EFFECT ON HANDOVER LATENCY IN MOBILE IPv6 WITH FAST HANDOFF

BY

SOMASUNDRAM MUNUSAMY

INTERNATIONAL ISLAMIC UNIVERSITY

MALAYSIA

SEPTEMBER 2004

EFFECT ON HANDOVER LATENCY IN MOBILE IPv6

WITH FAST HANDOFF

BY

SOMASUNDRAM MUNUSAMY

A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENT FOR THE DEGREE OF MASTER

OF SCIENCE IN COMPUTER AND INFORMATION ENGINEERING

KULLIYYAH OF ENGINEERING INTERNATIONAL ISLAMIC UNIVERSITY

MALAYSIA

SEPTEMBER 2004

ii

ABSTRACT Fast handover is becoming extremely important in mobile environment. With the

advent of more and more sophisticated and cheap mobile data devices, Internet users

are moving away from fixed connections to mobile connections in dealing with their

day-to-day activities. In order to remain connected to the Internet while on the go, the

Mobile Node must be handed over from one Access Router to another. During this

process, there is a time period when the Mobile Node is unable to send or receive IPv6

packets both due to link switching delay and IP protocol operations. This time period

is referred to as handover latency. In many instances, the handover latency resulting

from standard Mobile IPv6 handover procedures could be greater than what is

acceptable to support real-time or delay sensitive traffic. Thus a fast handover protocol

was defined to be implemented as part of Mobile IPv6. With this enhancement,

handover latency is expected to reduce so that real-time or delay sensitive traffic could

benefit from Mobile IPv6. The intent of this Thesis is to implement the enhancements

in NS-2 and execute simulations to verify the handover latency could be reduced.

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الملخص

نتيجة اختراع أجهزة متحركة معقدة . تعد عملية التسليم السريع هامة جدا في عالم الاتصالات اللاسلكية

ورخيصة في الوقت نفسه للتعامل مع البيانات، أصبح مستخدمي شبكة المعلومات يبتعدون عن الوصلات

لضمان البقاء على اتصال بشبكة . كةالثابتة إلى الوصلات المتحركة وذلك عند تعاملهم اليومي مع الشب

خلال عملية التسليم تلك، . المعلومات فإن جهاز الاتصال المتحرك يجب تسليمه من جهاز تحويل إلى آخر

هناك فترة زمنية يكون فيها جهاز الإتصال المتحرك غير قادر على إرسال أو إستقبال وحدات البيانات طبقا

وذلك نتيجة التأخير في تحويل الاتصال من ) الإصدار السادس( IPv6ومات لإجراءات التعامل مع شبكة المعل

تسمى الفترة االزمنية تلك . جهاز تحويل إلى آخر أو نتيجة لإجراءات التعامل مع شبكة المعلومات نفسها

".التأخير في عملية التسليم"

تعامل مع شبكة المعلومات أطول مما في كثير من الأحيان، تكون فترة التأخير في التسليم نتيجة إجراءات ال

من أجل هذا تم تطوير . هو مسموح به لدعم عملية نقل المعلومات أو تتسبب في تأخير نقل معلومات حساسة

سيؤثر هذا . إجراءات تسليم سريع وذلك لتطبيقها كجزء من إجراءات التعامل المتحرك مع شبكة المعلومات

الغرض من هذه . في نقل البيانات وكذلك عدم تأخير نقل معلومات حساسةبالتأكيد على تقليل عملية التأخير

وتنفيذ محاكاة لعملية نقل ) الإصدار الثاني( NSالرسالة هو تطبيق التطوير على برنامج محاكاة الشبكات

.المعلومات وذلك للتثبت من إمكانية تقليل التأخير الحادث من عملية التسليم

iv

APPROVAL

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 thesis for the degree of Master of Science.

______________________________ Name: Assoc. Prof. Dr 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 thesis for the degree of Master of Science.

______________________________ Name: Dr. Md. Rafiqul Islam

Internal Examinar 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 thesis for the degree of Master of Science.

______________________________ Name: Prof. Dr. Kasmiran Jumari

External Examinar This thesis was submitted to the Department of Electrical Engineering and is accepted as partial fulfillment of the requirements for the degree of Master of Science.

______________________________ Name: Assoc. Prof. Dr Farhat Anwar

Head, Dept. of Electrical Engineering This thesis was submitted to the Kulliyyah of Engineering and is accepted as partial fulfillment of the requirements for the degree of Master of Science.

_____________________________ Name: Prof. Dr. Ahmad Faris Ismail Dean, Kulliyyah of Engineering

v

DECLARATION

I hereby declare that this thesis is the result of my own investigations, except where

otherwise stated. Other sources are acknowledged by footnotes giving explicit

references and a bibliography is appended.

Name: Somasundram Munusamy Signature: ____________________ Date: ____________________

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INTERNATIONAL ISLAMIC UNIVERSITY MALAYSIA

DECLARATION OF COPYRIGHT AND AFFIRMATION OF FAIR USE OF UNPUBLISHED RESEARCH

©Copyright 2004 by Somasundram Munusamy. All rights reserved. Effect on Handover Latency in Mobile IPv6 with Fast Handoff 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 prior written 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: Somasundram Munusamy __________________ ___________________ Signature Date

"The knowledge of all knowledge is for a man to know that he knows nothing, and that God knows everything”

vii

To Swami Brahma Vidyananda…my inspiration…my goal!

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ACKNOWLEDGEMENT

My humble prostration to Gurudev Swami Brahma Vidyananda for his direction and

guidance in life…without which this thesis would not have been a reality.

Thank you Dr. Farhat Anwar for continues support and advice in all matters related to

this thesis. Last but not least, my fellow brothers and sisters from Sri Raja Raajesvarii

Samasthaanam for all the cheering and fun. May the Almighty bless us all with a

joyous and spiritual journey ahead.

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TABLE OF CONTENTS Abstract………………………………………………………………….. ii Abstract (Arabic)…………………….………………………………….. iii Approval Page…………………………………………………………… iv Declaration………………………………………………………………. v Copyright………………………………………………………………… vi Dedication………………………………………………………………... vii Acknowledgement………………………………………………………. viii Table of Contents……………………………………………………….. ix List of Figures…………………………………………………………… xiv List of Tables……………………………………………………………. xvi List of Abbreviations……………………………………………………. xvii CHAPTER 1: INTRODUCTION

1.1 Introduction…………………………………………………… 1

1.2 Literature Review…………………………………………….. 2

1.3 Thesis Statement and Objective………………………………. 4

1.4 Scope of Work…………………………………………………. 5

1.5 Thesis Structure……………………………………………….. 5

CHAPTER 2: QUALITY OF SERVICE

2.1 Introduction…………………………………………………… 7

2.2 QoS – An Overview…………………………………………… 9

2.2.1 Network QoS……………..…….…………………. 9

2.2.2 The Benefit of QoS……..……….………………… 10

2.2.3 QoS Parameters…………………………………… 10

2.2.3.1 Latency.………………….………………… 11

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2.2.3.2 Jitter……………………..………………… 11

2.2.3.3 Bandwidth……..………………………….. 12

2.2.3.4 Reliability………..………………………… 12

2.2.3.5 Maximum Transmission Unit…………....... 12

2.2.3.6 Handover Latency……………..………….. 13

2.3 Type of Service……………………………………………….. 13

2.4 802.1p………………………………………………………… 14

2.5 ATM – ISSLOW……………………………………………… 14

2.6 MPLS…………………………………………………………. 15

2.6.1 MPLS Basic Operation……………………………… 16

2.6.2 MPLS and Traffic Engineering……………………... 17

2.6.3 MPLS CoS/QoS…………………………………….. 18

2.7 Integrated Services……………………………………………. 19

2.7.1 Integrated Services Model………………………….. 19

2.7.1.1 Packet Scheduler………………………….. 20

2.7.1.2 Packet Classifier…………………………... 21

2.7.1.3 Admission Control………………………… 21

2.7.1.4 Reservation Setup Protocol……………….. 21

2.7.2 RSVP Operation…………………………………….. 22

2.7.3 Intserv QoS Classes…………………………………. 23

2.8 Differentiated Services………………………………………... 24

2.8.1 Diffserv Architecture Model………………………... 25

2.8.2 Diffserv Domain…………………………………….. 25

2.8.3 Per Hop Behaviors………………………………….. 26

2.8.3.1 The Default PHB………………………….. 27

2.8.3.2 Class-Selector PHBs………………………. 27

2.8.3.3 Expedited Forwarding PHB……………….. 27

2.8.3.4 Assured Forwarding PHB…………………. 28

2.8.4 Traffic Classification and Conditioning…………….. 29

2.8.4.1 Traffic Classifiers…………………………. 29

2.8.4.2 Traffic Conditioner………………………… 30

2.8.5 Bandwidth Broker…………………………………… 31

2.8.6 Diffserv Field Definition……………………………. 32

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2.9 MPLS and Diffserv…………………………..………………. 33

2.10 Marking Schemes…………………………..………………… 33

2.10.1 Leaky and Token Bucket Algorithm…………..…… 34

2.10.2 Single Rate Three Color Marker………..………….. 35

2.10.3 Two Rate Three Color Marker………………..……. 38

2.10.4 Time Sliding Window Three Color Marker……..…. 40

2.11 Summary…………………………………………………….. 44

CHAPTER 3: MOBILE INTERNET PROTOCOL

3.1 Introduction……………………………………………………. 45

3.2 Mobile IP – An Overview…………………………………….. 46

3.3 Mobile IPv6…………………………………………………… 46

3.3.1 Requirements, Goals and Applications……………… 46

3.3.2 Basic Operation……………………………………… 47

3.3.3 Binding Update Option……………………………… 48

3.3.4 Mobile Node Operation……………………………… 49

3.3.4.1 Sending Binding Updates………………….. 49

3.3.4.2 Movement Detection………………………. 50

3.3.4.3 Smooth Handoff with Overlapping Cells….. 51

3.3.5 Renumbering the Home Subnet……………………… 52

3.3.6 Correspondent Node Operation……………………… 52

3.3.6.1 Delivering Packets to a Mobile Node……… 52

3.3.7 Home Agent Operation………………………………. 53

3.3.7.1 Delivering Packets to a Mobile Node……… 53

3.3.7.2 Proxy Neighbor Advertisements…………… 54

3.3.8 Home Agent Discovery……………………………… 54

3.4 Comparison between MIPv6 and MIPv4……………………… 55

3.5 Summary………………………………………………………. 56

CHAPTER 4: IMPROVING QoS IN MIPv6 USING FAST HANDOVER

4.1 Introduction……………………………………………………. 57

4.2 Protocol Overview…………………………………………….. 57

4.2.1 Handover Initiation………………………………….. 58

xii

4.2.1.1 Network Initiated Handover………………. 58

4.2.1.2 Mobile Initiated Handover………………… 58

4.2.2 Tunnel Establishment………………………………... 58

4.2.3 Packet Forwarding…………………………………… 59

4.3 Protocol Details………………………………………………... 59

4.3.1 Detailed Description………………………………… 59

4.3.2 Stateless NCoA Configuration……………………… 61

4.3.3 Stateful NCoA Configuration……………………….. 62

4.3.4 Stateless vs Stateful NCoA Configuration…………... 63

4.4 Summary………………………………………………………. 64

CHAPTER 5: NS-2 AND SIMULATION SETUP

5.1 Introduction……………………………………………………. 65

5.2 Network Simulator version 2………………………………….. 65

5.2.1 The Architecture…………………………………….. 66

5.2.2 MIPv6 Extension – Mobiwan……………………….. 67

5.2.3 Fast Handover Implementation in NS2……………… 68

5.3 Simulation Setup………………………………………………. 69

5.3.1 Scenario #1……………………………………………69

5.3.2 Scenario #2………………………………………...… 73

5.3.3 TCL Codes…………………………………………… 75

5.3.4 Assumptions…………………………………………. 76

5.4 Summary……………………………………………………….. 77

CHAPTER 6: RESULTS AND DISCUSSION

6.1Introduction……………………………………………………. 78

6.2Handover Latency Study………………………………………. 78

6.2.1 Handover Latency…………………………………… 78

6.2.1.1 Scenario #1………………………………… 79

6.2.1.2 Scenario #2………………………………… 79

6.2.2 Packet Losses………………………………………… 80

6.2.2.1 Scenario #1………………………………… 80

6.2.2.2 Scenario #2………………………………… 85

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6.3 Scenario #1 vs Scenario #2………………………………….…. 89

6.4 Scenario #1 With Different Seeds……………… ………….…. 89

6.5 Assumptions Revisited………………………………………… 90

CHAPTER 7: CONCLUSION AND FUTURE WORKS

7.1 Conclusion…………………………………………………….. 93

7.2 Future Works………………………………………………….. 94

Bibliography………………………………………………………............. 95 Appendix A: IEEE 802.1Q/802.1p Tag Frame Format…………...………. 98 Appendix B: Overview of IPv6…………..……………………………….. 99 Appendix C: Mobile IP Terminologies………………………..………….. 101 Appendix D: Simulation Code……………………………………………. 104 Appendix E: Utility Program……………………………………..………. 113 Appendix F: Fast Handover Protocol Implementation…………………..... 115 Appendix G: Sample Trace File………….………………….……………. 116

xiv

LIST OF FIGURES Figure Page 1.1 – Handover…………………………………………………………… 5 2.1 – Basic Operation of MPLS Network………………………….……. 17 2.2 – Intserv Router Reference Model…………………………………… 20 2.3 – RSVP Data Flow…………………………………………………… 23 2.4 – Traffic Classifier and Conditioner………………………………….. 31 2.5 – Diffserv Domain and Bandwidth Brokers………………………….. 32 2.6 – Diffserv Field Structure…………………………………………….. 32 2.7 – IPv4 and IPv6 Octet Comparison ………………………………….. 33 2.8 – Block Diagram for srTCM and trTCM………………………….….. 35 2.9 – srTCW in Color-Blind Mode……………………………………….. 37 2.10 – srTCW in Color-Aware Mode…………………………………….. 37 2.11 – trTCM in Color-Blind Mode………………………………………. 39 2.12 – trTCM in Color-Aware Mode……………………………………… 39 2.13 – Block diagram for tswTCM……………………..………………… 40 2.14 – Example Rate Estimator Algorithm………………..……………… 41 2.15 – tswTCM Marking Algorithm(1)...…………………..…………….. 42 2.16 – tswTCM Marking Algorithm(2)……………………..……………. 43 3.1 – Components in Mobile IPv6……………………………..…………. 55 4.1 – Fast Handover Protocol Messages – Stateless NCoA Configuration……………….…………………….. 63 4.2 – Fast Handover Protocol Messages – Statelful NCoA Configuration………………………………………. 64

xv

5.1 – Links between TCL, OTCL and C++ Objects……………..………. 66 5.2 – Fast Handover implementation……………………………..……… 68 5.3 – Schematic diagram of simulation setup for scenario #1………….... 69 5.4 – Hierarchical node addresses for scenario #1..……………………… 70 5.5 – Base-station positions………………………………………………. 72 5.6 – Schematic diagram of simulation setup for scenario #2…………….. 73 5.7 – Hierarchical node addresses for scenario #2..………………….…… 74 6.1 – Handover – Scenario #1…………………………………………….. 86 6.2 – Handover – Scenario #2…………………………………………….. 86 6.3 – Packets condition without FH – Scenario #1……………………….. 87 6.4 – Packets condition with FH – Scenario #1…………………………… 87 6.5 – Packets condition without FH – Scenario #2……………………….. 88 6.6 – Packets condition with FH – Scenario #2…………………………… 88 A.1 – 802.1p/802.1Q Tagged Frame Format……………………………… 98 B.1 – IPv6 and IPv4 Header Comparison…………………………………. 100

xvi

LIST OF TABLES Table Page 1.1 – Recommendations by [Xavi02]…………………………………… 4 2.1 – DiffServ AF Codepoint Table…………………………………….. 29 5.1 – Simulation setup summary for Scenario #1.…………………….… 71 5.2 – Simulation setup summary for Scenario #2.…………………….… 75 6.1 – Handover details without FH – Scenario#1.…………………….… 81 6.2 – Handover details with FH – Scenario #1…………………….……. 82 6.3 – Handover details without FH – Scenario#2.……………..………… 83 6.4 – Handover details with FH – Scenario #2………………….………. 84 6.5 – Dropped Packets for Scenario#1..………………………………… 85 6.6 – Dropped Packets for Scenario#2..………………………………… 85 6.7 – Handover details without FH – Scenario#1.2.………………..…… 91 6.8 – Handover details with FH – Scenario #1.2………………….……. 91 6.9 – Handover details without FH – Scenario#1.3.………….………… 92 6.10 – Handover details with FH – Scenario #1.3………………..………. 92

1

CHAPTER 1

INTRODUCTION

1.1 Introduction

The invention of notebooks, personal digital assistants (PDAs), mobile phones and

various mobile devices have made mobile computing inevitable. The TCP/IP protocol

suite allows heterogeneous computer systems to seamlessly communicate with each

other. It is likely to find an Internet Protocol (IP) based network anywhere. It forms

the basis of Internet, a wide area network of millions of computers that literally span

the globe [Sofw]. The network is growing so rapidly that many issues such as the

shortage of IP address space has been introduced. The IP version 6 (IPv6) is

introduced to solve the problem of the shortage of IP address space. IPv6 can provide

up to 2218 or 340282366920938463463374607431768211456 IP addresses [Uore].

The abundance of IPv6 addresses facilitates the IP address assignment for mobile

devices and thus can boost mobility in an IP based network environment.

Mobile IPv4 (MIPv4) and recently Mobile IPv6 (MIPv6) have been proposed so that

mobile devices can still attach to the Internet without losing their mobility. However

the quality of service (QoS) to these mobile devices has always been a challenge.

Researchers in IP mobility and QoS are continuously looking for ways of

improvement. This thesis deals with one such QoS parameter in mobile environment,

which is handover latency.

2

1.2 Literature Review

In [Post81] the author has proposed IP, which is known as IP version 4 (IPv4)

nowadays. This protocol was specifically limited in scope to provide the functions

necessary to deliver package of bits from a source to a destination over an

interconnected system of networks. The main objective or motivation behind IPv4 was

to route packets in a wired communication network. The idea of mobile IP (MIP)

came much later as more and more mobile devices were built. This in turn was due to

improvement in mobile communication, which enabled higher data transmission rates

over the air. However, standard IPv4 was unable to address this mobility requirement

since it assumes that a node's IP address uniquely identifies the node's point of

attachment to the Internet [Perk96]. Thus, a mechanism was required to enable Mobile

Nodes (MN) or devices to be still attached to the network while moving.

This requirement was addressed in [Perk96], thus introducing MIP. Several new

terminologies such as care-of-address (CoA), home agent (HA), foreign agent (FA)

and etc were introduced in this RFC. Fundamentally, the idea is to assign a new

address to MN i.e. CoA, while retaining its home address. The packets addressed to

MN will be picked-up by HA and tunneled to MN’s CoA via the FA.

As indicated in Introduction, IPv4 is becoming scarce very fast. IP version 6 (IPv6)

was primarily introduced to address this problem. In addition, IPv6 also comes with

many other features, which is also required for IP mobility. The changes between IPv4

and IPv6 basically fall into the following categories [Deer98]:

3

• Expanded addressing capabilities

• Simplified header format

• Improved support for extensions and options

• Flow labeling capability

• Authentication and privacy capabilities

Some of the improvements or new features in Mobile IPv6 (MIPv6) compared to

MIPv4 are such as movement detection, route optimization, mobility header, address

auto-reconfiguration and etc [Perk03].

However studies in QoS in mobile environment has only been looked at in recent

years. This may be a natural process where by the building blocks need to be layed

before moving into QoS. One such paper is “Fast Handovers for Mobile IPv6” by

Rajeev Koodli from Internet Engineering Task Force (IETF) [Raje03]. In this paper

the author has suggested introduction of additional signaling messages between

mobile nodes and access routers known as “Fast Handover Protocol”. The handover

latency is expected to improve with the implementation of this protocol. This paper

discusses how to allow a mobile node (MN) to send packets as soon as it detects a

new link, and how to deliver packets to a MN as soon as its presence is detected by

the MN's new access router (AR). The solution allows a MN to keep using its Care of

Address (CoA) until it establishes itself as a Mobile IP end-point on its new AR. This

paper has been used as the basis of this thesis.

One other interesting paper [Xavi02], has investigated handover latency in different

types of MIPv6 implementation such as basic MIPv6, Fast MIPv6 (FMIPv6) and

Hierarchical MIPv6 (HMIPv6). The study was analytical in approach and simulations

4

were not performed. The study suggests that HMIPv6 and anticipated FMIPv6

outperforms basic MIPv6 during handover. However if only one option between

HMIPv6 and anticipated FMIPv6 should be implemented, then the best option

considering handover latency and packet losses would be anticipated FMIPv6. Using

both together will definitely outperform in terms of handover latency compared to

implementing one of them alone. Table 1.1 summarizes the previous

recommendations:

HMIPv6 +

FMIPv6

Anticipated FMIPv6

HMIPv6

Final recommendation

1 2 3

Table 1.1: Recommendation by [Xavi02]

1.3 Thesis Statement and Objective

Access routers (AR) which are in turn connected to base stations (BS) provides

connectivity to Mobile Node (MN). As the MN, which is connected to the Internet,

moves freely from one location to another, its connection to ARs also change from

one to the other in order to maintain connectivity. This process where MN changes

AR for another is referred to as handover as shown in Figure 1.1. During this process,

there is a time period when the MN is unable to send or receive IP packets both due to

link switching delay and IP protocol operations. This time period is known as

handover latency. Thus handover latency is the time between the last moment where

the MN can receive and send packets through the previous AR (PAR) and the first

moment where it can receive and send packets through the new AR (NAR).

5

This Quality of Service (QoS) parameter may be improved (minimized) by

introducing a set of new signaling messages between MN and ARs, which will

establish a tunnel between the ARs. Thus packets arriving at PAR may then be

forwarded to the NAR through this tunnel. The objective of this thesis is then to study

the benefit of implementing this protocol.

!Pv6 Network

NAR HA

MN

Movement

PAR

Home SubnetNew Visited Subnet

Old Visited Subnet

Figure 1.1: Handover

1.4 Scope of Work

The scope of work of this thesis is to simulate fast handover in MIPv6 environment,

analysis and presentation of the results.

1.5 Thesis Structure

Chapter One gives a general statement and describes the problem statement or the

thesis statement. This chapter also gives overview of the rest of the chapters.

6

Chapter Two attempts to describe QoS parameters in communication networks and

why it has become an important discussion topic in the Internet community today.

Many models have been suggested recently to give a better QoS to end-users. These

models are dealt with in this chapter. One of the QoS factor in mobile communication

is handover latency. Since this thesis is on handover latency in mobile

communication, Chapter Three explains in detail about Mobile IP (MIP) version 4

and version 6. The following chapter, Chapter Four, describes in detail what ‘Fast

Handover’, i.e. the protocol used to improve handover latency, means. The study of

the handover latency is done by simulation using Network Simulator version 2 (NS2).

The scenarios and simulation setup is detailed in Chapter Five. The results obtained

from these simulations are presented and discussed in Chapter Six. Finally, Chapter

Seven concludes the finding of this Thesis and proposes future exploration.