PERFORMANCE STUDY OF QUALITY OF SERVICE ROUTING PROTOCOLS IN MANETS

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PERFORMANCE STUDY OF QUALITY OF SERVICE ROUTING PROTOCOLS IN MANETS

BY

NUR IDAWATI MD ENZAI

INTERNATIONAL ISLAMIC UNIVERSITY MALAYSIA

2008

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PERFORMANCE STUDY OF QUALITY OF SERVICE ROUTING PROTOCOLS IN MANETS

BY

NUR IDAWATI MD ENZAI

A dissertation submitted in partial fulfilment of the requirements for the degree of Master of Science in

Computer and Information Engineering

Kulliyyah of Engineering International Islamic University

Malaysia

SEPTEMBER 2008

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ABSTRACT

Recent growth and widespread attention given to mobile communications has led to rapid proliferation in research and development involving mobile wireless networks.

The need for easy deployment and self-configured networks makes mobile ad-hoc networks (MANETs) an attractive choice for various applications. However, due to its dynamic nature and imprecise network state information, there are many challenges which need to be addressed including Quality of Service (QoS) routing. Numerous approaches have been proposed including QoS-AODV. It is proposed to enhance one of the existing routing protocols for MANETs namely AODV (Ad-Hoc On-Demand Distance Vector). QoS-AODV adds necessary new fields to cater QoS provisioning requirements. Due to its ease of integration and simplicity, this protocol has been selected for evaluation study. The existing QoS-AODV implementation utilizes minimum bandwidth extension in assuring QoS guarantee. Apart from bandwidth, delay is also a critical parameter with regards to multimedia application which has been garnering rising attention lately. The first aim of this thesis is to conduct evaluation study on two QoS-AODV approaches. One approach makes use of HELLO messages and another makes use of link-layer feedback. Meanwhile, our highlighted contribution includes the extension of maximum delay field in addition to the existing minimum bandwidth field as part of our enhancement proposal. The combination of bandwidth and delay metrics for AODV is vital for maximizing bandwidth and reducing end-to-end delay. In order to identify the pros and cons of both methods as well as to test our proposed mechanism, NS-2 Simulator is used to conduct the simulation study. Average Latency, Packet Delivery Ratio (PDR) and Normalized Overhead are the selected evaluation metrics. Our experiments study the effect of number of mobile nodes, mobility and traffic load on different enhancements of AODV protocol. Through the simulation study performed, the shortcomings and strengths of the simulated approaches have been identified thus directing to suggestions for future works.

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ﺚﺤﺒﻟﺍ ﺔﺻﻼﺧ

ﺙﻮﺤﺒﻟﺍ ﰲ ﻊﻳﺮﺴﻟﺍ ﺪﻟﺍﻮﺘﻟﺍ ﱃﺍ ﻞﻳﺎﺑﻮﳌﺍ ﺕﻻﺎﺼﺗﺇ ﱃﺍ ﻊﺳﺍﻮﻟﺍ ﺭﺎﺸﺘﻧﻻﺍﻭ ﻊﻳﺮﺴﻟﺍ ﻮﻤﻨﻟﺎﺑ ﻡﺎﻤﺘﻫﻻﺍ ﻯﺩﺃ ﺪﻘﻟ ﻲﻜﻠﺳﻼﻟﺍ ﻞﻳﺎﺑﻮﳌﺍ ﺔﻜﺒﺸﻟ ﺮﻳﻮﻄﺘﻟﺍﻭ .

ﺒﺸﻟﺍ ﻝﺎﻤﻌﺘﺳﺍ ﱃﺍ ﺔﺟﺎﳊﺍ ﻥﺇ ﺔﻜﺒﺷ ﻞﻌﺟ ﻖﺳﺎﻨﺘﻣﻭ ﻞﻬﺳ ﻞﻜﺸﺑ ﺔﻜ

ﻞﻳﺎﺑﻮﳌﺍ ) ﺱﺃ ﰐ ﻱﺇ ﻥﺃ ﻱﺃ ﻡﺃ (

ﺕﺎﻘﻴﺒﻄﺘﻟﺍ ﻒﻠﺘﺨﳌ ﺐﺴﻧﻷﺍﺭﺎﻴﺘﺧﻻﺍ .

ﻪﺘﻌﻴﺒﻄﻟ ﺔﺠﻴﺘﻧ ،ﻚﻟﺫ ﻊﻣ

ﰲ ﺕﺎﻣﺪﳋﺍ ﺔﻴﻋﻮﻧ ﻦﻤﻀﺘﺗ ﱵﻟﺍﻭ ﺎﻬﺘﻓﺮﻌﻣ ﺝﺎﺘﳓ ﱵﻟﺍ ﺕﺎﻳﺪﲢ ﺓﺪﻋ ﻙﺎﻨﻫ ﻥﺎﻓ ،ﺔﻗﺪﻟﺍ ﻡﺪﻋﻭ ﺔﻴﻜﻴﻣﺎﻨﻳﺍﺪﻟﺍ ﺕﺍﺭﺎﺴﳌﺍ ﻢﻴﻈﻨﺗ .

ﻧ ﺎﻬﻨﻤﻀﺑ ﻕﺮﻄﻟﺍ ﻦﻣ ﺪﻳﺪﻌﻟﺍ ﺡﺍﺮﺘﻗﺇ ﰎ ﺕﺎﻣﺪﳋﺍ ﺔﻴﻋﻮ

– ) ﰲ ﻱﺩ ﻭﺃ ﻱﺃ .(

ﻪﺣﺍﺮﺘﻗﺇ ﰎﻭ

ﻝ ﺕﺍﺭﺎﺴﳌﺍ ﻢﻴﻈﻨﺘﺑ ﺔﺻﺎﳋﺍ ﺕﻻﻮﻛﻮﺗﻭﱪﻟﺍ ﺪﺣﺃ ﺔﻳﻮﻘﺘﻟ )

ﺱﺃ ﰐ ﻱﺇ ﻥﺃ ﻱﺃ ﻡﺃ (

ﻰﻤﺴﳌﺍﻭ )

ﻱﺩ ﻭﺃ ﻱﺃ

ﰲ .(

ﺓﺩﻮﺟﻮﳌﺍ ﺔﺟﺎﳊﺍ ﻡﺪﳜ ﱴﺣ ﺔﻤﻬﳌﺍ ﺓﺪﻳﺪﳉﺍ ﻝﻮﻘﳊﺍ ﻒﻴﻀﻳ ﲑﺧﻻﺍﻭ .

ﺭﺎﻴﺘﺧﺇ ﰎ ﺪﻘﻓ ،ﻪﺘﻟﻮﻬﺴﻟ ﺔﺠﻴﺘﻧ

ﻟﺍ ﻩﺬﻫ ﰲ ﻪﻤﻴﻴﻘﺘﻟ ﻝﻮﻛﻮﺗﻭﱪﻟﺍ ﺍﺬﻫ ﺔﺳﺍﺭﺪ

. ﺽﺮﻌﻟ ﺪﻳﺪﲤ ﻞﻗﺃ ﻲﻄﻌﻳ ﹰﺎﻴﻟﺎﺣ ﺓﺩﻮﺟﻮﳌﺍ ﺔﻘﻳﺮﻄﻟﺍ ﻖﻴﺒﻄﺗ ﻥﺇ

ﺔﻣﺪﳋﺍ ﺔﻴﻋﻮﻧ ﻥﺎﻤﻀﻟ ﺔﻣﺰﳊﺍ .

ﺔﺒﺴﻨﻟﺎﺑ ﻢﻬﻣ ﻞﻣﺎﻋ ﹰﺎﻀﻳﺃ ﲑﺧﺄﺘﻟﺍ ﱪﺘﻌﻳ ، ﺔﻣﺰﳊﺍ ﺽﺮﻋ ﻦﻣ ﺀﺰﺠﻛﻭ

ﹰﺍﺮﺧﺆﻣ ﻊﺳﺍﻭ ﻡﺎﻤﺘﻫﺇ ﻰﻠﻋ ﺕﺫﻮﺤﺘﺳﺇ ﱵﻟﺍﻭ ﺎﻳﺪﻴﻣ ﱵﻠﳌﺍ ﺕﺎﻘﻴﺒﻄﺘﻟ .

ﻮﻫ ﺔﺣﻭﺮﻃﻻﺍ ﻩﺬﻫ ﻦﻣ ﻝﻭﻻﺍ ﻑﺪﳍﺍ

ﺔﻴﻋﻮﻧ ﱵﻘﻳﺮﻃ ﻢﻴﻴﻘﺘﻟ ﻭ ﺔﻣﺪﳋﺍ

) ﰲ ﻱﺩ ﻭﺃ ﻱﺃ .(

ﺔﻟﺎﺳﺭ ﻡﺪﺨﺘﺴﺗ ﱵﻟﺍ ﱃﻭﻻﺍ ﺔﻘﻳﺮﻄﻟﺍ )

ﻮﻠﻠﻴﻫ ( ﻯﺮﺧﻻﺍﻭ

ﺔﻴﺴﻜﻌﻟﺍ ﺔﻳﺬﻐﺘﻟﺍ ﻞﻴﺻﻮﺗ ﻡﺪﺨﺘﺴﺗ .

ﲑﺧﺄﺗ ﻰﺼﻗﺃ ﺪﻳﺪﲤ ﰲ ﺔﺳﺍﺭﺪﻟﺍ ﻩﺬﻫ ﻡﺎﻬﺳﺇ ﻥﺈﻓ ،ﺮﺿﺎﳊﺍ ﺖﻗﻮﻟﺍ ﰲ

ﺚﺤﺒﻟﺍ ﺡﺮﺘﻘﻣ ﺔﻳﻮﻘﺘﻟ ﺩﻮﺟﻮﳌﺍ ﺔﻣﺰﺤﻠﻟ ﺽﺮﻋ ﻞﻗﺃ ﱃﺍ ﺔﻓﺎﺿﻻﺎﺑ .

ﺽﺮﻋﻭ ﲑﺧﺄﺘﻟﺍ ﻞﻣﺎﻋ ﲔﺑ ﻂﺑﺮﻟﺍ ﻥﺇ

ﺔﻣﺰﳊﺍ ﱃﺍ ﺔﺒﺴﻨﻟﺎﺑ )

ﰲ ﻱﺩ ﻭﺃ ﻱﺃ (

ﲑﺧﺄﺘﻟﺍ ﻞﻴﻠﻘﺗﻭ ﺔﻣﺰﺤﻠﻟ ﺽﺮﻋ ﻰﺼﻗﺃ ﻰﻠﻋ ﻝﻮﺼﺤﻠﻟ ﻱﻮﻴﺣ ﱪﺘﻌﻳ

ﺔﻳﺎﻭ ﺔﻳﺎ ﲔﺑ .

ﰎ ﺪﻘﻓ،ﺔﺣﺮﺘﻘﳌﺍ ﺔﻘﻳﺮﻄﻟﺍ ﺺﺤﻓ ﻚﻟﺬﻛﻭ ﺲﻧﻮﻜﻟﺍﻭ ﺱﻭﱪﻟﺍ ﻕﺮﻃ ﻒﻳﺮﻌﺗ ﺽﺮﻐﻟﻭ

ﺱﺃ ﻥﺃ ﻲﻛﺎﶈﺍ ﻝﺎﻤﻌﺘﺳﺇ -

ﺓﺎﻛﺎﶈﺍ ﺔﺳﺍﺭﺪﺑ ﻡﺎﻴﻘﻠﻟ 2 .

ﻝﺪﻌﻣ ﺖﻧﺎﻛ ﻢﻴﻴﻘﺘﻠﻟ ﺎﻫﺩﺎﻤﺘﻋﺇ ﰎ ﱵﻟﺍ ﻞﻣﺍﻮﻌﻟﺍ ﻥﺇ

ﺕﺎﻣﻮﻠﻌﳌﺍ ﻡﻼﺘﺳﺇ ﱃﺍ ﺔﺒﺴﻧ ﺔﺑﺎﺠﺘﺳﻻﺍ ﺖﻗﻭ .

،ﺔﺳﺍﺭﺪﻟﺍ ﻩﺬﻫ ﰲ ﻞﻳﺎﺑﻮﳌﺍ ﺪﻘﻋ ﺩﺪﻋ ﲑﺛﺄﺗ ﺔﺳﺍﺭﺩ ﰎ

ﻝﻮﻛﻮﺗﻭﺮﺑ ﰲ ﺕﺎﻨﻴﺴﺤﺘﻟﺍ ﻒﻠﺘﺨﳌ ﺔﻛﺮﳊﺍ ﻞﻴﻤﲢﻭ ،ﺔﻛﺮﳊﺍ ﺔﻟﻮﻬﺳ ﻚﻟﺬﻛﻭ )

ﰲ ﻱﺩ ﻭﺃ ﻱﺃ .(

ﻝﻼﺧﻭ

ﱃﺍ ﺕﺩﺃ ﱵﻟﺍ ﺓﺪﻴﳉﺍ ﺞﺋﺎﺘﻨﻟﺍ ﺾﻌﺑ ﱃﺍ ﺔﻓﺎﺿﺇ ﺕﺎﻗﻮﻌﻣ ﺓﺪﻋ ﻙﺎﻨﻫ ﻥﺎﻛ ، ﻩﺬﻫ ﺓﺎﻛﺎﶈﺍ ﺔﺳﺍﺭﺩ ﺕﺎﺣﺍﺮﺘﻗﺇ

ﻲﻠﺒﻘﺘﺴﳌﺍ ﻞﻤﻌﻠﻟ .

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APPROVAL PAGE

I certify that I have supervised and read this study and that in my opinion; it conforms to acceptable standards of scholarly presentation and is fully adequate, in scope and quality, as a dissertation for the degree of Master of Science in Computer and Information Engineering.

………...

Farhat Anwar

Supervisor

I certify that I have read this study and that in my opinion; it conforms to acceptable standards of scholarly presentation and is fully adequate, in scope and quality, as a dissertation for the degree of Master of Science in Computer and Information Engineering.

...

Aisha Hassan Abdalla

Examiner (Internal)

I certify that I have read this study and that in my opinion; it conforms to acceptable standards of scholarly presentation and is fully adequate, in scope and quality, as a dissertation for the degree of Master of Science in Computer and Information Engineering.

………

Norsheila Fisal

Examiner (External)

This dissertation was submitted to the Department of Computer and Electrical Engineering and is accepted as a partial fulfilment of the requirements for the degree of Master of Science in Computer and Information Engineering.

……….

Othman O. Khalifah

Head, Department of Electrical and Computer Engineering This dissertation was submitted to the Kulliyyah of Engineering and is accepted as a partial fulfilment of the requirements for the degree of Master of Science in Computer and Information Engineering.

………

Ahmad Faris Ismail

Dean, Kulliyyah of Engineering

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DECLARATION

I hereby declare that this dissertation is the result of my own investigations, except where otherwise stated. I also declare that it has not been previously or concurrently submitted as a whole for any other degrees at IIUM or other institutions.

Nur Idawati Md Enzai

Signature:……… Date: ………

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INTERNATIONAL ISLAMIC UNIVERSITY MALAYSIA

DECLARATION OF COPYRIGHT AND AFFIRMATION OF FAIR USE OF UNPUBLISHED RESEARCH

PERFORMANCE STUDY OF QUALITY OF SERVICE ROUTING PROTOCOLS IN MANETS

No part of this unpublished research may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise without the permission of the copyright holder except as provided below.

1. Any material contained in or derived from this unpublished research may only be used by others in their writing with due acknowledgement.

2. IIUM or its library will have the right to make and transmit copies (print or electronic) for institutional and academic purpose.

3. The IIUM library will have the right to make, store in a retrieval system and supply copies of this unpublished research if requested by other universities and research libraries.

Affirmed by Nur Idawati Md Enzai

……….. ……….

Signature Date

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In Loving Memory of My Wonderful Mother, Khadijah binti Kadir

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ACKNOWLEDGMENTS

Thanks to Allah for His Great Blessing and Solawat to our beloved Prophet (P.B.U.H). This thesis is the outcome of years of research that has been done since I came to IIUM as a postgraduate student. By that time, I have worked with a great number of people whose contribution in various ways to the research and the making of the thesis deserved special mention. It is a pleasure to convey my gratitude to them all in my humble acknowledgment.

In the first place I would like to record my gratitude to Assoc. Prof. Dr. Farhat Anwar for his supervision, advice, and guidance from the very early stage of this research as well as giving me opportunities to present my findings at many international conferences throughout the work.

And of course, I am thankful for being blessed with support and understanding by my parents and siblings. They stand by me at all occasions, through the happy and tough times. To them, I am still their clumsy sister and daughter who would still go to them no matter what. They have been my inspiration all this while.

I also gratefully acknowledge my Networking Research Group Lab members: Bro Zeldi, Dr. Omer, Sis Naimah and Sis Fariza for their advice, supervision, and crucial contribution, which made them a backbone of this research and so to this thesis. I am grateful in every possible way and hope to keep up our collaboration in the future. Our friendship has also become a memorable one.

It is also a pleasure to pay tribute to Mr Ronan de Renesse and Mr Vinod Kone for their kindness of answering my inquiries regarding QoS in MANETs through emails.

They have been very generous in providing the information that I require.

Last but not least, collective and individual acknowledgments are also owed to my colleagues at IIUM whose presence somehow perpetually refreshed, helpful, and memorable. Many thanks go in particular to Sis Shuhada, Sis Rozaidah, Sis Winda, Sis Zakiah, Sis Yusnita, Sis Hasimah, Sis Hanani, Sis Syazilawati, Sis Iman, Sis Siti, Bro Iwan, Bro Turnad, Bro Hakim and Bro Amart for giving me such a pleasant time during my study, especially for the exhilarating time we spent together.

Finally, I would like to thank everybody who was important to the successful realization of this thesis as well as expressing my apology that I could not mention personally one by one.

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CHAPTER 2: LITERATURE REVIEW ... 5

2.1 Introduction ... 5

2.2 QoS Routing in Ad-Hoc Wireless Networks ... 6

2.2.1 QoS-AODV ... 8

2.2.3 QoS-DSR ... 18

2.2.4 QoS-TORA ... 19

2.2.5 Ticket-Based Routing Protocol ... 20

2.2.6 Trigger-Based Distributed Routing Protocol ... 21

2.2.7 Bandwidth Routing Protocol ... 23

2.2.8 On-Demand QoS Routing Protocol ... 24

2.2.9 On-Demand Link-State Multi-Path Routing Protocol. ... 25

Summary ... 30

CHAPTER 3: OPERATION OF QOS-AODV ... 31

3.2 QoS-AODV Overview ... 31

3.2.1 Route Discovery and Maintenance ... 33

3.2.1.1 Maximum Delay Extension ... 33

3.2.1.2 Minimum Bandwidth Extension ... 34

3.2.2 QoS Violation Detection and Maintenance ... 34

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3.3 QoS-AODV Format ... 35

3.3.1 Minimum Bandwidth Extension Implementation ... 36

3.3.2 ICMP_QoS_LOST Message ... 42

3.3.3 Connectivity Maintenance ... 42

3.3.3.1 HELLO Messages ... 43

3.3.3.2 Link-Layer Detection ... 45

3.4 Summary ... 46

CHAPTER 4: PROPOSED MODIFICATION TO AODV ... 47

4.2 General Idea ... 48

4.3 Packets ... 48

4.4 Routing Table ... 49

4.5 Definition and Implementation ... 50

4.6 Summary ... 54

CHAPTER 5: SIMULATION SETUP AND TRACE FILES ... 55

5.2 Overview of Network Simulator 2 ... 56

5.3 Mobile Networking in NS2 ... 56

5.3.1 Creating Wireless Topology ... 57

5.3.2Traffic Pattern ... 58

5.3.3 Mobility Pattern ... 59

5.4 Simulation Environment ... 60

5.6 Performance Metrics and Scenarios ... 60

5.7 Summary ... 63

CHAPTER 6: RESULTS ANALYSIS AND DISCUSSIONS ... 64

6.2 Effect of Number of Nodes ... 65

6.3 Effect of Mobility ... 68

6.4 Effect of Traffic Load ... 73

6.5 Discussions ... 78

6.6 Summary ... 79

CHAPTER 7: CONCLUSION AND FUTURE WORK ... 80

7.1 Conclusion ... 80

7.2 Recommendations ... 83

BIBLIOGRAPHY ... 84

APPENDIX I ... 88

APPENDIX II ... 90

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APPENDIX III ... 91

APPENDIX IV ... 93

APPENDIX V ... 94

APPENDIX VI ... 98

APPENDIX VII ... 100

APPENDIX VIII ... 103

APPENDIX IX ... 104

APPENDIX X ... 107

APPENDIX XI ... 108

APPENDIX XII ... 109

APPENDIX XIII ... 110

APPENDIX XIV : PUBLICATIONS ... 111

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LIST OF TABLES

Table No. Page No.

2.1 Summary of On-Demand QoS Routing Protocols 26

3.1 Default AODV Configuration Parameters 44

5.1 Summary of Simulation Environment 62

5.2 New Parameters for Bandwidth and Delay Extensions 62

6.1 Overview of the Simulated Protocols 64

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LIST OF FIGURES

Figure No. Page No.

3.1 AODV Overview 32

3.2 AODV Route Request Message Format 35

3.3 AODV Route Reply Message Format 35

3.4 AODV Message Extension Format 35

3.5 Minimum Bandwidth Extension Format 36

3.6 RREQ Flow Chart for AODV 38

3.7 RREP Flow Chart for AODV 39

3.8 RREQ Flow Chart for QoS-AODV with Minimum Bandwidth Extension

40

3.9

3.10

RREP Flow Chart for QoS-AODV with Minimum Bandwidth Extension

QoS LOST Message Format

41

42

3.11 HELLO Message Link Loss Detection 45

3.12 Link Layer Feedback 46

4.1 Flow Chart for function recvRequest( ) in aodv.cc 52 4.2 Flow Chart for function recvReply( ) in aodv.cc 53

5.1 NS2 Simulation Execution Structure 55

5.2 Ad-Hoc Routing NS2 Code 57

5.3 Mobile Node Creation NS2 Code 58

6.1 Effect of number of nodes on PDR 65

6.2 Effect of number of nodes on delay 66

6.3 Effect of number of nodes on overhead 68

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6.4 Effect of mobility on PDR 69

6.5 Effect of mobility on delay 70

6.6 Effect of mobility on overhead 71

6.7 Effect of traffic load on PDR 73

6.8 Effect of traffic load on delay 75

6.9 Effect of traffic load on overhead 77

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LIST OF ABBREVIATIONS

ABR Associativity-Based Routing AODV Ad-Hoc On-demand Distance Vector ARP Address Resolution Protocol

ATM Asynchronous Transfer Mode

BR Bandwidth Routing

CAR Call Acceptance Ratio CBR Constant Bit Rate

CDMA Collision Detection Multiple Access CMU Carnegie Mellon University

DiffServ Differentiated Services

DQoSR Distributed QoS Routing Algorithm

E-AODV Enhanced Ad-Hoc On-Demand Distance Vector Routing EED End-to-End Delay

DSR Dynamic Source Routing FIFO First In First Out

FORP Flow-Oriented Routing Protocol FQMM Flexible QoS Model for MANETs ICMP Internet Control Message Protocol ID Identifier

IETF Internet Engineering Task Force INIR Intermediate Node Initiated Routing

IP Internet Protocol

Intserv Integrated Services

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xvi LAN Local Area Network MAC Medium Access Control MANET Mobile Ad-hoc Network NOL Normalized Overhead Load NTT Node Traversal Time

OQR On-Demand QoS Routing PDR Packet Delivery Ratio QoS Quality of Service QRREP QoS Route Reply QRREQ QoS Route Request RREP Route Reply RREQ Route Request RRER Route Error RSV Reserve

RSVP Resource Reservation Protocol SIRR Source Initiated ReRouting TCP Transmission Control Protocol TDMA Time Division Multiple Access TDR Trigger-Based Distributed Routing TORA Temporally Ordered Routing Algorithm URSV Unreserve

VC Virtual Circuit

VoIP Voice Over IP

ZJ Zero Jitter

ZJPA Zero Jitter Phase Alignment

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CHAPTER ONE INTRODUCTION

1.1 BACKGROUND

The term Mobile Ad-Hoc Network (MANET) is defined as autonomous system of mobile nodes (e.g., a router with multiple hosts and wireless communications devices) which are free to move about arbitrarily. The nodes may be located in or on airplanes, ships, trucks, cars, perhaps even on people or very small devices, and there may be multiple hosts per router (Corson and Macker, 1999). Ad-hoc wireless networks are also defined as the category of wireless networks that utilize multi-hop radio relaying and are capable of operating without the support of any fixed infrastructure; hence they are also called infrastructure-less networks (Murthy and Manoj, 2004). Due to its mobility nature and dynamic nature, there are many challenges which need to be addressed in different approaches unlike wired network approaches.

The rapid emergence of MANET is due to the continuing advances in computing and wireless technologies, as well as constant growth in computing speed, memory, communication capabilities and features, while becoming more portable.

With this development and the proliferation of these devices in every aspect of society, the need for such devices to communicate in a seamless manner is becoming increasingly essential (Jawhar and Wu, 2004). Nevertheless, due to quickness and economically less demanding deployment, MANETs find applications in several areas ranging from military applications to emergency operations. There are many major issues and challenges that need to be considered in designing ad-hoc wireless systems.

One of the critical issues that need to be taken into account is the quality of service

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(QoS) provisioning (Murthy and Manoj, 2004). QoS is usually defined as a set of service requirements that needs to be met by the network while transporting a packet stream from a source to its destination. The network needs are governed by the service requirements of end user applications. The network is expected to guarantee a set of measurable pre specified service attributes to the users in terms of end-to-end performance, such as delay, bandwidth, probability of packet loss, delay variance (jitter), power consumption, etc. (Stüdi, 2003). One of the most important aspects of the communications process is the design of the routing protocols used to establish and maintain multi-hop routes to allow the communication of data between nodes. In the case of QoS provisioning, the routing protocols have to ensure that the QoS requirements are met (Jawhar and Wu, 2004).

1.2 PROBLEM STATEMENT

We are witnessing a rapid growth in research and development involving ad-hoc networks recently due to its promising potential. The ability to operate without the support of any fixed infrastructure as well as relative ease of deployment make ad-hoc networks an attractive choice for various applications including military, disaster recovery etc. Unfortunately unlike wired networks, it is a challenging task to ensure Quality of Service (QoS) provisioning including routing in ad-hoc networks due to the mobile and dynamic nature of the nodes. Challenges of QoS routing becomes more difficult due to the dynamic nature and imprecise network state information of MANETs.

Based on routing update mechanism, each QoS routing protocol and algorithm can be classified into three categories: reactive (on-demand), proactive (table-driven) and hybrid. Generally, the on-demand QoS routing protocols perform better than

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table-driven QoS routing protocols. Although all the on-demand QoS routing protocols share similar on-demand behavior, the differences in the protocol mechanics can lead to significant performance differentials (Gupta, 2005). Research on routing in MANETs which includes the QoS provisioning as well is still an on-going process.

There is no single QoS routing protocol developed which could satisfy all the requirements since each application has its own QoS key parameters. Therefore, the task of improving an existing QoS routing protocol has great potential for future applications in ad-hoc environment.

1.3 RESEARCH OBJECTIVES

1. To study applicability of QoS-AODV under various network size, mobility and traffic load based on a selected set of performance metrics through simulation

2. To propose QoS provisioning in AODV routing protocol by maximizing the usage of bandwidth and reducing delay

1.4 SCOPE

Solutions for QoS provisioning includes the on-demand (reactive) type as well as table-driven (proactive) and hybrid. This research is focused on evaluating the performance of on-demand type of QoS routing protocol. A QoS routing protocol namely: QoS-AODV is chosen for performance evaluation due to generous interest given to QoS-AODV in recent years, owing to its great potential.

We are specifically interested in studying the two methods employed by QoS- AODV in maintaining connectivity. Connectivity is maintained either by utilizing

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HELLO messages or making use of underlying MAC layer detection mechanism.

Consequently, pros and cons of these two approaches can be illustrated.

1.5 EXPECTED OUTCOME

This research is not about deciding or determining the best routing protocol for QoS provisioning since every type of application has its own specific QoS parameters and requirements. Targeting the multimedia type of application, its key QoS parameters are bandwidth and delay. At the end of this research, it is expected to come out with an appropriate performance analysis of QoS-AODV with focus of bandwidth and delay metrics. In addition, recommendations and suggestions to improve the existing protocol will be proposed as well as identifying future works.

1.6 METHODOLOGY

The methodology of this research is based on experimental simulation study. The tool used is Network Simulator 2 (NS2).

1.7 THESIS OUTLINE

The dissertation is organized as follows. Chapter 2 reviews the related works and proposals for QoS provisioning in Mobile Ad-Hoc Networks. Chapter 3 presents the explanation of the operation of QoS-AODV. Chapter 4 highlights the enhancement proposal implemented on QoS-AODV. Chapter 5 discusses the implementation which is done by simulation as well as its configuration and parameters involved. Chapter 6 discusses and analyzes the results obtained from the simulation experiments performed. Finally, Chapter 7 summarizes and concludes the dissertation.

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CHAPTER TWO LITERATURE REVIEW

2.1 INTRODUCTION

QoS routing is certainly essential in providing routing algorithms with the capability of identifying paths which satisfy the maximum possible number of flows with end-to- end limitations or restrictions. The key objectives of QoS routing can be summarized as follows:

1. Active establishment of feasible paths from among possibly many choices that will accommodate the requirements of the given flow.

2. Optimization of resource handling. Network resource can be utilized efficiently as well as total throughput can be improved.

3. Compensation for brief shortcomings in network which can lead to graceful performance degradation (Deng, Liu and Zheng, n.d.).

Due to the bandwidth constraints and dynamic network topology of MANETs, none of researches done on QoS support in the Internet can be directly used. Information such as delay, bandwidth, cost, loss rate, and error rate in the network should be available and manageable to provide QoS support. Unfortunately, it is very difficult to get and manage the information in MANETs since the quality of a wireless link could vary with the surrounding circumstances. Moreover, the resource limitations and the mobility of hosts require implementation of complex QoS functionality with limited available resources in a dynamic environment (Wu and Harms, 2001).

QoS support in MANETs consists of QoS models, QoS resource reservation signalling, QoS routing, and QoS Medium Access Control (MAC). The relationships

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among all these QoS components are as follows. First of all, a QoS model specifies an architecture in which some kinds of services could be provided in MANETs. It acts like the system goal that should be implemented. Meanwhile, all other QoS components such as QoS signalling, QoS routing, and QoS MAC must work together to achieve this goal. Second, QoS signalling acts as the control centre in QoS support.

It coordinates the behaviours of QoS routing, QoS MAC, and other components such as admission control and scheduling. QoS model determines the functionality of QoS signalling. Third, QoS routing looks for a path with enough resources. However, the resources reservation along the path is handled by QoS signalling. The reservation is decided by QoS routing or other routing protocols. The coordination between QoS signalling and QoS routing ensures enough resources can be guaranteed when resource reservation is required. (Wu and Harms, 2001)

Another essential component of QoS support in MANETs is QoS MAC protocol. In addition, other network architectures could lend some QoS components to be implemented in MANETs, such as scheduling and admission control. (Wu and Harms, 2001)

2.2 QUALITY OF SERVICE (QOS) ROUTING IN AD-HOC WIRELESS NETWORKS

The QoS routing algorithms for wired networks cannot be applied directly to ad-hoc networks. First, the performance of most wired network routing algorithms relies on the availability of precise state information. However, the dynamic nature of an ad hoc network makes the available state information inherently imprecise. Though some recent algorithms were proposed to work with imprecise information (e.g., the probability distribution of link delay), they require the precise information about the

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network topology, which is not available in an ad-hoc network. Second, nodes may join, leave, and rejoin an ad-hoc network at any time and any location where the existing links may disappear, and new links may be formed as the nodes move. Hence, the established paths can be broken at any time, which raises new problems of maintaining and dynamically reestablishing the routing paths in the course of data transmission. It is difficult to provide QoS in an ad-hoc network due to its dynamic nature. (Chen and Nahrstedt, 1999).

In order to address the challenges brought by nature of ad-hoc networks, QoS routing protocols have been proposed by researchers to provide QoS support in MANETs. Most of these protocols provide QoS support for the available bandwidth requirement for a given path. This is because bandwidth is the most critical parameter in most MANET applications due to the scarcity of this resource in the wireless environment. The protocols support quality of service to varying degrees, in different ways, and using various network and communication models (Jawhar and Wu, 2004).

QoS routing protocols have been classified into many different modes and categories such as the related best effort routing protocol, communication model, synchronization mechanisms used and the routing information update mechanism employed. Based on routing information update mechanism, QoS routing protocols can be classified into three categories, namely, table-driven (proactive), on-demand (reactive) and hybrid. In contrast to the table-driven approach, the on-demand approach, does not maintain any routing table at the nodes, and hence the source node has to discover the route on the fly. Meanwhile, the hybrid approach incorporates features of both the table-driven and the on-demand approaches (Manoj and Murthy, 2004).

PERFORMANCE STUDY OF QUALITY OF SERVICE ROUTING PROTOCOLS IN MANETS