improvements to better · · 2014-10-28such as ericsson .co and by high degree researches in...

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Improvements to Better Handoff Latency in Mobile IP

Amar Adel Khorshid BSc Computer Science

Session (2008/2009)

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Summary

As Mobile IP has recently occupying a big gap in the networking filed, where the

concept behind the idea is to maintain the same IP address within multiple networks. The

mobile IP protocol is still under investigation by many telecommunication companies and

researches, in particular the handoff latency generated by the Mobile IP protocol is high and

further suggestions were given by many researches, however optimal level hasn’t yet

achieved.

Overlapping the domains in the mobile IP network has shown faster handoff within

the network. However less throughput and more packets loss average were discovered by

the network during the handoff. It is the intended that this project will look to ascertain why

non-overlapping the domains within the network, can be a suitable solution to the mobile IP

network during the handoff rather than having overlapped domains.

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Acknowledgments

First of all, I would like to thank my supervisor Martine Dyer, for his help, supports and

guidance during this project. He was always tracking my progress and informing me with

many advises. I also would like to thank my assessor Jie Xu, who gave me the idea of

including the mathematical analysis which token the project to a more annalistic level.

Thanks must also go to my friends who were supporting me with documents related to the

subject.

A special thanks to my father Adel Khorshid who was always advising me when

things seems to be complicated for me. I also thank him as he offered me with

the opportunity of being a student in the school of computing at Leeds

University.

Finally I’d like to dedicate this project to the memory of Husam Nasher.

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List of Acronyms

In this report, the following acronyms are used.

• UDP - User Datagram Protocol

• TCP - Transmission Control Protocol

• FTP - File Transfer Protocol

• IP - Internet Protocol

• IPv4 - Internet Protocol version 4

• MIPv4 - Mobile Internet Protocol version 4

• HA - Home Agent

• MH - Mobile Host

• MN - Mobile Node

• CN - Correspondent Node

• QoS - Quality of Service

• ICMP - Internet Control Message Protocol

• MAC - Media Access Control

• ACK – Acknowledgment

• HMIP - Hierarchal Mobile IP routing Protocol

• RTT - Rounding Trip Time

• RTO - Retransmission Timeout

• BU - Binding Update (message)

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Contents

1. Introduction & Background Research 1.1. Introduction ...................................................................................................... 1 1.2. Aims.................................................................................................................. 3 1.3. The Objectives................................................................................................... 4 1.4. Minimum Requirements ................................................................................... 4 1.5. Schedule and Report Progress .......................................................................... 5 1.6. Background Research ....................................................................................... 7

1.6.1. Overview .............................................................................................. 7 1.6.2. Mobile IP Architecture ......................................................................... 7

1.6.2.1. Mobile Node ............................................................................. 7 1.6.2.2. Home Agent ..............................................................................7 1.6.2.3. The Foreign Agent ................................................................... 7 1.6.2.4. Correspondent Node ................................................................ 7

1.6.3. Care-of-Address (CoA) ........................................................................ 8 1.6.3.1. Discovering the Care-of-address .............................................. 8 1.6.3.2. Registering the Care-of Address .............................................. 9

1.6.4. Tunnelling .......................................................................................... 10 1.6.5. Micro Mobility ................................................................................... 11 1.6.6. Triangle Routing Problem .................................................................. 11 1.6.7. Route Optimization ............................................................................ 12

2. Topology Design

2.1. Overview ........................................................................................................ 13 2.2. Designing the Topology ................................................................................. 13

2.2.1. Setting the Hierarchical Routing ........................................................ 14 2.2.2. Setting Hierarchal Addresses ............................................................. 15 2.2.3. Create links Between Wired AND Wireless Nodes ........................... 15 2.2.4. Setup TCP Connections Between a Wired Node and The Mobile

Hosts.................................................................................................... 15 2.2.5. Mobile Nodes Movement in the Network .......................................... 16

3. The Overlapped-Domains Model

3.1. Overview ........................................................................................................ 17 3.2. Setting the Optimal Overlapping Area distance ............................................. 18

3.2.1. Throughput Calculation ...................................................................... 18

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3.2.2. Packet Loss Calculation ..................................................................... 19 3.2.3. Results and Explanations ................................................................... 19

3.3. 100-Overlapping Analysis Over MN Speeds ................................................. 20 3.3.1. 100-Overlapping Throughput Calculation ......................................... 20

3.3.1.1. Results and Explanations ...................................................... 22 3.3.2. 100-Overlapping Packet Loss Calculation ......................................... 23

3.4. Overlapping Region; Handover and Collision Events Analysis .................... 25 3.4.1. Case (1) .............................................................................................. 26 3.4.2. Case (2) .............................................................................................. 27 3.4.3. Case(3) ............................................................................................... 27 3.4.4. Case(4) ............................................................................................... 28 3.4.5. Case(5) ............................................................................................... 29 3.4.6. Case(6) ............................................................................................... 29

3.5. Collision Proof With NS-2 ............................................................................. 30 3.5.1. The Network Behaviour When W = 3/sec .......................................... 31 3.5.2. The Network Behaviour When W = 20/sec ........................................ 32 3.5.3. Discussion and Further Analysis ........................................................ 33

4. The Non-Overlapped-Domains Model

4.1. Overview ........................................................................................................ 34 4.2. Non-Overlapping Throughput Calculation .................................................... 34

4.2.1. Results and Explanations (1) .............................................................. 35 4.2.2. Results and Explanations (2) .............................................................. 36

4.3. Non-Overlapping Packet Loss Calculation .................................................... 38 4.4. Non-Overlapping Region Analysis ................................................................ 39

4.4.1. Case (1) .............................................................................................. 40 4.4.2. Case (2) .............................................................................................. 41 4.4.3. Case (3) .............................................................................................. 41

5. Delay Time

5.1. Overview ....................................................................................................... 42 5.2. End-To-End Delay In the Overlapping area ................................................. 42 5.3. End-To-End Delay For TCP Connections .................................................... 43

6. Evaluation and Conclusion

6.1. Evaluating the Project Accuracy .................................................................... 45 6.2. Evaluating the Experiments Results .............................................................. 46 6.3. Comparison With Previous Work .................................................................. 49 6.4. Conclusion ..................................................................................................... 51

Student: Amar Adel Khorshid Supervisor: Martin Dyer

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Section 1 Introduction & Background Research

1.1. Introduction

This document addresses issues regarding Mobile IP and how it can allow users to keep the

same IP address, stay connected, and maintain ongoing applications while roaming between

IP networks, this documentation aims to give a clear description of how Mobile IP was

created to enable users to keep the same IP address while travelling to a different network

without causing the connection to be lost during the handoff procedure.

Handoff in one side is representing the major IP network problem, these is due to the

protocol known as the Mobile IP Protocol (i.e. MIP) designed to proceed such a process,

which conceptually relay on an algorithm called Triangle Routing, where destined packets

take a long path in order to reach their final destination and delay time is increased.

Within Mobile IP network, cells are routing packets to other devices in the network in two

ways either via wired communication or wirelessly. With wireless communication, casting

distance is represented in domains (i.e. zones), thereby each cell has its own casting

domain. Domains with any large network can be designed in one of two model

architectures. The first one intending to overlap domains in the network and called

overlapped-domains model, the second one leaving the network domains independent from

each other, hence called non-overlapped-domains model.

Overlapping the domains has been adopted according to enable fast handoff (i.e. handover),

while on the other hand issues emerged with this concept and reasons behind that left blank

by many researches. One might ask “Would overlapping domains can be developed as to

propose a new handoff schema?”. Others might ask the same question but in different

manner, “What actually cause the high packet loss during the handoff when domains are

overlapped and is there any other model which can be adopted instead?”.


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Nevertheless, the inferences resulted by the researches in the telecommunication companies

such as Ericsson .co and by high degree researches in telecommunication engineering and

computer sciences degrees have lead to suspicion arguments and left so many questions

overhead.

During the investigation of the current telecommunication computerised system, I’ve been

informed by people such as the head of engineering department at Orange co. in Uganda

MR. Ezat Radman and the head of the maintenance department in MTN-YEMEN co. MR Hani

Al-Dubai. That, “in terms of loss in the network, non-overlapping domains within the current

2G and 3G networks are performing better than those when domains are overlapped”, but

reasons left blank again!!.

The subject area started to attract my attention and discovering the Mobile IP protocol

scientifically was related to my computer degree. Therefore this project is aiming to tackle

the problem generated in the overlapping area between the network domains, however the

problem has first to be observed. Thereby, research has to be planned with quality, and

investigating the network layer protocols have to be addressed.

Starting with Section (1), the main components of mobile IP networks will be described

along with their purpose and effectiveness in Mobile networks. Diagrams provided in this

documentation have not been copied from an internet resource as I thought it would be

more helpful if I can create my own diagrams after researching information from multiple

resources. Description of the Care-of-address importance is addressed as well as the

operations involved such as Discovering the care-of-address, Registering the Care-of

Address, Secure Mobile IP registration, Automatic home agent discovery and Tunneling

processes with related issues.

Second section will describes how the Topology is built, it will provide some core and

technical information about the topology’s components and how they have been placed in

order to take the final shape of the proposed network. It includes information such as;

Setting the hierarchical routing, creating the topology objects, setting positions for wireless

nodes and creating movements of the Mobile Hosts.


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In section (3), the real challenge will be started where technical problems are to be

discovered. In particular, the reason behind the high handoff latency when domains are

overlapped. The Network Simulator NS-2 is the proposed tool to obtain my experiments

along with AWK scripts to be used as an appropriate measurement tools to gather

information generated by NS-2. This section will be divided into three parts; the first part

will test the MIP with different overlapping area distances and chose the best one

accordingly as to be used with the next sections. These will be done in a small network

topology for accuracy purposes.

Part two will contains further experiments as to illustrate the impact of the transmission

quality when the overlapped area between wireless nodes changes in addition to the mobile

nodes speed. These will be tested on a more realistic topology mentioned in section [2].

Part three from section [3] will relay upon a second analysis methodology. Mathematical

analysis will be adopted as to prove the investigated assumptions inherited in part two.

Thereby the problem will be known and further efforts will be planned to produce a solution

to this problems.

Similar to section [3], section [4] will show the proposed solution as to solve or at least to

reduce the high latency and packet loss being disqualifying the MIP network performance

when domains are overlapped. Thus, the non-overlapping-domains model will be adopted

and further observation will be made according to mobile nodes speeds and non-overlapping

area distances. In addition, the solution will be analyzed mathematically in the next part of

this section, whereby comparison between the two models will be easier during the

evaluation part of this project. Section [5], will show the delay time routing in the MIPv4.

Finally, the evaluation part will be documented in section [6]. This section will covers three

evaluations sides as; 1- To evaluate the accuracy of the project, 2- To evaluate the solution

and what are the disadvantages and what can be done in order to give better results within

the MIP network and 3- To evaluate the project according to some other researches papers

available in the literature and what kind of struggles I’ve faced during the project phases.

1.2 Aim

The aim of this project is to evaluate the performance of the Mobile IP network and reduce

the handover latency in the overlapped area between base stations within the network.


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1.3 The objectives

The objectives of the project are to:

• Understanding of how the mobile IP protocol works and what other external processes

involved.

• Understand the performance of the Mobile IP network with overlapped areas between

network domains.

• Understand the performances of each possible situation that designed to handle the

handover situation in the Mobile IP network.

• Understand about the network simulations and which simulator application is appropriate

for this Project.

• Understand how to use ns-2 as to build the network and evaluate the performance of the

Mobile IP network in several cases.

• Investigate the reason behind the high handoff latency in the overlapped-domains model.

• Evaluate the new performance of the network according to the overlap and non-overlap

cases.

1.4 Minimum requirements

• Point to the necessarily improvement to reduce the handoff latency.

• Improvement in TCL-C++ based programming skills.

• Develop skills in the network simulation field with ns-2.

• Build a small network to be examined with ns-2 over different scenarios.

The possible extensions are:

• Develop scenarios to be run over different models.

• Develop scenarios with different values for the Mobile node speed and overlapping area

distance and select the best performance between them.

• Build scenarios to reduce the problems obtained in the overlapping area during handoff.

• Point to time delay generated by the routers in the Mobile IP network.


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1.5 Schedule and report progress

Technical Part

1.5.1 Background Research phase

This phase will contain the information needed to illustrate the understanding of the topic

and the problem to be talked. This phase assumed to take 5 weeks, starting from week 4 of

the 1st semester and finished by week 9 of the first semester.

In reality this phase has been obtained as planned where general research in the

subject has been reported. In particular an overview about the problem has been

generated.

1.5.2 Technical Requirements and Building the Topology

This phase considered to be the hardest phase, as I should be very accurate when building

the topology as well as it will take a bit of time for training on the applications that to be

used in order to obtain my network simulations (e.g. ns-2 and AWK). This phase will be

started on the 12th/Dec and stopped in the 30th/Dec until 23rd/Jan, for exam revision and

4- Evaluation 3- Generate the Solution

2- Technical

Requireme

1-Background Research


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training on the applications. On the 23rd Jan, It will be started again until week 3 of the 2nd

semester.

It is the case that problems within this phase are normally generated. Installation the

NS-2 was the issue, as I had to install it in vista via Cygwin and the lack of libraries in

Cygwin was disabling the smooth following of the intended plan. However the problem has

been overcame with 1 week delay, thereby I finished this phase week 4 of semester 2.

1.5.3 Generate the Solution

In this phase I am assuming to start evaluate the Mobile IP network with various scenarios

and chose the best one. This phase will starts by week 3 of the 2nd semester and completed

by week 7.

This phase has started in week 4 due to a delay happened in the previous phase.

However this phase has accomplished in the assumed period a long with the mathematical

analysis in each of the overlapping and non-overlapping domains models.

1.5.4 Evaluation

This phase will compare the new performance of the MIP network when handover situation

occurred- using the new best chosen model- with the old performance of the MIP network

when Overlap model was used. This phase will be started from week 4 (along with phase 3)

and stopped by week 9; taking into account that time will be short from week 8 because of

the exam revision.


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1.6 Background Research

1.6.1 Overview

In this section I am aiming to achieve the first two objectives of this project. This can be

done by investigating the Mobile IP architecture, what are the major ideas behind the

literature and what are the important protocols that been used as-in to maintain the

network operated and acceptable.

1.6.2 Mobile IP architecture

1.6.2.1 Mobile node

Mobile node is a device whose software enables mobility. Mobile IP supports mobility by

binding the home address of the mobile node with its care-of address.[20]

1.6.2.2 Home agent

The Home Agent is a router in the home network of the mobile node, packets are sent from

a Correspondent Node to the Mobile Node, and this procedure is done by establishing a

tunnel between the home agent router and the moving node in a foreign agent.

The home agent support a mobility binding table, the binding table identifies each mobile

node by the home address, temporary care-of address and association lifetime.[11, 20]

1.6.2.3 The Foreign agent

The Foreign Agent is the agent where the mobile node is attached to it when it roams out of

its Home Agent network. The Foreign Agent will be operated as to transfer data packets

from the Home Agent to the Mobile Node after attaching a care-of-address to the mobile

node. This care-of address will be added to the visitor list information table in the foreign

agent and in the binding table in the home agent.[20]

The visitor list in the Foreign Agent identifies each mobile node by the home address,

temporary care-of address, association lifetime and media address.

1.6.2.4 Correspondent node


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Foreign network

A node which is responsible to communicate with the mobile node in order to send the data

packets from the internet to the mobile node, a correspondent node can be either mobile or

stationary.[20]

Visiting foreign network Attached to the home agent

Figure (1.1.1) ; Mobile IP components with a mobile binding table and a visitor list.

1.6.3 Care-of-address

When the mobile node start to enter a new foreign agent domain it obtains a new

temporary care-of-address that’s to identify the mobile node current position of attachment

to as well as it allows the mobile node to be reached from different locations. The care-of-

address should change at each new point of attachment while the home agent IP address

remains the same.

[21]

1.6.3.1 Discovering the care-of-address

ICMP Routers are used to broadcast agent advertisement of the Home Agent and the

Foreign Agent, the mobile node listens to the advertisements to determine whether it is on

its home network or on a foreign network, if the mobile node has detected that it is in its

home agent it operates without mobility otherwise it obtains a care-of address on the

foreign network. If advertisements are no longer detectable from a foreign agent that

previously had offered a care-of address to the mobile node, the mobile node should

Mobile Node

Router (Foreign agent)

Router (Home agent)

Mobile Node

Home address care-of Address life time 131.163.121.4 225.172.23.87 100 sec 131.193.171.2 119.123.56.79 100 sec

Home network

Home address care-of Address Media address life time 131.163.121.4 225.172.23.87 00-60-08-95-66-E1 100 sec 131.193.171.2 119.123.56.79 00-60-08-68-A2-S6 100 sec

Correspondent node


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5- Update Visitor list

Foreign network

1- Send registration request

2- Send registration request

3- Update binding table.

4- Confirm registration

presume that foreign agent is no longer within range of the mobile node's network interface.

In this situation, the mobile node should begin to hunt for a new care-of address, or

possibly use a care-of address known from advertisements it is still receiving. The mobile

node may choose to wait for another advertisement if it has not received any recently

advertised care-of addresses, or it may send an agent solicitation as to inform its presence

to a foreign agent on the foreign network. [21]

1.6.3.2 Registering the Care-of Address

As shown in (figure: 1.1.2), when the mobile node start to move away from its home agent,

it registers with the foreign agent by sending a registration request message, this message

includes 2 addresses; 1- The permanent IP address of the mobile host and 2. IP address of

its home agent.

When the foreign agent receives the request from the mobile node and will send a message

request to the mobile home agent along with; the permanent IP address of the mobile node

and its IP address. After receiving the Registration Request by the home agent, it updates

its binding table by adding the care-of address of the mobile node with its home address,

the home agent then sends an acknowledgement massage to the foreign agent which in

turn updates its visitor list. [21]

Figure (1.1.2) ; The registration process between the Mobile IP Agents

Mobile Node


Router (Home agent)


Home network

Home address care-of Address Media address life time 192.168.122.8 131.198.32.77 00-63-43-55-S6-M1 80 sec 192.168.778.5 111.133.88.88 00-44-A8-55-A1-F7 80 sec


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1.6.4 Tunnelling

Process of encapsulating an IP packet within another IP packet in order of routing it to a

location other than the one specified in the original destination field, is called tunnelling.

When the Mobil Node sends a packet while it is operating on a foreign network, the packet

will be destined first to the foreign agent before it reaches the desired destination, where

then the foreign agent will farrowed the packet to the correspondent node.

On the reverse case, where the correspondent node wants to communicate with the mobile

node; the correspondent node will send an IP packet to the permanent IP address of the

mobile node, the mobile’s home agent receives the packet and checks the binding table to

find whether the mobile node is roaming on another foreign agent or at the home agent. If

the mobile agent is on another foreign agent, the home agent will finds out the mobile

node’s care-of address and constructs a new IP header that contains the mobile node’s care-

of address as the destination IP address. The original IP packet is put into the payload of

this IP packet. It then sends the packet. This process of encapsulating one IP packet into

the payload of another is known as IP-within-IP encapsulation, or Tunneling.

When the encapsulated packet reaches the mobile node’s current network, the foreign agent

will encapsulate the packet and finds out the mobile node’s home address stored on the

payload. It then searches into the visitor list to see if it has an entry for that mobile node.

If there is an entry for the mobile node on the visitor list, the foreign agent retrieves the

corresponding media address and relays it to the mobile node. (see Figure: 1.1.3)

The default encapsulation mechanism that must be supported by all mobility agents using

Mobile IP is IP-within-IP.

Using IP-within-IP, the home agent, the tunnel source, inserts a new IP header, or tunnel

header, in front of the IP header of any datagram addressed to the mobile node's home

address. The new tunnel header uses the mobile node's care-of address as the destination

IP address, or tunnel destination. The tunnel source IP address is the home agent, and the

tunnel header uses 4 as the higher level protocol number, indicating that the next protocol

header is again an IP header. In IP-within-IP the entire original IP header is preserved as

the first part of the payload of the tunnel header. Therefore, to recover the original packet,


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Find destination & Forward packet

Home network

Sending a packet to mobile node

Find the mobile nodes current point of attachment (5)

(7) Find the mobile node on the visitor list

the foreign agent merely has to eliminate the tunnel header and deliver the rest to the

mobile node. [12]

Foreign network

(2)

Encapsulating

Figure (1.1.3); Tunneling

1.6.5 Micro Mobility

Micro Mobility solutions aim to have a low latency handoff mechanisms for delay-sensitive or

real time applications, with low to zero packet loss and to ensure that registration signalling

is kept to a minimum. Several solutions have been proposed, one of these solution is

Cellular IP approach. The Cellular IP is a proposal to the IETF made by researchers from

Colombia University and Ericsson. The proposed supports fast handoff and paging

techniques. Cellular IP combines the capability of cellular networks to provide smooth fast

handoff and efficient location management of active and idle mobile users with the internet

flexibility, robustness and scalability found in IP network. [2, 29]

1.6.6 Triangle routing problem

As shown in figure 1.1.4, triangle routing a mobile node is enabled to send a packet to the

correspondent node directly, routed by the foreign agent where the mobile node is currently

visiting .However, packets sent from the correspondent node to the mobile node have to be

routed through three different sub-networks; The correspondent node subnet, the home

(1) Send packet

Mobile node


Correspondent

node

Router (Home agent)

Packet header Packet payload

Destination IP address “Care-of-address”

Permanent IP address of the mobile node

Dencapsulates

(3)

(4)

(6)

(8)

Home address care-of Address Media address life time 192.168.122.8 131.198.32.77 00-63-43-55-S6-M1 80 sec 192.168.778.5 111.133.88.88 00-44-A8-55-A1-F7 80 sec


IP within IP Packet


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Home network

Correspondent node network

Correspondent node network

agent’s subnet and the foreign agent where the mobile node is currently visiting. Therefore

packets destined to the mobile node take long path in order to reach their final destination.

Route optimization” has been proposed to address this problem. [3, 16]

Figure (1.1.4); Triangle routing

1.6.7 Route optimization

Route optimization addresses this problem by requiring all hosts to maintain a binding cache

containing the care-of address of mobile nodes. The binding cache is a cache of mobility

bindings of mobile nodes, maintained by a node to be used in Tunneling packets to Mobile

nodes. When sending an IP datagram to a mobile node, if the sender has a binding cache

entry for the destination mobile node, it may tunnel the datagram directly to the care-of

address indicated in the cached mobility binding. In the absence of any binding cache entry,

datagram destined for a mobile node will be routed to the mobile node's home network in

the same way as any other IP datagram -triangle routing.

Route optimization extension to mobile IP includes four messages: binding update, binding

warning, binding request, and binding acknowledgment. [10]

Figure 1.1.5; Routing optimization.

(2. Receive)

(4. Forward packet to mobile node)

Foreign network

Correspondent node

Router (Home agent)

(1.send

(3. Reply back to Mobile

(5. Receive)


Mobile node

Binding update

Foreign network


Mobile node Binding

acknowledgment

Correspondent node


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Section 2

Topology Design

2.1 Overview

In designing the topology to assess the performance of the network in the MIPv4, as to be

used in the next sections when evaluating the network with the overlapped-domains model

and the non-overlapped-domains model. It is necessary to ascertain what research has been

done in this area to not only understand the problem, but to also design suitable

experiments that will build on the existing work. The basic information on how to build a

Mobile IP topology in ns-2 is retrieved by [26].

2.2 Designing the Topology

In this part we regarding to the strategy when design MIP topology that should be followed

as to reflect precise results within the predicate experiments. Hierarchal Mobile IP (HMIP)

topology was adopted relating to the beneficial organised structure it uses in the routing

process. HMIP has been used as the formal design by [6, 2] when discovering the MIP

network behaviour. According to [1], HMIP is the best solution for researches if they are

aiming to result in accurate data generated during the simulation of the network.


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Figure (2.1); the topology structure that to be used in this project As it can be seen form figure (2.1), the network contains two wired nodes, three home

agents, three foreign agents and three mobile nodes.

I have tried to avoid placing all the nodes horizontally in order to give it a more realistic

structure.

Note: If all the nodes were placed horizontally the experiment results will be repetitive.

2.2.1 Setting the hierarchical routing

First defining the number of domains, in this scenario it contains 7 domains divided between

nodes as follows;

The first domain contains two wired nodes (0,1,) and they are both placed in separate

clusters which make them two clusters in the same domain, the second domain contains

two nodes (HA,MH) placed in the same cluster, the third domain contains one node (FA) and

obviously it is only placed in one cluster, the fourth domain has the second foreign agent

Second domain

First domain

MH2

0

1

FA HA2

HA

FA1

MH

Third domain

Fourth domain Sixth domain

HA2

MH2

FA

Fifth domain

Seventh domain


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(FA1) put in one cluster, as well as the fifth domain which contain the third foreign agent

(FA2) , the sixth domain contains two nodes (HA1,MH1) placed in the same cluster, the

Seventh domain contains two nodes (HA2,MH2) placed in the same cluster. These details

were implemented for both scenarios (overlapping and non-overlapping), however the

distance between the topology domains are different, further sections will show the best

distances chosen.

2.2.2 Setting hierarchal addresses

Hierarchal addresses are divided in three sections the first section indicates the wireless

node, the second section indicates the wired node and the third section indicates the mobile

node. The reader is always advised to look at appendix [B] to be provided with more details.

e.g.:

[ 1 . 0 . 1 ]

2.2.3 Create links between wired AND wireless nodes

The links are used to create physical links between the wired and the agents nodes (home

agents & foreign agents).

A link from the wired node (0) to the wired node (1) is created then a link from the wired

node (1) to each of the home agent and foreign agent nodes is created, the reason is to

create paths between the correspondent node and the agents to allow data flow

transmission.

2.2.4 Setup TCP connections between a wired node and the Mobile Hosts

TCP connections are established between the wired node (0) which, works as a

correspondent node and the three mobile hosts in this scenario.

In the experiments I will observe how packets destined for the mobile hosts are re-directed

by their home agents and from the home agents to the foreign agents using the mobile IP

protocol (triangle routing).

Mobile node Wireless node

Wired node


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2.2.5 Mobile Nodes Movement in the network

To enhance best results I have tested the MIP network in different situations as follows;

• MH moving from their HA to next FA(s) and return back to their HA

• MH visiting only one FA and MH1 & MH2 visiting more

• In overlapping area between FA1 and FA2, MH1 and MH2 will obtain handoff in the

same time, this as to evaluate the time delay generated in this case.

• The simulation over, when all MHs are reaching back their HAs. Therefore simulation

time will be various according to the MHs speeds.

These as a result will test the network handoff in many cases such as HA-FA handoff, FA-FA

handoff and vies-versa, which in turn will give an insight of network simulations to those in

real word, because in reality MHs are moving in different manners.


17

Section 3

The Overlapped-Domains Model;

Technical and Mathematical Analysis

3.1 Overview

This section will provide technical details to show the high handoff latency performed within

the overlapping area. In more details experiments in this section will detect the handoff

performance according to two factors, the MNs movement speeds and the overlapping area

distances. NS-2 will be used to obtain the experiments using the topology designed and

explained in section [2] of the project.


18

0

500

1000

1500

2000

2500

3000

3500

4000

4500

50 m 70 m 100 m 120 m 170 m

Throughputs

Throughputs

3.2 Setting the optimal overlapping area distance

As to achieve accurate results when testing the mobile IP network, I’ve run the topology

with different overlapping area distances, and accordingly choosing the best performance

recorded. These as a result will enable me to base the next experiments upon the best

performance average that the MIP with inter-domain (overlapping) cells can achieve. The

network performance will be monitored according to the throughput values and the packet

loss average during the experiments. Simple topology will be used as to enhance accurate

size for the overlapping area. The topology can be seen in appendix [B].

3.2.1 Throughput calculation

The throughput was calculated with 30 m/s for the MN movement speed, the MN will start

moving from its HA after 4 seconds with 512 KB as a static packet size and 128 KB as a

maximum packet rate. As it can be shown from figure (3.1) the network throughput average

is 895.06KB when the overlapping area distance is 50 m, and 1172.56KB with 70 meter

overlapping area, resulting in a difference of 277.59KB as to be lost. The network will reach

its maximum throughput when the overlapping area distance is 100 meter with 3826.89KB

as the throughput value pointing to more than 70% of throughput increasing compared to

the throughput generated 70 meter overlapping area. With an overlapping area distance of

more than 100 meter the throughput will start to be decreased resulting on 38% and 78%

decrease when overlapping area distance is 120 and 170 respectively.

Figure (3.1); Shows the MIP throughput in KB according to multiple overlapping area

distances in meter


19

0.00%

1.00%

2.00%

3.00%

4.00%

5.00%

6.00%

50 m 70 m 100 m 120 m 170 m

Packets loss percentage

Packets loss percentage

3.2.2 Packet Loss calculation

Figure(3.2) illustrate the packets lost during the simulation.

As it can be notice the same conclusion is repeated, where packet loss percentage

is reaching its minimum value of 1.61% when the overlapping area distance is set

to 100 meter and more packets are dropped otherwise.

3.2.3 Results explanation

When the MN is starting to send a UDP request as to be attached with new domain, packets

will be sent to CN and wait until replay message is received, in order to achieve that, MN will

need to send the request while it’s in the overlapping area and not beyond the overlapping

area boundary as mentioned by [5, 6, 12, 15, 25, 31]. Additionally, tunnelling process will

continue its progress until MN starts receiving the first package from the new point of

attachment. However before doing so, the MN will need to acquire new IP address, i.e.

encapsulate its original IP address with a new COA, where on the other hand binding and

updating messages have to be received by the HA and the new FA before the MN gets out

of overlapping area to enhance fast handoff with less handoff latency as mentioned by [5,

25].


20

Therefore when the overlapping area is small more packets are elected to be lost. This is

because with UDP there will be no grantee of such a packet to be successfully delivered to

the proposed node, these however will yield in more UDP packets to be dropped. As well as

TCP packets are to be lost when the new FA is starting to send packets to the MN while MN

is not yet finalized the handoff process, producing a decrease in the network throughput,

such as in the case of 50m overlapping when compared to the 100m overlapping area

distances.

On the other side of the experiments, packets loss is increasing and throughput is

decreasing when the overlapping area distance is set to value more 100m. This case is

generated due to dual-coverage situation, where MN is still roaming in the overlapping area

between two agents, and CN will keep sending data to the MN in its previous agent where

the previous agent has no media connection to such a MN and therefore packets are

dropped and collided. Similar results have obtained in [14].

To conclude, 100-m for overlapping area distance is yielding in an efficient

performance when compared to the other scales and therefore are elected to be used.

3.3 100-Overlapping analysis over MN speeds

As it has been mentioned, 100 meter to be the distance for the overlapping area will reflect

the best performance that can be achieved by the network. Using a more realistic topology

(the topology in section [2]), this section will analysis the Mobile-IP network when 100-

overlapping area model is adopted. Mainly this section should evaluate the fact of having

multiple speeds to be under taken by the Mobile Nodes. Seven speeds will be given for the

Mobile Nodes which are 10 meter/Sec, 20 meter/Sec, 30 meter/Sec, 50 meter/Sec, 60

meter/Sec, 100 meter/Sec and 150 metre/Sec.

3.3.1 100-Overlapping throughput Calculation

Packet size is (512 Kbps), packets rate is (128 Kbps), the overlapping distance between all

nodes is set to 100 meters and TCP-based FTP connection is enabled to all the mobile hosts

in the following scenarios.


21

As it can be seen from figure (3.3) and table (3.1), in this experiment the throughput

rate is reduced as the mobile hosts (MHs) increase the speed of their movements. This is

because the mobile hosts will experience higher handover latency due to MHs having less

time to prepare for the handovers. Therefore, there is a higher possibility that the packets

are forwarded to the outdated path and are lost.

Figure (3.3); these figure summaries 7-experiments done by NS-2 to test the MIP network

throughput according to 7-various MHs speeds.

Table(3.1); Throughput results in MB

05

101520253035

10 (m/s) 20 (m/s) 30 (m/s) 50 (m/s) 60 (m/s) 100 (m/s) 150 (m/s)

Throughput Calculation Vs. MHs Speeds

Throughput

MH Speed Throughput(MB) 10 29.9732 20 14.4717 30 6.10617 50 4.51353 60 3.63719 100 1.65873 150 1.33322

Student

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22

nt throughp

nt throughp

3.5) the ma

all MHs are

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put values w

ut value wh

aximum thro

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oughput wh

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Martin Dyer

Speeds are

peeds are 1

hich yielded

(See the Bl

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10 m/s.

00 m/s.

d by the

ack


23

points in the graphs), then it starts to decrease until it reach the minimum value when MHs

are starting to move away from their Home Agents (See the Blue points in the graphs). The

green points illustrate the time when the MHs’ are starting to get back to their Home

Agents, these was concluded by running the experiments in the .nam files generated by ns-

2 during the simulations.

The sharp shrink in throughput actually resulted due to the fact where all the mobile

hosts are roaming in the HA&FA-overlapping area, which means that HA-FA handoff is

taking place at this time. HA-FA handoff will precisely acquire higher handoff latency in an

overlapping case when compared with the FA-FA handoff [1]. These in a point of fact will be

generated as the MHs in the case of HA-FA handoff will send BU (Binding Update message)

to the HA directly, where MH will need to send the BU to the CN in the case of otherwise as

addressed in [1, 19].

Therefore higher latency in the case of HA-FA handoff will result in less throughput value,

i.e. the Mobile IP protocol will only offer 2-way handshake communications (MH-HA and MH-

CN-FA), when such a handoff accrue [1], whereby the MH is facing HA-FA handoff this will

result in less data throughput. As well as when the MH is roaming inside its HA, the

communication between the MH and its HA will discard the need of MH-CN communication.

Where it’s necessary when the MHs in not in their HA, resulting in more stoical delay and

dropped packets, therefore less throughput within the network is highly possible.

On the other hand, the movement speed of the MHs will gradually decrease the

throughput pointer as time allocated to achieve the HA-FA handoff will not be enough when

the MH speed is high, as well as less TCP packets will be sent and not equally received due

to less time by the MHs to receive packets from a single agent. These can be shown by

table (3.1). The maxima throughput reached by the network was when the MH speed is

10m/s and the minimum was when the Mobile speed is 105 m/s, this fact was also been

observed by [6, 14]. In fact these only shows us half of the picture and leading to the

question of “Would this affect the amount of data-packets to be lost?”.

3.3.2 100-Overlapping Packet Loss Calculation

The experiments here will illustrate the average of dropped data per second (Kbps) against

multiple MHs’ speeds.

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24

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25

3.4 Overlapping Region; Handover and Collision events analysis Overlapping area distance is 100m

R

FA I O P FA2

T

ξ 1 2

Figure(3.7); the overlapping region and handoff time points.

Handover in mobile IP network is the process when the Mobile Node (MN) moves out from

one cell domain to another one, i.e. change its position of attachment. In Mobile IP network

there will be three layers which are required to obtain such a handover as addressed by[ 18,

31], these are;

1- Link Layer handover; where the MN starts to send request messages to lookup for

Agents near to its position via CN.

2- Handover initiation Layer; i.e. movement detection.

3- Binding and change media direction Layer.

By figure (3.7), at time I the MN starts to carry out Layer 1 handoff, at time K the MN will

finish Layer 1 handover, where

, meaning that K is a position time point between I

and O. At time MN will start to carry out handover initiation, Where , is an

integer which upgrading the simulation to a time point after K. At time O MN will start to

send Binding and update message to the Correspondent Node (CN) and receive the binding

update from the CN. At time P, MN will receive the first packet from FA1. This information

was retrieved by[31] . Therefore, three positions of factors are important here;


26

1- The interval time that MN takes to starts caring out Layer 1 handover to the time

where MN will starts to send binding update message, we donate this by ξ. That is

ξ .

2- The time that MN takes to send the data to CN (the one-way delay time), we donate

this by 1.

3- The time that MN takes to receive the data from CN, we donate this by 2.

Now let fξ(x), fn1(y), fn2(z) represent the probability density function of ξ, n1 and n2. And let

ξ,n1,n2 , , represent their joint probability density function.

Thus, we have ξ 1 2, we can see that most of the handover layers have been

carried out in K at R, where R is called the radius of overlap region [18, 31]. Moreover, we

already know that the packet loss is increasing gradually according to the MN speed, so we

donate V as the movement direction and speed of MN, that is .

Now, let 1 donate the interval time when the MN start caring layer 1 handover to the time

when MN is in O, and S2 represent the interval time when MN caring out layer 1 handover

to the time when MN receives all the resides packets held on FA (if any). Hence;

1 , . 1 2 , where 1.

By the definition of , 1 2 we actually resulting in the following six cases:

3.4.1 Case (1):

I S2 T S1

Figure(3.8)

In this case we have 2 , 1 2 1. 2 meanings that in the overlap

region MN will receive all the Packets resided on FA, which will be forwarded by FA before

MN receive the first packet from FA1. 1 Meanings that MN will receive the first packet

from FA1 before it move out of the Overlapping area. Similarly, 2 1 means that all the

packets resided on FA will be forwarded to MN before MN reaches the P, i.e. packets held on

FA will be sent to MN before MN goes out of the Overlapping area.

In this case we have no packet lost during the simulation as all the packets from FA

have been forwarded to MN before MN reach T (i.e. S2 < T), as well as there is no packets

collision as MN has received all the resided packets on FA before it receives any packets

from the next point of attachment (FA1), i.e. (S2 < T and S2 < S1).


27

Therefore, as

probability of PacketLoss at time

P packetNotForwarded P Time where PacketCollided ;

.

3.4.2 Case (2):

I T S2 S1

Figure(3.9)

In this case we have 2, 1 2 1. 2 Meanings that MN will start

receiving packets from FA1 before receiving all the packets resided on FA if any. Similarly as

case (1), 1 Meanings that MN will receive the first packet from FA1 before it move out

of the Overlapping area. 1 2 (Same as case (1)).

Therefore we have the probability value of Zero for 1 1 2 as S1 > T > S2,

however > 0, i.e. there is probability of packets collision event as S2 > T.

Therefore packet loss probability duration is;

P( ) = , where P( ) . (1)

Equation(1) above saying that; in a time point K after the point time T, packets depending

on the MH speed and the overlapping area size are to be under the probability of collision

event. The W variable will be discussed in further parts of this section.

3.4.3 Case (3):

I T S1 S2

Figure(3.10)

In this case we have 1, 2 1 2. Here we have the same situations as

case (2) except for 1 2, which means that while MH is out of the overlapping are


28

between FA and FA1, there will be sort of packets that are resided on FA and not yet

forwarded. Packet loss in this case is high according to the number of packets that

belonging to MN held in FA, where In fact the resided packets will all be dropped because of

the basic Mobile IP architecture design, where there isn’t buffer and forwarded strategy as

mentioned by [31]. As well as there will be probability for packets to be collide as

2 1 . Therefore packet loss is:

P( ) = , where P( )

(2)

where is the Prps (packet rate/sec) , 3 is the velocity of MN to receive data packets from

FA and H1 is the number of packets resided in FA that have to be sent to MN. Case (3) is an

example of having a small overlap area.

In equation(2), part one of the formula saying that in a time between T and S2, before S1

packets are threatened to be collided after the point time K. The second part is showing the

calculation of the dropped packets caused by the failure of forwarding the resided packets

by the previous agent. The W variable will be discussed in further parts of this section.

3.4.4 Case (4):

I S2 S1 T

Figure(3.11)

In this case we have 2 , 1 1 2. Here we have a new case where 1

meaning that MN will start receiving the first packet from FA1 when it is actually out of

overlapping area region.

Packet loss in this case is zero, because packets resided in FA will be forwarded

before MN reaches O (i.e. before MN is out of the overlapping area) as S2 < S1, thus no

resided packets loss from FA to MN, as well as there will be no packets collision as S2 < T.


29

Therefore the overlapping area packet loss in this case is zero, i.e. P( ) = 0. Case

(4) is a simple example of having an optimal non-overlapping area network, besides I > S2

in the optimal non-overlapping domains design, see non-overlapped-domains model section.

3.4.5 Case (5):

I S1 S2 T

Figure(3.12)

In this case we have 1 2, 2 1 , as can be notice here we have the new

cases where S1,S2 < T and S1 < S2 at the same time, which means that when MN is in P

(out of the overlapping area) some resided packets on FA still haven’t yet forwarded. Packet

loss in this case is extremely depending on the number of packets that have not been

forwarded from FA. However packets collision is rear in this case, where S2 < T and some of

H1 is already been dropped before receiving any packets from new point of attachment

(FA1). Therefore packets loss is:

, (3)

Equation(3), showing the calculation of the dropped packets caused by the failure of

forwarding the resided packets by the previous agent.

3.4.6 Case (6):

I S1 T S2

Figure (3.13)

In this case we have 1 , 2 2 1. It is noticeable that for the first time we

have S2 < T and S2 > T at the same time. This case is very similar to case (5) where some

resided packets on FA (if any) haven’t yet been forwarded to MN, however in case (6). More


30

packets are to be dropped regarding the large time acquiring by the network to be

forwarded the resided packets from FA.

From figure (3.13) we can notice that S1 < T, which we can infer that MN will start

receiving packets after it moves out from the overlapping region. Therefore packet loss is

actually depending on the number of resided packets still not yet forwarded, where MN start

to roaming out from the overlapping area, therefore packet loss is equal to:

, (4)

3.5 Collision proof with NS-2

This section will provide technical and mathematical analysis to present deeply the problem

of data collision within the overlapping area and to show why non-overlapping model can be

a better case in this sense.

As it can be shown from table (3.2) below, that the simulation is consisting of 1 HA,

this contains one wireless node (MN) and 2 Foreign Agents (FA + FA1). The simulation will

be run at a MN speed of 30 m/s with direct movements between the agents in the network.

The cast distance of each agent (i.e. domain range) is 240m as it has been set by default in

ns-2. 100m is the range distance of the overlap area between the agents. At 4/sec the MN

will start moving between agents, and TCP connections is enabled.

The purpose of this simulation is to test the behaviour of the MIP network in the

overlapping area. In particular, to discover the point where collision event occurs and cause

the packets to be dropped during the handoff.

MN Speed 30 (m/s)

Number of wireless nodes 1 (MN)

Number of Agents 3 (HA + FA + FA1)

Cast distance 240m (set by default in NS-2 ) Overlapping distance 100m

Direction movement Direct movement

Time spent in the overlapping area 0 sec, 3sec, 13sec, 16sec and 20sec

Transport Layer Protocol TCP

Table (3.2); the simulation parameters used during these experiments

Student

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Martin Dyer

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32

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Martin Dyer

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33

request, however receiving the replay message failed at that time due to packets collision

occurrence, and further replay packet contains the COA is been send in latter time. In

25.9/sec to time 30.0 dropped packets has decreased to a constant level, this in fact support

the behaviour addressed in [27, 31], where sending/receiving processes are constant but

facing high handoff latency until MN finishing the registration processes with FA1.

3.5.3 Discussion and further analysis

ξ,n1,n2 , ,

Figure (3.17)

As been mentioned previously Case (2) and Case (3) are the situations which affected by

packets collision, therefore it is worthwhile to be mentioned here. According to equation 2

and 3, in particular the part is representing the interval time of the

probability number of collided packets in the overlapping area, here K is a time point where

collision is starting to occurs, in this case we have , that mean collision will take place

after FA1 starts to send data to MN, plus the interval time between S2 and S1, where any

packets exceeding this interval time point will be dropped as registration process has

finished, and Layer 3 handoff has already taken place in the network. Therefore FA has

updated its binding table resulting on a non-accessibility of any connection media with MN.

Figure (3.17) shows the function that represent the relation between the percentage

packet loss function with value of - that MN will stays after it reach . Therefore for

accuracy, the value of has to be taken into account and added to equation 2 and 3. Thus

we had w in; for case 2 and

for case 3.


34

Section 4 Non-Overlapped-Domains Model; Technical and Mathematical Analysis

4.1 Overview

In the non-overlapping area the mobile nodes will only obtain such a handoff when they

start to go beyond the current agent domain, where no 801.11 wireless communication is

shared by the current and the new agent as being addressed by[23, 28].

This section will represent the second part of the project. The non-overlap model will

be adopted to evaluate the Mobile IP Network. The same network characters will be used as

when used to evaluate the Mobile IP network with the overlapped model. This is because to

reach the conclusion of which model is representing the best performance. Thereby,

throughput and packet loss will be calculated over multiple speeds for the Mobile Nodes.

4.2 Non-Overlapping Throughput Calculation

In this experiment the throughput rate is gradually reduced as the mobile hosts increase

the speed of their movements. The distance between the domains are set to 58m, so when

mobile node moves faster more packets are lost particularly when handover occurs.


35

0

10

20

30

40

50

60

10 (m/s) 20 (m/s) 30 (m/s) 50 (m/s) 60 (m/s) 100 (m/s) 150 (m/s)

Calculating theThroughput

Throughput

From the scenario when the MH starts to move towards FA, as long as the MH is

roaming in the home domain- by[9, 14]- all packets will be forwarded via the home agent

but the problem occurs when the MH reaches the FA it will have less time to register with

the new FA and this will cause the packets which were distended to the MH to be lost as

they were sent to the MH before it has registers with the FA.

Figure (4.1); shows the network throughput performance according to several MH speeds

when non-overlapping domains are adopted.

Node Speed Throughput (MBytes)

10 meter/sec 56.7046 20 meter/sec 21.7311 30 meter/sec 11.2741 50 meter/sec 8.1893 60 meter/sec 7.37589 100 meter/sec 1.60801 105 meter/sec 1.10682

Table(4.1)

4.2.1 Results and Explanations (1)

According to figure(4.1) and table(4.1), a sharp decrease in the throughput is taken place

in two positions, the first, is where the MHs’ speeds are changing from 10 m/s to 20 m/s

representing 60% in a throughput difference. The second decrease can be noticed when

MNs moving within a speed over 60 m/s, which illustrate the highest decrease in the

network throughput. The reason behind these decreases is relating to the low Quality of

service (QOS) level in the non-overlap case in any transport protocol such as TCP.

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39

I O

PT

R

FAFA

to proceed the handoff will be considered as a network bottleneck in case of high speed.

However, in the case of non-overlapped domains between bases stations, particularly when

handoff occur, no packets collision is obtained as interfaces within the network are not

sharing any coverage areas between them. This was discovered by the trace file generated

during the NS-2 simulations, as no Packet ID is repeated due to collision. I.e. the only TCP

re-transition (RTO) happened is caused due to sample measurement of Round Trip Time

(RTT) experienced by the network during the handoffs.

4.4 Non-overlapping Region Analysis

Figure (4.5)

As been mentioned by section [3] 3-Layers have to be achieved during the handoff process

in MIP, where further details have been applied in section [3], thereby I will skip these in

here to avoid duplication. Moreover this analysis is based on the experiments held by the

first part of this section [4.2 and 4.3].

At time I the MH will start to reach the end-point of the first domain (FA) and carry

out layer-1 handoff, however MH will only listen to advertisements and not allowed to send

any binding-Update messages as addressed in [12, 24]. At time K, where K is time between

I and O, thereby . The MH will start to listen to advertisements after reaching the

point of O and therefore allowed to send BU messages. In time P the 3-Layes handoff will

be accomplished and MH will receive the first TCP packets form the new station (FA1). R

here is representing the space of the non-overlapping region, i.e. the radius of the non-

overlap region.


40

Similar to the overlapping case, non-overlapping here will suffer from three intervals times;

1- The interval time that MH takes to starts caring out Layer 1 handover to the time

where MN will start to send binding update message, we donate this by ξ. That is

ξ .

2- The time that MN takes to send the data to CN (the one-way delay time), we donate

this by 1.

3- The time that MH takes to receive the data from CN, we donate this by 2.

Besides, 2 and 3 will only be proceed after the MH reach O, i.e. finalizing ξ with no coverage

signals area placed between FA and FA1 because of non-overlapped domains structure.

Thus, we have ξ 1 2. Moreover we already know that the packet loss is

increasing gradually according to the MH speed, so we donate V as the movement direction

and speed of MH, that is .

Now let 1 donate the interval time when the MH starts caring layer 1 handoff to the

time when MH is in O, and S2 represent the interval time when MH caring out layer 1

handoff to the time when MH receives all the resides packets held on FA (if any). Hence

1 , 2 , where 1.

By the definition of , 1 2 one three cases behaviours are to be followed by the

network during any handoff situation.

4.4.1 Case (1):

S2 I S1 T

Figure(4.6)

Here, we have 2 , 1 2 1. 2 means that FA will forward

the resided packets before MH moves towards the end-point of FA. In the case of non-

overlapping domains it will always be the case that 1 , which means that MN will

receive the first packet from FA1 after reaching FA1 coverage domain, i.e. there will be no

collision event experienced by the network during the handoff as within the

overlapping case. As 2, 1 2, meaning that all resided

packets are to be forwarded before MN reaches the next station domain (FA1).


41

Concluding that smooth handoff is to be generated within this case with packet drops

probability of 0. Therefore:

.

4.4.2 Case (2):

I S2 S1 T

Figure(4.7)

This case is similar to case (1). Besides, resided packets held by FA will commonly be

dropped, as in a time point K, MH will roam in the region R with limited connectivity which in

turn will affect the throughput in this duration as addressed in [section [4] and in [4, 13,

23]] and resulting in more packets to be lost. Therefore:

, where (1).

4.4.3 Case (3):

I S1 S2 T

Figure(4.8)

This case is similar to case (2), however more packets are susceptible to be dropped during

the handoff process in this case. This is because time between I and S2 is high resulting in

risk of packets to be dropped as FA will need more time to forward any packets after MH

reach I. In addition, after MH reaches S1 all packets resided in FA will be dropped.

Therefore:

, where . (2).


42

Section 5

Calculating Delay Time

5.1 Overview

This section discuss the delay time generated in the MIPv4 network within two case studies,

the first one will give a general idea of the time delay behaviour when handoff occurred

within the overlapped area. The second case study will observe the behaviour of the MIP

sub-networks (i.e. agents) within the TCP.

This section is considering the stop point of this project, where any further

contribution by me or by anyone else can be started from here. Concluding that, as to solve

the high handoff latency it is worthwhile to solve the delay in wireless routers first and upon

that further investigation in the MIPv4 can be done efficiently.

5.2 End-to-end delay in overlapping area

End-to-end delay refers to the time taken for a packet to be transmitted across a network

from source to destination.[4]


43

In the first minute delay time is shown as (0ms) as the MH is still in it’s HA, as noticed there

is no delay reported until the MH starts getting closer to the overlapped area with the FA at

minute (6.01).

In the overlapped area delay time is slightly increased as handover is taking place,

again there is a delay increase noticed in minute (13.012566) as the mobile node is

roaming in a new foreign agent (FA). The delay time remains nearly the same until the end

of the simulation running time as the MH is roaming in different foreign agents and never

returns to its home agent.

Figure (5.1); shows the delay time calculation

Table (5.1)

5.3 End-to-End delay in TCP connections

NB: All TCP connections are enabled in this scenario.

At one point of this scenario two mobile nodes will end up sharing the same foreign

agent domain -MH and MH1 shares the same domain FA1-.

Description time delay Starts 0 0

closer to FA domain 6.0095 0.003077 overlapping with FA 7.7546 0.003077

Out of the overlapped area 7.8055 0.003077 reaches FA 13.012566 0.006231

overlapping with fa1 16.8147 0.006231 reaches fa1 21.099869 0.006230

Roaming In the FA1 domain 23.005895 0.006231

End to End Delay for MH

00.0010.0020.0030.0040.0050.0060.007

0 6.01 7.755 7.806 13.01 16.81 21.1 23.01

Running Time

Del

ay T

ime

Delay for MH


44

Delay time is increased at time (15.0144) as all mobile nodes in this point are roaming away

from the home agents domains.

Delay time is fairly steady until a slight increase in the delay time is reported at minute

(28.092933) where MH and MH1 are in the same domain (FA1). This can cause the packet

exchange between two mobile nodes in the same domain to be inefficient, therefore delay

time is increased to a certain level depending on the connection states.

Figure (5.2); time delay generated by TCP connections

Table (5.2)

description time delay starts 0 0

Out of the home agents domains 15.0144 0.00623 Out of the home agents domains 16.01242 0.00623 Out of the home agents domains 21.007564 0.006231

In the foreign agents domains 22.005476 0.006231 Two mobile nodes in the same domain 28.092933 0.006641

End to End Delay for all TCP Connections

00.0010.0020.0030.0040.0050.0060.007

0 15.0144 16.0124 21.0076 22.0055 28.0929

Running Time

Del

ay T

ime

Delay for MH


45

Section 6

Evaluation & Conclusion 6.1 Evaluating the project accuracy

Handoff in telecommunication computerised systems is the most issue disabling a good QOS

during the movement of the related mobile objects in the network. On the other hand, to

maintain an operating data flow service, problems generated by the handoff has to be

solved, or at least has to be taken to a certain level. With any network routing cells two

major models is adopted to handle such a handoff case, overlapped domains model and a

non-overlapped domains model.

In this project, the MIP network has been selected to evaluate the behaviours issues

resulted during the handoff in each model (overlapped and non-overlapped models).

Accuracy has always been under consideration along with this project, and therefore had to

be planed. Choosing the best overlapping area distance was the first step, this actually was

maintained as to give the best performance reached by the network when adopting the

overlapped-domains model. Indeed this concept has been merged along with accurate data

generated by the experiments in section [3]. The same method was allocated in the non-

overlapping model and experiments showed that with a non-overlapping area distance


46

between 55-65 meters are representing the best performance in the case of non-overlapped

domains, nevertheless, the work has been skipped to be aware of unnecessary data and

duplication; however the work can be seen in appendix [B].

The project was acquiring a total of 60 experiments to be done using the network simulator

(NS-2). Each in which has been ran 4 to 6 times as needed to enhance accuracy. However

the data generated by NS-2 in the trace file were complicated where each experiment trace

file was in the range of 22.9KB up to 1GB according to the simulation time and node speeds.

Therefore the second challenges was to simplify the confusion within these trace files, thus

AWK scripts was used to overcome these issue, and thereby more time was needed as to

improve my AWK skills, however this matter has been accomplished and accurate data have

been gathered from NS-2 trace file via AWK scripts.

6.2 Evaluating the Experiments Results

During the investigations in section [3,4] adopting the overlapped-domains model between

the network base-stations has leading to unsmooth data flow during the handoff when

compared to the case of having non-overlapped domains.

The table below (6.1) shows the throughput data summary in each model. Clearly a

throughput value enhancement is noticeable in the case of having non-overlapped domains

between network cells. For example with a MHs speeds of 10 (m/s), 48.2% increasing in the

throughput has been illustrated within the non-overlapped model when compared to the

overlapping model.

Table (6.1)

Similarly, packet drops are gradually increasing in both cases models according to

the MHs ground speed. However, as it can be seen from table(6.2), a non-overlapped based

model defining less packet loss per second resulting in 35.9% improvement in the packet-

MHs Speeds Throughput(MBytes) (Overlapping Case)

Throughput(MByets) (Non-overlapping case)

Improvement Percentage (%)

10 29.9732 56.7046 48.2% 20 14.4717 21.7311 34.5% 30 6.10617 11.2741 46.9% 50 4.51353 8.1893 45.9% 60 3.63719 7.37589 50.7% 100 1.65873 1.60801 -3.1% 150 1.33322 1.10682 -17%


47

loss rate when compared to the overlapped case when MHs speeds are set to 10 (m/sec)

and 46.9% of improvement when MHs speeds are 30 (m/sec).

MH Speed (m/s) Packet loss (Kbps) overlapping case

Packet loss (Kbps) non-overlapping case

Improvements Percentage (%)

10 1.325 0.8497 35.9% 20 2.6615 2.4661 7.4% 30 5.0656 3.6196 28.5% 50 9.4305 5.5408 41.2% 60 10.6753 6.9586 34.8% 100 24.7963 23.3611 5.7% 150 29.2235 32.3651 -9.7%

Table(6.2)

Section [3] has demonstrated the reason behind the inefficient performance showed by

overlapping area when handling the handoff procedure. This is due to collision event. To

make such a picture clear, in the overlapped-domains based network, packets are collided

when MH is receiving from more than one agent at a time. Retrieving the memory back to

section[3], these kind of event is taking affect in two major cases, both of them resulted

due to the fact of having T < S2,S1. Thereby, we have probability of collision times

represented in the two following equations;

• P( ) =

•

This problem is illustrating a serious harm to the network performance when the interval

value between T and S2 is large, these as a result will guide the network to unadvisable

situation where 52% of packets during the handoff are to be collide as shown in the

experiments done in section [3], additionally this could be much worries in real time

application, where the number of wireless nodes, nodes’ speeds and nodes position in the

network are not constant.

Overlapping model was a solution to reduce handoff latency for some researchers such

as [1, 6, 7, 31], however full achievement wasn’t reached completely due to the lack of time

in wireless routers during the routing process.

On the other side of the project, a non-overlapping model has showmen a particular

improvement to the network performance, where event such as the packets collision during


48

the handoff has been solved. This has been proved in section [4] where no packets have

been collided during handoff. i.e. it is always the case that T > S2 and therefore no

complains has been made due to collision, because of suspending the authentication from

the previous agent as to send data to the MH when MH is reaching the new domain of the

next agent, these has been also addressed by [7, 19, 22, 28] when explaining the behaviour

of the non-overlapping area in a cellular based network.

The non-overlapping solution has only solved half of the puzzle. Problems are still

roaming around, even when non-overlapping model is adopted. According to sections [3,4]

the M-IP protocol in both models (overlapping & non-overlapping) is facing the problem of

packets to be dropped during the handoff, due to the number of un-forwarded packets in

agents when MHs are in high speed.

In advance, when handoff occurs and MH hasn’t actually finished the registration

with the new agent, its HA will assume that this MH’s COA is the currently visited FA address

and will keep sending data to this FA. By the time, MH will reach the new FA (Depending on

the MH speed) and will be out of range from the old FA, hence the old FA is still receiving

data from HA and will not stop until BU-message is been received by HA. Therefore theses

packets will be dropped. By [6, 9, 19] these type of problem is obtained due to routing time-

delay as shown by this project in section [5].

In the next side of the project, mathematical analysis was reported to illustrate the

network behaviour in both cases (overlapped and non-overlapped domains). In the

overlapping model 2 out of 6 cases are concerning with packets to be collided, and 3 cases

out of 6 are affected by the problem of packets to be un-forwarded by the old agent during

handoff. This has been showed in section [3] by the following equations;

- P( ) = in case 3

- , in case 5

- , in case 6

In the non-overlapping model, this problem has taken to a certain level where 2

cases out of 3 are suffering. However, none of the cases have affected by the fact of

packets to be collided during the handoff.


49

Another problem found in the non-overlapping model, that as long as S2 > I, i.e. the

MH reach the non-overlapping area, the network will start to endure a sharp degrade in its

performance. This is due to the limited connectivity service faced by the MH in this area,

[19, 28, and 30].

Constantly, experiments done in section [3, 4] and according to tables (6.1, 6.2) and

research done by[6, 11, 14, 17], are all pointing to the same fact, where MH speed and

overlapping & non-overlapping area distances are affecting the performance of the MIP

network. One of the important conclusion in this project was that, a non-overlapping model

is a better choice when MHs are less than 100 (m/s), however the overlapping model is

better otherwise. This is because of several reasons, each in which happening when MH

moving with high speed in this area such as; within the non-overlapping model TCP is taking

0.8/sec to be re-transmitted when such failure occurs [24], as well as time allocated for MH

to register with the new point of attachment will be short. This is actually explaining the

negative values generated in table [6.1 and 6.2].

6.3 Comparison with previous work

This project was contributing to discover the issues generated by the MIP network with

overlapped domains. In particular to investigate the reason behind the degrade performance

when such a model used and solve these by implementing a new network with non-

overlapped domains within the network. To be more specific, the non-overlapped-domains

has solved the problem of packets to be collided in the overlapping area during the handoff

resulting.

The point of interest is that researches such as [1, 2, 6, 31], were pointing to the

overlapped-domains model as a solution to the slow handoff process occurred with the non-

overlapping domains architecture. It is the case that fast handoff will be achieved by

overlapped-domains, but this will generate data traffic overhead due to collision as been

discovered by this project.

The lack of resources was the big issue faced during this project, where particular

comparison between the overlapping and non-overlapping cases using technical tool like NS-

2 were not found in any of research papers, besides only the work done by ZHAO et al , in

[31] and Pablo Vidales, et al in [22], were actually summarising voluble information in the


50

literature. However their work depends upon telecommunication mathematical theories and

was hard to be understood, but eventually the main concept was delivered.

The paper research done by Taeyeon Park and Arek Dadej in [28] was involved to

investigate the general characters of the Mobile IP network and used buffering mechanism

to solve the packet loss rate during the handoff. However, this would increase instantaneous

packet delay variation undesirable with real time application as mentioned by [5]. With voice

over IP delay time routing considering the disaster problem, in particular when objects such

as MH are moving with fast speeds. However Taeyeon Park and Arek Dadej were not very

specific about the MIP speeds and more importantly the topology design, where nothing has

been mentioned about non-overlapping domains model and related issues such as the

topology accuracy level left unclear.

The work done by Hsieh et al and Seneviratne in [25, 11] were helpful as it gave an

insight about the behaviour of the MIP protocol when overlapping domains are used,

nevertheless nothing has been mentioned about the non-overlapping domains model. In

terms of the overlapped domains model, the investigation done in [25] has showed similar

results to those in the project.

Most of the researches such as [1, 6, 8, 19], were offering their results based on a

very simply topology. The topology in the project was bigger and much closer to realistic.

Thereby, new investigations have been noticed, such as the degrade in the throughput

average when HA-FA handoff occurs, and further explanation was hard to be gathered until

I asked some friends working in the engineering department in Orange Telecommunication

company to provide me with related paper research such as the one in [7, 9].

Mathematical analysis was involved in this project, this has gave the project more

strength and offered an opportunity of a second prove methodology to be used beside the

technical one used by NS-2. ZHAO et al in [31] and the work in [12, 18] were the more

contributors who offered me with the basic knowledge about the overlapping area analysis

in a mathematical way. Due to the advance way written by [12, 18 and 31] points within the

overlapping area had to be discovered alone from other researches paper. For example the

point “I” in the middle of the overlap region has been investigated by [15] quoting;

“The handoff is initiated roughly after the MN is half way into the overlapping region”.


51

Similarly, non-overlapping domains model was analysed mathematically and

technically. With the mathematical analysis it was very hard to retrieve information due to

limited resources covering the subject in terms of non-overlapped domains. This however

has been overcame by gathering as much information as possible about the non-overlapping

region, and based on that I had implemented the mathematical analysis in way similar to

the one used to analysed the overlapping region. These as a result made further

comparisons between the two regions models to be easier and simpler for the reader.

In terms of comparison, once again, it is hard to assess due to the differing

complexities of the topologies of [6, 9, 15, 25] and those used in this project. However, the

performance observed by [1, 2, 25] in the Mobile IPv4 scenarios is very similar to that

observed by this project, although further investigation is required.

6.4 Conclusion

To conclude, Mobile IP protocol is been investigated deeply in a science way relaying upon

two methods, technical methodology using the network simulator NS-2 version 3.38 and

AWK scripts, and mathematically , to observe and explain the behaviour of the protocol

during the handoff.

While designing the topology I faced some difficulties in understanding the codes

used for implementation as information from external resources are very limited. However, I

have overcome this struggle and I have considered documenting the implementation steps

as it contains some technical details, which are essential to understand the fundamentals of

ns2 implementation approach.

The project has intended to reduce the high latency and packet loss generated in the

overlapping area (between stations domains) when handoff takes place. The observation

made according to two major factors, those in which are the overlapping area distances and

the Mobile device speeds.

For accuracy purposes, the distance of the overlapping area between domains have

been taken under consideration, and further investigation has been made. Interesting

results have appeared during the simulations, where 100 meters to be the overlapping area


52

size has taken the network to its preferable performance with less handoff latency. This is

due to the time given to the MHs to finish their handoff schemas.

Evaluating the performance of the Network protocol (TCP) in the case of having

overlapping domains architecture, resulted in a sharp degrade in the throughput slope and

increase in the number of packet loss when MHs increase their movement speeds

accordingly. These points has been illustrated in section 3 of the project.

Mathematical analysis has been adopted to discover the issues behind the high

latency generated in the overlapping area during the handoff process. Six cases have been

reported, which are representing the most probable handoff situations that can be faced by

such a network. Additionally, mathematical formulas have been formulised as to explain the

number of packets to be lost in each of the 6-cases. I’ve investigated that degrade and

increase within the throughput and the packet loss respectively, has obtained due to the

interference collision event in the overlapped areas. In particular, collision during the

handoff is reaching its maximum level when MH reaches a specific point in the overlapped

area represented by W, where the most the MH stays in this point the more packet collisions

occur. Section 3 is showing these in more details.

Section 4 has implemented the target point intended by the project. Adopting the

concept of non-overlapped domains was the main idea in this section, these as to show the

performance of the MIP and solve the collision occurrence discovered in section[3]. The MIP

Network has been tested in this model along with multiple MHs speeds. Experiments results

showed the same performance as with those when overlapping domains model used, but

with enhancement in the slopes for both of the throughput and the packets loss, concluding

in a solution to the packet loss observed due to collision in packets transmission process.

Moreover, Technical and mathematical analysis has been applied here, as well, to report the

new investigations and to build further discussions when monitoring the behaviour of the

non-overlapped domains based network.

Within the non-overlapping area no collision is been reported and therefore increase

in the network performance has been reached. However the non-overlapping area has also

showed side-effects in terms of less QOS (Quality Of Service) when such a MH moves deeply

inside the non-overlapped zone. This is as been proved is due to connectionless situation

roaming in this area. Therefore I’ve came with the conclusion of, in larger none overlapped


53

scenarios (e.g.200m distance between wireless hosts) they show more handoff latency and

more packet loss as the distance between the Agents increases. Therefore overlapping the

nodes can considered as a good idea as it reduces the packet loss to a certain level.

Furthermore the project showed that the reason behind the high latency in both of

the cases (overlapped and non-overlapped domains) is due to time delay in wireless routing

within the MIP protocol. Investigations showed that delay time is increased when mobile

nodes roam away from the home agent domains and that’s due to the handoff experienced

in this point. When two nodes are sharing the same domain, packet exchange between the

mobile nodes is inefficient. Therefore delay time is increased to a certain level depending on

the connection states. This was mentioned as to give an insight for further work and

investigation by anyone who interested in solving the high handoff latency in the mobile IP

protocol.

The evaluation part of this project has evaluated the project in several points; the

accuracy level followed when designing the topology as to result in accurate data when

experimenting the network performances, whether overlapped domains or non-overlapped

domains adopted. Secondly I have made a comparison between the two performances

generated by the overlapped-domains model and the non-overlapped-domains model,

illustrating how the non-overlapped-model has reduced the latency and packet loss to a

certain level during the handoff.

Moreover, I have given an overview of what type of researches papers are in the literature

and what kind of contribution this project has made.


54

References

[1] Aisha H. A. Hashim, Farhat Anwar, Shaffiah Mohd and Hatina Liyakthalikh. Mobility

Issues in Hierarchical Mobile IP. 3rd International Conference: Sciences of Electronic,Technologies of Information and Telecommunications (2005).

[2] 7. Aisha Hassan Abdalla Hashim, Fauzana Ridzuan, and Nazreen Rusli. Evaluation of handover latency in intra- domain mobility, world academy of science, engineering and technology, volume 6, 2005, ISSN 1307-6884.

[3] 5. Charles, e. Perkins. (1998), mobile IP design principles and practices: route

optimization, Addison Wesley Longman.

[4] Chee Kong LAU. Improving Mobile IP Handover Latency TCP in End-to-End time delay. University of New South Wales. 2006.

[5] Christer Åhlund1, Robert Brännström1, and Arkady Zaslavsky2. M-MIP: Extended Mobile IP to Maintain Multiple Connections to Overlapping Wireless Access Networks. www.springerlink.com/index/NR77DHHDNM4HU2AW.pdf. Last accessed [24/02/2009].


55

[6] Claudio E. Palazzi, Brian Chin, Paul Ray, Giovanni Pau, Mario Gerla, Marco Roccetti . High Mobility in a Realistic Wireless Environment: a Mobile IP Handoff Model for NS-2 . www.math.unipd.it/~cpalazzi/papers/Palazzi-MobileIP.pdf. Last accessed [12/02/2009].

[7] Edward smith, 4G; Profit and Complexity. Orange co. 2006.

[8] Edwin Hernandez and Abdelsalam (Sumi) Helal. Examining Mobile-IP Performance in Rapidly Mobile Environments: The Case of a Commuter Train. http://www.harris.cise.ufl.edu/projects/rapmobile.htm. Last accessed [15/03/2009].

[9] Ericsson co. Mobile IP Conference; Between Adoption and Failure. 2007.

[10] 8. Ergen, Sinem coleri, Baris Dundar, Anuj Puri, Jean Walrand, Pravin Varaiya. position leverage smooth handover algorithm for mobile IP. Department of electrical engineering and computer science, university of California Mustafa. 2006.

[11] Fekri M. A. Abduljalil, Shrikant. K. Bodhe, Forward-Based Handoff Mechanism In

Cellular IP Access Networks, University of Pune, Ganeshkhind. India (2002).

[12] 3. G. pall et al., "point-to-point tunneling protocol--ppt," ftp://ftp.ietf.org/internet-drafts/draft-ietf-pppext-pptp-02.txt. Last accessed [03/11/2008].

[13] Gustavo M.T. Da Costa. Freeze TCP with Timestamps for Fast Packet Loss Recovery after Disconnections. www.elec.canterbury.ac.nz/research/Networking/documents/dacost.pdf. Last accessed [1/ 04/ 2009].

[14] Hai Lin and Houda Labiod. Hybrid Handover Optimization for Multiple Mobile Routers-based Multihomed NEMO Networks. GET – ENST ; LTCI-UMR 5141 CNRS; INFRES Department. (2007).

[15] Huai-An (Paul) Lin. Handoff for Multi-interfaced 802 Mobile Devices. IEEE P802 (2003).

[16] 9. J. c.-s. Wu , c.-w. Cheng, n. -f. Huang, and g. -k. ma, intelligent handoff for mobile wireless internet mobile networks and applications, vol. 6, pp. 67-79, Jan, 2001.

[17] Jiannong Cao, Liang Zhang, Henry Chan and Sajal K. Das. Design and Performance Evaluation of an Improved Mobile IP Protocol. www.ieee-infocom.org/2004/Papers/08_1.PDF. Last accessed [03/02/2009].


56

[18] Jongjin Park and Youngsong Mun, The Layer 2 Handoff Scheme for Mobile IP over IEEE 802.11 Wireless LAN, SpringerLink Journal . (2004). Vol. 3043/2004. PP 1144-1150. ISNB: 978-3-540-22054-1.

[19] Md. Mohiuddin Khan, Md. Arifur Rahman Bhuyan, Fiash Kiswar, A. S. M.

Ashique Mahmood. Overview and Comparison of Methods for Minimizing HandOff Latency in Mobile IP. IJCSNS International Journal of Computer Science and Network Security, VOL.8 No.3, March 2008.

[20] 1. Mobile ip (2004-2005) mobile ip components. http://www.dpo.uab.edu/~amit81/mip%20pages/terminology.htm. Last accessed [27/10/2008].

[21] 2. Mobile networking through mobile IP. http://www.cs.colorado.edu/~rhan/csci_7143_002_fall_2001. Last accessed [02/11/2008].

[22] Pablo Vidales, Leo Patanapongpibul, Glenford Mapp, Andy Hopper. Experiences with Heterogeneous Wireless Networks,Unveiling the Challenges. www.mdx.ac.uk/eis/research/groups/docs/HetNets04-Vidales.pdf. 2004. Last accessed[12/3/2009].

[23] R. Ramjee, T. La Porta, S. Thuel, K. Varadhan and S.Y. Wang. HAWAII: A Domain-based Approach for Supporting Mobility in Wide-area Wireless Networks. www.cse.psu.edu/~tlp/paper/hawaii.ps. Last accessed [12/02/2009].

[24] Ramon Caceres, Liviu Iftode. AT &T conference :Improving the Performance of Reliable Transport Protocols in Mobile Computing Environments. 2005.

[25] Robert Hsieh, Zhe Guang Zhou, Aruna Seneviratne. S-MIP: A Seamless Handoff Architecture for Mobile IP. www.ieee-infocom.org/2003/papers/43_04.PDF. Last accessed [02/03/2009].

[26] S.McCanne and S. Floyd. The network simulator — ns-2. http://www.isi.edu/nsnam/ns/, Last accessed [30/12/2007].

[27] Satyajit Chakrabarti, Son T. Vuong, Anirban Sinha, Rajashree Paul. BlueMobile – A mobile IP based Handoff system for Bluetooth, 802.11 and GPRS links. IEEE Consumer Communications and Networking Conference (CCNC) held at Las Vegas,


57

Nevada, USA.Gustavo. TCP with Timestamps for Fast Packet Loss Recovery after Disconnections. 2005.

[28] Taeyeon Park and Arek Dadej. OPNET Simulation Modeling and Analysis of Enhanced Mobile IP www.cse.iitb.ac.in/~varsha/allpapers/wireless/wcnc2003/opnet-enh-mob-IP.pdf . Last accessed [29/01/2009].

[29] 4. The TCP/IP code (2001) IP security (IPsec) protocols http://www.tcpipguide.com/free/t_ipsecurityipsecprotocols.htm. Last accessed [15/11/2008].

[30] Vijay K. Madisetti and Antonios D. Argyriou. Transport Layer QoS Management for Wireless Multimedia Services(2002). www.soft-networks.com/vkm-vomo.pdf. Last accessed[23/02/2009].

[31] ZHAO Qing-Lin, LI Zhong-Cheng , FENG Li , YANG Jian-Hua. Characterization of Handoff in Mobile IP. Journal of Software Vol.16, No.7 . 2005.

58

Appendix A

Personal Reflection

“All is well that ends well” and that is what I would like to think at this moment of time. It is

a sigh of relief, It is the time to hand in my final year project. Looking back in the time, I

can recall each and every moment of the time I spent in University of Leeds in pursuit of

“B.Sc computer Science.”. The time passed in a jiffy. There were highs and lows throughout

this period, both academically and personally, however, each passing thing has been a

learning experience. It started 2005 after summer, the first time I landed in the UK. I was

taken aback with the pace of the country. Everybody seemed to be busy, talking on the

phones, walking fast as if contesting in the marathon. But just a few acquaintances were

enough to familiarize me with the country. I would attribute it to desire I had to learn.

59

Choices & Challenges

Networking is the field which interacting my attention since I was 12 years old, when

internet revolution has started in my country. The idea of Mobile IP was abduct me in

moments, I started to look around about the inspired concept by my friends who are

working in telecommunication companies in my country and abroad. Maintaining voice over

IP within multiple networks in the world using the mobile phone will take the social

communities to a position where communication is much easier and simple with less money

cost. Maybe you would say that I am very ambitious, but I really want to be involved in

mobility concept even with little contributions. These was the only thing which made me

stay survive when things appeared complicated with me during this project.

When it came to select the project, it was the time of proving rather than choosing a

topic. The project topic has been chosen by my own satisfaction, but this is not enough

where I had to prove that to the staff in the school of computing. In the first meeting with

my supervisor I’ve been told that the project topic is been agreed and I can chose it to

accomplish the 40 credits, by this time I was really happy and flying like a bird.

The challenges were always along with this project, as I made this decision by

myself I knew that it is going to be my responsibility to guide myself to the correct path and

making a good work. In particular when good work can make a difference between a

classification degree of IIi and IIii.

The second challenge I faced is due to my basic background in this field I had to

develop my skills and discover the concepts and the protocols within the literature. Thereby

I had to make a good split between the project sections itself and between the project and

the other modules. Therefore I made the first semester for researching and gathering

information from different resources.

The third challenge was when the mathematical analysis has taken a place along

with this project, so I had to split my time to develop my technical skills with TCL-NS(2) and

AWK programming languages and to improve my mathematical analysis.

I do believe that life is an experience. During the final year project I have learnt

many things which in turn will help me in my future. One thing that I consider as an

60

achievement is that nothing is hard to be reached unless you wanted to be, where reaching

the target is not possible while you give it the required effort.

Recommendations

For those who wish to undertake a final year dissertation I would recommend the following;

• Be always a wear of choosing the topic that really interests you as when time is

tough this is the only thing that will make you stand back again. More importantly if

you wish to choose the topic by your own, be sure to draw a clear picture of your

plan and any possible risks – maybe not following mine.

• Issues and problems are all natural facts emerging within these stage, so these

should not take your ambitious and motivations down, but this should make you

more resilient and stronger.

• Discuss your project issues with your supervisor and don’t leave that until the last

minutes, therefore I really recommend you to not miss your supervisor meetings as

this will keep you update of your progress and will enable the supervisor to assist

your effort along the progression.

• Be sure to document any suggestions and observations discovered while conducting

the technical part. In addition, I would really advice you to accomplish the technical

part as soon as possible, I am not saying that do them roughly, as final product is

important for your results accuracy, but make sure to give an enough time for

documenting your report, as this is the only thing that will be assisted.

• Always plan to get a first class in your final year project as this will target you to

spend as much effort as can be done by good quality and planning.

61

• Finally, I would say that nothing is impossible, it is just the fact where can you reach

the level you want or not, and be ready for any problems that might face you during

the project phases and immediately deal with it.

A statement about the relevance of the project to

the degree course I am doing

I have always been interested in the network field and particularly in mobility and the

relevant wireless connections, this project has gave me a broad knowledge about mobility,

the development process of different (wired and wireless) networks and how to investigated

the efficiency of the data transport by the TCP and UDP protocols. This general

understanding is important for me as a computer science student as it helped me improving

my computing experiences and skills.

62

Appendix B

The Experiments results

&

Nam Screenshots

63

Some of the Experiments Results

The throughput calculation in an overlapped-domains model when MHs stays in the

overlapping region for 0/sec

64



The number of dropped packets caused by the collision in the overlapping area when MH

stays in the region for 3/sec.

65



The number of dropped packets caused by collision event in the overlapping area

when MH stays in the region for 13/sec.

66



The number of dropped packets caused by collision event in the overlapping area when

MH stays in the region for 16/sec.

67



The number of dropped packets caused by collision event in the overlapping area when

MH stays in the region for 20/sec.

68

The throughput calculation in an overlapped-domains model with overlapping area distance

of 50 meter

Packet to be lost per second in KB (Kbps) when overlapping area distance is set to 50/meter

69


of 70 meter

Packet to be lost per second in KB (Kbps) when overlapping area distance is set to 70/meter

70


of 100 meter

Packet to be lost per second in KB (Kbps) when overlapping area distance is set to

100/meter

71


of 120 meter


120/meter

72


of 170 meter


170/meter

73

Throughput calculation in the network when non-overlapping area set as 0 Meter

Packet loss Percentage in a network with 0-Meter non-overlapping area

74



75



76

*


Packet loss Percentage in a network with 58-Meter non-overlapping area (* The Best)

77



T

m

The Pac

are set

he through

meter/sec

cket to be

to 10 (Mete

put calcula

Dropped pe

er/sec)

tion in an o

er second i

78

overlapped-

n an overla

-domains m

apped-doma

model with

ains model

MHs’ speed

when MHs’

ds of 10

’ speeds

79

The throughput calculation in an overlapped-domains model with MHs’ speeds of 20

meter/sec

The Packet to be Dropped per second in an overlapped-domains model when MHs’

speeds are set to 20 (Meter/sec)

80

The throughput calculation in an overlapped-domains model with MHs’ speeds of

30 meter/sec

The Packet to be Dropped per second in an overlapped-domains model when MHs’ speeds

are set to 30 (Meter/sec)

81


meter/sec

]

The Packet to be Dropped per second in an overlapped-domains model when MHs’ speeds

are set to 50 (Meter/sec)

82


meter/sec



83


meter/sec



84


meter/sec



85

The throughput calculation in a non-overlapped-domains model with MHs’ speeds of

10 meter/sec

The Packet to be Dropped per second in a non-overlapped-domains model when

MHs’ speeds are set to 10 (Meter/sec)

86


20 meter/sec



87


30 meter/sec



88


50 meter/sec



89


60 meter/sec



90


100 meter/sec



91


150 meter/sec



92

The Topology in Nam

1- The Main Topologies

The Nam screenshot showing the Mobile IP network with overlapped-Domains

The Nam screenshot showing the Mobile IP network with non-overlapped

Domains

93

2- Topology used to calculate the overlapped

and non-overlapped area distances

The topology used to calculate the optimal overlapping distance

The topology used to calculate the optimal non-overlapping distance

improvements to better · · 2014-10-28such as ericsson .co and by high degree researches in...

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