popular and widely

used with many attributes when a particular host or nodes fails as it sends message


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regarding this to particular source. Performance will be on the downgrade. Pandya

and Shrivastava.,2013 observed the performance of AODV Reactive routing protocol

and Analyzes different attacks that could be possible on AODV. Their paper also

explained two layer signature schemes with security, which includes secure hash

algorithm which was further aimed at improving normal AODV's performance. Their

study also going proposed an extended version to the secure AODV protocol that

included secure hash algorithm, aimed at further improving its security with network

performance.

Qiu Wang et al.,2013 investigated the eavesdropping security of wireless ad-

hoc networks equipped with directional antennas. They studied the eavesdropping

possibility of OMN networks- SDA networks where each node is equipped with a

simplistic directional antenna and RDA networks were each node was equipped with

a realistic directional antenna. They conducted extensive simulations to evaluate the

eavesdropping possibility of OMN networks, SDA networks and RDA networks

while considering various environment factors, such as path loss attenuation and

shadowing effects.

The Cross Layer Design Architecture has been becoming more and

morepopular with its performance improvements. Kaur et al.,2013 proposed a security

architecture was proposed for Cross Layer Design Architecture of MANET. They also

analyzed the security mechanism in m-Governance applications in scope of proposed

security architecture. MANET security ideally takes place during the design phase of

the routing module.

Shurman et al., 2013 proposed a novel scheme that merged the process of

assigning IP addresses and security keys to the nodes in MANET and uses the


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protocol such that as soon as a node enters the network, it would be assigned an IP

address and security key. They assumed that no single protocol provides both IP

addresses and security keys for MANET nodes. The results of the proposed method,

which was based on T-DAAP, showed a significant reduction in the control packets

and packet delay. Additionally, it provided not only efficient security to the nodes

from the first moment they join the network, but also secure delivery of IP addresses

and security keys to the network nodes.

Since they allow fast and easy deployment and could cope with dynamic

topology changes. Ad-hoc network technologies were a candidate of choice for

military tactical networks. Bidan et al.,2013 presented the results of the PREVA

(PRotection and EVAluation) project whose goal was to study the use and security of

ad-hoc network technologies in the context of military tactical networks.

Soni and Nayak.,2013 presented a novel security mechanism to enhance

security & performance of AODV (Adhoc On-demand Distance Vector) routing

protocol under the attack for MANET (Mobile Ad-hoc Networks). The AODV

routing protocol was initially developed without considering the security factor.

Hence it was not able to defend against any kind of security attack. But there were

many security mechanisms available that make AODV secure. In their study, they

presented a novel security mechanism that integrates digital signature and hash chain

to protect the AODV routing protocol that was capable of defending itself both

against malicious and unauthenticated nodes with a marginal difference in

performance. The proposed security mechanism was also simulated in the Network

Simulator 2 (NS2) to show marginal performance difference under attack.


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Ad-hoc Networks were a new generation of networks offering unrestricted

mobility without any underlying infrastructure. Due to lack of centralized control,

secured communication in mobile ad-hoc network continues to be a crucial issue due

to dynamic nature of the network topology. Ramachandran and Ruban.,2013 proposed

an effective security AODV algorithm called ES-AODV to enhance data security.

Recently there has been an increasing interest in bio-inspired algorithms, such

as Ant Colony Optimization (ACO), for developing and designing communication

systems. These algorithms borrow the laws from nature by mimicking natural

biological behaviours. Memarmoshrefi et al., 2013, considered the dynamic nature of

ad-hoc networks in terms of nodes behavior and nodes' speed with regards to the

network size. They investigated the performance of a proposed autonomous bio-

inspired public key management against these parameters.

Donglai Sun et al.,2012 proposed a scheduling scheme under physical layer

security. This emerging technology was introduced to provide perfect secrecy to

wireless ad-hoc network. However, a big loss of network performance was also

imported to the system. As links with different physical layers coexist in the wireless

network, service qualities such as overall throughput could be affected if traditional

scheduling schemes were applied. Thus, it is important to develop a new MAC layer

scheduling scheme.. Here, opportunistic scheduling with scaled transmission rate was

used to solve the problem. A pure threshold policy could be derived for scheduling

scheme.

Nogueira et al., 2012 presented SAMNAR, a Survivable Ad-hoc and Mesh

Network ARchitecture. It aims at managing adaptively preventive, reactive and

tolerant security mechanisms to provide essential services even under attacks,


83

intrusions or failures. They used SAMNAR to design a path selection scheme for

WANET routing. The evaluation of this path selection scheme considers scenarios

using urban mesh network mobility with urban propagation models, and also random

way point mobility with two-ray ground propagation models.

Jeyakumar and Nithya.,2012 proposal combined both the technologies and

provided avenues for further research. In ad-hoc grid environment in particular,

resources were not always available as the nodes could spontaneously connect and

disconnect any time. They proposed a mobile agent based trust model in ad-hoc grid

environment for improving the performance considerations and security issues.

Simulation results demonstrated the effectiveness of the proposed work, to detect and

punish those nodes with malicious behaviour, such as selfish nodes, injected nodes

and so on.

Glowacka and Amanowicz.,2012 presented a concept of Dezert-Smarandache

theory application to enhance security in tactical mobile ad-hoc network. Tactical

MANET, due to its specification, requires collection and processing of information

from different sources of diverse security and trust metrics. The authors specified the

needs for building a node's situational awareness and identified data sources used for

calculations of trust metrics.

In Yue Ma et al., 2012 the authors proposed an Adaptive Risk Control and

Security Management (ARCSM) mechanism for centralized distributed systems.

ARCSM has the ability to guarantee the soft real-time and provide as strongest

possible security protection. To meet this requirement, the host server was able to

refuse to serve for those tasks that missed the deadline missed tasks. In each node, a

two-level scheduling framework was designed to implement the feedback control


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twice. In the first feedback, an appropriate initial security level was assigned for new

task. At the runtime, the second feedback could dynamically adjust the ready tasks'

security level based on runtime status. Considering the features of embedded systems,

they measured the energy and time costs of cryptographic algorithms and established

a method to quantify the security risk.

ZRP was one such protocols that help in creating and maintain routes in spite

of the dynamic network topology. This protocol was vulnerable to a number of

security threats that come from internal malicious nodes which have authorization

credentials to participate in the network. Malicious nodes deliberately drop data

packets and disrupt the correct operation of the routing protocol. ElRefaie et al.,2012

authors proposed a security enhancement of ZRP based on trust calculations. The

performance of a defenceless ZRP when a number of network's nodes misbehave and

drop data packets was evaluated. The impact of proposed enhancement was then

evaluated and compared to the performance of the defenseless ZRP.

Younchan Jung and Festijo.,2011 proposed the key agreement architecture

that could be realized by encrypting RTP (Real-time Protocol) packets with call-based

dynamic group key. They also proposed the key control device (KCD) that can legally

listen to any group call. They solved these contradictory sounding goals: encrypting

call traffic and monitoring call traffic. The key agreement part forced every group

member to calculate the key tree by means of an iterative Diffie-Hellman group key

exchange. In the proposed key management, the transaction manager (TM) was

designed to report call information so KCD may compute the same group key for

security control. In contrast to the called members, the calling user (that was, TM)

generated a random number that was temporarily used as its one time session key


85

doing duty for its original private key. This one time session key would stop the group

key from being re-used and prevent exploitation of group key weaknesses. Finally,

they analyzed the computational load (Cload) and message transmission load

(MTload) required for group key computation.

Securing the transfer of data in mobile ad-hoc networks (MANETs) was still a

challenging issue. Che-Yu Liu et al.,2011 proposed a method for providing message

security in MANETs when nodes cooperate in routing. Their approach combines a

trust-based multipath routing scheme and a real-time recurrent neural network-based

(RRNN) cipher (yielding TR-RRNN scheme) to deal with the issues underlying

message confidentiality, integrity, and access control. A recently proposed message

security scheme for MANETs (so- called Original Trust-based Multi-path Routing

scheme (OTMR)) used. The route selection time and trust compromised as the

performance criteria.

For transferring sensitive data as in military applications, it is necessary to

achieve integrity, confidentiality and authenticity. Diwanji and Shah., 2011 proposed

a scheme to generate encryption key with unimodal biometric fingerprint. As mobile

ad-hoc network does not have heavy computational power, multimodal biometric

approach is not feasible. Feature sets were generated from the receivers fingerprint

with the help of regression model using binomial distribution. The encryption key

generated was of 48 bits for the DES algorithm. Digital signature was used to achieve

authentication. The proposed scheme was evaluated for cryptanalysis, brute force

attack and it was found out that this scheme could withstand against all attacks. It was

observed that the that false accept rate was zero and that the false reject rate was

higher.


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Mariappan and Mohan.,2011 presented new protocol design scenario called

Re-Pro Routing Protocol (RPRP) Broadcasting wireless mobile Ad-hoc Network.

They also compared the performance of Mobile Ad-hoc Networks protocols like as

Ad-hoc On-Demand Distance Vector Routing protocol focusing on the effects of

changes such as the increasing number of receivers or sources and increasing the

number of nodes. Although some simulation results of MANET protocols have been

published before, these protocols have not been compared in isolation. The

performance evaluation of these protocols was systematically done by performing

certain simulations. The trust methods were one of the security methods in mobile

Ad-Hoc networks and though methods were prone to security risks, they however

found their acceptance due to efficiency over computationally expensive and time

consuming cryptographic methods. The major problem with the trust methods was the

period during which the trust grows and was yet to reach the requisite threshold. They

also proposed a security mechanism dependent upon Electronic Code (EC) combined

with permutation functions. Their proposed mechanism has the following advantages

lesser time complexity, easy implementation facility, computational inexpensive and

high brute force search value.

Koul et al.,2011 used system level security for deploying the overall security

in MANETs. The system level security was the security at node level as they believe

that if nodes behave properly and in a coordinated fashion, the insecurity level would

go down drastically.

Chi Zhang et al.,2011 analysed a general random network model, the

asymptotic behaviours of secure throughput and delay with the common transmission

range rn and the probability of neighboring nodes with having a primary security


87

association were quantified when the network size n was sufficiently large. The costs

and benefits of secure-link-augmentation operations on the secure throughput and

delay were also analyzed. In general, security has a cost: Since they require all the

communications operate on secure links, there was a degradation in the network

performance when pf <; 1. This implies that even when the pf goes to zero as the

network size becomes arbitrarily large, it was still possible to build throughput-order-

optimal secure WANETs, This is of practical interest since pf was very small in many

practical large-scale WANETs.

Ad-hoc m-commerce was an emerging method for conducting online trading

wirelessly within dynamic network communities. Osman and Taylor., 2011 authors

presented a scheme for identity support using PGP certificates in a fully self-

organised manner, where a trading pseudonym and photograph were used as identity

credentials. It let’s participating parties collaborate in a Peer-to-Peer (P2P) way to

establish their online identity in such a manner that was resistant to such attacks

without any mediation of a Certification Authority (CA). It also allowed the

participating parties handle the security settings of the trading system as well as share

knowledge about fellow participants' trading behaviour without relying on support

from a network service provider.

McNerney and Ning Zhang.,2011 investigated whether a single path should

be sought using a reservation-based or a non-reservation-based approach. They

compared INSIGNIA, an adaptive, reservation-based approach to QoS in MANETs,

with Dynamic Source Routing (DSR), a best-effort MANET routing protocol, using

simulation. The performance of these two approaches was evaluated in the presence

of a variable number of malicious nodes executing blackhole and grayhole data packet


88

forwarding attacks and a denial of QoS request attack. These findings indicated that

under certain conditions, e.g., when the network traffic level was high and the threat

level was medium-to-high, INSIGNIA's single-path adaptation mechanism was no

longer sufficient. Instead an adaptive multi-path routing may help in achieving better

QoS support.

According to identity-based cryptography, threshold sharing scheme and

mapping point algorithm, Hongru Wei, Chao Qi.,2011 presented a new Ad-hoc

network security model and verified its safety. Safe mode without third party KGC

includes sharing scheme, communication threshold key process of decrypted and

signature verification.

Quansheng Guan et al., 2011 proposed a topology control scheme to improve

throughput by jointly designing upper layer security schemes and physical layer

schemes related to channel conditions and relay selections for cooperative

communications.

Salmanian et al., 2011 considered nodes in multiple groups using the same

channel (one interface) and a hierarchical traffic pattern typical of a tactical operation.

They showed that the inter-group SAs, between group heads, require a different trust

model than that of intra-group SAs if the overhead of authentication was to be kept

manageable. They formed a new trust model, apply it to the group heads and adapted

their SA duration to their hopped distance away from their authenticators. Their

results showed that for group heads, the number of hops was found to be a more

effective parameter to which their SA duration should be adapted than their actual

link distance modelled by FER.


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To obtain the optimal scheme of combining continuous user authentication

and IDSs in a distributed manner, they formulated the problem as a partially

observable Markov decision process (POMDP) multi-armed bandit problem.

Shengrong Bu et al.,2011 presented a structural result method to solve the problem for

a large network with a variety of nodes. The policies derived from structural results

were easy to implement in practical MANETs.

Multimodal biometric technology provides potential solutions for continuous

user-to-device authentication in high-security mobile ad-hoc networks (MANETs).

Shengrong Bu et al.,2011 studied the distributed combined authentication and

intrusion detection with data fusion in such MANETs. Multimodal biometrics were

deployed to work with intrusion detection systems (IDSs) to alleviate the

shortcomings of unimodal biometric systems. The system decided whether user

authentication (or IDS input) was required and which biosensors (or IDSs) should be

chosen, depending on the security posture.

MANET poses a number of security challenges due to changeable topology,

wireless shared medium, diverse resources and inflexible resource constraints etc.

Ghosh et al., 2011 presented an elaborate view of issues of MANET with an emphasis

on security challenges in reactive protocol with different dimensions such as secure

routing, secured key management and trust management through reputation in order

to detect intrusion and protect.

Younchan Jung and Atwood.,2011 proposed a key agreement scheme that

could be realized by encrypting mobile traffic with the agreed secret session key.

They also proposed a key control device (KCD) that could legally listen to any

session call. The key agreement process forces a pair of call participants to calculate


90

the Diffie-Hellman session key just before a call session begins. It starts by sending

an SMS message for announcing its temporary IP address (TIP) and `nonce' from the

caller to the callee, so that the callee may learn the caller's TIP immediately at the

beginning of each call and send a `GET/nonce' command in an HTTP request line to

perform the Diffie-Hellman public key exchanges with the caller. In the proposed

security control, one of the call pair was designated to report call information so that

the KCD may compute the same secret session key as the call pair agree.

Abdelhaq et al.,2011 proposed a Local Intrusion Detection (LID) security

routing mechanism to detect Black Hole Attack (BHA) over Ad-hoc On Demand

Distance Vector (AODV) MANET routing protocol. In LID security routing

mechanism, the detection of intrusion was performed locally using the previous node

of the attacker node, instead of doing it via the source node as in Source Intrusion

Detection (SID) security routing mechanism. By performing LID security routing

mechanism, the security mechanism overhead would be decreased.

Based on the current researches on Ad-hoc Networks, a Cluster security model

has been proposed for Ad-hoc networks in theis study, which is authorized by user or

validated by the cluster headers in other clusters. Junlin Li et al.,2010 described the

cluster formation, the selection of the head of clusters and design ideas of this Cluster

security model.

Miede et al., 2010 proposed a generic metamodel for IT security capturing

both its major concepts and their relationships to each other. With a focus on attacks,

they demonstrated how this model was applied to different scenarios in distributed

systems, i.e., Peer-to-Peer systems, Service-oriented Architectures, and Mobile ad-hoc

Networks. This allowed for a better understanding of IT security in general and


91

attacks in particular, thus, enabling effective communication between different parties

during the development of security-critical IT systems.

Secure routing protocol attracts much more attention in mobile ad-hoc

networks for the purposes of secure data transmission. But the improvement of

security often sacrifices the delivery rate or other QoS. Minghu Wu et al.,2010

proposed a secure routing protocol by integrating multipath routing and secret

sharing, Selecting efficient and securing multiple disjoint routes were done by

integrating multiple metrics including hop count, traffic load, node compromising and

broken probability. This proved to be an effective mechanism proved to be in

protecting data security and simultaneously enhancing performance efficiency in the

whole transmission process.

In designing security mechanisms for mobile ad-hoc networks, one must

consider the attack variations and also as the characteristics of these attacks that could

be launched against the ad-hoc networks. Mishra et al., 2010 classified several

common attacks against the ad-hoc networks routing protocols based upon the

techniques that could be used by attackers to exploit routing messages. Some of those

techniques were modification, interception, fabrication, and interruption.

3.3 SUMMARY

This chapter gives a brief review about the quality of service and security

issues in MANET. Reviews of routing, importance of security, problems faced in

MANET by various dimensions were discussed in this chapter.


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