Degree project
Comparative Performance
Analysis of MANET Routing
Protocols in Internet Based
Mobile Ad-hoc Networks
Author: Roja Rani Mannam, Mahe
Zabin
Date: 2012-06-13
Subject: Computer Science
Level: Master
Course code: 4DV01E
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Abstract
In crucial times, such as natural disasters like Earthquakes, Floods,
military attack, rescue and emergency operations, etc., it is not
possible to maintain an infrastructure. In these situations, wireless
Mobile Ad-Hoc networks can be an alternative to wired networks. In our
thesis, due to the importance of MANET (Mobile Ad-hoc Network)
applications, we do research on MANET and its subtype IMANET
(Internet based Mobile Ad-hoc Network). In MANETs, finding an
optimum path among nodes is not a simple issue due to the random
mobility of nodes and topology changes frequently. Simple routing
algorithms like Shortest Path, Dijksta‟s and Link State fail to find route
in such dynamic scenarios. A number of ad-hoc protocols (Proactive,
Reactive, Hybrid and Position based) have been developed for
MANETs.
In this thesis, we have designed an IMANET in OPNET 14.5 and
tested the performance of three different routing protocols namely
OLSR (Optimum Link State Routing), TORA (Temporarily Ordered
Routing Algorithm) and AODV (Ad-hoc On-demand Distance Vector)
in different scenarios by varying the number of nodes and the size of
the area. The experimental results demonstrate that among the three
protocols, none of the routing protocol can ensure good quality HTTP
and voice communication in all our considered scenarios.
Key words: Mobile Ad hoc Network (MANET), OLSR, TORA, AODV, HTTP and
voice.
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ACKNOWLEDGMENT
We are grateful to Almighty for showering his blessings on us.
We are sincerely thankful to honorable supervisor Professor Ola Flygt, for his constant
directions to enhance the quality of the thesis.
We convey deep respect to our thesis coordinator Professor Mathias Hedenborg, who
supported us for the completion of the work. We extend our gratitude to our program
coordinator Professor Jonas Lundberg, Ph.D for his cooperation and inspiration to
complete our master degree at Linnaeus University, Sweden.
Roja Rani & Mahe Zabin
I am blessed to have my husband Mr. Praveen, your cherish and support in all aspects is
esteemed. Thank you and I love you forever. Heartfelt thanks to my parents and my
brother. Roja Rani
In this very moment, I passionately remember my beloved father Mr. M.M. Zakaria, a
true benefactor of learning throughout his life who tried by all his means to provide the
best possible education for me and my dearest mother Mrs. Rawshan Ara Begam who
gives unconditional love and affection for the happiness of me.
Finally, I would like to express my sincere gratefulness to my love, Jia, for his
unconditional support, devotion and care and to my father in law Golam Quader and
mother in law Ayesha Khatun whose encouragement helped me to reach at this stage.
This thesis is dedicated to my twins, Jasra and Jahra.
Mahe Zabin
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Contents 1. Introduction .................................................................................................................1
1.1 Problem Statement ...................................................................................................1
1.2 Research Challenges ................................................................................................1
1.3 Thesis Goal and Research Methodology .................................................................2
1.4 Thesis Outline ..........................................................................................................2
2. Background ..................................................................................................................3
2.1 Statistical data of Earthquakes .................................................................................3
2.2 Densities of Earthquakes ..........................................................................................4
2.3 Comparison of real densities and experimental densities ........................................4
3. Classification of Wireless Networks ...........................................................................5
3.1 Infrastructure Wireless Networks and Ad-hoc Networks ........................................5
3.2 Types of Ad-hoc Networks ......................................................................................6
4. Routing and Routing Protocols ..................................................................................7
4.1 Overview of Routing ................................................................................................7
4.2 Routing Protocols .....................................................................................................7
4.2.1 Routing Protocols for Wired Networks.............................................................8
4.2.2 Routing Protocols for Ad-hoc Networks...........................................................8
5. Overview of MANET ................................................................................................10
5.1 Properties of MANET ............................................................................................10
5.2 Limitations of MANET ..........................................................................................10
5.3 MANET Applications ............................................................................................11
5.4 Types of MANET ..................................................................................................11
5.5 The System Design of IMANET ...........................................................................12
5.5.1 An Aggregate Chaching Mechanism ..............................................................12
5.6 Devices supporting in MANET networks ..............................................................13
6. MANET Routing Protocols.......................................................................................16
6.1 OLSR (Optimized Link State Routing) .................................................................16
6.2 TORA (Temporary Ordered Routing Algorithm) ..................................................17
6.3 AODV (Ad Hoc On-demand Distance Vector) .....................................................18
6.4 GRP (Geographic Routing Protocol) .....................................................................19
6.4.1 GRP Quadrant .................................................................................................19
6.4.2 GRP Flooding .................................................................................................19
6.4.3 GRP Routing Table .........................................................................................20
6.4.4 HELLO Protocol in GRP ................................................................................20
6.4.5 GRP Routing Lookup ......................................................................................20
6.4.6 GRP Routing Backtrack ..................................................................................20
7. Experimental Environment Setup ...........................................................................21
7.1 Network Simulation tools ......................................................................................21
7.2 Detailed View of OPNET Simulator .....................................................................21
7.2.1 OPNET Simulator for MANET ......................................................................21
7.2.2 Workflow of OPNET ......................................................................................22
7.3 Description of Experimental Parameters ...............................................................22
7.4 Design the IMANET scenario in OPNET .............................................................24
7.5 Data Entities. ..........................................................................................................25
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7.5.1 Application Configuration ..............................................................................25
7.5.2 Profile Configuration. .....................................................................................26
7.5.3 Mobility Configuration ...................................................................................26
7.5.4 Server ..............................................................................................................26
7.5.5 Nodes ..............................................................................................................27
8. Experimental Results and Analysis .........................................................................28
8.1 Impact of the number of nodes on the QoS parameters of HTTP traffic for
different protocols ........................................................................................................28
8.1.1 Scenario 1(a), QoS of HTTP traffic for 10, 25 and 100 nodes in an area of
1km*1km .................................................................................................................28
8.1.2 Scenario 1(b), QoS of HTTP traffic for 10, 25 and 100 nodes in an area of
3km*3km .................................................................................................................29
8.1.3 Scenario 1(c), QoS of HTTP traffic for 10, 25 and 100 nodes in an area of
10km*10km .............................................................................................................30
8.2 Impact of the number of nodes on the QoS parameters of Voice traffic for
different protocols ........................................................................................................31
8.2.1 Scenario 2(a), QoS of Voice traffic for 10, 25 and 100 nodes in an area of
1km*1km .................................................................................................................31
8.2.2 Scenario 2(b), QoS of Voice traffic for 10, 25 and 100 nodes in an area of
3km*3km .................................................................................................................32
8.2.3 Scenario 2(c), QoS of Voice traffic for 10, 25 and 100 nodes in an area of
10km*10km .............................................................................................................33
8.3 Impact of network area on the QoS parameters of HTTP traffic for different
protocols .......................................................................................................................35
8.4 Impact of network area on the QoS parameters of Voice traffic for different
protocols .......................................................................................................................35
8.5 Theoritical Explanation of Simulation Results ......................................................35
9. Conclusion and Future Works .................................................................................37
9.1 Conclusion .............................................................................................................37
9.2 Proposed Solutions to the Research Questions ......................................................37
9.3 Future Works .........................................................................................................38
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Appendix
A. HTTP Server Configuration ...................................................................................... 41
B. Backbone Network Configuration ............................................................................. 42
C. Application Configuration ......................................................................................... 43
D. Profile Configuration ................................................................................................. 43
E. MANET Gateway Configuration ............................................................................... 44
F. Mobility Configuration .............................................................................................. 44
G. Scenario of HTTP for 10 nodes in different areas 1km*1km, 3km*3km, 10km*10km
........................................................................................................................................ 44
H. Scenario of HTTP for 25 nodes in different areas 1km*1km, 3km*3km, 10km*10km
........................................................................................................................................ 45
I. Scenario of HTTP for 100 nodes in different areas 1km*1km, 3km*3km, 10km*10km
........................................................................................................................................ 46
J. Scenario of Voice traffic for 10 nodes in different areas 1km*1km, 3km*3km,
10km*10km .................................................................................................................... 46
K. Scenario of Voice traffic for 25 nodes in different areas 1km*1km, 3km*3km,
10km*10km .................................................................................................................... 47
L. Scenario of Voice traffic for 100 nodes in different areas 1km*1km, 3km*3km,
10km*10km .................................................................................................................... 48
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List of Figures
Figure 3.1 A Wireless Network in Infrastructure Mode ................................................... 5
Figure 3.2 A Wireless Network in Ad hoc ModeMode ................................................... 5
Figure 5.1Indirect connection between the devices........................................................ 10
Figure 5.2 System design of IMANET ........................................................................... 12
Figure 5.3 MANET configuration .................................................................................. 14
Figure 6.1 Overview of MANET routing protocols ....................................................... 16
Figure 6.2 HELLO message in MANET using OLSR ................................................... 16
Figure 6.3 Route discovery procedure in TORA (Query Message) ............................... 17
Figure 6.4 Height of each node updated as a result of UDP message ............................ 18
Figure 6.5 RREQ and RREP messages in AODV ......................................................... 19
Figure 6.6 Concept of Quadrants in GRP ....................................................................... 20
Figure 7.1 Workflow of OPNET .................................................................................... 22
Figure 7.2 A Backbone Network of an IMANET .......................................................... 26
Figure 7.3 A Scenario of IMANET with MANET gateways ......................................... 27
Figure 8.1 Analysis of QoS parameters of different protocols in HTTP traffic (10, 25,
100 nodes in 1km*1km area).......................................................................................... 28
Figure 8.2 Analysis of QoS parameters of different protocols in HTTP traffic (10, 25,
100 nodes in 3km*3km area).......................................................................................... 29
Figure 8.3 Analysis of QoS parameters of different protocols in HTTP traffic (10, 25,
100 nodes in 10km*10km area) ..................................................................................... 30
Figure 8.4 Analysis of QoS parameters of different protocols in voice traffic (10, 25,
100 nodes in 1km*1km area).......................................................................................... 32
Figure 8.5 Analysis of QoS parameters of different protocols in voice traffic (10, 25,
100 nodes in 3km*3km area).......................................................................................... 33
Figure 8.6 Analysis of QoS parameters of different protocols in voice traffic (10, 25,
100 nodes in 10km*10km area) ..................................................................................... 34
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List of Tables
Table 2.1 Stactstics of Earthquakes .................................................................................. 3
Table 2.2 Densities of people using communication devices .......................................... 4
Table 2.3 Statistics of the densities of our designed network scenarios........................... 4
Table 7.3 List of Experimental Parameters .................................................................... 23
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Acronyms
ABR Associativity Based Routing
AODV Ad hoc On-demand Destance Vector
AP Access Point
ASL Ad hoc Support Library
BSN Body Sensor Network
DAG Directed Acyclic Graph
DSDV Distance Sequence Distance Vector
DSR Dynamic Source Routing
DV Distance Vector
FTP File Transfer Protocol
GloMoSim Global Mobile Information system Simulator
GPS Global Positioning System
GRP Geographical Routing Protocol
GSM Global System for Mobile communication
GSR Global State Routing
GUI Graphical User Interface
HTTP Hypertext Transfer Protocol
IETF Internet Engineering Task Force
INVANET Intelligent Vehicular Ad hoc Network
IMANET Internet based Mobile Ad hoc Network
MAD Media Access Delay
MANET Mobile Ad hoc Network
MFR Most Forwarding Progress within Routing
MN Mobile Node
MOS Mean Opinion Score
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MPR Multi Point Rely
NS Network Simulator
OLSR Optimized Link State Routing
OPNET Optimized Network Engineering
OSPF Open Shortest Path First
PDA Personal Digital Assistance
PNR Position and Neighborhood based Routing
QoS Quality of Service
RERR Route Error
RIP Routing Information protocol
RREP Route Reply Packet
RREQ Route Request
SPF Shortest Path First
TBRPF Topology Broadcast based on Reverse Path Forwarding
TC Topology Control
TCP Transmission Control Protocol
TORA Temporarily Ordered Routing Algorithm
VANET Vehicular Ad hoc Network
WAP Wireless Access Point
WLAN Wireless Local Area Network
WMN Wireless Mesh Network
WRP Wireless Routing Protocol
WSN Wireless Sensor Network
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1. Introduction
An Ad-hoc network is a wireless network without infrastructure like fixed routers in
wired network and access point in wireless network. Instead of infrastructure, here
every node participates in routing by forwarding the data to other nodes.
A Mobile Ad-hoc Network (MANET) is a wireless system, where nodes are moving
randomly. There are different subtypes of MANETs such as, IMANET (Internet-based
Mobile Ad hoc Network), VANET (Vehicle Ad-hoc Network), WSN (Wireless Sensor
Networks), and BSN (Body Sensor Network). At present, researchers are continuing to
explore and develop MANETs. Routing is a key concern in the design of all such
communication networks.
1.1 Problem Statement
The performance of IMANETs may be influenced by mobility, scalability and traffic
load. These factors may affect the QoS parameters of different traffics by either
increasing or decreasing the overall efficiency of network. In this thesis, we will
design network scenarios of IMANET and measure the different QoS (Quality of
Service) parameters to evaluate the performance of different routing protocols by
varying the two important network parameters- network area and number of nodes. So far, research studies on performance analysis of MANET routing protocols
have shown distinctive results based on the different network conditions by
using different network simulators such as, Packet Tracer, NS-2/NS-3 [5, 28], GloSim,
QualNet, OPNET[2, 3].
1.2 Research Challenges
In this section, we address the following research questions as research challenges.
1. Is MANET a viable solution to the communication demands that exist in a
disaster area without a fixed infrastructure?
2. Why routing is a key issue in MANETs? By theoretical study in
background chapter we try to focus on it.
3. Among different types of routing protocols, such as table driven, on
demand and position based; which type of routing protocols can perform
better performance in IMANETs?
4. Which networks factors influence on the performance of MANET routing
protocol in IMANET? To observe it in our experimental setup, we designed
different network scenarios of IMANET changing the network area, no. of
nodes, node speed, etc.
5. How to design IMANET scenarios in OPNET to collect proper simulation
results?
6. Which protocol shows better performance in different network traffics,
such as HTTP and voice in IMANETs?
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1.3 Thesis Goals and Research Methodology
Our goal is to gain the theoretical knowledge on MANET [1] routing protocols and
gather the knowledge on the development of MANET routing protocols. In our thesis,
we will study details on a proactive protocol OLSR (Optimized Link State Routing) [2,
3], reactive protocol TORA (Temporary Ordered Routing Protocol) [4] and AODV (Ad
hoc On-demand Distance Vector) and a position based protocol GRP (Geographic
Routing Protocol) [2, 3].
In the simulation part, we will carry out the experimental work using a network
simulation tool- OPNET 14.5 as it has attractive GUI interface rather than other existing
simulators such as Qualnet, GloMoSim, NS-2/ NS-3(Network Simulator version 2/3).
We will design different IMANET scenarios in OPNET by varying the network area,
node density for different traffics such as HTTP and voice. We will also test the
performance of different routing protocols- OLSR, TORA and AODV by collecting
simulation results of different network metrics - throughput, network load, media access
delay, MOS, and download page response. At the end of the report, we will summarize
the findings based on theoretical and empirical study of our research.
Finally we will conclude our works by analyzing the protocols and lining up the better
protocol in performance among the three routing protocols for different IMANET
scenarios. As we know the geographical based protocols need to update the positions of
neighbor nodes as well as the source node itself, differentiating GRP to other protocols
in such dynamic scenarios is also a key issue in our research.
1.4 Thesis Outline
This thesis report is divided into nine chapters. First chapter gives an introduction of
MANETs. Second chapter presents the background of the research work. In chapter
three we classify wireless networks and the ad hoc networks. Forth chapter gives a brief
overview of routing and Ad-hoc routing protocols. Fifth chapter contains the theoretical
discussion on MANETs and IMANETs. The overview of different MANET routing
protocols such as, OLSR, TORA, AODV and GRP is presented in chapter six. Seventh
chapter mainly discuss about the OPNET simulator and design procedure of network
scenarios of IMANET. The simulation results and analysis are presented in chapter
eight followed by conclusion in final chapter nine.
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2. Background
In this chapter, we present the background studies of our research work.
Mobile Ad-hoc networks play a key-role in today‟s wireless communication due to its
infrastructure less feature. The MANET is designed for electronic communication
devices such as mobile phones, smart phones, PDAs, laptops, etc. As the nodes in
MANET are randomly mobile, it can be helpful in different real scenarios such as,
disaster areas, emergency and rescue situations, military applications, etc. The people in
the disaster situations may move randomly, and then the electronic devices with
MANET setup can be useful to communicate with each other. In disaster situations [6],
any kind of infrastructure in that disaster prone area may have been destroyed and then
there is a demand for the communication systems that are independent of infrastructure
in that “disaster area scenario”. Therefore, MANETs satisfy the requirements of being
independent of any kind of infrastructure. At present, researchers are improving their
studies to implement MANET for disasters like earthquakes, floods, etc.
2.1 Statistical data of Earthquakes
In this section, for the background works our thesis, we have collected the real statistics
of some earthquakes from the year 1964 to 2011 occurred in different places. According
to this real data, we designed our experimental parameters for our designed IMANET
scenarios.
Table 2.1 Statistics of earthquakes
According to the Table 2.1 the great Alaska earthquake occurred on 27th March-
1964, with a magnitude of 9.2 and is one of the largest earthquake causing extensive
damage over 800 km area and being a least densely populated area, only 200 people
were effected among the total population of 226167 [7]. In January, Haitian capital
Port-au-Prince was hit with a 7.0 magnitude, damaging 15km area and yet it had taken
over 150000 lives among the total population 897859 [8]. The Alaska earth quake was
affected in a large area with a high magnitude, but less people were affected whereas
Year Place Magnitude Time scale Area
Effected(km)
People
Effected
1964 Alaska 9.2 Nearly 4min 800km 200
2000 MadhyaPradesh,
India
4.4 1min 70km 1000
2007 Lima and Pisco in
Peru
7.7 and 8.8 3min 150km and
745km
2000
2008 Tibet 6.6 15min 100km 100,000
2008 China 7.9 3-5min 360km 75,000
2010 Port-au-Prince 7.0 7-8min 15km 150,00
2010 NorthernSumatra,
Indonesia
7.7 3-4min 200km 310,000
2010 central part of
Chile
8.8 2min 20sec 500km 1.8million
2011 Northeastern Japan 9.0 2-3min 500km 800000
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the earthquake in Port-au-Prince was small and yet it took a lot of lives. Apart from
these two, the statistics of some other earthquakes are given in the Table 2.1.
2.2 Densities of Earthquakes
For the countries mentioned in Table 2.1, we have drawn the statistics of people using
electronic communication devices in Table 2.2, which is one of the important factors to
design the network for a disaster scenario. According to theses statistics we also
calculated the density of the electronic devices used in the coverage area. However this
might be an over estimation since most of the devices cannot work as MANET node
today but expected to be changed in few years. In our experiment we also considered
the electronic devices density similar to the studied real time scenarios in background
chapter. For these statistics, we have considered the square area and calculated the
density within the area as the number of electronic devices used per square kilometer by
applying the following formula.
Density = Population of effected area*percentage of electronic/Area effected;
Table 2.2 Densities of people using communication devices
2.3 Comparison of real densities and experimental densities
By analyzing all these calculations of all real time network scenarios in different areas,
it is observed that the least density value is 0.273 in Alaska, medium density value is
8.72 in Northern Sumatra, and the high density value is 98.13 in China. Comparing
these real densities in Table 2.2 with the experimental densities in Table 2.3 have good
similarities as the experimental densities fall in the real scenarios statistics.
The statistics of the density of our designed network scenarios is demonstrated in Table
2.3.
Table 2.3 Statistics of the densities of our designed network scenarios
Area Effected Population of
the effected area
Use Electronic
devices (%)
Density
800km*800km 2,69057 65 0.273
70km*70km 11,9805 40 9.78
150km*150km &
745km*745km
60,7392 37.5 0.280
100km*100km 24,649 40 0.98
360km*360km 1,3824746 92 96.45
15km*15km 15,000 53 35.33
200km*200km 1,163921 30 8.72
500km*500km 5,579726 51 11.38
500km*500km 800,000 95 3.04
Network Area Density
10 nodes 25 nodes 100 nodes
1km*1km 10 25 100
3km*3km 1.11 2.7 11.11
10km*10km 0.1 0.25 1
5
3. Classification of Wireless Networks
In this chapter, we give a brief discussion on the classification of wireless networks
such as infrastructure wireless networks and ad hoc networks and also further classify
the ad hoc networks.
3.1 Infrastructure Wireless networks and Ad-hoc networks
The wireless networks have become tremendously popular in the computing industry.
The reason of their popularity is that the information can be accessed regardless of the
user‟s geographical location [9]. There are two types of wireless networks namely
infrastructure and Ad hoc networks.
The Infrastructure wireless networks are also known as cellular networks having
fixed base stations. The mobile unit connects and communicates with each other within
these networks [10]. In infrastructure wireless networks a Wireless Access Point (WAP)
exists between the sender and receiver. Among multiple access points, the node selects
an access point having better signal strength. The typical application of infrastructure
wireless network is office Wireless Local Area Network (WLAN). The Figure 3.1
represents a wireless network with infrastructure.
Figure 3.1 A Wireless Network in Infrastructure Mode
The Ad hoc networks are the networks without any pre-structure. This type of
network does not have any predefined infrastructure [10]. From the Figure 3.2, the Ad-
hoc networks have no fixed routers as in wired networks, and no base station or access
point as in wireless networks. Every node of this network participates in routing by
forwarding the data to other nodes.
Figure 3.2 A Wireless Network in Ad hoc Mode
Notebook
PC
Desktop
PC
PDA
Wireless
Access Point
Notebook
PC
Desktop PC
PDA
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3.2 Types of Ad-hoc Networks
The most popular types of Ad hoc networks are Mobile Ad hoc Networks (MANET),
Wireless Mesh Networks (WMN) and Wireless Sensor Networks (WSN).
In MANET, all the nodes are randomly moving without any dedicated physical
medium. The structure does not follow a fixed topology; it may change at any time
depending on network characteristics and node mobility. In such dynamic networks,
routing is a challenging and complex issue. The applications of Ad-hoc networks are in
emergency search, rescue operations, meetings and conferences where people can easily
and quickly share information. The research is being improved to setup a MANET in
catastrophic failure situations, such as earthquakes, floods, etc.
In WMN, the nodes in the network are divided into wireless mesh routers and
wireless mesh clients. The nodes that act as mesh routers are responsible for
transmitting the data to and fro from the mesh clients. If one node fails in this network
architecture, a new path is automatically established by its neighbor node maintaining
the network connectivity. The WMN is mainly applicable in automatic electric meters,
military forces, supports VoIP, etc.
The WSN consists of sensing devices known as sensors. These sensors have the
capability to sense its surrounding environment, gather the information and
communicate among each other. The WSN differs from other networks that exhibit poor
performance as the network size increases whereas WSNs are much stronger and
perform better as the number of nodes increase in the network. The WSN have some
limitations, such as low bandwidth, short communication range, more memory space
and frequently changes network topology. The application areas are monitoring air and
water pollution, agriculture, detecting forest fires, medical and health care, etc.
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4 Routing and Routing protocols
Routing is the core problem in both wired networks and ad-hoc networks. Discovering
the optimum route is a challenging task and till now several routing protocols are
developed to overcome the problem.
4.1 Overview of Routing
Routing is the process of selecting an optimum path in a network, along which the
network traffics are sent. Routing is the key issue in wireless networks for delivering the
data from one node to another node. In wireless networks, no dedicated channel exists
between the sender and receiver; multiple paths exist between the source and
destination instead of single channel.
Types of Routing:
1. Dynamic Routing
2. Static Routing
In dynamic routing, the decisions are based on the pre-defined scenarios. The router
performs the routing. In this routing, the routing table is maintained to route the traffic.
This routing is flexible, reduces traffic overload and multiple paths are used to transfer
the data packet from source to destination [11].
In static routing the decisions are based on the administrators. These administrators
manually forward the packets to the desired destinations. In this routing, no routing
tables are used, instead the routing is performed manually, as per the administrators
instruction [11].
There are two routing techniques named Link State and Distance Vector, these
algorithms are used by the routing protocols to calculate the routes between nodes.
The link state routing algorithm also known as the Shortest Path First (SPF)
algorithm and follow the Dijkstra‟s technique. This routing algorithm can be used by
both table-driven and on-demand routing protocols. In link state routing, every node
maintains the link-state information of the entire network and based on this information
the route decision has made [12]. The link state routers directly meet the other nodes by
continuously exchanging HELLO messages. It minimizes the broadcast overhead and
maintains reliable communication. The OSPF routing protocol is an example of wired
network, which uses the Link State algorithm. The OLSR (Optimized Link State
Routing) routing protocol is an example of Mobile Ad hoc Network which is also using
the Link State algorithm.
The distance vector routing can also be used by both table-driven and on-demand
routing protocols. In distance vector, each node maintains a routing table with the
details including the destination IP address, distance to it and next node in the path. The
router periodically broadcasts the information to neighbor nodes and updates the routing
tables with received information from the neighbor nodes [13]. Thus, always the
updated routing table is maintained. The distance vector uses the Bellman-Ford
algorithm to calculate the paths [13]. The Distance Vector reduces the computational
complexity. The Routing Information Protocol (RIP) is an example of wired networks
which are designed by the Distance Vector algorithm. The MANETs routing protocols
TORA, AODV are also designed by the Distance Vector algorithm.
4.2 Routing Protocols
Routing is used to discover and maintain the routes between the source and destination.
It is complex task in wired networks to overcome this problem many routing protocols
8
are developed. The routing protocol establishes communication between the routers and
transfers the data packets. The main function of the routing protocol is determining the
best path to deliver the network traffic. In the case of ad hoc networks, the routing
protocols play a very major role as all the nodes are randomly mobile and the topology
changes frequently. In such dynamic structures it is difficult to find the best route and
thus protocols play an important role in Ad-hoc networks communications.
4.2.1 Routing Protocols for Wired Networks
The following are the examples of routing protocols in wired networks.
1. Open Shortest Path First
2. Routing Information Protocol
The Open Shortest Path First (OSPF) is a routing protocol developed by the Interior
Gateway Protocol (IGP) working group for Internet Protocol (IP) networks. This
protocol identifies the changes in the network topology, updates very quickly and
maintains a loop-free router structure. This protocol computes the shortest-path using
the Dijkstra‟s algorithm.
The Routing Information Protocol (RIP) is a distance vector routing protocol. This
protocol stops the routing loops in the network by implementing the Hop Count i.e. it
limits the number of routers through which the data packets are passed from source to
destination. The hop limit may also limit the network size. The maximum numbers of
hops allowed in RIP are 15, if the hop count exceeds to 15 then it is considered as an
infinite distance.
4.2.2 Routing Protocols for Ad-hoc Networks
The routing protocols play an important role in ad hoc networks. The following are the
major types of protocols in ad hoc networks.
1. Proactive Routing Protocol (Table-driven)
2. Reactive Routing Protocol (On-demand)
3. Position Based Routing Protocol
In Proactive, each node maintains a routing table with the updated routing
information of all the neighbor nodes. When a source node needs to transmit data from
source to destination, it searches the routing table to find the destination node match
[14]. The proactive routing protocols have both advantages and disadvantages. One of
the main advantages is that the nodes can easily find routing information from the
routing table and it‟s easy to establish a session. The disadvantages are: low bandwidth
and wastage of memory i.e. nodes handle too much updated routing information which
slows its restructure process at the times of link failures.
In Reactive, the routes are discovered only when the source node needs to transmit
the data packet to the destination node, so the packet overhead will be minimized [14].
The reactive routing protocols have both advantages and disadvantages. One of the
advantages is efficient bandwidth. High latency and network congestion are the main
constraints of this protocol as it uses several acknowledgement query packets and
flooding techniques during the selection of new route for sending the data.
The Position Based Routing protocol was recently developed. The routing is based
on geographical position of the destination node. Every node needs to know its own
9
position and also the position of its very neighboring node in order to forward the data
packet. In position based routing [15], the mobile nodes calculate the position using
GPS (Global Positioning System) technology. The advantages are: having better
scalability forming better routes and also minimizes the packet overhead. The
disadvantages are: problem of inaccuracy of node positions which increases the load of
the network.
10
5. Overview of MANET
MANET is a wireless ad hoc network. In MANETs, the nodes act as clients and servers.
These mobile nodes move randomly without any fixed topology. The absence of the
infrastructure and dynamic topology has created challenges in today‟s communication
world. In MANETs every node has the routing ability of forwarding the data to their
neighbor nodes. In a MANET, devices can be directly and indirectly connected with
each other. The devices establish indirect connection via other devices. The Figure 5.1
illustrates the indirect connection between the devices.
Figure 5.1 Indirect connections between the devices
The device X and device Z are connected indirectly by relaying on the device Y. The
device X sends a message to device Y with the address of the destination device Z. The
device Y after receiving the message deletes the address and delivers the message to the
destination device Z. In this chapter, we discuss the properties, limitations, applications,
types of MANETs followed by system model of IMANETs.
5.1 Properties of MANET
The MANETs are self-configuring and self-management networks establishing wireless
connection. The following are some of the features of MANETs [16].
1. The MANETs are formed without any pre-existing structure.
2. As the nodes are mobile, the communication can be created anytime and anywhere.
3. The mobile nodes open up alternative paths automatically.
4. Every node acts as a router forwarding the packet to its neighbor nodes. And thus,
mobile nodes play a vital role in communication.
5. The very important and challenging task of MANET is providing service and
information to the peoples when infrastructure networks are destroyed, e.g. during the
times of natural disasters.
So, MANETs have many interesting aspects that make it important for present
communication world. The features like self-organizing, flexibility and low-cost are
favorable to deploy the MANET network easily. The property, non-preexisting structure
of the MANETs is still under research which will be very beneficial to the humans.
5.2 Limitations of MANET
Unfortunately, MANET network is limited by some restraints.
1. The MANETs are not efficient in large network area due to the random mobility
nature of nodes and dynamic network topology.
2. The MANETs have limited physical security, attacked by many security threats
which minimize the network performance.
3. Limited bandwidth.
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4. Limited resources and power in mobile nodes.
In spite of advantages, there are some restraints that minimize the network
performance. The expensive routing in MANETs is one of the main restraints i.e. as the
nodes are randomly moving, it is difficult to form best routes and due to which the
network cannot be configured successfully.
5.3 MANET Applications
The self-configuring, low cost of deployment, flexibility and infrastructure independent
features of MANET originates many services as follows:
1. In emergency services like rescue operations, medical services etc.
2. In military operations, when the soldiers roam in the battle field can communicate
easily with one another.
3. The most challenging application of MANET is in the catastrophic failures such as
earthquakes, floods, fire explosions, etc. In these situations, when the infrastructure
network collapse, MANETs play a key role in helping the effected people. The people
can communicate easily with each other and the rescue teams can be activated
immediately.
4. In business and educational conferences, meetings and web applications, etc.
5. In maintaining the records of weather conditions, checking air/water pollution, etc.
6. In traffic management, avoiding road accidents, maintaining traffic signals, etc
MANET comprises a wide variety of effective applications like disaster-recovery,
military, conferences etc. These are very general and important situations; especially the
role of MANETs in disaster prone area or rural areas, help the people to communicate
with each other without extra cost. The researchers are still working on successful
implementation of MANETs.
5.4 Types of MANET
The MANET is further classified into 3 types
1. VANET
2. INVANET
3. IMANET.
The VANET (Vehicle Ad-hoc Network) is mainly used for vehicles, dealing with
vehicular devices. The main purpose of VANET is to provide safety. The vehicles
having the VANET devices can communicate with each other by sending and receiving
messages. The examples of VANET are automatic parking system, traffic signal system,
etc.
The INVANET (Intelligence Vehicle Ad-hoc Networks) works under artificial
intelligence mechanism. These types of networks establish communications between
Vehicle-Vehicle (V2V) and Vehicle-Road side (V2R). The main purpose of an
INVANET is; in road side emergency situations, such as the accidents between the
vehicles, other road accidents, etc. If the vehicle having an INVANET device is met
with an accident, then an alarm is automatically generated from the vehicle [17].
The IMANET is combination of wired network (e.g. internet) and MANET. The
wireless communication infrastructures are being developed to make the users access
the internet services and information anytime and anywhere [18]. The growing interest
12
in accessing the internet leads to integrate the MANET with internet. The integration of
MANET with internet is known as an IMANET.
5.5 The System Design of an IMANET
The system design of an IMANET is an extended developing architecture of MANET
which directs to connectivity and accessibility of Mobile Nodes (MNs). The MN can
connect to the internet and can also communicate with other MNs through Wi-Fi (e.g.
IEEE 802.11). The Figure 5.2 illustrates the system design of an IMANET [18]. In
Figure 5.2, we can see that an IMANET consists of a set of MNs connecting and
communicating with each other through ad hoc routing protocols. Some of the MNs can
directly connect with the internet and turn into Access Points (APs) serving as relays to
the rest of the MNs. Thus, an AP acts as gateway for the internet accessing information.
The APs are connected with the routers. Some of the APs are connected to fixed routers
while others can have a satellite connection to the internet. The MNs can move
anywhere and can communicate with MNs in the network. The MN which moves out of
bound of one AP can access the internet through the relays of another AP. The MNs
located nearby an AP can connect directly to that AP whereas the MNs located far from
an AP have to go through several routes to reach that AP [18].
LEO or GEO satellite
IMANET
Fixed network
Fig: AN IMANET Model [x]
Figure 5.2 System design of IMANET [18]
However all the MNs cannot be connected directly with the internet due to the
following limitations of IMANETs:
1. Limited accessibility i.e. all the Mobile Terminals (MNs) cannot access the wired
internet.
2. Lack of wireless bandwidth due to the mobility of MNs, a set of MNs can be
separated from the rest of the MNs and get disconnected from the internet.
3. Longer message latency.
4. The network performance metrics limit the selection of multiple gateways to the
internet.
An Aggregate Caching mechanism has been proposed to address these limitations.
5.5.1 An Aggregate Caching Mechanism
In Aggregate Caching mechanism scheme, the local cache of each MN forms a unified
aggregate cache that reduces the communication latency and improves the information
accessibility. As MNs are forming aggregate cache, the cache of the data item not only
depends on the MN itself, but also on the neighboring MNs [18]. Therefore, an
MN
AP
Fixed router
13
Information Search and Cache Management are proposed in an Aggregate Caching
mechanism.
An Information Search algorithm called Simple Search (SS) is proposed to
determine the data item from the local cache of MNs or APs. A Simple Search
algorithm in an IMANET broadcasts using four control messages; request, Ack, confirm
and reply. This algorithm can be implemented on the top of the existing routing
protocols for MANET [18].
The concept of Cache Management is to employ the cache efficiency by avoiding
the replications of data items. It allows two methods for efficient caching:
1. Cache admission control
2. Cache replacement policy
The Cache admission control [18] is triggered when a MN receives requested data
item and decides whether the MN can or cannot accept the data item for caching. The
decision to cache a data item depends on the distance of other MNs or APs which have
the requested data item.
The method Cache replacement policy is triggered when the MN wants to cache a
data item, but the cache is full and thus selects the data item as a victim. Two elements
are proposed in selecting a victim [18]:
1. The distance (δ), measured by the number of hops away from the APs or MNs which
has the requested data item. The data item with the least δ value is selected as a victim.
2. The elapsed time (τ) caching the last updated δ.
The main goal of our thesis is to analyze the performance of routing protocols and the
possibility to get coverage in a disaster area. Although we are interested in the
performance of the network and the effect of routing, we can see that the caching
mechanism is not affecting the routing. We therefore do not elaborate on this scheme
further in the report.
5.6 Devices supporting MANET networks
The MANETs are purely peer-to-peer networks. The random movement of nodes and
dynamic nature of the network makes the MANET system complex. The MANET
meets many technical challenges in evolving applications and operating systems, to
make the system easy to develop, easy to deploy and easy to use [19].The MANET is a
virtual network and we configure the nodes with the features of electronic devices and
deploy these nodes in the network. For example we can configure a fixed node with the
features of fixed devices like desktop or we can configure some other mobile nodes
with the features of mobile devices like using the phones in trains, buses, etc. And then,
all these nodes can be deployed in the network. Along with the nodes we use
application configuration, mobile configuration, profile configuration, etc to design the
MANET scenario.
In the following section, we explore the support of MANET in today‟s
communication devices like mobile phones, laptops etc. We briefly discuss the
operating systems and software‟s that can be applicable for MANETs at present. For
example, the Ad-hoc Support Library (ASL) is a user space library implementing on-
demand ad hoc routing protocols in Linux [19]. The mobility support of IPv6 for Linux
detects a mobile device and forwards the packet to where the device is currently located
[20].
Most of the devices like laptops, PDAs, smart phones, etc are built up by Linux
platform that supports a MANET. Qolyester is a c++ execution of OLSR protocol for
MANET networks.
The CoCo Node software is Apple‟s Application Programming Interface (API), which
runs on PCs, laptops, mobile phones, smart phones and PDAs. This CoCo‟s MANET
14
provides services irrespective of the size and location of the network. This application is
completely disaster-proof, maintaining the IP applications running without
infrastructure and routes the network traffic in rapidly changing mobile environments.
The CoCo Node supports all existing IP applications [21].
The Android-Gingerbread supports ad hoc networks, acting as wireless base-stations
for other devices. When other devices connect to the mobile (acting as base-station) an
uplink can be provided via USB---> PC---> any internet [22].
The Internet Engineering Task Force (IETF) is currently working on MANETs. The
implementation study is conducted at Ericsson Mobile Data Design (ERV) in
Gothenburg proved that it is possible to set up and run the MANET [23]. The ERV
implemented several mobile ad hoc routing protocols in current operating systems. A
well-developed implementation was built on AODV routing protocol in Linux using
ASL (Ad-hoc Support Library).
The MANET is not yet implemented successfully and is still under research, so at
present most people cannot configure MANET network directly in their electronic
communication devices like mobile phones, laptops, etc.
Figure 5.3 MANET configuration
The mobile devices such as PDAs, smart phones, etc can be connected with each other
in a MANET. From the Figure 5.3, a middle ware establishes connection between
different kinds of mobile devices using wireless interfaces like Bluetooth, Wi-Fi, etc.
The QT toolkit is one such middleware that was developed by Trolltech and it
implements the MANET for mobile devices [24]. The middle ware developed with QT
can be easily activated in different devices with different operating systems; it can be
developed on desktop PC and then can be moved to an embedded system through cross-
compiling. The wireless interface searches, connects and communicates with the
neighboring mobile devices. The service manager has four modules namely device
discovery, profile exchange, participant management and messaging service. It helps to
configure the MANET network automatically without the user interference [24].
At present we can easily configure normal wireless network (Wi-Fi) in general
devices like mobiles, iphones and laptops.
Application layer
Device Discovery
Participant Manager
Contents Exchange
Profile Exchange
Messaging Service
Service Deriving
Wireless interface (Bluetooth, Wi-Fi etc)
QT
Operating System (Linux, Windows)
15
Normally Wi-Fi setup in laptops with windows 7 and vista is possible by following
steps:
Connecting to available networks:
click on internet access icon located on the right hand down corner of the system bar,
there appears all currently available connections ->click on the connection you want to -
> tap connect -> give the security key.
Creating a new connection:
start menu ->control panel ->network and sharing center ->set up a new network
connection ->manually connect to a wireless network and next ->give network name,
security type (WEP), security key and check the ”start this connection automatically”
and next.
Wireless Ad hoc network setup in laptops by following steps:
By configuring ad hoc networks, one device can connect and communicate with other
device directly in a peer-to-peer fashion without the need of access points or routers.
Click on windows control panel->network and internet->network and sharing center-
>click setup a new connection or network->select setup a wireless ad hoc (computer-to-
computer) network and click next->give network name, security key, choose security
type (WPA2-personal).
The Swedish company Terranet designed an ad hoc mesh network in mobiles. They
found a solution to connect the mobile devices without infrastructure network. They
have developed chip that can be built in a mobile phone [25]. This solution might be
very beneficial to people in disaster and other emergency situations. The Terranet‟s
innovation will be tested in 2012. The CoCo communications have developed some
MANET enabled devices like Motorola MC75, Motorola ES400, AMREL RF8, etc and
these can be deployed in most difficult environments [21].
The above discussions show that the research is still going on in analyzing the
possibilities to set up a MANET in the present electronic communication devices and to
deploy it in real applications. The MANET network cannot be easily configured by
oneself like normal wireless setup; it has to be designed by the manufacturers or
administrators. There are two important challenges: the technical challenge which we
have already discussed above and the other is an administrative challenge. In
administrative, the issues like who will decide to set up an ad hoc network in such an
area? Deciding the network name, security settings etc? How will this information be
distributed? Can the devices connect automatically in such situations? Who will pay for
the service etc? However, it takes some more time to solve all these issues and
successfully implement the MANET.
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6. MANET Routing Protocols
Routing protocols in Ad hoc networks have become an interesting issue due to the fact
that the existing routing protocols supports only the fixed infrastructure and are not
suitable for MANET. The routing protocols are necessary to maintain the network. The
Figure 6.1 shows a classification of MANET routing protocols.
This paper focus on the comparative performance analysis of MANET routing
protocols-OLSR protocol which is proactive/table driven type, TORA and AODV are
reactive/on demand type of routing protocols and GRP. In this chapter, we present the
theoretical concepts of the standardized MANET routing protocols, such as OLSR,
TORA, AODV and GRP.
Figure 6.1 Classification of MANET routing protocols
6.1 OLSR (Optimized Link State Routing)
The optimized link state routing protocol is a well-known pro-active routing protocol.
OLSR is an optimization of pure Link State algorithm in ad hoc networks. Hop by Hop
routing is used in forwarding packets. The nodes in the network use the topology
information from the HELLO protocol and Topology Control (TC) messages in order to
discover their neighbor nodes.
Asymmetric
Asymmetric
Symmetric
Figure 6.2 HELLO message in MANET using OLSR
In OLSR, every node uses the updated information to route a packet. Each node in the
network selects a set of nodes in its neighborhood which retransmits its packets. This
set of selected neighbor nodes is called the Multi Point Rely (MPR) of that node [26].
The MPR is used to reduce the overhead in network. So in OLSR, packets are not
MANET
Proactive Reactive
Link
State Distance
Vector
Link State
Distance
Vector
OLSR
GSR
TBRPF
DSDV
WRP
DSR AODV
TORA
ABR
Position Based
GRID
PNR
GRP
MFR
Node X Node Y
17
broadcasted by all the nodes in the network, instead only the nodes selected as MPR
forward the traffic reducing the size of control message [27]. Every node in the network
maintains an updated routing table. The OLSR uses MPR nodes and the routing
overhead is higher than the other routing protocols. The OLSR is mainly suitable for
large and dense networks. The smaller set of Multi Point Rely provides more optimal
routes.
In OLSR, a HELLO message is periodically broadcasted to their neighbors at a pre-
determined interval. These messages determine the status of the links. For example, if
node X and node Y are neighbors, node X sends HELLO message to node Y. If node Y
receives the message, then the link is said to be Asymmetric. Similarly, it is the same
for the HELLO messages sent by node Y to node X. If two way communications is
established, then the link is said to be Symmetric as shown in Figure 6.2.
These HELLO messages contain all the information about their neighbors. Every node
in the network maintains a routing table with information of multiple hop neighbors.
When the symmetric connections are made, a node chooses a minimal number of MPR
nodes that broadcast Topology Control (TC) messages. The TC messages contain the
information of selected MPR nodes [26, 27]. The HELLO and Topology Control (TC)
are used to discover and disseminate the information throughout the MANET.
6.2 TORA (Temporally Ordered Routing Algorithm)
The Temporally Ordered Routing Algorithm (TORA) is a reactive routing protocol that
establishes quick routes. A key concept in its design is that it decouples the generation
of potentially far-reaching control message propagation from the rate of topological
changes [9]. TORA possess the following attributes:
Loop-free routes
Provide minimal routing functionality
Minimize algorithm reaction
Multiple routing
(-,-,-,-,B)
Source(-,-,-,-,A) (-,-,-,-,C)
(-,-,-,-,E) (-,-,-,-,D)
(-,-,-,-,F)
(0,0,0,0,H)
(0,0,0,0,G ) Destination
Figure 6.3 Route discovery procedure in TORA (Query Message)
TORA is mainly used in MANETs to enhance scalability. The basic functionality of
TORA protocol consists of creating routes, maintaining routes and clearing routes. The
protocol models the network structure as a graph. TORA establishes scaled routes
between the source and destination using the Directed Acyclic Graph (DAG) built in the
destination node. The links in the network can be directed or undirected from source
node to destination node.
18
TORA builds optimized routes using four messages [28]. It starts with a Query
message followed by an Updated message, then Clear message finally Optimization
message. This operation is performed by each node to send various parameters between
the source node and destination node. The parameters include time to break the link (t),
the originator id (oid), reflection indication bit (r), frequency sequence (d) and the nodes
id (i). The first, three parameters are called the reference parameters and the last two are
offset for the respective reference level.
Each node maintains a metric ‟height‟. The links between the nodes are directed based
on the heights [9]. At the beginning, the height of all the nodes is set to NULL i.e. (-,-,-
,-,i) and the destination is set to (0,0,0,0,dest). As the network topology changes, the
heights of the nodes also change.
TORA is a source initiated protocol providing multiple routes for any desired
source/destination pair [29].The source node sends a query message to the destination
node with the id of that intended destination. When a query packet reaches the
destination node, a response known as an update is sent on the reverse path. The height
value of the neighbor node is set to an update message. In Figure 6.3, source node A
sends a query message to destination node H. The neighboring nodes forward the
message to one another and finally the packet is reached to the destination node by its
one hop neighbors G and H.
(-,-,-,3,B) (-,-,-,2,C)
Source(-,-,-,3,A)
(-,-,-,2,F) (-,-,-,1,D)
(-,-,-,2,E)
(0,0,0,0,H)
(-,-,-,1,G) Destination
Figure 6.4 Height of each node updated as a result of UDP message (Update Message)
The source node is represented by A and the destination node is represented by H. A
query message is broadcasted across the network by source node A. Only one-hop
neighbors of the destination reply to the query. In this case, node D and node G are one
hop away from the destination, represented by green color. Therefore, these nodes will
send an updated message in reverse path with the height value set as shown in Figure
6.4.
The main disadvantage of this algorithm is that it is highly dependent on the number
of nodes activated at initial set up [30]. The other disadvantage is that the response to
demand for traffic is dependent on the number of nodes (or rate of change of traffic) in
the networks.
6.3 AODV (Ad hoc On-demand Distance Vector)
AODV is another reactive type routing protocol. In AODV, every node maintains a
routing table. It creates routes in broadcast fashion, where source node broadcasts route
request packet (RREQ) to its neighbor node.
19
The RREQ packet contains the destination IP address and destination sequence
number. The neighbor node accepting the RREQ constructs the reverse path with route
reply packet (RREP). In Figure 6.5, the RREQ message is broadcasted from source
node A to destination node D. The source node „A‟ broadcasts the RREQ message to its
neighbor nodes; the neighbor nodes suited with the RREQ message sends a RREP
incrementing the hop count by one. The neighbor node checks if it suits the RREQ
message, if so then it broadcasts RREP to source node A or if not it broadcasts the
RREQ message in the network again with incremented hop count. When a link failure
occurs, it generates a route error (RERR) message.
The advantage of AODV is that this routing is followed in on-demand fashion by
using the destination sequence number. The disadvantages of this protocol is that it
requires more time to establish a connection, and multiple RREPs are responded to
single RREQ leads to heavy traffic overhead.
b
RREQ (D)
RREQ (D)
RREP (D) RREP (D)
a d
RREQ (D) RREQ (D)
c
Figure 6.5 RREQ and RREP messages in AODV
6.4 GRP (Geographic Routing Protocol)
Geographic Routing Protocol (GRP) is a kind of position-based protocol [31], and each
node is identified by the location. The node positions will be marked by GPS and will
optimize the flooding by dividing into quadrants. A HELLO message is periodically
broadcasted between the nodes to identify their positions and their neighbors. In GRP,
by means of route locking a node can return its packets to the last node when it cannot
keep on sending the packet to the next node.
6.4.1 GRP Routing Lookup
There are two kinds of GRP routing lookup. One is that source and destination are lying
at the same quadrant. In this case, the source node finds the closest neighbor node and
forwards the packet. The packets are broadcasted to the neighbor nodes until the final
destination receives the data packet. The other is that source and destination are at
different quadrants, but belong to the same quadrant at a higher level. The source node
then finds the neighbor node that is closest to the entry point of the destination node‟s
quadrant, and this process is repeated till the packet reaches to the destination.
6.4.2 GRP Flooding
Flooding takes place when the node crosses a quadrant or when the node moves longer
distance than user specified area.
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6.4.3 GRP Routing Table
In GRP every node maintains one or more routing tables with the updated information
of its neighbor nodes. For different quadrants, the highest level neighboring quadrant
information is maintained.
6.4.4 HELLO Protocol in GRP
HELLO messages are periodically broadcasted in order to keep the information about
the neighbor nodes. Local connectivity is testified through the HELLO messages which
are received from the neighbor nodes. If HELLO message is not received in a specified
period then the message expires and called as “Neighbor expiry time”.
6.4.5 GRP Quadrant
GRP divides ad hoc network into many quadrants to minimize the flooding. The
position of the nodes can be easily identified. Every 4 quadrants in a square form a
higher level quadrant [31]. For example: Aa1, Aa2, Aa3 and Aa4 are four individual
quadrants at level 1, but they belong to quadrant Aa at level 2. Aa, Ab, Ac and Ad are
four individual quadrants at level 2 belonging to quadrant A at level 3. The Figure 6.6
shows the quadrants in GRP.
level 3
Ab
level 2
Ab Ad Bb Bd
Aa Ac Ba Bc
Ab4 Ab3 Ad4Ad3
Ab1 Ab2 Ad1Ad2 level 1
Aa4Aa3 Ac4 Ac3 Ba4 Ba3
Aa1 Aa2 Ac1 Ac2Ba1 Ba2
Size of the quadrant
Figure 6.6 Concept of Quadrants in GRP routing protocol
6.4.6 GRP Routing Backtrack
The backtracking mechanism is used when the routes are blocked, so packets return to
the previous hop and then again a new route is defined. It can occur when the packets
send from source to destination is occupied by default routes.
A B
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7. Experimental Environment Setup
In this chapter, we will discuss the different networking simulation tools, detailed study
about the environment of OPNET modeler and we have designed our experimental
network model of IMANET with configuration procedures explaining the configuration
of a MANET.
7.1 Network Simulation Tools
It is a challenging task to design an efficient network with high performance. A number
of network simulation tools have been introduced for measuring the performance of the
network. For examples, some commonly used network simulators are given bellow:
The GloMoSim (Global Mobile Information System Simulator) is a scalable
simulation environment for the wireless networks [32]. It is built on Parsec compiler
(Parallel Simulation Environment for Complex Systems) by a C-based simulation
language. Therefore, due to the coding it takes many time frames. For working on
GloMoSim software users need to have a good knowledge about Parsec.
The Packet Tracer, a network simulator is created by Cisco Systems [33]. This tool
supports only the wireless networks. The main purpose of this software is to provide
real time simulation environment. However, ad hoc network feature is not supported by
it. This software doesn‟t support the network modeling, and it is not a free tool for
general use.
The QualNet is a network simulation tool used for analysis of wireless network
environments. This tool is best suited for heterogeneous (wired and wireless) large scale
networks. It is a commercial simulator [34]. C++ programming language is used to
design networks on it. The extension of QualNet is sQualnet which deals with sensor
networks.
The NS2 is the second version of NS (Network Simulator). This simulation software
is based on two programming languages, C++ and OTcl. This tool supports real time
environment and it is not very user-friendly software. It does not support visual and
graphical features [35]. The combination of C++ and OTcl maximizes the performance
of the tool. Therefore, it is widely used by the developers.
The NS-3 is the third version of NS. This tool is also written in C++ and Python
scripting. This software focuses on the real time applications. As it is a recently
developed simulator and is still under development. It requires specialized people to
interact with the users and to maintain the system [36].
The OPNET (Optimized Network Engineering Tool) is one of the popular simulation
software for designing networks and to analysis the network performance [35]. The
reason of its popularity is, it has attractive GUI (Graphical User Interface) and visual
features. The OPNET provides free Academic Edition (IT Guru) for students.
7.2 Detailed View of OPNET Simulator
In this thesis, we have used OPNET 14.5 to design the IMANET scenarios and to
evaluate the performance of state-of-art protocols.
7.2.1 OPNET Simulator for MANET
We designed number of network scenarios of an IMANET to evaluate the performance
of different MANET routing protocols such as OLSR, TORA, and AODV in OPNET
simulator. Although initially, OPNET is developed for military uses only, but now-a-
day‟s it is used in verities of networks like Wi-Fi, UMTS, WiMAX etc [37, 38]. There
are number of reasons for using OPNET modeler such as, it is very user-friendly tool
that provides attractive and intuitive GUI and visual features. The Graphical
22
environment is used to create the routing protocols models intuitively and it also
supports broad range of wireless networks with modeling simulation and analysis. It is
reliable, robust and efficient and also possible to simulate heterogeneous networks with
different protocols. Another advantage of this simulator is that the users need not have
the knowledge of any programming language to use the OPNET.
7.2.2 Workflow of OPNET
The working procedure of OPNET is generally divided into four sections. Figure 7.1
illustrates the basic workflow of OPNET.
Figure 7.1 A general Workflow of OPNET
First, users need to design the network in OPNET based on the experimental model.
For example, in our thesis, we implemented the IMANET scenarios in OPNET 14.5
modeler.
Secondly, after designing or implementing the network model in OPNET, you apply
the statistics on the designed model. The Table 7.3 represents the list of parameters that
we applied to design our network.
Thirdly, test the network scenarios by selecting the run option for a specific time to
collect simulation results and statistical values of simulation results.
Finally, you analyze the performance of network scenarios based on the collected
experimental results.
7.3 Description of Experimental Parameters
The Table 7.3 gives the list of simulation parameters that we used to design our network.
The simulators are the simulation network software. Some examples of network
simulators are GloMoSim, Qualnet, NS 2/3, Packet Tracer, OPNET etc. The OPNET
14.5 is used as a simulator in our thesis.
The Network Scale is a scenario. OPNET supports following network scales such as
world, enterprise, campus, office etc. In our thesis, we have selected campus network
scale, but this is not fixed. The areas of network scale can also vary in simulations.
The Network Area is the region in which users design the network. For example,
selecting campus network scale, we selected three different network areas; 1km*1km,
3km*3km and 10km*10km.
In a wireless network no dedicated path exists between source and destination nodes
similar to wired networks, instead multiple paths exist among nodes in wireless network.
In such situations, finding an optimum path is an important issue. Network Protocols
Design network model
Specify statistics
Run simulations
Analyze results
23
helps to find the optimum paths. In this thesis we study three routing protocols; OLSR,
TORA and AODV.
Network
Parameters
Variation in the
number of node
Variation in the network area
Terrain Size (m2) 1km*1km, 3km*3km,
10km*10km
1km*1km, 3km*3km,
10km*10km
MAC Protocol IEEE-802.11b (Direct
Sequence)
IEEE-802.11b (Direct Sequence)
Traffics HTTP, voice HTTP, voice
Routing Protocols AODV, TORA, and
OLSR
AODV, TORA, and OLSR
Bandwidth 11Mbps 11Mbps
Pause time 100s 100s
Node Placement Random Random
Transmission
Range
300m 300m
Network Address IPv4 IPv4
Mobility Model Random-Waypoint Random-Waypoint
No. of nodes 10, 25, 100 nodes 10, 25, 100 nodes
Network Metrics Throughput, Network
Load, Media Access
Delay, page download
response time, MOS
Throughput, Network Load,
Media Access Delay, page
download response time, MOS
Table 7.3 List of Experimental Parameters
There are different network traffics applications such as database, email, FTP (File
Transfer Protocol), TCP (Transmission Control Protocol), HTTP (Hyper Text Transfer
Protocol), voice, print, video conferencing that can be used to test the performance of
the designed networks. The http traffic is data sent and received over the protocol
between an end device and the web server. The http traffic analyzer captures all http
traffic between an end device and the Internet; It provides various information about
this traffic in real-time. And now a day‟s communication widely means of voice
communication. Therefore, in our thesis to complete our empirical study we considered
two important traffics, HTTP and voice.
There are two types of nodes such as, fixed nodes and mobile nodes. In our study we
designed an IMANET that consists of a MANET (infrastructure less) and a backbone
network. To implement the MANET scenarios we selected 10, 25 and 100 mobile nodes
and 3 fixed gateway nodes.
There are a number of network types available for wireless networks, such as Wi-Fi
(IEEE 802.11), Bluetooth, Zigbee, Microwave etc. As OPNET 14.5 supports the Wi-Fi
(IEEE 802.11), in this thesis, the designed network scenarios follow the Wi-Fi IEEE-
802.11b (Direct Sequence) with maximum data rate 11Mbps and packet size 512 byes.
The Data Rate is a physical characteristic and it depends on the type of the network.
Usually data rate depends on the technology or type of the network.
In a MANET, Multiple paths exist between source and destination nodes with the
random mobility of the nodes. The time period is calculated when the node stops for a
while before taking a random destination, it is known as Pause Time. The stability of
24
networks depends on the value of it. Higher pause time stands for stable network and
vice versa.
In the designed network the issues like: How the nodes move, how we calculate
routing path from one node to other node, how we calculate displacement; all these
depend on the propagation model. There are a number of propagation models tested in
different simulators such as Trajectory Model, random way point model, Okumura
Model, Hata Models for Urban, Suburban and Open Areas, COST Hata Model, etc. In
our experiment, these IMANET scenarios are designed for providing different services
for the affected peoples in a disaster area. Within the affected area peoples can move
with random speeds and random directions. The characteristics of random way point
model are similar to the behavior of these scenarios, where mobile devices can move in
random motion and with random directions. Therefore, we used Default Random Way
Point Model in our designed network scenarios.
This is the speed of the nodes within the network terrain. This parameter varies
depending on the network scenarios. Normally within the affected area, peoples can
move in different ways, such as walk, bus, train, car etc. In order to design a real type
scenario by considering all moving peoples we considered uniform 0-20 (m/s) speed for
the mobile nodes in our designed IMANET scenarios.
The network metrics are the parameters used to observe the performance of the
designed networks. There are a number of network metrics considered depending on the
network traffic or applications. For HTTP and voice traffics, we considered throughput,
network load, media access delay, Mean Opinion Score and page download response.
Here, by observing the throughput and network load we can get overall performance of
the designed network scenarios. Download page response is a key concern of HTTP
traffic, and by a numeric value, MOS we can get the idea of quality of voice in the
designed scenarios.
The output or the average rate of successful message delivery is known as
throughput. It is measured in bit/sec.
The network load is the maximum handling capacity of the mobile nodes i.e., the
amount of data (traffic) being carried by the network.
The latency or delay time i.e., the time taken to carry the data packet between two
nodes somewhere along the path.
The quality of voice for a communication system is measured based on a numerical
value, Mean Opinion Score (MOS). It is given as a number from 1 to 5. Different
values stand for a specific quality of voice, 5 stands for perfect quality of voice, 4 is for
fair, 3 is for annoying quality, 2 is for very annoying and 1 is for impossible to
communicate.
The simulation time is the time taken during the process of simulations. We observed
that if we run the simulation for a long time, millions of simulations evens need to
consider for measuring the average QoS parameters of HTTP and voice traffics, as
nodes are considered as in random motions with random directions. Therefore, to get
correct simulation results from our designed IMANET scenarios, we run the scenarios
for 300 seconds only.
7.4 Design the IMANET scenario in OPNET
In the model design, first we have to run the OPNET 14.5 modeler and select an empty
blank scenario from the start-up wizard, there appears the workspace. In the workspace,
we can design our IMANET backbone network selecting a global scenario as illustrated
in Figure7.2. The backbone network is connected with a MANET scenario through the
different MANET gateways. To configure MANET scenarios, we need to configure
different parameters like application configuration, profile configuration, mobility
25
configuration, MANET Gateway, mobile nodes. For example, a scenario of a MANET
with 25 nodes is demonstrated in Figure 7.3. For our experiment, we generated HTTP
traffic from the HTTP server which is connected with a router of the backbone network
for an IMANET scenario. The details of configurations for overall scenarios of
IMANET are presented in Appendix A to F.
In order to configure a MANET gateway in OPNET 14.5, we need to connect it with a
MANET and a wired Network/LAN. Therefore, we connected a MANET gateway with
a MANET via Wi-Fi (IEEE-802.11b) and with a wired LAN by connecting an Ascend
router via a 10baseT physical link. In Figure 7.2, router 0, router 3 and router 4 are
directly connected with MANET Gateway, MANET Gateway1 and MANET Gateway2,
respectively (see Figure 7.3).
In Figure 7.3, all mobile nodes can communicate with each other‟s (if in range of each
other). They can communicate with a MANET gateway directly if the nodes come close
enough of it or via different neighboring mobile nodes. For selecting optimum route
these mobile nodes use some MANET routing protocols. The mobile nodes can receive
the HTTP and voice traffics which are generated from the server and the server is
connected with a MANET scenario through router and MANET gateways. To analyze
the performance of the state-of-art protocols with respect to different network metrics
we applied the HTTP and voice traffics and collected the experimental results.
Step by step setup of the IMANET scenario:
1. A MANET is a network without fixed topology as nodes are considered to be
mobile. In our network, we considered 10, 25 and 100 mobile nodes to form a
MANET in different areas 1km*1km, 3km*3km and 10km*10km.
2. In order to form an IMANET scenario, we formed a backbone network with
different routers. MANET Gateways are used as intermediary devices to link the
MANET and the backbone network.
3. All mobile nodes in the MANET can communicate with MANET gateways to
connect with a server which is connected in the backbone network.
4. The mobile nodes can communicate with MANET gateways directly if it gets
close enough or via the neighbor nodes. The MANET routing protocols finds an
optimal route to communicate with the MANET gateways and to connect with a
server.
5. Employing HTTP and voice traffics for different routing protocols, we collected
the simulation results varying the number of nodes and areas in order to measure
the performance of routing protocols for our designed IMANET scenarios.
7.5 Data Entities
The data elements are used to design the network scenarios in work space. The different
entities are available in the object palette. For designing the network scenarios, we have
used application, profile, mobility configuration, nodes and server as data entities.
7.5.1 Application configuration
The application configuration in OPNET modeler supports a variety of network
traffics/applications such as FTP, HTTP, TCP, voice, video streaming, etc. According
to the requirements you can choose or configure traffics for every new project. In our
network scenarios for 10, 25 and 100 nodes respectively, we defined two applications in
the application configuration namely HTTP with high load and voice with PCM Quality
Speech. By right clicking on the application configuration on the workspace, we can
26
create a new application with a new name and also can configure the different
parameters for each individual application.
Figure 7.2 A backbone network of an IMANET
7.5.2 Profile configuration
For individual application traffic we need to configure the profile. For our network
scenarios, we have generated two profiles; HTTP with high load and voice with PCM
quality in the application configuration. In order to configure the profile configuration,
we have selected the edit attribute and set the profile name, adjust the number of rows,
we can also set other parameters like operation mode: to run the application randomly
or sequentially one after the other, start time: the starting time of the profile, duration:
default set to the end of simulation, and repeatability; i.e. how often we like to run our
profile during the time it is set for.
7.5.3 Mobility configuration
The mobility configuration specifies the type of mobility model set to the nodes in the
network. In the network scenarios, we have selected random way point for these mobile
nodes. The mobile nodes follow the path of this model to transmit the data packet from
source to destination. We configure the mobility type by selecting edit attribute option
where we set the following attributes: start time, speed, stop time, pause time, etc. The
mobility of the nodes is controlled by these attributes.
7.5.4 Server
The WLAN server normally provides the different services, such as FTP, HTTP, voice,
video etc. for the end users. In our experimental study, server generates the HTTP and
27
voice traffic and it is located outside the MANET. It is connected with a fixed router,
Router-1 as illustrated in Figure 7.2. In order to do that we configured the HTTP and
voice traffics in the server, as the client nodes are relying on the HTTP and voice
profiles.
Figure 7.3 A scenario of IMANET with MANET Gateways
7.5.5 Nodes
In order to design the IMANET scenarios, we configured scenarios in different areas for
10, 25 and 100 nodes. These mobile nodes support maximum data rate 11Mbps. We can
configure the mobile nodes for the following attributes: speed, start time, end time and
pause time, etc. In this network, we set the random way point mobility model for the
mobile nodes. We have employed three routing protocols namely OLSR, TORA and
AODV to configure the scenarios with different number of mobile nodes. In the
workspace, by right clicking on mobility configuration, we can set the different
parameters of mobility configuration. We can select the MANET routing protocols by
configuring the all mobile nodes.
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8. Experimental Results and Analysis
In this chapter, we collect the simulation results from the designed network scenarios to
analyze the performance of the MANET routing protocols OLSR, AODV and TORA by
varying different network parameters.
8.1 Impact of the number of nodes on the QoS parameters of HTTP traffic for
different protocols
In this section, the experimental results demonstrate the comparison among OLSR,
AODV and TORA protocols by varying the number of node for different network areas.
For examples, the simulation results in section 8.1.1, 8.1.2 and 8.1.3 exhibit the
different QoS parameters of HTTP traffic for different number of nodes such as, 10, 25
and 100 in different network sizes- 1km*1km, 3km*3km and 10km*10km, respectively.
8.1.1 Scenario 1(a) QoS of HTTP traffic for 10, 25 and 100 nodes in an area of
1km*1km
(a) (b)
(c) (d)
Figure 8.1 QoS parameters of HTTP traffic for different protocols (10, 25 and 100 nodes in 1km*1km
area): (a) media access delay (sec), (b) network load (bit/sec), (c) page response time (sec), (d) throughput
In scenario 1(a), the media access delay graph illustrates that TORA shows
comparatively higher values with the increment of the number of node, and OLSR
shows almost steady characteristic curve for the different amount of node as depicted in
Figure 8.1(a). For example, in 10 nodes scenario the average media access delay of
29
OLSR, AODV and TORA are approximately 0.001sec, and 0.003sec, respectively.
However, for 100 nodes the average value of OLSR, AODV and TORA experienced
0.001sec, 0.009sec and 0.0108sec, respectively. In Figure 8.1(b), the network load
graph illustrates that at 10 and 25 nodes all three protocols show almost equal amount
of network load which is comparatively very lower than the average value of larger
amount of node. However, in 100 nodes scenario, AODV shows slightly higher network
load than other two protocols. It is usually causes for route break due the move way of
source node. To re-establish the broken routes it uses query messages to the upstream
node [39]. But in multi-hop scenarios with high mobile nodes upstream links may also
broken down, in this case node backwards a error message to the source and again
reinitiate the new route which causes additional network load in the scenario. The page
response time graph shows that the variation of amount of node does not much
influence on characteristic curve of TORA and OLSR as depicted in Figure 8.1(c). But
the average value of AODV increases with the increment of node. Similar to the
network load graph, different protocols show almost average equal amount of
throughput for lower amount of node. But for 100 nodes scenario, OLSR shows
significantly higher throughput than other two protocols. It uses routing tables to
establish a new route which is faster in route establishment and causes less network
congestion in a small area scenario.
8.1.2 Scenario 1(b) QoS of HTTP traffic for 10, 25 and 100 nodes in an area of
3km*3km
The scenario 1(b) gives a detail comparison of QoS parameters of different protocols for
various amount of node within a fixed 3km*3km area. In Figure 8.2(a), the media
access delay graph illustrates that the average value of 25 node scenario is
comparatively higher than the values of 10 and 100 nodes scenarios for different
protocols. And OLSR shows comparatively lower media access delay for different
amount of node compare to other state-of-art protocols. The Page response time also
shows characteristics curve almost similar to the media access delay as depicted in
Figure 8.2(c). The network load graph exhibits that all three protocols show average
equal amount of network load at 10 and 25 nodes scenarios.
(a) (b)
30
(c) (d)
Figure 8.2 QoS parameters of HTTP traffic for different protocols (10, 25 and 100 nodes in 3km*3km
area): (a) media access delay (sec), (b) network load (bit/sec), (c) page response time (sec), (d) throughput
However, OLSR shows comparatively greater network load than other two protocols at
100 nodes scenario. In Figure 8.2(d), the throughput graph shows similar characteristic
graph of network load. But, OLSR shows comparatively higher throughput at 25 and
100 nodes scenarios.
We observe the following differences in Figures 8.1 and 8.2. In Figure 8.1 for 100
nodes scenario, the network load of AODV higher than others. However, in Figure 8.2
it shows very low network load compare to others. However, OLSR shows
comparatively higher value of it. AODV illustrates comparatively higher average page
response value In Figure 8.1. But in Figure 8.2, TORA shows higher average value of it.
However, in both Figures OLSR shows lower page response time. The average
throughputs of different protocols in Figure 8.2 fall down compare to Figure 8.1. But in
both Figures, OLSR always shows higher throughput than others.
8.1.3 Scenario 1(c) QoS of HTTP traffic for 10, 25 and 100 nodes in an area of
10km*10km
(a) (b)
31
(c) (d)
Figure 8.3 QoS parameters of HTTP traffic for different protocols (10, 25 and 100 nodes in 10km*10km
area): (a) media access delay (sec), (b) network load (bit/sec), (c) page response time (sec), (d) throughput
In section 8.1.3, scenario 1(c) presents the different QoS parameters of HTTP traffic for
various amount of node within a fixed area 10km*10km. Figure 8.3(a) illustrates that
OLSR shows very few media access delay for the scenarios with different amount of
node. However, TORA shows very higher media access delay at greater number of node.
The different protocols show almost equal amount of network load at 10 and 25 nodes
scenarios as depicted in Figure 8.3(b). But, OLSR shows significantly higher average
network load compare to other two protocols. The Figure 8.3(c) shows that page
response time of TORA is experienced very few in the scenarios with various amount of
node. On the other hand, AODV illustrates very high and steady page response time in
the observed scenarios. At 10 and 25 nodes scenarios, similar to the network load graph
we observe almost equal amount of the average for different protocols. However, for
100 nodes scenario the throughput of OLSR is significantly higher than other two
protocols as depicted in Figure 8.3(d).
8.2 Impact of the number of nodes on the QoS parameters of voice traffic for
different protocols
The experimental results illustrate the comparison of QoS parameters of voice traffic
among OLSR, AODV and TORA protocols by varying the number of nodes for
different network areas. The simulation results presented in the sections 8.2.1, 8.2.2 and
8.2.3 show the different QoS parameters of voice traffic for different number of nodes
such as, 10, 25 and 100 in different network sizes-1km*1km, 3km*3km and
10km*10km, respectively.
8.2.1 Scenario 2(a) of Voice traffic for 10, 25 and 100 nodes in an area of 1km*1km
The scenario 2(a) presents the QoS parameters of voice traffic in different amount of
nodes scenarios within a fixed 1km*1km area. The Figure 8.4(a) illustrates that
different protocols exhibit almost equal amount of media access delay at 10 and 25
nodes scenarios. However, at 100 nodes scenario, AODV and TORA show higher
average values of it compare to the average value of OLSR.
32
(a) (b)
(c) (d)
Figure 8.4 QoS parameters of voice traffic for different protocols (10, 25 and 100 nodes in 1km*1km
area): (a) media access delay (sec), (b) network load (bit/sec), (c) MOS value, (d) throughput
In Figure 8.4(b), the network load graph illustrates almost similar characteristic graph
of media access delay graph. For example, very few and almost equal amount of
average network loads show in 10 and 25 nodes scenarios. But at 100 nodes scenario,
TORA and OLSR shows much higher values of it compare to the average value of
AODV. The MOS graph presents that different protocols shows almost equal amount of
average value of MOS at 10 and 25 nodes scenarios, which is slightly higher than the
average value of it at 100 nodes scenario as illustrated in Figure 8.4(c). The Figure 8.4(d)
demonstrates that the variation of number of node does not influence much on the
average throughout of TORA and AODV by maintaining steady characteristic curve.
However, at 100 nodes scenario, OLSR shows significantly higher throughput than the
other two protocols.
8.2.2 Scenario 2(b) of Voice traffic for 10, 25 and 100 nodes in an area of 3km*3km
The scenario 2(b) demonstrates the different graphs of QoS parameters of voice traffic
for various amounts of node within a fixed 3km*3km area. The Figure 8.5(a) illustrates
that different protocols show almost equal amount of media access delay. But, with the
increment of number of node, the media access delay of different protocols also
33
increase. Among three protocols, AODV exhibits higher media access delay at 25 and
100 nodes scenarios. On the other hand, at the lower amount of node, for example 10
and 25 nodes scenarios the different protocols show almost equal amount of network
load and at 100 nodes scenario, TORA shows slightly higher average value of it than
OLSR as depicted in Figure 8.5(b). At lower amount of node, different protocols
illustrate almost equal amount of average MOS value as shown in Figure 8.5(c). But at
100 nodes scenario, TORA shows very low MOS value compare to other two protocols.
The throughput graph shows that the variation of the number of node does not much
influence on the average value of it at 10 and 25 nodes scenarios of different protocols
as demonstrates in Figure 8.5(d). But at 100 nodes scenario, OLSR shows very higher
throughput than others.
(a) (b)
(c) (d)
Figure 8.5 QoS parameters of voice traffic for different protocols (10, 25 and 100 nodes in 3km*3km
area): (a) media access delay (sec), (b) network load (bit/sec), (c) MOS value, (d) throughput
8.2.3 Scenario 2(c) of Voice traffic for 10, 25 and 100 nodes in an area of
10km*10km
The different QoS parameters of voice traffic for different protocols are presented in
scenario 2(c) by varying the number of node within a fixed area 10km*10km. In Figure
8.6(a), although all three protocols show approximately equal amount of media access
delay in the scenario of 10 nodes, AODV shows comparatively higher average value of
it at 25 and 100 nodes scenarios. Figure 8.6(b) illustrates that the scenarios of low
amount of node, for example 10 and 25 nodes, different protocols demonstrate almost
34
equal amount of network load. But at 100 nodes scenario, OLSR exhibits large amount
of network load compare to other two protocols.
(a) (b)
(c) (d)
Figure 8.6 QoS parameters of voice traffic for different protocols (10, 25 and 100 nodes in 10km*10km
area): (a) media access delay (sec), (b) network load (bit/sec), (c) MOS value, (d) throughput
The variation of the number of node does not much influence on the MOS value of
AODV and TORA. But it affects on the MOS value of TORA as presented in Figure
8.6(c). Similar to the MOS graph throughput graph also demonstrates that the variation
of the number of node does not affect on the average throughput of AODV and TORA.
However, it influences on the throughput of OLSR as shown in Figure 8.6(d). For
example, at 10 and 25 nodes scenarios OLSR shows almost equal amount of throughput
of AODV and TORA, but at 100 nodes scenario the OLSR demonstrates much higher
throughput than other two protocols.
We observe the following points in the Figures 8.4, 8.5 and 8.6. Similar to the HTTP
traffic, OLSR shows lower media access delay and it also demonstrates higher
throughput in all scenarios compare to others. As voice traffic is heavier traffic than
HTTP it causes heavy congestion in the network. Therefore, we observe the average
lower throughputs for different protocols in these figures compare to HTTP traffic
scenarios.
35
8.3 Impact of network area on the QoS parameters of HTTP traffic for different
protocols
In our experimental study, we also observed the impact of variation of network area on
different routing protocol for a fixed number of nodes. In appendix G, H and I we can
see the QoS of parameters of HTTP traffic in various network areas such as, 1km*1km,
3km*3km and 10km*10km for a fixed 10, 25 and 100 nodes, respectively.
Similar to the variation of number of node, the variations of network sizes also causes
the impact on the QoS parameters of HTTP traffic for different routing protocols. In
appendix G, we see that the QoS parameters, media access delay and throughput
decrease with the increase of node in TORA. And, the variation of network area much
influences on the QoS of parameters of HTTP for TORA. However, for various network
sizes, OLSR shows better performance by demonstrating lower media access delay and
greater throughput than other protocols. In appendix H, for 25 nodes scenarios, the QoS
parameters of HTTP traffic degrade for different protocols with the increase in network
sizes. In appendix I, for a large number of nodes (100 nodes), the variation of network
size strongly influences on the QoS parameters of different routing protocols. The QoS
of parameters sharply reduce with the increase in network area. Although, OLSR shows
better throughout in an area 1km*1km than others, but for 3km*3km and 10km*10km
areas the throughput of all protocols is very poor and all protocols show much lower
throughput than other scenarios.
8.4 Impact of network area on the QoS parameters of Voice traffic for different
protocols
We also observed the impact of variation of network area on the QoS parameters of
voice traffic for a fixed amount node. The simulation results are also illustrated at the
end of the report in Appendix J-L. The simulations demonstrate that the variation of
network sizes also influences the QoS parameters of voice traffic for different routing
protocols. In appendix J, for 10 nodes scenario, the simulation results illustrate that the
throughput of OLSR fall down sharply with the increment of network area. The media
access delays of all protocols also increase with the increment of network area.
However, no significant influence is observed on different protocols for the variation of
network size. And, the QoS parameters of 25 and 100 nodes for different protocols in
various areas are presented in appendix K and L, respectively. In appendix K, the media
access delay of AODV is much influenced by the variation of network size and it shows
increasing trend with the increment of network size. The network load graphs of various
protocols are also increasing with the increment of network sizes. However, the
throughput and MOS value does not influence much on the variation of network size. In
appendix L, the variation of network sizes also influences on different QoS parameters
of voice traffic for different protocols. The media access delay graph shows that in a
large area AODV protocol shows lower delay than others and the other two protocols
maintain almost similar values of delay for various areas. The network load of OLSR
protocol gradually increases with the increment of network sizes. Although AODV
maintains a steady curve of network load, TORA shows a decreasing trend with the
increment of network sizes. And in a large network area, all protocols show higher
MOS value than other scenarios. The throughput of different protocols is gradually
decreasing with the increment of network areas.
8.5 Theoritical Explanation of Simulation Results
In chapter 6 we explained how the different protocols work and in Chapter 7 we
presented the result of the simulations. In this section we will discuss the results of the
simulations and compare their expected behavior from the theoretical presentation.
36
OLSR is a proactive routing protocol and to perform its routing operations each node
uses one or more routing tables. Routing of proactive is faster than reactive. Therefore,
for a small network and less number of nodes, OLSR may show better performance than
other protocols. But in highly mobile MANET scenarios, for a large number of nodes
and large network size scenario OLSR protocol will not perform well. And in our
empirical study, OLSR shows similar behavior as we get in theoretical study. Although,
in small network OLSR shows greater throughput than others, but for a large network
size the value of it degrades.
TORA is a reactive protocol and it uses different strategies to ensure loop free route. It
uses different query packets instead of routing table to perform its routing operations. It
also considers multiple routes in parallel to find the optimum route. By theoretical study
it is clear that TORA is designed for scalable networks. But in our empirical study, for
larger network it shows poor QoS in case of both HTTP and voice traffics and it might
be due to high mobility of nodes in our scenarios.
AODV, reactive routing protocol uses some unique strategies such as destination
sequence number rather than other reactive protocol to perform its routing operation.
AODV requires more route establish time as it doesn‟t establish multiple routes for
finding the best route. If any existing route fails it again initiates whole route query
process as routing information is not maintained. In our experimental scenarios, we
consider highly mobile scenarios and so, the considered scenarios are unstable.
Therefore, AODV does not demonstrate the high QoS of HTTP and voice traffic in our
network scenarios.
GRP is a GPS based geographic routing protocol. To find out the position of a node
within the network area, it considers different level of quadrants. It uses table driven
approach and as well as query packets to find out the optimum route. Presently
researchers are trying to test it in different MANET scenarios. But in our experiment,
we cannot simulate it as some devices, such as MANET gateways do not support the
GRP.
37
9. Conclusion and Future Work
9.1 Conclusion
In this thesis, to reach the research goal, first we implemented an IMANET in a network
simulator OPNET and then the designed network models are demonstrated in Figures 7.2
and 7.3. Secondly, we designed different network scenarios in OPNET 14.5 by varying
the amount of nodes and sizes of networks to observe the impact of number of nodes and
network size on different routing protocols. Thirdly, we measured the average QoS
parameters of HTTP and voice traffics from our designed IMANET scenarios.
The scenarios 1 and 2 demonstrated the impact of the number of nodes for different
routing protocols in QoS parameters of HTTP and voice traffics. A detailed analysis on
the performance of the three protocols is presented in sections 8.3 and 8.4 in the report.
We analyze all these works and conclude the following points.
Different routing protocols demonstrate various performances by showing dissimilar
QoS parameters for various numbers of nodes and for various network areas. It is
observed that in a fixed small and medium network area for numerous nodes, although
OLSR shows higher network load, it shows better performance than other two protocols
by demonstrating lower media access delay, page response time and greater throughput.
However, in a large network, although TORA illustrates lower page response time but
yet, OLSR protocol demonstrates comparatively better performance than other protocols.
And in all scenarios for various nodes, TORA protocol demonstrates poor performance.
According to the simulation results demonstrated in appendix G to L, we observe that
the variation of network sizes are also affected on the QoS parameters of HTTP and
voice traffics for different routing protocols similar to the variation of number of nodes.
For a fixed less number of nodes, comparing to other two protocols the performance of
TORA is much influenced by the variation of network area. The performance of OLSR
is comparatively better than other protocols as it shows lower media access and greater
throughput. For a fixed 25 nodes scenario, the throughput of different routing protocols
decrease with the increase of network area. However, for a fixed 100 nodes scenario, the
QoS of parameters falls down with the increment of network area.
9.2 Proposed Solutions to the Research Questions
Working on this thesis, six (research) questions have been revealed in different chapters
as follows.
Q.1 A detail survey of different disaster scenarios is presented in chapter 2. As the
existing communication system is based on infrastructure, it might completely fail during
the disaster situations and so there is a need for MANETs. In MANET, all the devices
are considered as mobile and can communicate without using infrastructure network
topology. If the existing electronic devices can configure both infrastructure as well as
ad-hoc networks, then the MANET is a viable solution to the communication demands
that exist in a disaster area.
Q.2 Nodes are considered as highly mobile in wireless MANETs. Therefore, finding an
optimum route between any two nodes in such dynamic unstable network is a complex
task and an efficiency of designed MANET scenarios in a disaster area depends on the
efficiency of routing protocols. The classification and the working principle of widely
used MANET protocols is presented in the chapter 4.
Q.3 In Table driven protocols, each node maintains one or more routing tables. In order
to find out a new route it collects the route information of destination node from the table
and then forwards the packet toward the route. However, maintaining updated routing
tables for number of nodes in a MANET is not a simple issue. To overcome the
38
limitation of table driven approach, reactive protocols are developed. The reactive
protocols use different query packets instead of maintaining up-to-date routing table. But
it takes more routing time than table driven approach. Among these two approaches, on
demand approach is more effective in MANETs.
Q.4 Different parameters like number of nodes, pause time, node mobility model,
network size, data rate, packet size etc effect the performance of MANET routing
protocols. Normally, the number of nodes in a scenario depends on the application of
selected area. Pause time is an important parameter by which we can design the
different types of networks depending on the applications. For the designing unstable
network (example, Vehicle networks) we need to set the pause time very short and a
long pause time sets for the designing of stable networks (example, Sensor network).
Data rate and packet size depend on the communication environment. For example, in
IEEE 802.11b (Wi-Fi) the data rate is 11Mbps and packet size is 192μs. In our
experimental study keeping all other network parameters constant, we vary the number
of nodes and network area. We observed that the variation in number of nodes had more
influence on the QoS parameters of different routing protocols rather than network area.
Q.5 A model of IMANET scenario in OPNET is demonstrated in chapter 7 and the
details of configuration procedure of IMANET in OPNET are illustrated in Appendix
A-L. To analyze the performance of different routing protocols we measure the
different QoS parameters of HTTP and voice traffics such as media access delay,
network load, page response, MOS and throughput.
Q.6 The theoretical study of different routing protocols is illustrated in chapter 4 and the
figures in chapter 8 demonstrate the QoS parameters of HTTP and voice traffics of
different MANET routing protocols. Based on the theoretical as well as empirical study
we conclude that the OLSR shows comparatively better QoS for both HTTP and voice
traffics. However, for a large network the throughput of OLSR fall down. The protocol
TORA shows comparatively poor QoS in different scenarios and the performance of
TORA is much influenced by varying the network area. However, AODV shows
medium QoS parameters in our considered scenarios.
9.3 Future Works
During the course of the thesis, we noticed some constraints which we did not find at the
start. Initially, we fixed our goal to evaluate performance of MANET routing protocols
along with GRP in our designed network scenarios. Although OPNET simulator has
many advantages, we also observed some limitations; in our designed IMANET model
we used few MANET gateways, but these devices do not support the GRP routing
protocol. Therefore, we failed to evaluate it in our scenarios.
As OPNET has less flexibility to design network, we designed scenarios with IEEE
802.11b with maximum bandwidth 11Mbps and the transmission range of each mobile
node is always fixed 300m. To design more efficient scenarios we should configure
more flexible networks.
For better understanding, observation of the traffic flow is also an important part in
designing a network model. As OPNET does not support the traffic flow with
visualization we fail to do it.
A wide number of routing protocols are proposed for MANETs, but till now no routing
protocol ensured the reliable multimedia communication in MANET environments.
All these findings may help future researches to continue their research in the
development of IMANET as well as other Ad-hoc networks.
39
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41
APPENDIX
A. HTTP Server Configuration
(a) (b)
(c)
42
B. Backbone Network Configuration
(a) (b)
(c)
43
C. Application Configuration
(a) (b)
D. Profile Configuration
(a) b)
44
E. MANET Gateway Configuration
(a) (b)
F. Mobility Configuration
(a) (b)
G. Scenario of HTTP for 10 nodes in different areas 1km*1km, 3km*3km,
10km*10km
(a) (b)
45
(c) (d)
QoS parameters of HTTP traffic different protocols (10 nodes in 1km*1km, 3km*3km and 10km*10km
areas): (a) Media Access Delay (sec), (b) Network Load (bits/sec), (c) Page response time(sec), (d)
Throughput.
H. Scenario of HTTP for 25 nodes in different areas 1km*1km, 3km*3km,
10km*10km
(a) (b)
(c) (d)
QoS parameters of HTTP traffic different protocols (25 nodes in 1km*1km, 3km*3km and 10km*10km
areas): (a) Media Access Delay (sec), (b) Network Load (bit/sec), (c) Page response time(sec), (d)
Throughput.
46
I. Scenario of HTTP for 100 nodes in different areas 1km*1km, 3km*3km,
10km*10km
(a) (b)
(c) (d)
QoS parameters of HTTP traffic different protocols (100 nodes in 1km*1km, 3km*3km and 10km*10km
areas): (a) Media Access Delay (sec), (b) Network Load (bit/sec), (c) Page response time(sec), (d)
Throughput.
J. Scenario of Voice traffic for 10 nodes in different areas 1km*1km, 3km*3km,
10km*10km
(a) (b)
47
(c) (d)
QoS parameters of voice traffic different protocols (10 nodes in 1km*1km, 3km*3km and 10km*10km
areas): (a) Media Access Delay (sec), (b) Network Load (bit/sec), (c) MOS Value, (d) Throughput
K. Scenario of Voice traffic for 25 nodes in different areas 1km*1km, 3km*3km,
10km*10km
(a) (b)
(c) (d)
QoS parameters of voice traffic different protocols (25 nodes in 1km*1km, 3km*3km and 10km*10km
areas): (a) Media Access Delay (sec), (b) Network Load (bit/sec), (c) MOS Value, (d) Throughput
48
L. Scenario of Voice traffic for 100 nodes in different areas 1km*1km, 3km*3km,
10km*10km
(a) (b)
(c) (d)
QoS parameters of voice traffic different protocols (100 nodes in 1km*1km, 3km*3km and 10km*10km
areas): (a) Media Access Delay (sec), (b) Network Load (bit/sec), (c) MOS Value, (d) Throughput