The networks not present of any centralized or pre-established structure are known as Ad hoc networks. Ad hoc Networks are the class of wireless networks that use multiple hop radio relay. Mobile Ad-hoc Network (MANET) is a combination of wireless mobile nodes and connected other in a dynamic way. ThesisScientist.com

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CHAPTER 1
INTRODUCTION
1 Introduction:
The higher demand of wireless communication and wireless devices have tends to
research on self-organizing, self-healing networks beyond the interference of some
centralized or pre-established infrastructure/authority. The networks not present of any
centralized or pre-established structure are known as Ad hoc networks. Ad hoc Networks
are the class of wireless networks that are uses multiple hop radio relay. Mobile Ad-hoc
Network (MANET) is a combination of wireless mobile nodes and connected other in
dynamic way. Nodes make a temporary/short-term network without any fixed
infrastructure where nodes are fully free to move arbitrarily.
FIGURE 1.1 Mobile Ad Hoc Network
The Nodes must behave like routers, take part in discovery and keep routes to other nodes
in the network [1] Wireless links in MANET are highly error level and can go down easily
due to mobility of nodes. Stable routing is a complicated assignment due to highly
dynamic environment in Mobile Ad-hoc Network [2]. So mobile ad-hoc network
(MANET) is a self-organised network of mobile routers (and associated hosts) associated
by wireless links - the union of which form a random topology. The routers free to move
randomly and organize themselves at random. a network operates in a separate fashion, or
may be link to the higher level of Internet. Minimal configuration and fast deployment

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make ad hoc networks flexible for emergency situations like natural or human prompted
disaster areas, military conflicts, and emergency medical situations. [3]
1.1 Research Motivation
With the speedy area of mobile devices and their extensive use in modem lifestyle, the
paradigm of networking has transfer from fixed networks to mobile wireless networking
technologies with limited or without infrastructure support. This paradigm transfer was
designated in [8] [9], where unworkable researchers describe the future integration of
mobile networking technology with the Internet. Mobile ad hoc networks have fast
significance in current pervasive networking due to their desirable characters such as fast
deployment and without infrastructure.
• Lack of routers, nodes in the network have to participate and accept the routing and
service of data requirement.
• so the free architecture of the network where the nodes are independent join in and
leave any time, a rogue node can join the network to reason harm.
• Most widely used ad hoc routing protocols such as Ad hoc On-demand Distance Vector
routing (AODV) [to] and Dynamic Source Routing (DSR) [11] are created under the
assumption that all nodes trust each other and there are no malicious attacker nodes in the
network. Therefore, the presencey of any such nodes imposes the security challenges.
Malicious nodes can creat disturbance through a wide range of attacks including both
routing and data forwarding attacks.
• Exacting resource constraints exist in MANETs; for example, most of the nodes in
MANETs rely on exhaustible battery resources and intruders can activity this to
compromise routing and data forwarding service in the network.
• Highly dynamic topology of the network due to nodes' mobility makes it difficult to
detect the attacking node. Therefore, the fundamental motivation of the research described
in this thesis appear from realizing the need to secure mobile ad hoc networks from a wide
variety of attacks. Attacks from intruder or malicious nodes cause various degree of
damage to the network depending on the type of attack used. We note that a considerable
research effort has already been made to secure MANETs. We can find some examples in
literature where various routing attacks are examined and their proposals are made to

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detect these individual attacks. However, our views in this thesis is that most of the work
distinguish previously in the literature has focused on detecting and preventing a single
attack; but very few have suggested a generalize approach that can secure against a wide
variety of attacks. We consider that security is a major service for MANETs, where there
is no central administration or control to monitor and identify attacks or activities that
compromise network security. We also note the lack of research on mechanisms with the
capability to detect and prevent a range of possible attacks in MANETs. Therefore in our
opinion, further research is needed on mechanisms that can protect MANETs against a
wide variety of attacks effectively. This is especially true for reactive routing protocols
since they are more widely used.
1.2 Background and Related Work:
Technological advances in field of communications take place at an incredible pace in the
last few decades that has changed the manner we live and communicate; in particular,
breakthroughs in the "wireless world" have revolutionized our behaviour. Developments
in technology have not only brought change in personal behaviour but also from a
commercial perspective companies are adapt to the advancement in wireless networking
technology to upgrade customer services. One of the high advances in the wireless
networking technology is the concept of ad hoc networking. Mobile ad hoc network is
attracted the research community since 1990s, due to the fast growth of wireless devices
and Wi-Fi (IEEE 802.11). As part of this, a significant amount of research in MANETs
has looked at giving desirable level of security services. This chapter first describe the
paradigm of mobile ad hoc networking include its characteristics, application and routing.
We can consider security aspects, describing vulnerabilities, classifying possible attacks
and reviewing existing proposals that secure MANETs from attacks. Finally, in these
section we present logic of disturbance detection and prevention (IDP) including, category
of IDS, ID techniques, IDS challenges in MANETs, and review existing IDS architectures
and acceptance from the literature.
1.3 MANETs Paradigm:
1.3.1 Background& Standards

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In 1997 the IETF produce the Mobile Ad hoc Networking Working Group [14] and since
then considerable effort has been put in by the research community for similarity on this
arrive paradigm. The aim of this working group is to similarity the routing protocol by
considering their suitable functionality in MANETs environment. They established two
standard track routing protocol particular as reactive MANET protocols and proactive
MANET protocols. One of the main considerations for the similarity of routing protocols
is their performance matter such as loop freedom, demand based operations, distributed
operation and proactive operations [15]. Take into consideration the configuration matter
of MANETs, IETF recently figure another working group called Ad Hoc Networks Auto
configuration (auto conf) [16]. The main purpose of this working group is to describe the
matter in addressing model for ad hoc networks that is how the nodes in ad hoc network
constract their address both locally and globally when they connect to other networks. The
auto configure working group has addition in a form of internet draft [17], where they
propose and describe a model for constract IP addresses in ad hoc networks. The research
society perspective on this multi hop ad hoc networking technology has chang as the
technology has developed in the last two line. In [18] they define the term pure MANETs
referring to an ad hoc network with no infrastructure help as compared to one with
bounded infrastructure support.
1.3.2 Ad-Hoc Networks
Ad-Hoc networks have without arrangement where the nodes are free to add and left the
network. The nodes are attached with each other through a wireless link. A node can serve
as a router to send the data to the neighbors’ nodes. Therefore this type of network is also
known as infrastructure low networks. These networks have no centralized administration.
Ad-Hoc networks have the able to handle any malfunctioning in the nodes or many
changes that its experience due to topology changes. Whenever a node in the network is
down or leave the network that reason the link between other nodes is broken. The
effected nodes in the network simply request for advanced routes and advanced links are
established Ad-Hoc network can be considered in to stable Ad-Hoc network (SANET) and
Mobile Ad-Hoc network (MANET).
1.3.3 Static Ad-Hoc Networks:

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In static Ad-Hoc networks the geographic place of the nodes or the stations are static.
There is no mobility in the nodes of the networks, that’s why they are known as fixed Ad-
Hoc networks.
1.3.4 Mobile Ad-Hoc Networks
Mobile Ad-Hoc network is an uncontrolled system, where nodes/stations are connected
with each other over wireless connection. There is no limit on the nodes to join or leave
the network, therefore the nodes add or leave freely. Mobile Ad-Hoc network topology is
dynamic that can change speedily because the nodes move freely and can organize
themselves in any case. This property of the nodes makes the mobile Ad-Hoc networks
insecure from the point of view of scalability and topology.
1.4 Applications of MANETs:
Ad hoc networks are fitted for use in situations where an infrastructure is unaccessible or
to deploy one is not total effective [39]. The following are selected of the important
applications.
 Business Applications: many possible uses of mobile Ad hoc networks is in any
business environments, where the need for Gray Hole computing might be most
important outside the office environment than inside, such as in a business meeting
outside the office to brief clients on a given work. Work has been going on to
introduce the fundamental aim of game theory and its applications in
telecommunications. Game theory originated from economics and has been
applied in various fields. Game theory contract with multi-person decision making,
in which each decision maker tries to maximize his speciality. The concert of the
users is necessary to the operation of Ad hoc networks; therefore, game theory
give a good basis to analyse the networks. People playing multi-player games
usually do so over the Internet, uses a remote host. This model is call the client-
server model. In the class of multiple users, each user just connected to a common
server, and the server forwards the packets to connected users.
 Military Applications: Military applications have motivated recent research on
Ad hoc networks. The capability to quickly set up a network among military units
in hostile territory without any infrastructure help can provide friendly forces with

6. 6
a considerable tactical advantage on the battlefield. For instance, each soldier can
transfer a mobile device that represents one of the mobile nodes in an Ad hoc
network connected all soldiers, tanks, and other vehicles as shown in Fig 3.3.
Recently advances in robotics have also motivated the plan of automated
battlefields in which unmanned fighting vehicles are send into battle. Supporting
military applications requires self-maintained mechanisms that provide robust and
reliable communication in dynamic battle condition.
 Emergency Operations: other promising application field for Ad hoc networks is
emergency services, including search and rescue and disaster recovery operations.
for example of search and rescue, consider airline that attached to small wireless
devices to the life jackets under each seats. Guess that the plane has mechanical
problem and has to made an emergency landing in the water.
1.6 Challenges of Mobile Ad hoc Network
Ad hoc networking has become a favoured field of study in the last few years. . Every
aspect of the network has been found in one way or other way at various level of problem.
Yet, no permanent solution to any of the problems is found or, at least, agreed upon. In
contrast, more questions have been raised. The topics that require to be solved are as
follows-
 Scalability
 Routing
 Quality of service
 Client server model shift
 Security
 Energy conservation
 Node cooperation
 Interoperation
The mechanism to solve above aspects has been proposed and possible update solutions
have been discussed. In this current research work one of the aspects “the routing” has
been reviewed for appropriate protocol which is performing better under the dynamic
condition of network.

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 Scalability: Most of the innovative thinker portraying applications which are
anticipated to benefit from the Ad hoc network technology take scalability as
granted. For example, assume that, the vision of omnipresent computing where
networks can be of "any size". However, it is doubtful that how such large
networks can actually grow. Ad hoc networks can suffer, from the scalability
problems in volume, by nature. The throughput per node decline at a rate 1/√N,
where N is the number of nodes, in a non-cooperative network, where Omni-
directional antennas are being utilised [32]. That means, in a network with 110
nodes, a device can get, maximum, about one tenth of the theoretical network data
rate. This problem, cannot be resolved except by the advancement of physical
layer, such as directional antennas. If the available capacity like bandwidth,
radiation pattern of antenna sets some restrictions for communication. This
requires the formation of new protocols to overcome circumvents. Route
acquisition, service location encryption key exchanges, are some of the examples
of tasks that will need considerable overhead as the network size grows. If the
scarcely available resources are lost with profuse control traffic, then these
networks may see never the day dawn. Hence, scalability is a hot research topic
and needs to be taken into account for the design of solutions for Ad hoc networks.
Routing: Routing in wireless Ad hoc networks is necessary due to highly dynamic
environment. An Ad hoc network is a bunch of wireless mobile nodes differently
creating a temporary network without the use of any centralized administration or
pre-existing network infrastructure. In a typical Ad hoc network, mobile nodes
arise simultaneously for some period of time to exchange information over the
network. During the interchange of information, the nodes may continue to move,
and so the network must be prepared to establish routes continuously among
themselves without any external support.
 Quality of Service (QOS): The heterogeneity of existing Internet applications
gave a summon to network designers. These network designers make the network

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to serve best-effort service only. Live video, voice and file transfer are some of the
applications having very manifold requirements. Qualities of Service aware
solutions are created to meet the emerging requirements of these applications.
QOS is guaranteed by the network which helps in providing certain performance
for a given flow, or a collection of flows regarding QOS parameters like jitter,
bandwidth, delay, packet loss probability, and so on. In spite of the current
research efforts in the QOS area, QOS is still an untraversed area in Ad hoc
networks. Some issues of QOS are robustness, QOS in routing algorithms, policies
and protocols with multipath, and pre-emptive, priorities remain to be addressed.
 Client-Server Model Shift: A network client is usually designed to use a server as
its partner for network transactions in the Internet. These servers can be found
either by static configuration or automatically. In Ad hoc networks, the network
formation cannot be defined by assembling IP addresses into subnets. There may
not be servers, but the basic services demand still exists. Authentication, name
resolution, service location and address allocation itself are some examples of the
very basic services which are required but their location in the network is possibly
even changing over time and still unknown. Because of the infrastructure less
nature of these networks and node mobility a different addressing approach is
required. Besides, it is still unclear that who is responsible for managing various
network services. Hence, while there has been large scale research initiatives in
this area, the issue of shift from the traditional client-server model remains to be
properly addressed.
 Security: Security is an essential issue that has to be addressed in Ad hoc
networks. Many applications of MANET such as Military and Confidential
Meetings require intense security against active/passive eavesdropping attacker
and enemies. Ad hoc networks are particularly prone to malicious behaviour. Any
centralized infrastructure or lack of certification authority makes these dynamically
changing wireless structures very vulnerable to infiltration, interference,
eavesdropping and so on. Security is considered to be the main "roadblock" for
commercial application.

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 Energy Conservation: Within the Ad hoc networking research energy protective
networks have become very popular. At this time, energy preservation is being
addressed in every layer of the protocol stack. There are two main research topics
which are maximization of the lifespan of the whole network and maximization of
existence of a single battery which are almost identical. The latter is associated
with commercial applications and node cooperation issues while the former is
more fundamental, for example, in military environments where node cooperation
is expected. The goals can be fulfilled either by developing batteries better than
before, or by making the network terminals operation more energy efficient. The
first perspective gives a 50% increase in battery life in the near approach. As to the
power consumption of the device, the primary aspect are achieving to the energy
savings through the low power hardware development using some techniques such
as variable clock speed CPUs, flash memory, and disk spin down. However, from
the networking point of view, our interest should focuses on the device's network
interface, which is often consumes largest power. At the network interface, energy
efficiency can be improved by developing transmission/reception technologies on
the physical layer. Much research has been carried out at three layers which are the
physical, medium access control (MAC) and routing layers, while some little
research has been done at the transport and application layers. Yet, there is still
much more investigation to be carried out.
 Node (MH) Cooperation: The node cooperation stands in the way of commercial
application of the technology because it is closely related to the security issues.
There is no alternative to receive the corresponding services from others but one
has to depend on other people’s data. However, when there is a difference found in
amount and priority of the data, the situation becomes further more complicated.
Also, it should not denied access to other nodes because of such limited behaviour.
Encouraging nodes may cooperate which lead to the introduction of billing, similar
to the idea referred for Internet congestion control. Reward could be given to some
well-behaving network members. While malicious node could be charged with
higher rates. The implementation of any kind of billing process is a very
challenging task. These issues are still largely open.

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 Interoperation: The self-organization of Ad hoc networks is a difficult task when
two independent formed networks come physically close to each other. This is yet
an unexplored research subject that has implications on all levels of the system
design. When two independent Ad hoc networks move into same area whose
interference with each other becomes inevitable. Preferably, the networks would
recognize the condition and be merged. However, the issue of joining two
networks is not important. These networks might be using different
synchronization, or even several routing or MAC protocols. However, security is a
major concern. For example; a situation like a military unit moving into an area
covered by a sensor network where different routing protocol can be used by
military moving unit with location information support, whereas the sensor
network would have a easier stable routing protocol. One of the most important
objective of recent research on all wireless networks is to provide smooth
integration of all types of networks.
1.7 Issues to be considered when deploying MANET
Some of the main routing issues to be considered when establishing MANETs are as
follows:
 Unpredictability of Environment
 Reckless nature of Wireless Medium
 Amenity-Constrained Nodes
 Dynamic Topology
 Transmission Errors
 Node Failures
 Connection Failures
 Route malfunction
 Overfull Nodes or Links
 Unpredictability of Environment: Ad hoc networks may be situated in
dangerous conditions, unknown territories, and even aggressive environments

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where tampering or the actual destruction of a node is about to happen. Depending
on the environment, node can be failed frequently.
 Unreliability of Wireless Medium: Communication over the wireless medium is
reckless and subjected to errors. The quality of the wireless link is uncertain due to
varying environmental conditions such as inclement weather or high levels of
electro-magnetic interference (EMI).
 Resource-Constrained Nodes: MANET nodes are generally battery powered as
well as limited in processing and storage capabilities. MANET nodes may be
situated in areas where it is not possible to re- charge and thus they have limited
lifetimes. Due to these constraints, they must have algorithms which are energy
efficient. These algorithms can also be operated with restricted processing and
memory resources. The wireless medium may also have limited bandwidth
because these nodes may not be able to sacrifice the energy consumed by operating
at full link speed.
 Dynamic Topology: As nodes are free to move anywhere in an Ad-hoc network,
the topology of the network may change constantly. As nodes can move in and out
of range of each other, some links break while new links are created between
nodes. As a result, MANETs are vulnerable to several types of faults.
 Transmission Errors: The unreliability and unpredictability of the wireless
medium and the environment respectively may lead to transmitted packets being
distorted and thus received packet errors.
 Node Failures: Due to different types of harmful conditions in the environment,
MANET nodes may fail at any time. MANET nodes may leave the network either
voluntarily or when their energy supply is depleted.
 Link Failures: Either changing environmental conditions (e.g., increased levels of
EMI) or node failures may cause links between nodes to break. Because of the link
failures source node has to discover new routes through other links.
 Route Breakages: If the network topology is changed due to node/link failures
and/or node/link additions to the network, then the route becomes out-of-date and

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thus incorrect. Packets are forwarded through stale routes may either eventually be
dribble or be detained depending upon the network transport protocol.
 Congested Nodes or Links: Because of the dynamic topology of the network and
the nature of the routing protocol, certain nodes or links may become over
congested. This will lead to either packet loss or larger delays.
1.8 Applications of Mobile Ad hoc Network
Ad hoc networks are best suited for use in circumstances where an infrastructure is
unavailable or to deploy one is not cost effective. The following are some of its important
applications.
 Business Applications: One of the use of mobile Ad hoc networks is in some
business environments, where the need for Gray Hole computing might be more
important outside the office environment than inside, like in a business meeting
outside the office to brief clients on a given assignment. Work has been done on to
introduce the some basics concepts of game theory and its applications in
telecommunications. Game theory arises from economics and has been
successfully applied in various fields. Game theory tackles with multi-person
decision making, in which each decision maker tries to maximize its utility. The
coordination among users is necessary to the operation of Ad hoc networks; hence,
game theory provides a good basis to analyse the networks. Generally people
playing multi-player games over the Internet, with a remote host. This model is
known as the client-server model. In case of multiple users, each user just connects
to a common server, and the common server forwards the data packets to the
connected users.
 Military Applications: Military applications have encouraged early research on
Ad hoc networks. The Ad-hoc networks have the ability to quickly set up a
network among military units in hostile territory without any infrastructure support
and can provide friendly forces with a considerable tactical benefits on the
battlefield. For instance, in the battlefield each soldier can carry a mobile device
that represents one of the mobile nodes in an Ad hoc network linking all soldiers,
tanks, and other vehicles as. Recent improvements in robotics have also gave the

13. 13
idea of automated battlefields in which unmanned fighting vehicles are sent into
battle. Supporting military applications requires self-organizing and self-
configuring mechanisms that provide robust and reliable communication in
dynamic battle situations.
 Emergency Operations: Emergency services is another promising application
area for Ad hoc networks, which includes search, rescue and disaster recovery
operations. For an example of search and rescue, assume an airline which attaches
small wireless devices to the life jackets under each seat. Now assume that the
plane has some mechanical problems and has to make an emergency landing in the
water.