Routing AODV DSR and ZRP

Published on January 2017 | Categories: Documents | Downloads: 29 | Comments: 0 | Views: 236
of 97
Download PDF   Embed   Report

Comments

Content

CHAPTER 1
INTRODUCTION
1.1 MOBILE AD-HOC NETWORK (MANET):
A Mobile Ad-hoc Network (MANET) consists of a number of mobile battery
powered energy constraint nodes communicating with each other in single or multiple
hops over wireless links. They are temporary and infrastructure less without any central
controller. Every node generates its own data traffic and cooperatively forwards others
which are not in direct communication range of each other i.e. acts both as an end
terminal and router. Due to the mobility and dynamic addition/deletion of nodes,
topology changes frequently and on-demand routing protocols are required. MANETs
should be capable of handling these topology changes through network reconfigurations.
Routing protocols for MANET should be adaptive to the topology changes and be
capable of discovering new routes when old routes becomes invalid due to such change.
The number of nodes in MANET changes with time so the routing protocols should be
scalable.
A mobile ad hoc network is a collection of wireless mobile nodes that are
dynamically and arbitrarily located in such a manner that the interconnections between
nodes are capable of changing on a continual basis. There are some unique characteristics
of mobile ad hoc networks.

1.1.1 CLASSIFICATION OF MOBILE AD HOC NETWORK
Current researches classify mobile ad hoc networks into two categories. The first
one is called a managed environment, where a common, trusted authority exists to
provide certain services, such as a certificate authority. Another is called open
environment, where a common authority that regulates the network does not exist.

1

It is also referred as full self-organization environment, namely the network has
the ability to work without any external management and configuration. Extensive work
has been done recently in both areas.
The routing protocols can be roughly divided into three categories: proactive
(table driven routing protocols), reactive (on-demand routing protocols), and hybrid. The
primary goal of such an ad hoc network routing protocol is to provide correct and
efficient route establishment between pair of nodes so that messages may be delivered in
time. Cluster Based Routing Protocol (CBRP) is a routing protocol designed for use in
mobile ad hoc networks. The protocol divides the nodes into a number of overlapping or
disjoint clusters in a distributed manner. A cluster head is elected for each cluster to
maintain cluster membership information. Inter-cluster routes are discovered dynamically
using the cluster membership information kept at each cluster head. By clustering nodes
into groups, the protocol efficiently minimizes the flooding traffic during route discovery
and speeds up this process as well.

1.1.2 WHAT IS MOBILE AD HOC NETWORK?
Mobile Ad-hoc network is a set of wireless devices called wireless nodes, which
dynamically connect and transfer information. Wireless nodes can be personal computers
(desktops/laptops) with wireless LAN cards, Personal Digital Assistants (PDA), or other
types of wireless or mobile communication devices. Figure 1.1 illustrates what MANET
is. In general, a wireless node can be any computing equipment that employs the air as
the transmission medium. As shown, the wireless node may be physically attached to a
person, a vehicle, or an airplane, to enable wireless communication among them.

2

FIG 1.1 OVERVIEW OF MOBILE AD-HOC NETWORK
In MANET, a wireless node can be the source, the destination, or an intermediate
node of data transmission. When a wireless node plays the role of intermediate node, it
serves as a router that can receive and forward data packets to its neighbor closer to the
destination node. Due to the nature of an ad-hoc network, wireless nodes tend to keep
moving rather than stay still. Therefore the network topology changes from time to time.
Wireless ad-hoc network have many advantages:


Low cost of deployment: Ad hoc networks can be deployed on the fly; hence no



expensive infrastructure such as copper wires or data cables is required.
Fast deployment: Ad hoc networks are very convenient and easy to deploy since



there are no cables involved. Deployment time is shortened.
Dynamic Configuration: Ad hoc network configuration can change dynamically
over time. When compared to configurability of LANs, it is very easy to change
the network topology of a wireless network.

MANET has various potential applications. Some typical examples include
emergency search-rescue operations, meeting events, conferences, and battlefield
communication between moving vehicles and/or soldiers. With the abilities to meet the
new demand of mobile computation, the MANET has a very bright future.

3

1.2 CURRENT CHALLENGES
In a mobile ad hoc network, all the nodes cooperate with each other to forward the
packets in the network, and hence each node is effectively a router. Thus one of the most
important issues is routing. This thesis focuses mainly on routing issues in ad hoc
networks. In this section, some of the other issues in ad hoc networks are described:


Distributed network: A MANET is a distributed wireless network without
any fixed infrastructure. That means no centralized server is required to



maintain the state of the clients.
Dynamic topology: The nodes are mobile and hence the network is selforganizing. Because of this, the topology of the network keeps changing
over time. Consequently, the routing protocols designed for such networks



must also be adaptive to the topology changes.
Addressing scheme: The network topology keeps changing dynamically
and hence the addressing scheme used is quite significant. A dynamic
network topology requires a ubiquitous addressing scheme, which avoids
any duplicate addresses. In wireless WAN environments, Mobile IP is
being used. Because the static home agents and foreign agents are needed,



hence, this solution is not suitable for ad hoc network.
Security: Security in an ad hoc network is extremely important in
scenarios such as a battlefield. The five goals of security – availability,
confidentiality, integrity authenticity and non-repudiation - are difficult to
achieve in MANET, mainly because every node in the network
participates equally in routing packets. Security issues in MANETs are
discussed in Chapter III.

1.3 OBJECTIVE:

4

To study various cluster based routing schemes in mobile ad-hoc networks and
schemes in mobile ad-hoc networks and implement distributed weighted cluster based
implement distributed weighted cluster based routing algorithm.
Design a routing protocol for MANET that is Efficient, scalable, distributed and simple to
implement. Evaluate CBRP through simulation compare with different design alternatives
compare against other MANET protocols.

1.4 MOTIVATION:
Major design decision use clustering approach to minimize on-demand route
discovery traffic, use “local repair” to reduce route acquisition delay and new route
discovery traffic suggest a solution to use uni-directional links
A lot of research is currently going on in moiled-hoc networks. Chief occurs being to
develop an efficient routing protocol which provides for efficient communication with
minimum energy requirement.

1.5. ROUTING PROTOCOLS BENEFITS
1.5.1 TABLE-DRIVEN (PROACTIVE) ROUTING
This type of protocols maintains fresh lists of destinations and their routes by periodically
distributing routing tables throughout the network. The main disadvantages of such
algorithms are:



Respective amount of data for maintenance.
Slow reaction on restructuring and failures.

5

FIG 1.2: OLSR-OVERVIEW
EXAMPLES OF PROACTIVE ALGORITHMS ARE:


Optimized Link State Routing Protocol (OLSR) Optimized Link State Routing
Protocol RFC 3626.



Babel RFC 6126



Destination Sequence Distance Vector (DSDV)

BENEFITES


Being a proactive protocol, routes to all destinations within the network are
known and maintained before use. Having the routes available within the standard
routing table can be useful for some systems and network applications as there is
no route discovery delay associated with finding a new route.



The routing overhead generated, while generally greater than that of a reactive
protocol, does not increase with the number of routes being created.

6



Default and network routes can be injected into the system by HNA messages
allowing for connection to the internet or other networks within the
OLSR MANET cloud. Network routes are something reactive protocols do not
currently execute well.



Timeout values and validity information is contained within the messages
conveying information allowing for differing timer values to be used at differing
nodes.

1.5.2 ON-DEMAND (REACTIVE) ROUTING
This type of protocols finds a route on demand by flooding the network with Route
Request packets. The main disadvantages of such algorithms are:


High latency time in route finding.



Excessive flooding can lead to network clogging.

Examples of on-demand algorithms are:


Ad hoc On-demand Distance Vector (AODV) (RFC 3561}



Dynamic Source Routing (RFC 4728)



Flow State in the Dynamic Source Routing



Power-Aware DSR-based

BENEFITS


The main advantage of this protocol is having routes established on demand and
that destination sequence numbers are applied to find the latest route to the
destination. The connection setup delay is lower.

7



One disadvantage of this protocol is that intermediate nodes can lead to
inconsistent routes if the source sequence number is very old and the intermediate
nodes have a higher but not the latest destination sequence number, thereby



having stale entries.
Also, multiple RouteReply packets in response to a single RouteRequest packet
can lead to heavy control overhead. Another disadvantage of AODV is
unnecessary bandwidth consumption due to periodic beaconing.

1.5.3 HYBRID (BOTH PROACTIVE AND REACTIVE) ROUTING
This type of protocol combines the advantages of proactive and reactive routing. The
routing is initially established with some proactively prospected routes and then
serves the demand from additionally activated nodes through reactive flooding. The
choice of one or the other method requires predetermination for typical cases. The
main disadvantages of such algorithms are:



Advantage depends on number of other nodes activated.
Reaction to traffic demand depends on gradient of traffic volume.

EXAMPLES OF HYBRID ALGORITHMS ARE:


ZRP (Zone Routing Protocol) ZRP uses IARP as pro-active and IERP as reactive
component.

BENEFITS:


What is called the Intra-zone Routing Protocol (IARP), or a proactive routing
protocol, is used inside routing zones. What is called the Inter-zone Routing
Protocol (IERP), or a reactive routing protocol, is used between routing zones.
IARP uses a routing table. Since this table is already stored, this is considered a



proactive protocol. IERP uses a reactive protocol.
Any route to a destination that is within the same local zone is quickly established
from the sources proactively cached routing table by IARP. Therefore, if the
8

source and destination of a packet are in the same zone, the packet can be



delivered immediately.
Most existing proactive routing algorithms can be used as the IARP for ZRP.
In ZRP a zone is defined around each node, called the node's k-neighborhood,
which consists of all nodes within k hops of the node. Border nodes are nodes



which are exactly k hops away from a source node.
For routes beyond the local zone, route discovery happens reactively. The source
node sends a route request to the border nodes of its zone, containing its own
address, the destination address and a unique sequence number. Each border node
checks its local zone for the destination. If the destination is not a member of this
local zone, the border node adds its own address to the route request packet and
forwards the packet to its own border nodes. If the destination is a member of the
local zone, it sends a route reply on the reverse path back to the source. The
source node uses the path saved in the route reply packet to send data packets to
the destination

9

1.5.4 HIERARCHICAL ROUTING PROTOCOLS
With this type of protocol the choice of proactive and of reactive routing depends on the
hierarchic level in which a node resides. The routing is initially established with some
proactively prospected routes and then serves the demand from additionally activated
nodes through reactive flooding on the lower levels. The choice for one or the other
method requires proper attributation for respective levels. The main disadvantages of
such algorithms are:


Advantage depends on depth of nesting and addressing scheme.



Reaction to traffic demand depends on meshing parameters.

EXAMPLES OF HIERARCHICAL ROUTING ALGORITHMS ARE:


CBRP (Cluster Based Routing Protocol)



FSR (Fisheye State Routing protocol)

1.5.4.1 APPLICATION USED ON ADHOC:


To understand their application we have to see what they offer and how they



establish
Establishing this type of networks requires mobile devices with the right



communicating chip on.
While they could ideally be deployed at any where or in other words



instantaneous deployment.
The cooperation of the users is necessary to the operation of ad-hoc networks;



therefore, game theory provides a good basis to analyze the networks.
Work has been going on to introduce the fundamental concepts of game theory



and its applications in telecommunications.
Crisis management services applications

1.5.4.2 ADVANTAGES AND DISADVANTAGES
10

Table 1.1: Protocol Advanages and Disadvantages
PROTOCO
L
Proactive

ADVANTAGES





Upto date routing information
Quick establishments of routes
Small Delay
A route to every other node in
the network is always.

DISADVANTAGES





Reactive

Hybrid





Reduction of routing load
Saving resources
Loops-free







Scalability
Limited search cost
Up-to date routing information
within zones









Slow convergence
Tendency of creating
loops
Large amount of
resource are needed.
Routing information in
not dully used.
Not always up to date
routes
Large delay
Control traffic and
overhead cost
Arbitrary proactive
schemes within zones.
Inter zone routing
latencies.
More resource for large
size zones.

The study has been done to compare the efficiency of the various categories of
routing protocols: DSDV, AODV, FSR, LAR, OLSR, STAR, and ZRP. The overall goal
of our simulation study is to analyze the behavior and performance of the protocols under
a range of various scenarios. Simulations have been run using a mobile ad hoc networks
composed of 10, 15, 25, 50 and 75 nodes moving over a rectangular 1500 m × 1500 m
space and operating over 30 seconds of simulation time. All nodes move according to the
random way point mobility model.
Table 1.2: Traditional Routing Protocols

11

1.5.4.3 TRADITIONAL ROUTING PROTOCOLS:


Border Gateway Protocol (BGP) is the protocol backing the core routing
decisions on the Internet. It maintains a table of IP networks or ‘prefixes’ which
designate network reach-ability among autonomous systems (AS). It is described
as a path vector protocol. BGP does not use traditional Interior Gateway
Protocol(IGP) metrics, but makes routing decisions based on path, network
policies and/or rule-sets. For this reason, it is more appropriately termed a reachability protocol rather than routing protocol.



Open Shortest Path First (OSPF) is an adaptive routing protocol for Internet
Protocol (IP) networks. It uses a link state routing algorithm and falls into the
group of interior routing protocols, operating within a single autonomous
system (AS).
Table 1.3: Routing Property

Routing property
Routing structure
Route availability

Proactive
Both flat and
hierarchical
Always available, if

Reactive
Mostly flat, except
CBRP
Determined when

12

Hybrid
Mostly hierarchical
Depends on the

the nodes reachable

needed

Traffic control

Usually high

Low

Mobility handling
effects

usually updates
occurs based on
mobility at fixed
intervals
High

ABR introduced
LBQ, AODV uses
local route
discovery
Usually lower than
proactive protocols

Delay level

Some all routes are
predetermined

Higher than
proactive

Scalability level to
perform efficient
routing

Usually up to 100
nodes

Source routing
protocols up to few
100 nodes point to
point may scale
higher

Storage
requirements

location of the
destination
Mostly lower than
proactive and
reactive
Usually more than
one path may be
available
Usually depends on
the size of each
cluster
For local destination
small, since inter
zone may be as
large as reactive
protocols.
Designed for up to
1000 or more nodes

1.6 THESIS TARGET
The mobile ad hoc network is a new model of wireless communication and has
gained increasing attention from industry. As in a general networking environment,
mobile ad-hoc networks have to deal with various security threats. Due to its nature of
dynamic network topology, routing in mobile ad-hoc network plays a vital role for the
performance of the networks. It is understandable that most security threats target routing
protocols – the weakest point of the mobile ad-hoc network. There are various studies and
many researches in this field in an attempt to propose more secure protocols. However,
there is not a complete routing protocol that can secure the operation of an entire network
13

in every situation. Typically a “secure” protocol is only good at protecting the network
against one specific type of attacks.
Many researchers have been done to evaluate the performance of secure routing
protocols in comparison with normal routing protocols. One of the objectives of this
research is to examine the additional cost of adding a security feature into non-secure
routing protocols in various scenarios. The additional cost includes delay in packet
transmission, the low rate of data packets over the total packets sent, etc.
It is well known that the real-world network does not operate in an ideal working
environment, meaning that there are always threats and malicious actions affecting the
performance of the network.
Thus, studying the performance of secure routing protocols in malicious
environments is needed in order to effectively evaluate the performance of those routing
protocols. In the thesis, I have implemented two secure routing protocols: a secure
version of the dynamic source routing - DSR (OLSR) and Secure Ad hoc On-demand
Distance Vector routing protocol (SAODV) in the OPNET simulation environments. I
will also create malicious scenarios by implementing several attacks in the simulation
environments.

In ad hoc networks, nodes are not familiar with the topology of their networks.
Instead, they have to discover it: typically, a new node announces its presence and listens
for announcements broadcast by its neighbors. Each node learns about others nearby and
how to reach them, and may announce that it too can reach them.

1.7 THESIS OUTLINE
This thesis is composed of six chapters. Following the Introduction Chapter (I),
Chapter II classifies the routing protocols. The working description of two reactive
protocols is provided. The chapter is concluded with a summary.

14

Chapter III discusses security issues in MANETs with a focus on secure routing in
MANETs. It focuses on the attacks and exploits that are possible in an ad hoc wireless
network. It explains the working mechanism of four of the state-of-the-art routing
protocols including OLSR and Secure Ad hoc On-demand Distance Vector routing
protocols.
Chapter IV discusses the system Architecture employed to study the performance
of routing protocols in MANETs. A brief description of the OPNET Modeler simulator
environment is provided. The scenarios, metrics and the issues faced are explained. A
summary concludes the chapter.
Chapter V discusses the simulation approach employed to study the performance
of routing protocols in MANETs. A brief description of the OPNET Modeler simulator
environment is provided. The scenarios, metrics and the issues faced are explained. A
summary concludes the chapter.
Chapter VI forms the core of this thesis and discusses the experiments carried out
to analyze the performance of DSR, OLSR-INRIA, AODV, ZRP and SAODV. The
experimental results and their analyses follow the experiments.
Chapter VII concludes this thesis along with suggestions for future work in the
area of mobile ad hoc networks.

CHAPTER 2
LITERATURE SURVEY
2.1 PERFORMANCE ANALYSIS OF ROUTING PROTOCOLS
BASED ON IPV4 AND IPV6 FOR MANET
Ad hoc network is a collection of wireless mobile nodes where wireless radio
interface connects each device in a MANET to move freely, independently and randomly.
Routing protocols in mobile ad hoc network helps to communicate source node with
15

destination node by sending and receiving packets. Many authors have compared various
routing protocols such as AODV, DSR, DSDV, TORA, DYMO, OLSR etc in the past. In
this paper, we have analyzed the behavior of three routing protocols AODV (Ad hoc on
demand distance vector), DYMO Dynamic MANET On demand), and OLSR (Optimized
link state routing) in the network protocol IPV4 & IPV6 and compared the performance
of these protocols using Qualnet5.0.2 simulator. The performance metrics are
Throughput, Average Jitter, Packet Delivery Ratio & Total Packets Received. To test
competence and effectiveness of all three protocols under IPV4 & IPV6, Changing the
speed and mobility. Finally results are scrutinized from different scenarios to provide
qualitative assessment of the applicability of the protocols.
A mobile ad hoc network (MANET) is a self- configuring network of mobile
devices connected by wireless links. In other words, a MANET is a collection of
communication nodes that wish to communicate with each other, but has no fixed
infrastructure and no predetermined topology of wireless links. Each node in a MANET
is free to move independently in any direction, and will therefore change its links to other
devices frequently. Individual nodes are responsible for dynamically discovering other
nodes that they can directly communicate with. Due to the limitation of signal
transmission range in each node, not all nodes can directly communicate with each other.
Each node must forward traffic unrelated to its own use, and therefore be a router. The
primary challenge in building a MANET is equipping each device to continuously
maintain the information required to properly route traffic. Therefore, nodes are required
to relay packets on behalf of other nodes in order to deliver data across the network.
Ad hoc networks can be built around any wireless technology, including infrared,
radio frequency (RF), global positioning system (GPS), and so on. Usually, each node is
equipped with a transmitter and a receiver to communicate with other nodes. Military
application, Collaborative & Distributed Computing, Emergency Operation, Wireless
Mesh Network and the routing protocol should be able to provide quick, secure and
reliable multicast communication with support for real time traffic. The paper is
distributed as follows. In section 2 we have discuss three routing protocols taken for
16

comparison. Section 3 gives the details of simulation environment. The simulation results
are shown in section 4. Sections 5 describe conclusion and future scope.
SIMULATION RESULTS, WE CONCLUDE THAT FOR IPV4 AND IPV6:




DYMO have better throughput than AODV and OLSR with IPV4.
DYMO have better throughput than AODV and OLSR with IPV6.
OLSR have low jitter and average end to end delay corresponds to high efficiency



than DYMO and AODV with IPV4.
OLSR have low jitter and average end to end delay corresponds to high efficiency





than DYMO and AODV with IPV6.
OLSR have better packet delivery ratio than DYMO and AODV with IPV4.
OLSR have better packet delivery ratio than DYMO and AODV with IPV6.
OLSR have better average packed received and broadcast packet received than



AODV and DYMO with IPV4.
OLSR have better average packed received and broadcast packet received than



DYMO and AODV with IPV6.
We also conclude that IPV6 performs better than IPV4.

2.2. PERFORMANCE COMPARISON OF OLSR, GRP AND TORA
USING OPNET
A MANET is an autonomous collection of mobile users that communicate over
relatively bandwidth constrained wireless links. Since the nodes are mobile, the network
topology may change rapidly and unpredictably over time. The network is decentralized,
where all network activity including discovering the topology and delivering messages
must be executed by the nodes themselves, i.e., routing functionality will be incorporated
into mobile nodes.. In this paper routing protocols OLSR, GRP and TORA for mobile ad
hoc network are compared on the basis of delay, load, media access delay and
throughput.

17

MANET is a dynamic distributed network [1], in which mobile devices with
limited energy can move arbitrary. MANET is a self-configurable network without
infrastructure in which nodes are free to move randomly, so topology may change and
this event is unpredictable [6]. Because of these characteristics, routing is a critical issue
and an efficient routing protocol needs to be chosen to make the MANET reliable [2].
The most popular routing protocols [3] in MANET are OLSR (proactive) and
TORA(reactive) and GRP(hybrid) .Proactive protocols are table driven protocols and find
routes before they need it. Reactive protocols find the routes when they are needed And
finally hybrid routing protocols offer an efficient framework that can simultaneously
draw on the strengths of proactive and reactive routing protocols. In this paper, three
MANET routing protocols ,OLSR, TORA and GRP are evaluated on the basis of four
parameters : delay, load, throughput and routing overhead.

ROUTING PROTOCOL:
The performance investigation of reactive and proactive MANET routing
protocols, namely AODV, DSR, TORA and OLSR is done by Ashish Shrestha and Firat
Tekiner. They have concluded that with regards to overall performance, AODV and
OLSR performed pretty well. However,
AODV showed better efficiency to deal with high congestion and it scaled better
by successfully delivering packets over heavily trafficked network compared to OLSR
and TORA. Comparison of OLSR and TORA has been done by Pankaj Palta and Sonia
Goyal in.They have concluded that OLSR is better in those scenario where bandwidth is
large as OLSR always updated their nodes so large bandwidth is used than TORA on
same conditions. Simulation and analysis of GRP routing protocol has been done by
kuldeep vats, Mandeep Dalal , Deepak Rohila and Vikas Laura.Simulation results show
18

that GRP protocol has better performance in terms of delay , total traffic sent and
received routing traffic sent and received in packet and bit form ,packet copy, packet
created and packet destroyed. Manijeh Keshtgary and Vahide Babaiyan, used OPNET
14.5 for simulation. The simulation study for MANET network under routing protocols
AODV, DSR, OLSR,

and GRP were deployed using FTP traffic analyzing. These

protocols were tested with QOS parameters. From their analysis, the OLSR outperforms
others in overall performance and GRP has least media access delay and delay. This
result is verified by Kuldeep Vats, Monica Sachdeva and Dr .Krishan Saluja in. They
also concluded that OLSR is best in overall performance followed by GRP.
In this paper, performance of three routing protocols namely OLSR, GRP and
TORA was analyzed .OLSR performs best in terms of load and throughput.GRP performs
best in terms of delay and routing overhead.

2.3. PERFORMANCE ANALYSIS OF MULTICAST ROUTING
PROTOCOL FOR WIRELESS AD HOC NETWORK BASED ON
TRAFFIC PATTERN WITH VARYING NODE MOBILITY
Data and information transmission in a wireless mobile ad-hoc networks
(MANET) mainly relies on the performance of the traffic pattern (application traffic
agent and data traffic) used in a network. The reliability and capability of routing
protocols can be determined using different traffic scenarios, which insist its performance
analysis using traffic patterns TCP/FTP and UDP/CBR with routing protocol generally
implemented in a mobile ad-hoc environment. This paper describes the performance
analysis and comparison of CBR and TCP traffic over conventional AODV and multicast
AODV. The performance metrics, such as throughput, packet delivery ratio and average

19

end to end delay is used for comprehensive performance analysis. The average end to end
delay of CBR/UDP for MAODV and AODV is lesser than TCP/FTP. The Average
End2End Delay of MAODV is lesser than that of AODV for both traffics. The results
follow these trends over a wide range of simulations based on node mobility.
The mobile ad-hoc network is a self-configuring infrastructure less network
without the need of any central administration. Therefore, they are well suited for the
environments as earthquake prone areas, military battlefield operation, virtual
classrooms, and many other emergency services. AODV is a protocol which is capable of
unicast and multicast transmission. Multicasting in a wireless network is a diverse
technique through which the message can be transferred to multiple nodes simultaneously
using fewer links. The information is delivered to each of the links only once, and copies
are created when the link to the destination splits, thus creating an optimal distribution
path.
In general, for multicast transmissions there are two types of nodes, source node
and multicast member node. The source node primarily spreads out a multicast data to
multiple multicast member nodes that want to receive that data and join the multicast
group.
A big challenge in the design of ad hoc networks is the development of dynamic
routing protocols that can find routes, transfer information and data efficiently between
two nodes. Each node in the network also acts as a router, forwarding data packets for
other nodes.
The study of performance of two protocols, unicast AODV and multicast
MAODV has been analysed over different scenarios. The analysis has been carried out
with two traffic types, TCP/FTP and CBR/UDP. From the analysis it is concluded that
MAODV performs slightly better than AODV in terms of Packet Delivery Ratio,
End2End delay with varying node speed over two traffics, TCP and CBR. From
experimental analysis it is concluded that in low density and in low speed the Packet
Delivery Ratio (PDR) is high for both TCP and CBR. In the same scenario the End2End
20

Delay for CBR traffic is lower than TCP traffic for both protocols. With mobility model it
is also concluded that MAODV performs better than AODV for both TCP and CBR
traffic patterns. In future the analysis may be extended to analyze the performance with
node density, packet generation rate, varying pause time etc. By evaluating the
performance of these two protocols over different scenarios, it will help in designing a
new protocol or improvement in the existing protocol.

2.4. AD HOC WIRELESS NETWORKS: ANALYSIS, PROTOCOLS,

ARCHITECTURE AND TOWARDS CONVERGENCE
Traditional routing protocols were developed to support user communication in
networks with a fixed infrastructure with reliable, high-capacity links. On the other hand
Mobile Ad-hoc Network is a collection of wireless mobile nodes which dynamically
forms a temporary network without the use of any existing network infrastructure or
centralized administration. These networks need efficient routing protocols; various ad
hoc routing protocols have been proposed and compared based on some metrics. We
present the analytical simulation results of routing protocols DSR, AODV, OLSR and
GRP for two applications namely ftp and email, using the network simulator OPNET
14.0.
21

Traditional routing protocols were developed to support user communication in
networks with a fixed infrastructure with reliable, high-capacity links. However, in the
mobile ad hoc network, the network infrastructure is dynamically changing, and the links
are wireless with less capacity and more prone to errors. These nodes generally have a
limited transmission range and, so, each node seeks the assistance of its neighboring
nodes in forwarding packets and hence the nodes in an ad-hoc network can act as both
routers and hosts, thus a node may forward packets between other nodes as well as run
user applications. Some examples of the possible uses of ad hoc networking include
students using laptop computers to participate in an interactive lecture, business
associates sharing information during a meeting, soldiers relaying information for
situational awareness on the battlefield and emergency disaster relief personnel
coordinating efforts after a hurricane or earthquake.
It is evident from Table 6 that the performance of DSR for all parameters is worst
as compared to the other protocols. On the other hand OLSR is performing well for all
parameters. The performance of GRP is also very close to OLSR but not better than it.
As far as the present results are concerned in the given scenario the protocols are
ordered in the increasing order of their performance as DSR, AODV, GRP and OLSR.
GEOGRAPHIC ROUTING PROTOCOL (GRP)
GRP is a kind of position-based protocol which belongs to Proactive Routing
Protocol. Each position of the node will be marked by GPS and flooding will be
optimized by quadrants. Flooding position updates on distance the node moved and
neighborhood crossings. A hello protocol will be exchanged between nodes to identify
their neighbors and their positions. At the same time, by means of route locking a node
can return its packet to the last node when it can’t keep on sending the packet to the next
node.
AD-HOC ON DEMAND DISTANCE VECTOR (AODV)

22

AODV discovers routes on an as needed basis via a similar route discovery
process. However, AODV adopts a very different mechanism to maintain routing
information. It uses traditional routing tables, one entry per destination. Without source
routing, AODV relies on routing table entries to propagate an RREP back to the source
and, subsequently, to route data packets to the destination. AODV uses sequence numbers
maintained at each destination to determine freshness of routing information and to
prevent routing loops. All routing packets carry these sequence numbers. An important
feature of AODV is the maintenance of timer-based states in each node, regarding
utilization of individual routing table entries. A routing table entry is expired if not used
recently.

2.5. SIMULATION AND PERFORMANCE ANALYSIS OF AODV, TORA & OLSR
ROUTING PROTOCOLS
An ad hoc network is a collection of wireless mobile nodes dynamically forming
a temporary network without the use of any pre-existing network infrastructure. A
number of ad hoc routing protocols have been developed during the time, but none of
these is able to produce efficient routing of packets in large number of nodes due to their
own limitations. Therefore, scalability is an open issue in all routing protocols.
In this paper, we presented our observations regarding the scalability comparison
of the three MANET routing protocols, Ad hoc On Demand Distance Vector (AODV),
Temporally Ordered Routing Protocols (TORA) and Optimized Link State Routing
(OLSR) by varying the number of nodes.
23

In last three decades, wireless network has grown enormously. Although, wireless
network has eased the information sharing and communication but we have to setup static
links before we can start the communication between two systems. This form of network
is known as infrastructure network. These networks can only work in the environment
where a fixed infrastructure exists. This motivates the need of infrastructure less networks
which are known as ad hoc networks. Ad-hoc means “for one specific purpose only”.
Hence, these networks are formed when needed. All available nodes are aware of all
other nodes within range. The entire collection of nodes is interconnected in many
different ways. The topology of such networks changes very rapidly because the nodes in
ad hoc network are mobile and independent of each other. This makes the routing very
difficult.
In this research study, we have performed simulations of three MANET routing
protocols AODV, TORA and OLSR to evaluate their scalability and then compared them.
Simulation is done using the OPNET Modeler 14.5. In the research work, Average end to
end delay and throughput are considered as the performance evaluation parameters.
HTTP heavy browsing is used for traffic generation. The simulation results conclude that
on increasing the number of nodes there is performance degradation in all protocols, but
it varies from protocol to protocol. As the number of nodes increased the network average
end to end delay also increased for all three routing protocols. However, OLSR protocol
outperformed the AODV and TORA protocols and has least network latency. TORA
performed worst even it uses the localization.
In case of network throughput too, it is observed that on varying the number of
nodes performance of TORA protocol was very poor. Whereas, the performance of the
OLSR protocol was far better than the AODV and TORA in terms of throughput. AODV
performance was average during the simulation however; it reduces the routing overhead
to great extent and reacts quickly during its operation. Hence, this paper concludes that
the OLSR protocol in highly scalable with reference to varying network size, however the
AODV protocol is almost equally scalable but less than OLSR. This comparative analysis

24

is done to identify the suitable protocols according to the network size, so that the routing
could be more efficient and cost effective.

TABLE 2.1: ANALYZING METHOD
Author Name

Protocols Used

Simulator

Performance

Variable

References
Guntupalli et al.

DSDV, DSR,

NS2

Metrics
Average End to

Parameters
Number of

End Delay,

nodes, Speed,

Normalized

pause time,

Routing Load,

Transmission

Packet Delivery

Power.

Ratio
Packet Delivery

Number of

Ratio, End to

nodes, Speed,

End Delay,

pause time

AODV

Yogesh et al.

AODV, DSR

GLOMOSIM

Normalized
routing overhead.
25

Chenna et al,

DSDV, AODV,

NS2

DSR, TORA

Throughput,

Traffic Loads,

Routing

Movement

Overhead, Path

Patterns.

Optimality,
Packet Loss,
G. Jayakumar et

AODV, DSR

NS2

al,

Average DeLay
Packet Delivery

Speed

Ratio, Routing
Overhead, MAC
load and average
End to End

Birdar et al,

Delay
Packet Delivery

AODV, DSR

Pause Time

Ratio, Routing
Overhead,
Normalized
Routing
Overhead and
Average End to
Vijayalaskhmi

DSDV, AODV

NS2

et al,

End Delay
Packet Delivery

Number of

Ratio, Average

Nodes, Speed,

End to End

Time

Delay and
Shaily et al,

AODV, ZRP

Qual Net

Throughput.
Packet Delivery

Pause Time

Traction, Average
End to End
Delay and
Li Layuan st al,

DSDV, AODV,

NS2

26

Throughput.
Average Delay,

Network Size.

DSR, TORA

Jitter, Routing
Load, Loss Ratio,
Throughput and
Connectivity

CHAPTER 3
SYSTEM ANALYSIS
In MANET the wireless links between adjacent nodes are subject to interference from external sources, intra
and inter transmission in the network, ambient noise in the system and jamming signals from malicious nodes. The
cumulative effect of all these factors results in low link capacity and reliability. In literature Kumar et al modifies the
MANET routing protocols to reduce network congestion without taking into account the reliability of wireless links. It
resulted in an only traffic load aware routing to reduce congestion. On the other hand Vijayavani et al modifies and
compares various routing protocols in MANET based on network size, density and node mobility. Here also the
wireless link status is not considered. Ghosh et al considered the status of wireless links in DSR and achieved good
results.
In our work we have modified the route discovery process of OLSR-INRIA, DSR and ZRP to select the most
reliable path amongst multiple available paths based on its SNR value. The reliability of a path is the minimum SNR
value of the wireless links constituting the path as it defines the weakest portion of the path. The structure of the RREQ
packet is modified to include an additional field known as ROUTE_MIN_SNR, to store the minimum SNR value
among all the path links. It gives us a measure of the path reliability. During the initial stages of the route discovery
process the source node broadcasts RREQ packets to its immediate neighborhood. The ROUTE_MIN_SNR field of the
RREQ packets received by the neighborhood nodes is updated with the SNR value of the link from the physical layer.
After this updating the RREQ packets are further broadcasted in the immediate neighborhood. This process continues
until the RREQ packets reaches destination node
. When the destination node receives the RREQ packets, it compares the SNR value of each path to the
source which is above a certain threshold (10dB in our method). Among the possible paths one with the maximum SNR
value is selected as it gives the maximum throughput, reliability with minimum delay.

27

HOW TO ANALYZE (MOBILE AD HOC) NETWORKS?

FIG 3.1: ADHOC NODE

3.1 CHALLENGE:


Qualify and quantify the effects of Node misbehavior on the overall performance





of the routing system.
We would like to see how the system behaves.
What about choice of evaluation technique?
Real world observations are not possible because there is no large scale manet,






and it would be expensive to set up a new one.
Emulation / Tested experiments are possible but in a small scale.
Simulation studies are being conducted.
Security,
QoS,
TABLE 3.1: SUMMARY RESULT FOR TEST AODV, ERS, 250 NODES

28

It is for sure that there are many issues need to be handled if an optimized ad hoc network
needs to be implemented which does not seem possible with today's technology.

3.2 ROUTING DEPENDABILITY IN AD HOC NETWORKS



The effects of node misbehavior.
Modeling adhoc networks.

There might be cases that the protocols that we have discussed cannot help out. For
instance what if there are some nodes that do not want to cooperate? Or some other
problems related proximity to each other. Some might behave as malicious and etc.
Recall that in ad hoc networks, there is mobility, dynamic situations. In this part, our
concern is Routing system.

29

FIG 3.2: ROUTING SYSTEM

3.2.1 NODE MISBEHAVIOR
A node in the middle may keep the message and not forward to package. It can
affect the overall performance of the system. There are three different nodes.
1. Well-behaving nodes: that works, forwards the packet.
2. Malicious nodes: the ones that inject false information into messages or remove them
completely from the network (black holes).
It has been proven that if the number of selfish nodes increases the packet loss in the
network increases linearly as well.
Besides that, in case of AODV, if there are many selfish nodes in the network we need to
incerase the number of control messages ( to keep the track of what is going on in the
network , and reestablish route if a node does not forward the packet ) . It results in
increase of routing overhead. Selfish nodes: the ones that receives the packet but do not
forward it.

30

3.2.2 ROUTING DEPENDABILITY PROBLEMS
Most ad hoc routing algorithms assume only well-behaving nodes to support
multi-hop operation of the network. However if something goes wrong in between,
everything can be affected in a negative way.
UNDERLYING PROBLEMS




Induced by mobility : High topology dynamics
Induced by wireless communication
Induced by node misbehavior ( we might want to add some extra mechanisms to
overcome this)

3.2.3 SYSTEMATIC PERFORMANCE EVALUATION


Performance analysis = analysis + computer systems



System = any collection of hardware + software



Metrics = the criteria used to evaluate the system performance



Workloads = the requests made by the users of the system

You need to know what you want to characterize in your system. You need to have a
proper goal first. There is no such thing as general model.
Goals -> correct metrics, workloads, methodology.
Your performance evaluation should represent the actual usage of the system.

31

TABLE 3.2: SYSTEMATIC PERFORMANCE EVALUATION

3.3 AD HOC WIRELESS ROUTING PROTOCOLS
3.3.1 CLASSIFICATION OF BASIC ROUTING PROTOCOLS
Routing protocols in ad hoc mobile wireless network can generally be divided
into three groups (Figure 3.2):

FIG 3.3 HIERARCHY OF AD-HOC ROUTING PROTOCOLS

32



Table driven: Every node in the network maintains complete routing
information about the network by periodically updating the routing table. Thus, when
a node needs to send data packets, there is no delay for discovering the route
throughout the network. This kind of routing protocols roughly works the same way
as that of routing protocols for wired networks.



Source initiated (or demand driven): In this type of routing, a node
simply maintains routes to active destination that it needs to send data. The routes to
active destinations will expire after some time of inactivity, during which the network
is not being used.



Hybrid: This type of routing protocols combines features of the above two
categories. Nodes belonging to a particular geographical region or within a certain
distance from a concerned node are said to be in the routing zone and use table driven
routing protocol. Communication between nodes in different zones will rely on the
on-demand or source-initiated protocols.

In the rest of this chapter, I will give an overview of two of the most common routing
protocols used in mobile ad hoc network: Dynamic Source Routing protocol (DSR) and
Ad hoc On-demand Distance Vector routing protocol (AODV)

3.4 DYNAMIC SOURCE ROUTING PROTOCOL (DSR)
The Dynamic Source Routing Protocol is one of the on-demand routing protocols,
and is based on the concept of source routing. In source routing, a sender node has in the
packet header the complete list of the path that the packet must travel to the destination
node. That is, every node in the path just forwards the packet to its next hop specified in
the header without having to check its routing table as in table-driven routing protocols.
Besides, the nodes don’t have to periodically broadcast their routing tables to the
neighboring nodes. This saves a lot of network bandwidth. The two phases of the DSR
operation are described below:

33

3.4.1 ROUTE DISCOVERY PHASE
In this phase, the source node searches a route by broadcasting route request
(RREQ) packets to its neighbors. Each of the neighbor nodes that has received the RREQ
broadcast then checks the packet to determine which of the following conditions apply:
(a) Was this RREQ received before ? (b) Is the TTL (Time To Live) counter greater than
zero? (c) Is it itself the destination of the RREQ? (d) Should it broadcast the RREQ to its
neighbors? The request ids are used to determine if a particular route request has been
previously received by the node. Each node maintains a table of RREQs recently
received. Each entry in the table is a <initiator, request id> pair. If two RREQs with the
same <initiator, request id> are received by a node, it broadcasts only the one received
first and discards the other. This mechanism also prevents formation of routing loops
within the network. When the RREQ packet reaches the destination node, the destination
node sends a reply packet (RREP) on the reverse path back to the sender. This RREP
contains the recorded route to that destination.
Figure 3.2 shows an example of the route discovery phase. When node A wants
to communicate with node G, it initiates a route discovery mechanism and broadcasts a
request packet (RREQ) to its neighboring nodes B, C and D as shown in the figure.
However, node C also receives the same broadcast packets from nodes B and D. It then
drops both of them and broadcasts the previously received RREQ packet to its neighbors.
The other nodes follow the same procedure. When the packet reaches node G, it inserts
its own address and reverses the route in the record and unicasts it back on the reversed
path to the destination which is the originator of the RREQ.
The destination node unicasts the best route (the one received first) and caches the
other routes for future use. A route cache is maintained at every node so that, whenever a
node receives a route request and finds a route for the destination node in its own cache,
it sends a RREP packet itself instead of broadcasting it further.

34

FIG 3.4: ROUTE DISCOVERY IN DSR
3.4.2

ROUTE MAINTENANCE
The route maintenance phase is carried out whenever there is a broken link

between two nodes. A broken link can be detected by a node by either passively
monitoring in promiscuous mode or actively monitoring the link. As shown in Figure 3.3,
when a link break (F-G) happens, a route error packet (RERR) is sent by the intermediate
node back to the originating node. The source node re-initiates the route discovery
procedure to find a new route to the destination. It also removes any route entries it may
have in its cache to that destination node. DSR benefits from source routing since the
intermediate nodes do not need to maintain up-to-date routing information in order to
route the packets that they receive. There is also no need for any periodic routing
advertisement messages.

35

FIG 3.5: ROUTE MAINTENANCE IN DSR

3.5 AD-HOC ON-DEMAND DISTANCE VECTOR (AODV) ROUTING
PROTOCOL
To find routes, the AODV routing protocol uses a reactive approach and to
identify the most recent path it uses a proactive approach. That is, it uses the route
discovery process similar to DSR to find routes and to compute fresh routes it uses
destination sequence numbers. The two phases of the AODV routing protocol are
described below.
3.5.1

ROUTE DISCOVERY
In this phase, RREQ packets are transmitted by the source node in a way similar

to DSR. The components of the RREQ packet include fields such as the source identifier
(SId), the destination identifier (DId), the source sequence number (SSeq), the destination
sequence number (DSeq), the broadcast identifier (BId), and TTL. When a RREQ packet
is received by an intermediate node, it could either forward the RREQ packet or prepare a
Route Reply (RREP) packet if there is an available valid route to the destination in its
36

cache. To verify if a particular RREQ has already been received to avoid duplicates, the
(SId, BId) pair is used. While transmitting a RREQ packet, every intermediate node
enters the previous node’s address and its BId. A timer associated with every entry is also
maintained by the node in an attempt to delete a RREQ packet in case the reply has not
been received before it expires.
When a node receives a RREP packet, the information of the previous node is
also stored in it in order to forward the packet to it as the next hop of the destination. This
plays a role of a “forward pointer” to the destination node. By doing it, each node
contains only the next hop information; whereas in the source routing, all the
intermediate nodes on the route towards the destination are stored.
Figure 3.5 depicts an example of route discovery mechanism in AODV. Suppose
that node A wishes to forward a data packet to node G but it has not an available route in
its cache. It then initiates a route discovery process by broadcasting a RREQ packet to all
its neighboring nodes (B, C and D).

FIG 3.6: ROUTE DISCOVERY IN AODV

37

All the SId, DId, SSeq, DSeq, BId, and TTL fields are inserted in the RREQ packet.
When RREQ packet reaches to nodes B, C and D, these nodes immediately search their
respective route caches for an existing route. In the case where no route is available, they
forward the RREQ to their neighbors; otherwise a comparison is made between the
destination sequence number (DSeq) in the RREQ packet and the DSeq in its
corresponding entry in the route cache. It replies to the source node with a RREP packet
consisting of the route to the destination in the case the DSeq in the RREQ packet is
greater. In Figure 2.4, node C gets a route to G in its cache and its DSeq is greater when
compared with that in the RREQ packet.
3.6 OLSR-INRIA
The Optimized Link State Routing (OLSR) protocol was designed by the French
National Institute for Research in Computer Science and Control (INRIA) for mobile adhoc networks. It is a proactive routing protocol that employs an efficient link state packet
forwarding mechanism called multipoint relaying on its way to optimize pure link state
routing protocol. There is a two way optimization. One by reducing the size of the control
packets and other by reducing the number of links that are used for forwarding link state
packets. The reduction in the size of the link state packets is made by declaring only a
subset of the links in the link state updates which are assigned the responsibility of packet
forwarding known as Multipoint Relays. Periodic link state updates are facilitated by the
optimization done by multipoint relaying facilities. No control packet is generated on the
event of a link break or addition of a new link by the link state update mechanism which
achieves higher efficiency when operating in a highly dense network.

38

FIG 3.7: ROUTE OLSR.

39

3.7HYBRIDS - ZRP

FIG 3.8: ZONES A PRO-ACTIVE ROUTING PROTOCOL IS USED WHILE A
RE-ACTIVE PROTOCOL IS USED BETWEEN ZONES.
Hybrid protocols seek to combine the proactive and reactive approaches. An
example of such a protocol is the Zone Routing Protocol (ZRP). ZRP divides the
topology into zones and seek to utilize different routing protocols within and between the
zones based on the weaknesses and strengths of these protocols. ZRP is totally modular,
meaning that any routing protocol can be used within and between zones. The size of the
zones is defined by a parameter r describing the radius in hops. Figure 3.6 illustrates a
ZRP scenario with r set to 1. Intra-zone routing is done by a proactive protocol since
these protocols keep an up to date view of the zone topology, which results in no initial
delay when communicating with nodes within the zone. Inter-zone routing is done by a
reactive protocol. This eliminates the need for nodes to keep a proactive fresh state of the
entire network.
ZRP defines a technique called the Border cast Resolution Protocol (BRP) to
control traffic between zones. If a node has no route to a destination provided by the

40

proactive inter-zone routing, BRP is used to spread the reactive route request.
Figure 3.7 illustrates the different components of ZRP.

FIG 3.9: THE DIFFERENT COMPONENTS OF THE ZONE ROUTING
PROTOCOL.

3.8 SECURITY AWARE ROUTING PROTOCOLS
MANETs have certain unique characteristics that make them vulnerable to several
types of attacks. Since they are deployed in an open environment where all nodes cooperate in forwarding the packets in the network, malicious nodes are difficult to detect.
Hence, it is relatively difficult to design a secure protocol for MANET, when compared
to wired or infrastructure-based wireless networks. This section discusses the security
goals for an ad hoc network. Sample attacks and threats against existing MANET routing
protocols are then discussed. I then discuss the working of two secure routing protocols
to address these threats, OLSR and SAODV.
3.8.1 SECURITY GOALS
To secure the routing protocols in MANETs, researchers have considered the
following security services: availability, confidentiality, integrity, authentication and
non-repudiation

41



Availability guarantees the survivability of the network services despite attacks. A
Denial-of-Service (DoS) is a potential threat at any layer of an ad hoc network.
On the media access control layer, an adversary could jam the physical
communication channels. On the network layer disruption of the routing operation
may result in a partition of the network, rendering certain nodes inaccessible. On
higher levels, an attacker could bring down high-level services like key
management service.



Confidentiality ensures that certain information be never disclosed to
unauthorized entities. It is of paramount importance to strategic or tactical
military communications. Routing information must also remain confidential in
some cases, because the information might be valuable for enemies to locate their
targets in a battlefield.



Integrity ensures that a message that is on the way to the destination is never
corrupted. A message could be corrupted because of channel noise or because of
malicious attacks on the network.



Authentication enables a node to ensure the identity of the peer node. Without
authentication, an attacker could masquerade as a normal node, thus gaining
access to sensitive information.



Non-repudiation ensures that the originator of a message cannot deny that it is
the real originator. Non-repudiation is important for detection and isolation of
compromised nodes.
The networking environment in wireless schemes makes the routing protocols

vulnerable to attacks ranging from passive eavesdropping to active attacks such as
impersonation,

message

replay,

message

littering,

network

partitioning,

etc.

Eavesdropping is a threat to confidentiality and active attacks are threats to availability,
integrity, authentication and non-repudiation. Nodes roaming in an ad hoc environment
42

with poor physical protection are quite vulnerable and they may be compromised. Once
the nodes are compromised, they can be used as starting points to launch attacks against
the routing protocols.
3.8.1.1 ATTACKS AND EXPLOITS ON THE EXISTING PROTOCOLS
In general, the attacks on routing protocols can generally be classified as routing
disruption attacks and resource consumption attacks. In routing disruption attacks, the
attacker tries to disrupt the routing mechanism by routing packets in wrong paths; in
resource consumption attacks, some non-cooperative or selfish nodes may try to inject
false packets in order to consume network bandwidth. Both of these attacks are examples
of Denial of Service (DoS) attacks. Figure 3.1 depicts a broader classification of the
possible attacks in MANETs.

FIG 3.10: CLASSIFICATION OF ATTACKS ON MANET ROUTING
PROTOCOLS

CHAPTER 4
43

SYSTEM ARCHITECTURE
4.1 TECHNICAL APPROACH:


Uses the Open Access Research Test bed for Next-Generation Wireless Networks
(ORBIT), which consists of open API wireless terminals, forwarding nodes,
access points, switches and routers, to evaluate different approaches both in terms
of protocol functionality and software performance.



Compatible upgrades to WLAN protocols for service features such as flow QoS
and multicasting; interworking (global roaming, handoff, etc.) of multiple radio
link technologies such as Bluetooth, 802.11, GPRS and 3G/WCDMA.



Self-organizing ad-hoc network protocols for discovery and routing, with
particular focus on a hierarchical 802.11b architecture consisting of mobile nodes
(MN), radio forwarding nodes (FN) and access points (AP).



Theoretical analysis of the capacity and scaling properties of the three-tier
hierarchical hybrid wireless network, and system evaluation for an 802.11-based
hierarchical network.



Cross-layer approaches to MAC, routing and transport in ad-hoc network
scenarios.



Global Control Plane (GCP) approach to help disseminate control information
among ad-hoc nodes and facilitate cross-layer algorithms such as the integrated
routing/MAC scheduling algorithm and cross-layer transport protocol.



Content delivery techniques for mobile users, including those based on proactive
Infostations caching and novel semantic routing techniques. [This project involves
collaboration with Semandex Networks, Princeton, NJ
44

FIG 4.1: INTERNET SYSTEM ARCHITECTURE

4.2 TECHNICAL RATIONALE:
Mobile networks have traditionally been designed via extensions of existing fixed
network protocols to support key mobility functions such as location management,
authentication and handoff. Typically, these protocols were used in the context of
homogeneous vertical architectures in which a single service such as GSM or 3G is
provided to large numbers of mobile users. With the emergence of various new shortrange and medium-range wireless data networks (such as Bluetooth and WLAN), there is
a need for a more horizontal network architecture that accommodates heterogeneous
radio links and permits evolution of mobile network services to include basic mobility
features as well as newer requirements such as self-organization, ad-hoc routing, QoS,
multicasting, content caching, etc.

45

Such “4G” wireless networks can be realized with an IP-based core network for
global routing along with more customized local-area radio access networks that support
features such as dynamic handoff and ad-hoc routing.
4G is all about an integrated global network based on an open-systems approach.
Integrating different types of wireless networks with wireline backbone networks
seamlessly and the convergence of voice, multimedia, and data traffic over a single IPbased core network will be the main focus of 4G. With the availability of ultrahigh
bandwidth of up to 100 Mbps, multimedia services can be supported efficiently.
Ubiquitous computing is enabled with enhanced system mobility and portability support,
and location-based services and support of ad hoc networking are expected. The
illustration below shows the networks and components within the 4G network
architecture.

46

FIG 4.2: 4G NETWORK ARCHITECTURE

4.3 STRUCTURE CHART

AD-Hoc Mobile routing protocols

Table Driven
proactive

Hybrid

47

On demand driven
reactive

DSDV

WRP

ZRP

CGSR

STAR

ABR

DSR

CBRP

RDMBR

TORA

AODV

FIG 4.3: MANET ROUTING PROTOCOLS
Survey of applications of MANET : We shall now get an overview of different types of
MANET and their uses.
4.3.1 PURE GENERAL PURPOSE MANET
The mostly discussed application scenario for pure general-purpose MANET is
Battlefield or disaster-recovery networks. However, these kinds of networks have not yet
achieved the envisaged impact in terms of real world implementation and industrial
deployment.

4.3.2 MESH NETWORKS
Mesh networks are built upon a mix of fixed and mobile nodes interconnected via
wireless links to form a multihop ad hoc network. Unlike pure MANETs, a mesh network
introduces a hierarchyin the network architecture by adding dedicated nodes (called mesh
routers) that communicate wirelessly to construct a wireless backbone. An example is
MIT Roofnet providing the city of Boston, with broadband access with an 802.11b-based
wireless network backbone infrastructure.
Opportunistic Networking (Delay Tolerant Networking)
(I)POCKET SWITCHED NETWORKS IN THE HAGGLE PROJECT

48

It targets solutions for communication in autonomic/opportunistic networks. In
this framework, researchers are studying the properties of Pocket Switched Networks
(PSNs), i.e., opportunistic networks that can exploit any possible encountered device
(e.g., cell phones and PDAs that users carry in their pockets) to forward messages.
(II)WILDLIFE MONITORING
Wildlife monitoring is an interesting application field for opportunistic networks.
It focuses on tracking wild species to deeply investigate their behavior and understand the
interactions and influences on each other, as well as their reaction to the ecosystem
changes caused by human activities.
(III)VEHICULAR AD HOC NETWORKS
VANETs use ad hoc communications for performing efficient driver assistance
and car safety. The communications include data from the roadside and from other cars.
VANET research aims to supply drivers with information regarding obstacles on the road
and emergency events, mainly due to line-of-sight limitations and large processing
delays. VANET can be used to communicate premonitions, notification of emergencies,
and warnings about traffic conditions.
(IV) WIRELESS SENSOR NETWORKS (WSN)
Benefit from the advances in computing technology, which led to the production
of small, wireless, battery powered, smart sensor nodes. These nodes are active devices
with computing and communication capabilities that not only sample real world
phenomena but also can filter, share, combine, and operate on the data they sense.

The general process of creating a simulation can be divided into several steps:-

49



Topology definition:- To ease the creation of basic facilities and define their
interrelationships, ns-3 has a system of containers and helpers that facilitates this



process.
Model usage:- Models are added to simulation (for example, UDP, IPv4, pointto-point devices and links, applications); most of the time this is done using



helpers.
Node and link configuration:- Models set their default values (for example, the
size of packets sent by an application or MTU of a point-to-point link); most of



the time this is done using the attribute system.
Execution:- Simulation facilities generate events, data requested by the user is



logged.
Performance analysis:- After the simulation is finished and data is available as
a time-stamped event trace. This data can then be statistically analysed with



tools like R to draw conclusions.
Graphical Visualization:- Raw or processed data collected in a simulation can
be graphed using tools like Gnuplot, matplotlib or Xgraph. Xgraph is the
plotting tool bundled with many of the installation packages.

4.4 FRONT END DESIGN
Start

Broadcast Packets
(BP)
Authentication
Neighbor discovery
and exchange of ID

50

Cluster maintenance
by detecting events

Received NBR Info ?

Data aggregation at
CH & Upload at BP
Create neighbor
table
Wait for Time T (stop)

Wait for Time T
(boostrap)

Transmit CH

Compute counter
weight values

Receive CH &join
Selected CH by
CH

Counter Expired

Stop

FIG 4.4: FLOW CHART OF ROUTING PROTOCOL
The Secure Ad hoc On-Demand Distance Vector (SAODV) protocol was
proposed to answer the challenge of securing a MANET network. SAODV is an
extension of the AODV routing protocol, and it can be used to protect the route discovery
mechanism by providing security features like integrity, authentication and nonrepudiation.
SAODV assumes that each ad hoc node has a signature key pair from a suitable
asymmetric cryptosystem. Further, each node is capable of securely verifying the
association between the address of other node and the public key of that node. A key

51

management scheme is needed for SAODV. Two mechanisms are used to secure the
AODV messages:



Digital signatures to authenticate the non-mutable fields of the messages, and
Hash chains to secure the mutable hop count field of the message.
For the non-mutable fields, authentication can be performed in a point-to-point

manner, but the techniques cannot be applied to the mutable information. Route error
messages are protected in a different manner because of a big amount of mutable
information. According to the author, it is not important which node started the route
error and which nodes are just forwarding it. The important information is that a neighbor
node is informing other nodes that it is not able to route messages to certain destinations
anymore. Therefore, every node (generating or forwarding a route error message) uses
digital signatures to sign the whole RERR message and that any neighbor that receives
RERR verifies the signature. The RREQ and RREP have the following extension fields

TABLE 4.1: HASH FUNCTION
Value
0
1
2
3 – 127
128 – 255

Hash function
Reserved
MD5HMAC96
SHA1HMAC96
Reserved
Implementation dependent

4.5 ROUTE DISCOVERY
52

TESLA handles the authentication of RERR messages in a way similar to how the
RREQ messages are handled. In order to avoid the injection of invalid route errors
(RERR) into the network by any node other than the node that sees a broken link, each
node on the return path to the source node just forwards the RERR. On the other hand
TESLA authentication is delayed, so all the nodes on the return path buffer the error but
do not process it until it is authenticated. Later, the node that saw the broken link
discloses the key and sends it over the return path, which enables nodes on that path to
authenticate the buffered error message. The RERR contains six fields

FIG 4.5: ROUTE REQUEST AND ROUTE REPLY

4.5.1 CHARACTERISTIC OF MANET
TABLE 4.2: SURVEYING DIFFERENT TECHNIQUES WE DEFINE THE
ADVANTAGES AND DISADVANTAGES OF TECHNIQUES
Techniques

Advantages/

Merits

Disadvantages
/Future
Improvement

MANET, AODV,

The proposed approach is the

Direction
Using simulation results,

Trusted Networks;

extension of existing AODV

the performance of this

Trust Model

routing protocol for creating

protocol is not sufficient

secure route for communication.

justified. In the future, it

53

Proposed modifications are in

will be incorporate with

acceptable limit. With this

other MANET routing

minimum overhead, we can easily protocols.
eliminate the malicious node as
well as they can establish a best
trusted route between source and
DAAODV, Secure

destination.
They presented a secure ad hoc

This protocol doesn't use

Routing Protocol

routing protocol which can

TTP, and doesn't add

prevent most attacks including

much overhead in ns-2

worm-hole attacks, vertex cut

simulation. In future

attacks, and traffic analysis

work is to make a fine-

attacks, and adopt a new efficient grained construction of
signing and verifying scheme

the routing software, as

preventing DoS attacks.

the design of DAAODV
on software level is a
little coarsegrained.

Multipath Routing, Ad- The results show that AODVsec

The AODVsec still has

hoc Networks, AODVsec outperforms traditional multipath some imperfect points. As
routing on ensuring security. As a a future work, it will need
common case, attacker cannot

to focus on designing the

intercept all the paths, AODVsec

synchronization control

avoids maliciously accessing a

mechanism to solve this

entire data packet, so it improves

problem .

system's security with negligible
routing overhead.
WirelessSsecurity1,;

The efficient security algorithm

MANE, IEEE 802.11b4 ES-AODV enhances the security

54

The routing protocol
performs Does not better

in ad hoc wireless networks.

than the existing secure

According to the analysis of the

AODV routing protocol

results obtained from extensive

with increased mobility

simulation, it concludes that the

in the network. It should

secure routing solution scales well be improve in future
MANET, Routing,

to both mobility and network size. extension .
In the implementation of such
In future it will require

Security

routing protocols, the need is to

more specifically

eliminate the shortcoming of these SAODV to decrease the
protocols by evaluating

processing requirements

performance of them on a

to tackle hash chains and

simulation platform. To minimize digital signatures to
the associated overhead like delay, implement the security.
routing overhead demands an
intensive optimization in both the
protocols.
MANET, SecureAODV This paper, presents the protocol

The transmission

being proposed which utilizes the capacity factor into the
dual cooperative mobile agents

networking as MANET

and stationary agents for routing

of the protocol will need

in dynamic networks as MANET. to improve in future.
Every mobile agent computes the
transmission capacity of all the
nodes so that Routing Agent
System (RAS) can take the
efficient reliable decision which
routing path is more efficient and
reliable.
TABLE 4.3: COMPARISON BETWEEN MANET-PROTOCOL
55

56

FIG 4.6: SOFTWARE ARCHITECTURE OF THE AODV

The component called AODV defines the main flow of control inside the AODV
routing daemon. The control flow is based on an event-driven design. The set of possible
events include reception of routing control packets, expiration of various timers, and
reception of route requests on the ASL socket. Possible actions include sending out
packets, setting new timers and updating various data structures. The daemon program is
essentially a big select() loop which monitors various file descriptors for the events and
takes the appropriate actions. This component also initializes ASL by calling the
functions int route_add() and open\_route\_request().
57

The RREQ, RREP and RERR components take care of both generating as well as
processing incoming route requests, route replies and route error packets respectively.
The Routing Table component (routeTable) handles updates to the aodv routing table as
well as to the kernel routing table. It also maintains a route cache using the aodv-helper
module through the corresponding API function query_route_idle_time_aodv(), as
explained

in

the

next

subsection. The

Pending

Route

Request

component

(rreqPendingList) implements the expanding ring search and RREQ retransmission
features of the AODV routing protocol. The Forward Route Request component ensures
that a node does not process a particular RREQ packet multiple times, by storing a list of
recently seen RREQ packets. The Local Repair component attempts to repair links locally
and the Blacklist component takes care of routing in the presence of uni-directional links.
Finally, the TimerQueue component maintains various AODV timers including reboot
timer, periodic refresh timer, hello timer and rreq retransmission timer.

4.5.2 A SPLIT DESIGN
As we have explained earlier, due to the inseparable forwarding and routing
functions, there are usually two ways to implement such protocols: a complete in-kernel
approach, and a complete user-space approach. Both approaches have pros and cons. A
complete user-space approach will be inefficient for the forwarding function, but an inkernel approach is different to maintain, different to modify, and different to port to other
operating systems.
In our implementation, we attempt a split-system approach. The idea is to
segregate the forwarding and routing functions to some extent, even though they are
intermixed in the protocol design. We believe that the core of the source-routing based
forwarding activities, i.e., to send a data packet to the next-hop based on its DSR header,
should be as efficient as possible and reside inside the kernel. We call this the source
forwarding function. The majority of other source routing activities, which are induced
by source forwarding, need to be flexible and can reside in user-space.

58

FIG 4.7: SPLIT DESIGN

59

CHAPTER 5
EXPERIMENTAL SETUP
5.1 SIMULATION TOOL
One common method to conduct research in the networking and security fields is
to simulate and evaluate the protocol(s) in various scenarios. Fortunately, there are
various computer simulation applications that are available for doing those tasks, such as
NS-2, OPNET, GLOMOSIM, etc. My thesis is heavily based on the implementation and
experiments in the OPNET simulation environment. OPNET Modeled was chosen as a
simulation environment because it is one of the leading environments for network
modeling and simulation. It supports large number of built-in industry standard network
protocols, devices, and applications. In addition, its programming library helps
researchers to easily modify the network elements and measure their performance in the
simulation environment. OPNET also provides rich data analysis features.

5.2 OPNET ARCHITECTURE
OPNET provides a comprehensive environment to model and do performance
evaluation of networks and distributed systems. The OPNET package includes numbers
of tools. Those tools fall into three categories corresponding to the three phases of
modeling and simulation projects: Specification, Simulation and Data Collection, and
Analysis. These phases should necessarily be in sequence and form a simulation cycle as
in Figure 4.1.
OPNET uses the concept of modeling domains to represent its modeling
environments, and graphical editors for editing the Network, Node and Process models.
Specifically, there are several editors in OPNET: project editor, node editor, process
editor, external system editor, link model editor, packet format editor, Interface Control
Information editor, and probability density function editor.
60

FIG 5.1: SIMULATION CYCLE IN OPNET
Network Domain is used to define the network topology of a communication network.
The communicating entities are called nodes. Network domain is created by using the
Project editor tool of the OPNET modeler.
Node Domain describes nodes’ internal architecture in terms of functional elements in
the node and data flow between them.
Process defines the behavior of processes, including protocols, algorithms and
application, specified using infinite state machines and an extended high-level language.
External System specifies the interfaces to the models provided by other simulators
running concurrently with an OPNET simulation (a co-simulation).

61

5.3 NETWORK SIMULATOR
Network simulator 2 is the result of an on-going effort of research and
development that is administrated by researchers at Berkeley. It is a discrete
event simulator targeted at networking research. It provides substantial
support for simulation of TCP. Routing, and multicast protocols.
The simulator is written in C++ and a script language called OTcl2. Ns
uses an Otcl interpreter towards the user. This means that the user writes an
OTcl script that defines the network (number of nodes, links), the traffic in
the network (sources, destinations, type of traffic) and which protocols it
will use. This script is then used by ns during the simulations. The result of
the simulations is an output trace file that can be used to do data processing
(calculate delay, throughput etc) and to visualize the simulation with a
program called Network Animator (NAM). See Appendix C for a screenshot
of NAM. NAM is a very good visualization tool that visualizes the packets
as they propagate through the network. An overview of how a simulation is
done in
Ns
The current version of the Network simulator does not support mobile
wireless environments. The Network simulator alone is only intended for
stationary networks with wired links. This caused us some problems in the
beginning of this master thesis. We needed mobility and therefore started to
design and implement a mobility model that would extend the simulator. We
also started to implement the AODV protocol. This implementation of
AODV is compatible with NAM and therefore gives a good picture of how

62

AODV behaves. It is very easy to follow for instance the route discovery
procedure. About two months later, in August 1998. two separate mobility
extensions were released. These extensions had everything that we wanted
from a n extension, so we decided to use one of them. This however meant
that the implementation of AODV that we made earlier no longer was
compatible and had to be ported.

5.3.1 AODV
We have implemented the AODV protocol The implementation is done
accord to the AODV draft released in August 1993. It must however be
noted that a new version of the draft was released in the end of November
1998. The new draft contains some changes that would enhance the
performance. These changes that affect the unicast routing part is primarily:
• Reduced or complete elimination of hello messages.
• Updates to important parameters to reflect recent simulation

experiences.
To be able to test how the hello messages and link layer support affects
the behavior of the protocol we have implemented three versions:
• AODV with only IP-based hello messages
• AODV with only Link Layer notification of broken links
• AODV with both IP-based hello messages and Link layer notification

of broken links

63

The implementation of the different versions lias some major differences
that will affect the performance. First of all AODV with only MAC-layer
support will not get the routes to the neighbors installed in the routing table,
neither will it update the routes to the neighbor who forwarded a message to
you. Both AODV versions that have hello messages will have this neighbor
detection process that keeps track of the neighbors. This means that the
protocols with this feature will have more information in the routing tables.
Without this support buffering of the packets may be necessary while a
request is sent out in search for a node that could be a neighbor. It must
however be noted that the removal of hello messages somewhat changes the
behavior of the AODV protocol. The hello messages add overhead to the
protocol, but also give us some prior knowledge of link breakages.
Removing the hello messages makes the protocol completely on-demand,
broken links can only be detected when actually sending something on the
broken link.
The DSR implementation that was included in the mobility extension
used a sendbuffer that buffered all packets that the application sent while the
routing protocol searched for a route. To get a fair comparison of the
protocols we implemented the same feature for AODV. This buffer can hold
64 packets and packets are allowed to stay in the buffer for 8 seconds.
The parameters that can be adjusted for AODV and the values we have
used is . Some of these parameters are very important and affects the
performance of the protocol in drastic ways. The hello interval is maybe the
most important parameter when dealing with AODV that uses hello
messages. If the interval is too long, link breakages would not be detected
64

fast enough, but if the interval is to short, a great amount of extra control
overhead would be added. Most of the parameters in Table 3 are obvious.
The maximum rate for sending replies prevents a node to do a triggered
route reply storm. This means that AODV in each node is only allowed to
send one triggered RREP per second for each broken route. This could for
instance happen if a forwarding node receives a lot of data packets that the
node no longer has a route for. In this case the node should only send a
triggered RREP. as a response to the first data packet and if the node keeps
receiving data packets after that, a triggered RREP is only allowed to be sent
once per second.
TABLE 5.1: CONSTANTS USED IN THE AODV IMPLEMENTATION
.
Parameter

Value

Hello interval

1,5 s

Active route timeout

300 s

Route reply lifetime

300 s

Allowed hello loss

2

Request retries
Time between retransmitted requests

3s

Time to hold packets awaiting routes

8s

5.3.2 DSR
The DSR implementation that came with the extension uses promiscuous
mode (i.e. eavesdropping), which means that the protocol learns information
from packets that it overhears. The question is how realistic this is in a real
environment. In a real case scenario we will probably have some sort of
65

encryption, probably IP-Sec that uses IP-Sec tunneling to transport
messages. We have made some small change to DSR that makes it possible
to turn the eavesdropping feature on and off. The parameters that are
configurable for DSR are shown in These values are the values specified in
the DSR draft and have not been changed. The no propagating timeout is the
time a node waits for a reply for a no propagating search. A no propagating
search is a request that first goes to the neighbors. If the neighbors do not
answer in this specified amount of a tune, a new request that will be
forwarded by the neighbors will be sent. The send buffer in the DSR can
hold 64 packets and the packets are allowed to stay in the buffer for 30
seconds
FIG 5.2: CONSTANTS USED IN THE DSR
Parameter
Value
Time between retransmitted requests
500 ms
Size of source route header carrying n 4n +
addresses
Timeout for no propagating search
Time to hold packets awaiting routes

4

bytes
30 ms
30 s

5.3.2.1 FLOODING

We have implemented a simple flooding protocol that simply floods
all user data packets to all nodes m the network. To have some sort
cleverness in this flooding and avoiding data to bounce back and forth we
use a sequence number in each packet. This sequence number is incremented
for each new packet.
66

Each node keeps track of (source IP, sequence number) for all
destinations and does not process a packet if the packet has a sequence
number smaller than the stored sequence number. The idea was to do the
simulations on the flooding protocol and compare the results with the results
for the routing protocols. After some initial simulations on flooding this plan
was abandoned. The simulations took too long to complete. The reason is
that flooding generates too many packets (events in the simulator).

5.4 OPNET MODELER WIRELESS SUPPORT
The Wireless module in OPNET provides a flexible and scalable wireless network
modeling environment, including a broad range of powerful technologies. The Wireless
module integrates OPNET’s full protocol stack modeling capability, including MAC,
routing, higher layer protocols, and applications, with the ability to model all aspects of
wireless transmissions, including:


Radio Frequency propagation (path loss with terrain diffraction, fading, and





atmospheric and foliage attenuation)
Interference
Transmitter/receiver characteristics
Node mobility, including handover
The wireless module has rich protocol model suites to optimize the R&D

processes, and more effectively design technologies such as MANET, 802.11, 3G/4G,
Ultra Wide Band, 802.16, Bluetooth, and Transformational Communications systems.
Wireless network planners, architects, and operations professionals can analyze end-toend behavior, tune network performance, and evaluate growth scenarios for revenuegenerating network services.

67

5.4.1 IMPLEMENTING THE PROTOCOLS IN THE OPNET MODELER
In this thesis, I have implemented two secure routing protocols, SAODV and
OLSR, in the OPNET Modeler simulation environment, using the Application
Programming Interface functions of the OPNET development kit and the embedded C
language. The malicious feature of a wireless node is integrated into the routing protocol
model, so that each wireless node can be easily switched back and forth between the
normal mode and the malicious mode.
We can use the C/C++ language to implement/modify the behavior of a module.
For easy development, OPNET provides quite a large library with over 400 predefined
functions and procedures .
Figure 5.2 shows steps to add new secure routing protocols OLSR and SAODV
into the OPNET Modeler. OLSR and SAODV are respectively based on the DSR and
AODV protocols, which are supported in OPNET, so I did not have to re-implement the
whole protocols. Instead, I duplicate the original protocols (DSR and AODV) and then
add security features to turn them into the secure versions (that is, OLSR and SAODV).

FIG 5.2: STEPS TO ADD NEW SECURE ROUTING PROTOCOLS INTO OPNET
Step 2 in Figure 5.2 (Add security features into new protocols) is further
concretized in Figure 5.3. At the origin nodes that generate the routing packets, the
security fields are added into the routing packets at the packet creation phase of the
routing process. These security fields will be verified against the secure conditions at the
intermediate nodes and at the destination node. If the security conditions are not met, the
nodes will discard the routing packets; otherwise they accept the packets and proceed to
next appropriate processing phase. These conditions are defined by each specific protocol
and added at the processing phase of the routing process.

68

FIG 5.3: SECURE CONDITIONS AT THE INTERMEDIATE NODES

TABLE 5.3: HASH CHAIN FUNCTION

Function Name

Purpose

initialize_hash (<arguments>)

Convert a string into an array of bytes

generate_hash_chain (<arguments>))

Hash an array for a given number of times

generate_signature (<arguments>))

Generate a digital signature based on the
private/public key pair of a wireless node

publickey_extraction (<arguments>))

Get the public key of a wireless node (to

verify_signature (<arguments>))
verify_hop_count (<arguments>))

be sent to other nodes)
Verify the signature of a routing packet
Verify the hop count field contained in a

initialize_mac (<arguments>))

routing packet
Generate a hash value based on the MD5

OLSR_generate_hash (<arguments>))

algorithm
Generate a hash value for the OLSR

OLSR_verify_hash (<arguments>))

protocol
Verify the hash values in an OLSR routing
packet

69

5.4.2 IMPLEMENTING THE ATTACK MODELS IN THE OPNET MODELER
In the simulation, the attack models are implemented as part of the routing
process. Figure 4.4 illustrates how attack models are integrated into the routing processes.
Each wireless node, during the routing process, will check if it itself is a malicious node.
If it is, it will turn on the appropriate attacking process; otherwise, it will process the
routing packets as a normal node.

FIGURE 5.4: PROCEDURE TO INTEGRATE ATTACK MODELS IN THE
ROUTING PROCESS

5.4.3

RUNNING

SIMULATIONS

IN

COLLECTING EXPERIMENT RESULTS

70

THE

OPNET

MODELER

AND

Figure 5.5 shows the steps to run experimental scenarios in OPNET. There are
two ways to collect the experimental data from OPNET. The first approach is to use the
OPNET Statistic Analysis tool. Values such as average number of routing packets,
number of data sent or received over various points during the simulation time, etc., are
collected by this tool. Other values like average number of end-to-end delay of data
packets are dumped into a scalar file. This scalar file needs to be converted into a text file
to be readable by other tools.

FIG 5.5: THE FLOW CHART ILLUSTRATING THE PROCESS OF RUNNING
SIMULATION EXPERIMENTS AND COLLECTING EXPERIMENTAL DATA
TABLE 5.4: IMPLEMENTATION MATRIX OF ROUTING ATTACK
MODELS.
PROTOCO
L
DSR
OLSR
AODV
SAODV

ATTACK-1
Route Drop
Route Drop
Route Drop
Route Drop

ATTACK-2
Route modification
Route modification
Route modification
Route modification

ATTACK-3
Route Fabrication
Route Fabrication
Impersonation
Impersonation

5.5 SCENARIO SETUP
In this thesis, I set up a network with 25 wireless nodes moving at random, each
with various speed between 1 and 10 meters per second, which is the average speed of a
walking person or a running vehicle. This is a medium group that represents some of the
typical scenarios, such as a rescue team working in a disastrous area, a group of moving
71

vehicles in the city, a squad of soldiers or armored vehicles in an army operation, or a
place of an event. The pause time values represent the movement of the objects. Each of
the objects can move at a random direction, stop for some time (per the pause time), and
then change its direction at random and move again. The traffic pattern models the voice
data transferred from one node to the other. The data is sent at a rate of 2 kbps to
represent compressed voice data. The number of data source nodes is chosen based on the
assumption that a half of the nodes send the data and a half of the nodes receive the data.
The destination of data is determined at random to mimic the real situations. The
simulation scenario is summarized below:
-

Mobility Model: Random Waypoint

-

Simulation time: 400 seconds

-

Network setup:
o

Number of nodes: 25

o

Mobility model: random mobility

o

Simulation Area: 4000m x 4000 m

o

Node speed : 1-10 m/second

o

Mobility pause time values (seconds): 0, 10, 20, 30, 40, 50, 60, 70, 80, 90,
100.

o

Number of data source: 10 nodes–node 8, 9, 11, 13, 14, 15, 17, 22, 23 ,24

o

Traffic pattern:


Type of traffic: Constant Bit Rate (voice)



Packet size: 512 bytes (or ~ 4096 bits)



Sending frequency: 4 packets/second



Traffic destination: random

72

To create the malicious environments, five nodes are selected to launch the attacks
discussed in the previous section. The attacks are launched separately with various
numbers of malicious nodes. Table 4.2 shows the nodes assigned to implement the
attacks, given different number of malicious nodes.

TABLE 5.5 MALICIOUS NODE ASSIGNMENTS
Number of
malicious nodes
1
2
3
4
5

Malicious nodes assigned
node 24
node 24, node 3
node 24, node 3, node 7
node 24, node 3, node 7, node 16
node 24, node 3, node 7, node 16, node 18

The order in which malicious nodes are involved in attacking the network remains the
same for each protocol’s evaluation.

CHAPTER 6
EXPERIMENTAL RESULTS
6.1 RESULT ANALYSIS:

73

We have considered two different network scenarios with the first one having 52 nodes with 7 different
source and destination pairs (Figure 6.1) and the second one having 72 nodes with 7 different source and destination
pairs (Figure 6.2) respectively. Qualnet 4.5 network simulator is used to extensively simulate the above mentioned
scenarios. We have taken the packet size to be 512 bytes. User Datagram Protocol (UDP) is used as the transport layer
protocol and Constant Bit Rate (CBR) traffic is used as the application layer protocol applied between the source and
destination. In the first scenario CBR traffic is applied between seven source destination node pairs namely (3, 40), (5,
38), (13, 47), (17, 49), (19, 46), (28, 35) and (39, 07) respectively as depicted in figure 1 over randomly deployed 52
nodes in the deployment area. In the second scenario similarly CBR traffic is applied between seven source destination
node pairs namely (2, 39), (12, 30), (19, 27), (23, 41), (45, 31), (55, 29) and (65, 16) respectively as shown in figure 2
over randomly deployed 72 nodes in the deployment area. In both the scenarios Random Waypoint (RWP) mobility
model is considered.
It gives a list of various simulation parameters. We have enhanced both security and throughput at the same
reducing end-to-end delay and jitter in our proposed schemes. This can be attributed to the fact by taking only links
with high SNR value we ensure reliability, increased throughput and security. Jamming and interfering signals from
intruder or malicious nodes lowers a link's SNR ratio and provides a good indication about its reliability and security

FIG 6.1. NETWORK SCENARIO COMPRISING OF 52 MOBILE NODES AND 7
DIFFERENT SOURCES - DESTINATION TRAFFIC PAIRS.
74

6.2 EXPERIMENTS IN THE BEGIN ENVIRONMENT
In this phase, the performance data of four routing protocols (DSR, OLSR,
AODV and SAODV) are collected. A scenario is set up for data collection. This scenario
is run 11 times with 11 different values of the mobility pause time ranging from 0 to 100
seconds. The data is collected according to two metrics – Packet Delivery Fraction and
Normalized Routing Load. In general, the actual values of the performance metrics in a
given scenario are affected by many factors, such as node speed, moving direction of the
nodes, the destination of the traffic, data flow, congestion at a specific node, etc.
It is therefore difficult to evaluate the performance of a protocol by directly
comparing the acquired metrics from individual scenarios. In order to obtain
representative values for the performance metrics, we decided to take the average values
of multiple simulation runs. The average values of these 11 simulation runs are then
calculated for the two metrics and used as a baseline to evaluate the performance of
routing protocols in malicious environments.

75

FIG 6.2 CLUSTERING CREATION AND NODE DISTRIBUTED

FIG 6.3: PACKET DELIVERY FRACTION VS. PAUSE TIME VALUES IN

76

BENIGN ENVIRONMENT
As shown in Figure 6.1, the percentage of packets delivered in AODV and
SAODV is fairly close to each other, and both methods exhibit superior performance
(~90% in general). The security features in SAODV lower the performance a little bit.
Actually, the generation and verification of digital signatures depends on the power of the
mobile nodes and causes a delay in routing packet processing. In the simulation
environments, this delay depends on the simulation running machine and is not high
enough to make the significant difference for the PDF metric. On the other hand, the
packet delivery fraction in DSR and OLSR are 20-40% lower than that of
AODV/SAODV across the board given different mobility pause times.
The major difference between AODV and DSR is caused by difference in their
respective routing algorithms. It was reported by other researchers that, in high mobility
and/or stressful data transmission scenarios, AODV outperforms DSR. The reason is that
DSR heavily depends on the cached routes and lack any mechanism to expire stale
routes. In the benign environment of our experiments, the default expiry timer of cached
route for DSR and OLSR is 300 seconds, while this number is 3 seconds for AODV and
SAODV. In respect to the protocol design, these values are kept unchanged through all
the simulation scenarios.
Furthermore, DSR and OLSR store the complete path to the destination. Hence,
if any node moves out of the communication range, the whole route becomes invalid. In
MANETs, the nodes are mobile, so route change frequently occurs. Without being aware
of most recent route changes,
The situation is even worse for OLSR, mainly because OLSR relies on the
delayed key disclosure mechanism of TESLA when authenticating packets, including the
RERR packets (see section III.3.1 for details). When an intermediate node in OLSR
notices a broken link, it sends a RERR message to the source node of the data packet. The
source node, however, simply saves the RERR message, because it has not yet received
from the intermediate node the key needed to authenticate the route error. The source
node keeps sending the data until the second route error is triggered, and another RERR

77

is received. Only then would the previous route error be authenticated, and the broken
link not be used any more. This explains the worse performance of OLSR in comparison
with DSR and other protocols.

FIG 6.4: NORMALIZED ROUTING LOAD

78

FIG 6.5: NORMALIZED ROUTING LOAD VS. PAUSE TIME VALUES IN
BENIGN ENVIRONMENT
As shown in Figure 5.2, the NRL metric is, in general, inversely proportional to
the PDF metric (Figure 5.1). A low PDF value (for example, OLSR in Figure 5.1)
corresponds to a high NRL value (Figure 5.2). This relationship between PDF and NRL is
further illustrated in Table 5.1, which lists the average values of the two metrics over 11
simulation runs for each of the four protocols.

6.1 THE “BASELINE” METRICS OF THE FOUR PROTOCOLS
Packet

Normalized

Delivery

Routing

Fraction (%)

Load

DSR

68.41%

1.72

OLSR

54.70%

2.58

AODV

93.45%

1.01

SAODV

92.00%

0.98

Pause Time
(seconds)

79

The comparison between the normal routing protocols (DSR and AODV) and
their respective secure version (that is, OLSR and SAODV) in benign environments has
been extensively conducted by other researchers. In the next section, I will discuss the
performance of the protocols in various malicious environments.

FIG 6.6: THROUGHPUT

80

Fig 6.7.Comparision of Jitter for OLSR-INRIA & SOLSR-INRIA, DSR & SDSR and ZRP & SZRP for 52 & 72 Nodes.

6.2.1 THROUGHPUT

We have measured end to end throughput in Kbits/sec for each source destination
pair over both the network scenarios. A high individual and average throughput is
observed in all the cases by the modified protocols. The result obtained can be attributed
to the fact that due to the selection of the path having highest SNR value the impact of
interference and jamming signals are less and path bandwidth is increased which is
reflected as higher throughput that is desirable for almost every envisaged application of
MANET. A considerable improvement in average throughput is observed in both the
scenario for all routing protocol.

In case of the end-to-end packet delay is calculated as the elapsed time interval
when the packet is sent by the source to the time when it is received at the destination
node. The modified protocols exhibits a low end to end delay every source destination
pair and on the average as well. This can be attributed to the fact due to the selection of
high SNR value paths offering high bandwidth resulting in lower queuing delay at the
intermediate nodes.

The overall end to end delay is reduced which is an important QoS in applications
such as video streaming, live telecast and others. Fig 6 shows the end to end delay for
scenario 1 and scenario 2 as well. A significant reduction in average end to end delay is
observed which makes this type of modified protocol suitable for video streaming
operations.

81

6.2 THROUGHPUT

End-to-End Delay
(In Sec)
OLSR-INRIA
SOLSR-INRIA
DSR
SDSR
ZRP
SZRP

52 Nodes
Scenario
0.818
0.329
01.48
0.178
0.185
0.126

72 Nodes
Scenario
0.727
0.131
1.404
0.235
04.04
0.171

6.2.2 END TO END DELAY PERFORMANCE
In case of SOLSR-INRIA the End-to-End Delay is decreased by 59% for the first
scenario and 81% for the second scenario. In case of SDSR the End-to-End Delay is
decreased by 87% for the first scenario and 83% for the second scenario. As well as for
SZRP the End-to-End Delay is decreased by 32% for the first scenario and 95% for the
second scenario.
generates an evenly spaced stream, unavoidable jitter is introduced by the network due to
the variable queuing and propagation delays, and packets arrive at the destination with a
wide range of inter-arrival times. The jitter increases at switches along the path of a
connection due to many factors, such as conflicts with other packets wishing to use the

Figure 6.8 . Comparison of End-to-End Delay for OLSR-INRIA & SOLSR-INRIA, DSR & SDSR and ZRP & SZRP for 5
Nodes.
82

same links, and nondeterministic propagation delay in the data-link layer. In our modified
protocol average jitter decreases for SOLSR-INRIA, SDSR and as well as for SZRP. .
In case of SOLSR-INRIA the Jitter is decreased by 52% for the first scenario and 67% for
the second scenario. In case of SDSR the Jitter is decreased by 84% for the first scenario
and 75% for the second scenario. As well as for SZRP the Jitter is decreased by 68% for
the first scenario and 76% for the second scenario
TABLE 6.3: END TO END DELAY
Jitter
(In Sec)
OLSR-INRIA
SOLSR-INRIA
DSR
SDSR
ZRP
SZRP

52 Nodes
Scenario
0.124
0.059
0.497
0.077
0.067
0.021

83

72 Nodes
Scenario
0.112
0.036
0.493
0.120
0.264
0.061

FIG 6.9: DELAY VS TIME

84

Fig 6.10: Delivery Ratio

6.3 EVALUATION RESULT:

85

The AODV protocol performance was evaluated with the "Network Simulator 2"
(ns–2), which is one of the most powerful tools used to simulate wired and wireless
network protocols. For our case of study, three simulation scenarios were considered: in
the first one the simulation was carried out in normal conditions, in other words, all the
nodes participated correctly in the routing functions. In the second scenario, one of the
nodes was a malicious node which accomplished the sequence number attack. In the third
scenario, an attack detection module was proposed and it was incorporated in the AODV
protocol and simulated again.
The metrics that we used to evaluate the attack detection module performance are
the following: (1) Packet delivery ratio or percentage (considered as our most important
metric), (2) Number of RREP packets sent by node number 2 (the malicious node), (3)
Accuracy on attack detection, and (4) Average latency of the transmitted packets.

FIG 6.11: PACKET DELIVERY RATIO VS NUMBER OF CONNECTIONS
6.3.1 NUMBER OF RREP PACKETS SENT BY NODE 2 (MALICIOUS NODE)

86

It shows the number of RREP packets sent by node 2 (the malicious node) versus
the number of connections in normal conditions. In order to evaluate this metric and
observe the behavior of the curves, we have placed the respective graphics on separate
figures. Figures 9 and 10 depict the number of sent RREP packets versus the number of
connections without or with the module incorporated, respectively, and both under attack
conditions.

FIG 6.12: NUMBER OF RREP SENDS BY NODE 2 VS NUMBER OF
CONNECTIONS
The three graphics show a proportional behavior between the number of
connections and the number of RREP packets sent by node 2. This is normal since a great
number of traffic connections in the network provides a greater chance to the malicious
node to send RREP packets. Nevertheless, when the attack takes place the number of sent
RREP messages (false messages in this case) is much bigger than the number of
messages sent under normal conditions.

87

This is because the attack is implemented in such a way that the malicious node
replies with a false RREP to any route request that reaches it.
With the detection module incorporated the number is even bigger; this is because
there is a moment in which the source node discards any RREP it receives (due to broken
links or increments in the sequence number). In that moment there is not an available
route for the source node, which is continuously sending route requests, and that explains
the increment on the number of RREP.

FIG 6.13: NUMBER OF RREP SENDS BY NODE 2 VS NUMBER OF
CONNECTIONS UNDER ATTACKS

88

6.3.2 TRANSMITTED PACKETS AVERAGE DELAY
It show the graphics obtained when analyzing the packets' average delay versus
the number of connections and the node mobility for every simulation scenario. We are
including here the possible delays due to buffering during the route discovering delay, the
interface queue, the MAC layer's transmission delay and the time for transferring.

FIG 6.14: AVERAGE DELAY VS NUMBER OF CONNECTIONS
It shows that there is a decrease on the average delay when the protocol in under
attack (compared with the normal operation). It is important to mention that in this case
the average is obtained from a fewer quantity of packets, that is, only those that are
delivered to their destinations. When the detection module is incorporated there is a light
increasing on the average delay due to the time used by the source node in determining
whether it is being attacked or not.

89

FIGURE 6.15: AVERAGE DELAY VS MAX SPEED OF NODE
MOVEMENTS

90

CHAPTER 7
CONCLUSION AND FUTURE WORK
CONCLUSION
From the simulation results it can be concluded that for SOLSR-INRIA, SDSR
and SZRP average throughput increases while average end-to-end delay and jitter
decreases considerably as compared to OLSR-INRIA, DSR and ZRP in both the
scenarios. The modified protocols avoid malicious nodes and noisy links by choosing the
highest SNR path which increases overall network reliability. Random Waypoint (RWP)
mobility model is considered as it encompasses most of the envisaged application areas
of MANETs. We have extensively simulated our methods using QualNet 4.5 network
simulator. As a future work other mobility models and data traffic might be considered.
Intrusion detection methods may be incorporated in the route discovery phase of OLSRINRIA, DSR and ZRP for detection of malicious nodes to enhance network reliability.
In this thesis, I have implemented two secure routing protocols, OLSR and
SAODV, based on their respective underlying protocols, DSR and AODV, in the OPNET
simulation environment. I have also simulated four popular network attack models that
exploit the weakness of the protocols. The attack models are used to make malicious
wireless nodes and create various malicious environments, in which the performance of
DSR, AODV, OLSR, and SAODV are evaluated. With three different attack models for
each of the protocols, and with the number of malicious nodes varying from one to five,
totally 65 scenarios are created to evaluate the four protocols.

91

The ultimate goal of a routing protocol is to efficiently deliver the network data
to the destinations; therefore, two metrics, Packet Delivery Fraction (PDF) and
Normalized Routing Load (NRL), are used to evaluate the protocols. In order to get the
accurate experimental results, each scenario is run eleven times in order to calculate the
average value for the two evaluation metrics. Through the collected evaluation metrics
from the various scenarios, the impacts of attacks upon the routing protocols are then
studied. The procedure is summarized below:
First, the four protocols are used in a benign environment, in which there is no
network attack, in order to collect baseline values for the metrics. The differences
amongst baseline values of the protocols are also discussed in order to get better
understanding of each protocol’s operation.
Second, each of the protocols is evaluated in various simulated malicious
environments. The collected metrics are compared with the respective baseline values, in
order to assess the impact of a particular network attack on the protocol operation. Based
on the results we’ve collected, we conclude that, in all the malicious environments,
normal routing protocols (DSR and AODV) can not guarantee to deliver data to the
destinations as well as in the benign environments. In other words, the data is redirected
or discarded due to the attacks on the routing protocol. When the number of malicious
nodes increases, the number of received data packets decreases. For the secure versions
of the routing protocols (OLSR and SAODV), they are designed to detect the changes in
routing packets; hence, even under attacks, they are still able to deliver the data to the
destinations. However, under specific attacks like route fabrication attack for OLSR and
impersonation attack for SAODV, the protocol requires the existence of a specific
security mechanism, in order to maintain the normal operation. That is the key
management center for SAODV and the secure cached routes for OLSR.
Another conclusion is that the mobility model of the malicious nodes affects the
number of data packets to the destinations. Preliminary analysis and discussions of this
issue can be found in Chapter VI

92

FUTURE WORK
More research is needed in the following issues:


The OLSR protocol needs to be improved in order for the cached route feature to



be secure and effective in malicious environments.
A public key verification mechanism, such as certificate-based authentication, is
needed for SAODV, in order to verify the binding between the node’s identity and



its public key.
More research is needed in the mobility of the nodes in order to comprehensively
evaluate the impact of the malicious nodes’ movement on the protocol’s
performance.

93

BIBLIOGRAPHIC
[1] T.H Clausen, G.Hansen, L.Christensen, G. Behrmann, “ The Optimised Link State
Routing Protocol Evaluation Through Experiments and Simulations”, Proceedings of
IEEE Symposium on Wireless Personal Mobile Communications, 2001, September 2001.
[2] D.B Johnson, D.A. Maltz, “Dynamic Source Routing in Ad Hoc Wireless Networks”,
Mobile Computing, Kluwer Academic Publishers, 1996, vol. 353, pp. 153-181.
[3] D. Sivakumar, B. Suseela, R. Varadharajan, “A Survey of Routing Algorithms for
MANET”, IEEE International Conference on Advances in Engineering, Science and
Management (ICAESM), March 30-31, 2012, pp. 625- 640. Available in IEEE Explore.
4] V.Jha, K. Khetarpal, M.Sharma, “A Survey of Nature inspired Routing Algorithms for
MANETs”, IEEE 3rd International Conference on Electronics, Computing Technology
(ICECT), April 8-10, 2011, pp. 1-4. Available in IEEE Explore.
[5]

S.Weber, J.G Andrews, N. Jindal, “An Overview of Transmission Capacity of

Wireless Networks”, IEEE Transactions on Communication, vol. 58, Issue. 12, 2010, pp.
3593-3604.
[6] Royer E M, Toh C K, “A review of current routing protocols for Adhoc mobile
wireless networks” IEEE Journal of Personal Communications, Dec. 2006, vol. 6(2), pp.
46- 55.
[7] Z.J Haas, “The Routing Algorithm for the Reconfigurable Wireless Networks”,
Proceedings of ICUPC 1997, vol. 2, pp. 562-566, October 1997.
[8] P. Nand, and S.C. Sharma, “Performance study of Broadcast based Mobile Ad hoc
Routing Protocols AODV, DSR and DYMO”, Proc. International Journal of Security and
Its Applications, Vol. 5, No. 1, January, 2011, pp. 53-64.

94

[9] D.B. Johnson, D.A. Maltz and J. Borch, “DSR: The Dynamic Source Routing
Protocol for Multi-Hop Wireless Ad Hoc Networks”, Computer Science Department
Carnegie

Mellon

University

Pittsburgh,

PA15213-3891,

Dec.

2009.

http://www.monarch.cs.cmu.edu.
[10] J. Liy, H. Kameday and Y. Panz, “Study on Dynamic Source Routing Protocols for
MANET”, Institute of Information Science and Electronics, University of Tsukuba,
Japan. Department of CS, Georgia State University. University Plaza, Atlanta, GA 30303,
USA.
[11] Scalable Networks Technologies: Qualnet Simulator 4.5

http://www.scalable-

networks.com .
[12] Saurav Ghosh, Chinmoy Ghorai, “ Evaluating the Performance of Modified DSR in
Presence of Noisy Links using QUALNET Network Simulator in MANET”, Proc.
International Journal of Smart Sensors and Ad Hoc Networks (IJSSAN) ISSN No. 22489738 Volume-1, Issue-2, 2011, pp. 35-40.
[13] Arun Kumar B. R., Lokanatha C. Reddy, Prakash S. Hiremath, “Performance
Comparison of Wireless Mobile Ad-Hoc Network Routing Protocols” International
Journal of Computer Science and Network Security, VOL.8 No.6, June 2008, pp.337343.
[14] G.R Vijayavani, G. Prema, “Performance Comparison of MANET Routing Protocols
with Mobility Model derived based on Realistic Mobility Pattern of Mobile Nodes”,
IEEE Conference on Advanced Communication, Control and Computing Technologies
(ICACCCT) 2012, pp. 32- 36. Available in IEEE Explore.
[15] Zygmunt J. Haas and Marc R. Pearlman and Prince Samar, “The Intrazone
Routing Protocol (IARP) for Ad Hoc Networks”, Draft-ietf-manet-zone- iarp-01.txt,
June 2001.

95

[16] Zygmunt J. Haas and Marc R. Pearlman and Prince Samar, “The Interzone
Routing Protocol (IERP) for Ad Hoc Networks”, Draft-ietf-manet-zone- ierp 02.txt July
2002.
[17]. M.N. SreeRangaRaju and Dr. Jitendranath Mungara, “Optimized ZRP for MANETs
and its Applications”, proceedings of International Journal of Wireless & Mobile
Networks (IJWMN) Vol. 3, No. 3, June 2011.
[18]. DSR, internet draft, http://tools.ietf.org/html/draft-ietf- manet-dsr-10 .
[19]. AODV, internet draft, http://tools.ietf.org/html/draft-ietf- manet-aodv-09 .
[20]. ZRP, internet draft, http://tools.ietf.org/id/draft-ietf-manet- zone-zrp-04.txt .
[21].

ZRP

patch,

http://magnet.daiict.ac.in/magnet_members/MTech/2007/PatelBr

ijesh/Simulation.html#Sec_2.
[22].ZRP

Agent

Implementation

documentation,

http://magnet.daiict.ac.in/magnet_members/MTech/2007/PatelBr
jesh/Thesis_files/MyZRP/ZRPManual.pdf .
[23]. Yinfei Pan, “Design Routing Protocol Performance Comparison in NS2: AODV
Comparing to DSR as Example”, Deptt of CS, SUNY Binghamton, Vestal NY 13850.
[24].NS2 Trace format - http://nsnam.isi.edu/nsnam/index.php/NS-2_Trace_Formats .
[25].The ns Manual (formerly ns Notes and Documentation) by Kevin Fall, Kannan
Varadhan. http://www.isi.edu/nsnam/ns/doc/ns_doc.pdf
[26]. NS Simulator for beginners, http://wwwop.inria.fr/members/Eitan.Altman/COURS-NS/n3.pdf.

96

97

Sponsor Documents

Or use your account on DocShare.tips

Hide

Forgot your password?

Or register your new account on DocShare.tips

Hide

Lost your password? Please enter your email address. You will receive a link to create a new password.

Back to log-in

Close