978 3-659-41237-0-e-book -adaramola michael

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DEDICATION
This M.Sc. thesis is highly dedicated to the Almighty God (the Alpha and Omega), for
His assistance and sustenance throughout the course of this research work. This work is
also dedicated to my beautiful wife Mrs. Edna Adaramola for her support and
encouragement.
This thesis is however dedicated to my Sons (Olusegun, Oluwapelumi and
Oluwaferanmi) for making the home conducive for the writing of this research work.

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ACKNOWLEDGEMENTS
I would like to first express my gratitude to God for giving the wisdom and grace to be
able to carry out this research work.
My profound gratitude goes to my project supervisor, Dr. M.N Daikpor for the guidance
he has provided me throughout my M.Sc. programme. He has demonstrated an enviable
competence in his supervisory work and I pray that God will continue to assist him in all
his work.
I would like to specially thank Engr. Michael Adelabu for helping me during a rather
hard time at the University of Lagos, Akoka, Yaba in the year 2009. I would like to
thank Mr. Tunde Shofolahan, a colleague student for his help in this research work.
I will not forget Mr. Sunday Akinseloye, the co-ordinator for the Internet service room
of the University of Lagos for exposing me to the various network issue of the
institution.
Lastly, I would like to thank those who really made it possible for me to embark on my
M.Sc degree course at UNILAG because of their patience and emotional support, my
wife (Edna), My children (Olusegun, Oluwapelumi, Oluwaferanmi), my parent, my
brothers and my sisters.
My love and gratitude goes to all of you.

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ABSTRACT
This thesis studies the performance of the internet services of institution of higher
learning in Nigeria. Data was collected from several universities and polytechnics to
determine their level of internet operation. The performance of the Network Interface
Cards were studied and from the analysis of the collected data, it is found that there is
need to upgrade the various nodes of this WAN from a 10/100Mbps Ethernet to
10,000Mbps type in our institution of higher learning. The 10,000Mbps Ethernet was
proposed because it has the highest throughput and fastest data transmission time. The
problem of Internet Bandwidth optimization in the institution of higher learning in
Nigeria was extensively addressed in this thesis. The operation of the Link-Load
balancer which provides an efficient cost-effective and easy-to-use solution to maximize
utilization and availability of Internet access is discussed. In this project work, the
Lagrange’s method of interpolation was used to predict effective actual internet
bandwidth for considerably increasing number of internet users. The predictions allow
us to view the effective actual bandwidth with respect to the corresponding acceptable
number of internet users and this was proposed for each institution of higher learning. In
this research work, the performance of the installed unshielded twisted pair cable was
studied and from the analysis we proposed an upgrade to fiber optic type in all the
institution.

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TABLE OF CONTENTS
CONTENT PAGES
(i) Dedication . . . . . . . 1
(ii) Acknowledgments . . . . . . 2
(iii) Abstract . . . . . . . . 3
(iv) Table of Content . . . . . . . 4-5
(vii) List of Figures. . . . . . . . 6
(viii) List of Tables. . . . . . . . 7
(ix) Abbreviations . . . . . . . 8-12
1.0 Chapter One: Introduction . . . 13-15
1.1 Background . . . . . . 15-17
1.2 Statement of Problem. . . . . . 17
1.3 Aim and Objectives . . . . . 18
1.4 Scope of Study . . . . . . . 18-19
2.0 Chapter Two: Literature Review . . 20
2.1 The operation of TCP/IP . . . . 20
2.2 Internet Bandwidth Scheme . . . . 20-21
2.3 Data Transmission on the Internet . . . 21
2.4 Internet Packet Dynamics . . . . . 21-22
2.5 Throughput Maximization on the Internet . . 22
3.0 Chapter Three: Methodology . . . 23
3.1 Theoretical Frameworks . . . 23-56
3.2 Data Gathering Analysis . . . 57-58
4.0 Chapter Four: Results and Discussion. . . 59-67
5.0 Chapter Five: Concluding Remarks . . 68
6.0 Chapter Six: Recommendations . . . 69-71

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References 72-73
Appendix A . . . . . . . 74-75
Appendix B . . . . . . 76-92
Appendix C . . . . . . 93
Appendix D . . . . . . . 94-97
Appendix E . . . . . . 98-103
Appendix F . . . . . . 104-121
Appendix G . . . . . . 122-128
Appendix H . . . . . . . 129-131

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LIST OF FIGURES
Fig 4.1: The performance of 10Mbps Ethernet Card
Fig 4.2: The performance of 100Mbps Ethernet Card
Fig 4.3: The performance of 1,000Mbps Ethernet Card
Fig 4.5: Graph of effective actual bandwidth versus acceptable number of internet
users

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LIST OF TABLES
Table 3.1: Common UTP Media standards
Table 3.2: Total number of internet users
Table 3.3: Actual Bandwidth versus Number of Internet Users
Table 3.4: Actual Bandwidth Versus. Acceptable Number of Internet Users
Table 3.5: Data Gathering Analysis
Table 4.1: The performance of 10Mbps Ethernet card
Table 4.2: The performance of 100Mbps Ethernet card
Table 4.3: The performance of 1,00Mbps Ethernet card
Table 4.5: The Interpolated Actual bandwidth Versus Acceptable
Number of Internet Users.

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ABBREVIATIONS
ACK - Acknowledgments (packet)
AIFS - Arbitrary Inter-frame Spacing
AP - Access point
ARP - Address Resolution Protocol
CAP - Controlled Access period
CBR - Constant Bit Rate
CCK - Complementary Code Keying
CFP - Contention Free Period
CSMA/CA - Carrier Sense Multiple Access with Collision Avoidance
CSMA/CD - Carrier Sense Multiple Access with Collision Detection
CTS - Clear to send
DNS - Domain Name Service
DHCP - Dynamic Host Configuration Protocol
DIFS - Direct Inter-Frame Spacing
EDCF - Enhanced Distribution Co-ordination Function
EDCA - Enhanced Distribution Channel Access
FCS - Frame Check Sequence
FEC - Forward Check Correction
FHSS - Frequency Hopping Spread Spectrum
Gbps - Gigabit per second
HTML - Hypertext Mark-up Language
HTTP - Hypertext Transfer protocol
IEEE - Institute of Electrical and Electronics Engineers
IETF - Internet Engineering Task Force
IFS - Inter-frame Spacing
ISP - Internet Service Provider

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IP - Internet Protocol
ITU – T - International Telecommunication Union,
Telecom Standardization.
LAN - Local Area Network
LLC - Link Logical Control
MAC - Media Access Control
IPsec - IP Security
Mbps - Megabit Per second
NIC - Network Interface Card
OSI - Open System Interconnection
PC - Personal computer
PCF - Point Coordination Function
PIFS - PCF IFS
Pd - Packetization Delay
PLR - Packet Loss Rate
POC - Packet Order Correction
POS - Point of Sale
POTS - Plain Old Telephone Service
QoS - Quality of Service
RARP - Reverse Address Resolution Protocol
RFC - Request for Comment
RTS - Request to Send
RTT - Round Trip Time
SA - Source Address
SFD - Start of Frame Delimiter
SNMP - Simple Network Management Protocol
SMTP - Simple Mail Transfer Protocol

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SIFS - Short Inter Frame Spacing
STA - Station (wireless)
TCP - Transmission Control Protocol
TCP/IP - Transmission Control Protocol/Internet Protocol
UDP - User Datagram Protocol
UTP - Unshielded Twisted Pair
VCH - Virtual Collision Handler
VoD - Video on Demand
VoIP - Voice over IP
WAN - Wide Area Network
WLAN - Wireless LAN
WM - Wireless Medium
ICMP - Internet Control Mail protocol
IPV4 - IP Version 4.0
IP V6 - IP Version 6.0
NAT - Network Address Translation
VPN - Virtual Private Network
CIDR - Classless Inter-Domain Routing
NSAP - Network Service Access Point
IPX - Internetwork Packet Exchange
TLA - Top Level Aggregator
TTL - Time to Leave
VSAT - Very Small Aperture Terminal
ESP - Encapsulating Security Payload
SKIP - Simple key-Management for Internet Protocols
ISAKMP - Internet Security Association and Key- Management
Protocol

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SPI - Security Parameter Index
EMI - Electro Magnetic Interference
FDX - Full-duplex Communication System
MMF - Multimode Fiber
SMF - Single-Mode Fiber
MHz - Mega Hertz
Nm - Nanometers
DSF - Dispersion Shifted Fiber
DWDM - Dense Wavelength Division Multiplexing
NZDSF - Non-zero Dispersible Shifted Fiber
- Micrometers
TIA - Telecommunications Industry Association
USB - Universal Serial Bus
AWG - American Wire Gauge
OUI - Organizationally Unique Identifier
SAE - Stochastic Arbitration Event
CRC - Cyclic Redundancy Check
PCS - Physical Coding Sub-layer
PMD - Physical Media Dependent
MAN - Metropolitan Area Network
BGP - Border Gateway Protocol
HA - High –Availability
IBSS - Independent Basic Service Set
DSSS - Direct Sequence Spread Spectrum
EIFS - Extended Inter Frame Spacing
CP - Contention Period
IFS - Inter Frame Spacing

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BSS - Basic Service Set
VMM - Virtual Machine Matrix
ASICs - Application-Specific-Integrated Circuits

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CHAPTER ONE
1.0 INTRODUCTION
Today, the development of modernized Information Technology infrastructures and the
way they are interconnected with each other on the network of institutions of higher
learning will exhibit a dramatic change. The Wide Area Network (WAN) and internet
services performance of the campuses will change as well. Campuses cannot be isolated
from the rest of the world; they will be integrated into the ebb and flow of information
and computer technology (ICT).
How will these devices be operated when apparently everything around us are
networked? For example, in the transport layer, the fundamental issues include reliable
communication over an unreliable channel, connection establishment or teardown,
handshaking, congestion and flow control and multiplexing. In the routing layer, two
fundamentally important issues are on how to find “Good” paths between routers or a
router and client system, and how to deal with large and heterogeneous data systems. In
the data link layer, a fundamental problem is how to share a multiple access channel to
achieve transmission protocol knowledge and management. The combination of using
the internet to get the user’s foot in-door and then emphasizing the issues and solution
approaches will allow the internet users to quickly understand just about any networking
technology including implementation, improvisation, reliability and scalability. One
protocol that has the ability to share data across all types of networks is the Internet
protocol. Internet Protocol (IP) addresses the issues of millions of Personal Computers
(PC’s) and devices with different operating systems and platforms communicating with
each other. The internet protocol is able to translate or mediate whatever form of
information it receives, regardless of what network backbone (Copper wire, optical
fiber, wireless) or Service (native IP, frame relay, ATM) it may run on. Some examples
of the types of network Operations meditation it handles includes:
• Incompatible client /service software

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• Incompatible LAN environments (i.e. Windows and Linux)
• Different communication System (i.e. IP and Plain Old Telephone Service
(POTS), IP and Point-of-Sale (POS)).
• Different Quality of Service Mechanisms (I.e. IP Version 4.0, IP Version 6.0 and
ATM).
• Different Bandwidth capabilities (i.e. Caching, Mirroring and Load distribution).
This mediation capability was built into the Transport Control Protocol and Internet
Protocol (TCP/IP) suite from the start. As a platform-independent set of standards,
TCP/IP bridges the gap between dissimilar computers, operating systems and networks.
It is supported on nearly every computing platform, from PCs, Laptops, Palmtops,
Macintoshes and Unix systems to thin clients and servers, legacy mainframe, and the
newest supercomputers. In supporting both local and wide Area Network connections,
TCP/IP provides seamless interconnectivity between the two environments [1].
IP allows computers link to one another without having to know anything more than an
address. It is the cornerstone of the internet connectivity and will be an excellent
protocol for campus network.
In today’s Wide Area Network of the Campus, there may be dozens of new devices that
are installed. There will be new application. IP will definitely be a part of the network,
but as the needs and conditions change, the protocol will have to continue to evolve.
There are two possibilities to this. The first possibility is that IP version 4.0 remains the
dominant protocol and IP version 6.0 never gets off the ground. The second is that IP
version 4.0 will be slowly transitioned over to IP version 6.0. In either case, new issues
will continue to surface and new solutions will be created.
Internet access is initially only available on fixed lines. Recently, wireless medium
access is growing astronomically for both private and public usage. In particular, IEEE

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802.11 wireless Local Area Network (WLAN) has become increasingly popular with
both network operators and end-users. Based on carrier sense Multiple Access with
Collision Avoidance (CSMA/CA) technique, WLAN provides a flexible medium for
wireless Internet access.
1.1 BACKGROUND
Campus networking will be more of a necessity than it is today. The campus will make
academic works easier in many ways, as microprocessors become less expensive and
require less power supply, they will be embedded into most communication equipment.
Information devices and components will evolve into smart devices that communicate
with each other. Connecting these devices on the internet will become more important as
new technologies evolve. It will be necessary to build a Wide Area Network (WAN) that
can handle the needs of this type of computing environment. The WAN of the campuses
will require many of the same features that can be found in today’s corporate networks.
However, there will be seven issues that will determine the level of success of
implementing and managing the WAN and Internet Services performance on institution
of higher learning. The first issue is the increase in volume of the devices accessing and
utilizing the internet. Of course, the number of users has experienced an astronomical
growth. Security will be a high priority for the users, since the data that accumulates and
circulates in and out of the WAN is very sensitive. The second issue is the need for
upgrade of Internet Protocol (IP) addressing from IP version 4.0 to IP Version 6.0
standard. The third critical issue is the replacement of the Unshielded Twisted Pair
(UTP) category 5e Network cable with optic fiber type. The fourth is the need to
upgrade the Network Interface Card (NIC) from the present 100Mbps to 10Gbps
Ethernet card starting from the servers to all workstations. The fifth is the optimization
of data transfer speed within the Local Area Network (LANs) using high performance

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switches. The sixth critical issue is the urgent need for Wireless Network configuration
and implementation. University of Lagos has over 20,000 users connected with its Wide
Area Network and Internet Services. Also, internet access is no longer a luxury but a
critical component of the overall network infrastructure that must be highly reliable and
always available. As a means of reliability of Internet access, the management of Unilag
had already leased for three Internet Service Provider (ISP) links connecting the WAN
to the internet in order to give room for multi-homing. However, the need for link load
balancer will provide an efficient, cost-effective and availability of Internet access while
minimizing cost. One of the links acts as a backup while the primary link is being
utilized. The last issue that will be important in the Campus is the increased need for
bandwidth and the ability to accommodate all types of data traffic.
There is no doubt that the internet protocol will be important in improving the WAN
based in Unilag and other campuses. Some proponents of IP say “IP over everything”.
The trend has been finding new ways of making IP the answer to all types of voice and
data communications. Initially, the internet protocol was designed for a specific
application. Over time, IP Version 4.0 has been able to successfully adapt to the
changing needs and demands of the internet. At one point in the early 90’s, it was feared
that IP Version 4.0 would not be able to meet the future needs. As a result, the Internet
Engineering Task Force (IETF) developed a next generation internet protocol, referred
to as Internet Protocol Version 6.0. The implementation of IP Version 6.0 has been
extremely slow since the imminent danger of declining address space has been
temporarily addressed. IP Version 6.0 has many new features built into the protocol that
will streamline and enhance many aspects of the campus networks, but these features
alone may be enough to cause the total displacement of the massive infrastructure of IP
Version 4.0. Will IP version 6.0 be better at handling the demands of the WAN of the
future, or will the additions and updates for IP Version 4.0 be sufficient? What are some
of the resolutions that are being developed or are already implemented for the key issues

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in campus networks – the increasing number of devices, security, and ease of use and
data flow? In addition, the entire networks cabling of the campus has to be replaced by
optic fiber which support the highest broadband in performance. One other means of
improvement is to introduce the 10Gigabit Ethernet interconnect solutions. The
10Gigabit Ethernet networks can result in data center optimization by introducing
flexibility and preventing latency. There is need for high performance switches for the
entire network. We find out that these switches come in stackable and chassis models.
These kinds of switches also provide other functions, such as better management
capabilities, support for the Simple Network Management Protocol (SNMP) and Remote
Monitoring (RMON) and the capability to create Virtual LANs (VLANs). Lastly, there
is need for the provision of Wireless Network Connections for individual student/staff
laptops or palmtops which would aid better efficiency and performance of internet
services.
1.2 STATEMENT OF PROBLEM
In this thesis, the major problems addressed with appropriate solutions are as follows:
- The problem of poor Internet Bandwidth optimization which has resulted to high-level
of service downtime in the availability of Internet access was sufficiently addressed.
- The problem of inability to predict the actual internet bandwidth with respect to the
corresponding acceptable number of internet users in higher institution of learning was
considerably solved.
-The problem of low throughput and slow data transmission time on the Network
Interface Cards of the nodes in the WAN of the higher institution of learning was also
solved.
-The challenges of low-speed switches and cables in the campus WAN was addressed
and appropriately solved.

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1.3 AIM AND OBJECTIVES
1.3.1 AIM
The aim of this research work is to adequately study the performance of the internet
services of various institutions of higher learning in Nigeria.
1.3.2 OBJECTIVES
There are six objectives of this research:
1. To investigate the performance of the IP addressing standard of the entire
WAN of institution of higher learning and make commendable
recommendations.
2. To study the cabling system of LANs in institutions of higher learning and
make appropriate recommendations.
3. To investigate the performance of Network Interface Cards used for the
servers and client systems and make recommendations.
4. To study the performance of Internet Services Bandwidth management
technique of the WAN and make appropriate optimization, prediction and
recommendation.
5. To investigate the performance of the Network switches used for the LANs
and make appropriate recommendations.
6. To study the effect of wireless Network and Internet Services over the WAN.
Also, to recommend relevant wireless internet service that will provide better
performance and efficiency.
1.4 SCOPE OF STUDY
The scope of this research work is strictly on the following:
- The IP standard of the institutions at the moment is a critical issue. There is need to
upgrade from IPV4 to IPV6.

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-The Bandwidth management of the institutions of higher learning and the Internet
Access require better optimizations. These were majorly addressed based on the findings
made.
-The departmental and sectional LANs cabling of the institutions were of UTP category
5 or 5e and need to be replaced by a better performance cable (i.e. the optic fiber).
-The Network interface cards presently installed on the Server systems of the institutions
calls for upgrade. The service of the entire network largely rest on the NIC. Although,
only the services are used by the end-users, their performances are affected by the
underlying structure of the internet. Within this scope, an important role is played by
Transmission Control Protocol (TCP), which is designed for reliably sending data over
the internet is used for browsing the web and downloading or uploading files. TCP has a
feedback mechanism that is able to detect loss packets and retransmit them.
Furthermore, TCP is able to dynamically adapt its packet sending rate to the network
conditions in order to achieve the highest possible throughput.
-The network switches installed in all the institution are the store-and-forward type and
there is need for urgent upgrade to the Layer 3 stackable and chassis ones.

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CHAPTER TWO
2.0 LITERATURE REVIEW
2.1 THE OPERATION OF TCP/IP
The TCP/IP performance over Network was extensively studied since its introduction in
[2]. In this package, a large number of internet applications that are sensitive to overload
conditions in the network were examined. While these applications have been designed
to adapt somewhat to the varying conditions in the internet, they can benefit greatly
from an increased level of predictability in network services. They proposed minor
extensions to the packet queuing and discard mechanisms at the source that enable the
network to guarantee minimal levels of throughput to different sessions while sharing
the residual network capacity in a cooperative manner. The service realized by the
proposed mechanisms is an interpretation of the controlled-load service being
standardized by the internet engineering task force. The focus in this paper is on
understanding the controlled-load service interaction with Transmission Control
Protocol (TCP). Specifically, the study of the dynamics of TCP traffic in an integrated
service network that simultaneously supports both best-effort and controlled-load
sessions were carried out.
2.2 INTERNET BANDWIDTH SCHEME
The adaptive Bandwidth Reservation Scheme for high-speed Networks was also studied
from its grassroots in [3]. This paper proposed an admission control scheme based on
adaptive bandwidth reservation to provide QoS guarantees as they are expected to
support multimedia applications. This paper proposed an admission control scheme
based on adaptive bandwidth reservation to provide QoS guarantees for multimedia
traffic carried in high-speed wireless cellular networks. The proposed scheme allocates
bandwidth to a connection in the cell where the connection request originates and
reserves bandwidth in all neighboring cells. When a user moves to a new cell and a

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handoff occurs, bandwidth is allocated in the new cell, bandwidth is reserved in the new
cell’s neighboring cells, and reserved bandwidth in more distant cells is released.
2.3 DATA TRANSMISSION ON THE INTERNET
The performance analysis of Data Packet discarding in ATM Networks was also studied
in [4]. Data performance in Asynchronous Transfer Mode (ATM) networks should be
measured on the packet level instead of the cell level, since one or more cell losses
within each packet are equivalent to the loss of the packet itself. Two packet-level
control schemes, packet tail discarding and early packet discarding, were proposed to
improve data performance. In this paper, a new stochastic modeling technique is
developed for performance evaluation of two existing packet-discarding schemes at a
single bottleneck node. It was assumed that the data arrival process is independent of the
nodal congestion, which may represent the unspecified bit-rate traffic class in ATM
networks, where no end-to-end feedback control mechanism is implemented. Through
numerical study, the effects of buffer capacity, control, threshold, packet size, source
access rate, underlying high-priority real-time traffic, and loading factor on data
performance were sufficiently explored. The study shows that a network system can be
entirely shut down in an overload period if no packet-discarding control scheme is
implemented under the assumption that there are no higher layer congestion avoidance
schemes.
2.4 INTERNET PACKET DYNAMICS
The end-to-end Internet packet (IP) Dynamics was also extensively studied since its
introduction in [5]. Findings from a large-scale study of Internet Packet (IP) dynamics
conducted by tracing 20,000 TCP bulk transfers between 35 internet sites were
discussed. Each 100 Kilobyte transfer at both the sender and the receiver was
successfully traced. The measurements allow us to distinguish between the end-to-end
behaviors due to the different directions of the internet paths, which often exhibit

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asymmetries. The prevalence of unusual network events such as out-of-order-delivery
and packet replication was characterized. A robust receiver-based algorithm for
estimating “bottleneck bandwidth” that addresses deficiencies discovered in technique
based on “packet pair” was discussed. Investigation of the pattern of packer loss, finding
that loss events are not well modeled as independent and that the distribution of the
duration of loss events exhibits infinite variance. Variations in packet transit delays as
indicators of congestion periods also span a wide range of time scales were analyzed.
2.5 THROUHPUT MAXIMIZATION ON THE INTERNET
A scheme for throughput maximization in a dual-class CDMA system was greatly
studied in [6]. The work focused on the problem of efficient exploitation of the available
bandwidth in order to provide high bit rates on the wireless link, as will be required in
future wireless system interfacing to broadband fixed networks. In particular, the Uplink
of a CDMA system with two user classes was considered. One of the classes consists of
delay–tolerant users needing support for an information bit rate larger than a given
value. It was assumed that when no transmitting information, synchronization contact is
maintained with the base station at a given rate. The objective is to maximize the
throughput of the delay-tolerant users, while ensuring that the interference to other cells
is as low as possible by minimizing the sum of all of the transmit powers used by the
mobiles.

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CHAPTER THREE
3.0 METHODOLOGY
In order to achieve the aim of this thesis, data was collected from different universities
and polytechnics. The institutions were visited and relevant questions were asked from
their Network Administrators. The Network Administrator supplied correct data of the
performance of the internet services in the institution and also discussed their
challenges. For the actual internet bandwidth data, the acceptable number of internet
users was measured through the SNMP software installed on the Internet Server System
of University of Lagos, (i.e. the case study of this research work).
3.1 THEORETICAL FRAMEWORKS
3.1.1 IP ADDRESSING STANDARD
The Internet has already made an impact in many countries all-over the world, but it is
only the beginning. The internet will dominate as the resource for sharing data as
networks of the campuses become more powerful and robust. It will be a vast matrix of
wireless and wire line devices; all trying to create a seamless system of information that
will improve the academia. There are many aspects of a seamless communications
system, and one of the most important aspects is the ability to interface physical
networks with multiple operating systems. The internet protocol is merely software
designed to be this interface. Users, application programs and higher layers of protocol
software use the internet protocol addresses to communicate [2]. Obviously, this is the
essence of the communication that occurs throughout the internet.
The internet protocol remains important issue for several reasons. It is non- proprietary,
open, and it offers ways to merge voice and data traffic on a common platform (i.e.
convergence). IP networks meet the requirements for interoperability and integration,
scalability, mediation, reliability, manageability, security, and have global reach [1].
Each version of the internet protocol has similar characteristics and abilities. Though the

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campus WAN operates internet protocol version 4.0, a majority of the features in IP V6
are not all new. Internet protocol version 6.0 retains all of the positive features of IPV4,
but incorporates of the lessons that have been learned over the last twenty years. IPV6
has taken advantage of IPV 4’s history and will be the only protocol that will meet the
needs of campus network [7].
3.1.1.2 LIMITATIONS OF IP VERSION 4.0
IPV6 is simpler than IPV4 for a couple of many reasons. The designers had twenty years
of experience before IPV6 was designed. In fact, there has been time to identify the
weaknesses in IPV4 and make corrections. Some of these weaknesses are highlighted as
follows:
3.1.1.3 Volume
IPV4 is limited to 4.2 billion devices communicating on the global network at any given
point in time. For better analysis, IPV4 uses 32 bit, the total addressing space is shown
below:
IPV4 = 232
= 4, 294, 967, 296 = 4.2 Billion.
Eventually, it will not be enough. The volume of devices will increase dramatically as
smart devices are developed and incorporated into the campus network. Although not
every WAN on the planet will have the need for multiple devices connected to a global
network, the number will continue to grow. Many campuses today have computers,
laptops, palmtops, GSM Mobile phones with internet connections, but this does not
resemble the campus networks of the future. They will have a high density of nodes and
will consist of many complex systems that are made up of many individual devices [7].

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3.1.1.4 Security
Security needs to be present inside and outside of the campus community. Therefore,
campus WAN will not accept outsiders (i.e. intruders) being able to monitor the
activities inside the entire community.
Presently, IPsec had been implemented in both IPV4 and IPV6. As IPsec has been
implemented in IPV4, there are very few differences between the two protocols when it
comes to security.
IPV4 will not be able to sustain the volume of devices that will be needed in campus
network. Eventually, Classless Inter-Domain Routing (CIDR) will not provide the level
of aggregation required, and Network Address Translation (NAT) will be available. The
NAT already has limitations with IPsec which is gaining more popularity because of
Virtual Private Networks (VPNs). NAT is just a temporary solution to an existing
problem; it is not a long-term solution. CIDR is still not supported in all parts of the
internet. Even if the addresses were not completely depleted, the addresses would still
need to be managed carefully. It is already difficult to manage a depleting address space
and will only become more difficult in the next generation [7].
3.1.1.5 Data Flow
The Key to effective data flow is the ability to efficiently handle packets. The less
handling that is needed to allow the packets to traverse the network optimally, the more
flexible the protocol will be. IP has mostly been used for data applications that are
suitable for a best effort delivery system. Streaming video and voice has not been widely
distributed via the Internet because of bandwidth limitations and the lack of Qualify of
Service (QoS).This is very peculiar to the Unilag WAN and Internet Services. Data flow
is not efficient in IPV4. The IPV4 headers vary in size, which means the routers have to
calculate the length of an IPV4 payload, which creates additional overhead.
Fragmentation occurs at intermediary nodes, and anytime an option is added to the

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header it takes additional overhead and also creates inefficiencies because each router
has to analyze the header. IPV4 was not designed to handle the needs of voice, video
and other that need quality of service [7].
3.1.2 NETWORK CABLING SYSTEM
In any network, most of the specifications deal with the physical makeup of the cabling
involved in connecting the individual components of the network. Actually, media
refers to the environment through which communication or data transmission can take
place. Until very recently, this environment has been limited to some type of cabling
such as co-axial cabling or twisted- pair copper wire or even fiber-optic cabling.
Understanding the cable types, the number of wires in a cable (both shielded and
unshielded varieties), and several other electrical factors is critical to successfully
upgrading or maintaining your network system. The type of cable you use depends on
the type of LAN you are creating. The connectors, terminators and distance that can be
covered by particular cable types will be a factor in determining any cable length
restrictions and overall quality of LAN you can create [8].
However, with the rapid development of wireless technologies, media doesn’t have to be
a physical cable for data transmission to take place in a local area network.
Some of the features that network analysts and Administrators look for are reliability,
security, flexibility, adaptability and longevity. Ease of installation is always a nice
feature too, but not at the expense of other key features. In this chapter, we will explore
the various types of cabling that can be implemented in a local area network as well as
why campuses choose various types of communication media [9].
3.1.2.1 TWISTED – PAIR CABLING
Twisted-pair cabling has become one of the most popular data transmission media used
in local area network. From research, this is the cabling installed in the Unilag LAN

27
environments. From a technology standpoint, twisted-pair cabling consists of several
two-wire pairs enclosed in a synthetic sheath. Each of the twisted-pair is composed of
an insulated 22- or 24-gauge copper wires twisted together: the twisting configuration
reduces unwanted electronic and magnetic interference (EMI- Electro-Magnetic
Interference) from disrupting the existing data transmission on the wires.
Economically, twisted-pair cabling is very popular because it is relatively inexpensive
and easy to install and maintain. It is highly reliable to an extent, supports high data
rates and it is a standard for Ethernet networks that has become pervasive in the business
would for LAN data transmission. It is available in several different formats and various
categories as described in the following sections [9] and [10].
3.1.2.2 UNSHIELDED TWISTED - PAIR
Unshielded Twisted – Pair cabling or UTP as it is commonly called consists of two,
three or four unshielded twisted –wire pairs. Each individual wire is coated in vinyl or
other plastic derivative and the entire bundle of wires is wrapped in a plastic sheath.
The sheathing does not however provide any protection from EMI [9]. The UTP is
classified into six different categories.
Category 1 UTP was originally specified for voice transmission. This is universally
adopted as ordinary telephone wire. Once an existing building is wired with this grade
of UTP cabling, it should not be used for data transmission purpose in a local area
network.
Category 2 UTP is also used in telephone voice applications, but it will support data
transmission at speeds only up to 4 Megabits per second in a local area network.
Category 3 UTP is considered data grade, as it supports data transmission at speeds up
to 16 Megabits per second over a distance of 100 meters. At distances greater than 100
meters, degradation of the data transmission signal can result in entire data loss.

28
Category 4 UTP is another data grade cable, but capable of supporting data
transmission rates up to 20 Megabits per second at distances of 100 meters.
Category 5 UTP is also data- grade, unshielded twisted – pair cable and was originally
developed to handle 100 Megabits per second data transmission on local area network at
distances of up to 100 meters. The support for a greater transmission rate comes from
twisting the cable more times per foot and using better materials than the lower
categories. With any category 5 UTP installation, installation of connectors on the cable
ends is critical to supporting the high data transmission rates. Category 5 UTP was
originally designed for bandwidths of up to 100 Mbps, and it will support 1,000Mbps
(1Gbps) data transmission according to the original IEEE 802.3z Gigabit Ethernet
specifications, but for best results, category 5e UTP is strictly recommended in Gigabit
Ethernet environment. Category 5e UTP is much the same as category 5 UTP, but with
strict, adherence to manufacturing and installation specifications, category 5e UTP is
designed to support data transmission rates of 1Gbps and greater.
Category 6 UTP supports higher frequency transmission across the cable, which
translates into higher data rates. Whereas category 5 and 5e support signaling
frequencies as high as 100MHz, category 5 UTP will support signal frequencies as high
as 250MHz. This category is also capable of handling data transmission rates as high as
10Gbps [9].
Category 7 UTP The latest category, category 7 UTP cabling, offers a different
approach to twisted–pair cabling architecture. The cable is assembled with an overall
shield and individually shielded pairs. The most significant improvement with this type
of cable will be in the higher performance bandwidth achieved with signal frequencies

29
up to 600MHz. It is also designed to be backward-compatible with lower performance
categories and classes, although it appears it will have a new interface for the jack and
plug [8]. The common UTP media standards are shown in Table 3.1 below.
TABLE 3.1: COMMON UTP MEDIA STANDARDS [10].
Media type Maximum data rate Application
Cat 1 UTP Less than 1 Mbps Home telephone lines.
Cat 2 UTP 4 Mbps 4 Mbps Token Ring Networks,
older POTS lines (1983-1993)
Cat 3 UTP 100Mbps 4 Mbps, Token Ring
Networks, 10Mbps Ethernet
LANs, same 100Mbps
Ethernet LANS and POTSs
lines installed after 1993.
Cat 4 UTP 100 Mbps 4 or 16 Mbps Token Ring
Networks, 10Mbps Ethernet
LANs, same 100Mbps
Ethernet LANs
Cat 5 UTP 1,000Mbps 4 or 16 Mbps Token Ring
Networks, 10 and 100 Mbps
Ethernet LANs, 1Gbps
Ethernet LANS with four
pairs ATM at 155Mbps.
Cat 5e UTP 10Gbps 1,000 and 10,000 Mbps
Ethernet ATM at 155Mbps.
Cat 6 UTP 10Gbps High-speed multimedia

30
applications. Over Ethernet
LANs with speeds greater than
1Gbps.
Research work shows that the LANs installed in the University of Lagos and the
suburban employed the category 5 UTP media with 10/100Mbps Ethernet. This is a
discovery that formed part of the main objective of this M.Sc. thesis.
3.1.2.3 SHIELDED TWISTED-PAIR
Shielded twisted-pair (STP) cabling provides the same connectivity benefits as
unshielded twisted-pair, however, where unshielded twisted- pair uses only a synthetic
jacket to house the twisted pairs, shielded twisted-pair cabling aids two levels of
shielding material to protect the transmission from electromagnetic interference.
In applications where cabling might come in close contact with powerful electric
motors, multiple banks of fluorescent lights or higher-voltage electrical cable runs each
of these generates EMI that can interfere with your local area network data transmission.
We might find it advantageous to budget for the extra Naira cost of STP cabling and
extra installation time associated with properly grounding the metallic shielding [9].
3.1.2.4 THE LIMITATIONS OF UNSHIELDED TWISTED-PAIR
i. The sheathing on the UTP does not provide any protection from EMI.
ii. The UTP categories are not designed for data bandwidths above 100Mbps.
iii. During data transmission, there is high-level of signal attenuation at high
frequencies (i.e. degradation of data signal).
iv. UTP categories handle data transmission on local area network at distances of up
to 100 meters maximum.
v. With UTP cabling, special care must be taken in attaching a RJ-45 connector so
that there is no exposure of the twisted-pair wires.

31
vi. The biggest drawback of UTP cable is that signal loss increases with signal
frequency. Signal loss is always higher at 100MHz than at 10MHz.
vii. In UTP cable, high-speed data increases power loss and decreases practical
transmission distance.
3.1.3 ETHERNET DATA TRANSMISSION ANALYSIS
The Ethernet data transmission analysis is needed in order to sufficiently support
reasons for the Unilag WAN NIC upgrade. The analysis is basically carried out using
the maximum or highest Round Trip Time (RTT) of the Ethernet Cards and the
maximum period of data acknowledgement (Tack) in [6] and [11].
I. Considering a message size of 1MB to be transmitted having a one-way delay
round trip time (RTT) of 1ms in order to receive an acknowledgement in 1ms. For this
scenario, determine the throughput of the Ethernet data transmission
i. If the link has a capacity of 10Mbps
ii If the link has a capacity of 100Mbps
iii. If the link has a capacity of 1.000Mbps
iv. If the link has a capacity of 10,000Mbps
In the first case,
The total Round Trip Time is given as RTT total = RTT + Tack
:. RTT total = 1ms + 1ms = 2ms = 0.002 second
The Transmission Time is given as
Ttx =
andwidthEthernet
SizeMessage
B
= 1 x 8 x 106
10 x 106
Ttx = 0.8 second
The total time delay is given as

32
Ttotal = RTTtotal + Ttx
= 0.002 + l0.8
:. Ttotal = 0.802 second
The throughput is given as
Throughput =
delayTimeTotal
sizeMessage
= 6
6
1097.9
802.0
1081
×=
××
∴ Throughput = 9.97Mbps
In the second case,
The Ethernet bandwidth = 100Mbps
Transmission Time,
BandwidthEthernet
SizeMessage
Ttx =
= 6
6
10100
1081
×
××
∴ ondTtx sec08.0=
txtotaltotal TRTTT +=
= 0.002 + 0.08
∴ ondTtotal sec082.0=
Throughput =
delayTimeTotal
sizeMessage
=
6
6
1056.97
082.0
1081
×=
××
:. Throughput = 56.97 Mbps

33
In the third case,
The Ethernet bandwidth = 1,000Mbps
Transmission Time,
BandwidthEthernet
SizeMessage
Ttx =
= 6
6
10000,1
1081
×
××
ondTtx sec008.0=∴
ondT
TRTTT
total
txtotaltotal
sec01.0
008.0002.0
=∴
+=
+=
Throughput =
DelayTimeTotal
SizeMessage
= 01.0
1081 6
××
= 6
10800 ×
MbpsThroughput 800=∴
In the fourth case,
The Ethernet bandwidth = 10,000Mbps
Transmission Time,
BandwidthEthernet
SizeMessage
Ttx =
= 6
6
10000,10
1081
×
××
ondTtx sec0008.0=∴

34
0008.0002.0 +=
+= txtotaltotal TRTTT
ondTtotal sec0028.0=∴
Throughput =
delayTimeTotal
sizeMessage
=
6
6
1014.857,2
0028.0
1081
×=
××
:. Throughput = 14.857,2 Mbps
II. Considering a message size of 5MB to be transmitted having a one-way delay
round trip time of 1ms in order to receive an acknowledgement in 1ms. For this
scenario, determine the throughput of the Ethernet data transmission.
(i) If the link has a capacity of 10Mbps
(ii) If the link has a capacity of 100Mbps
(iii) If the link has a capacity of 1,000Mbps
(iv) If the link has a capacity of 10,000Mbps
In the first case,
The total Round Trip Time is given as
msmsms
TRTTRTT acktotal
211 =+=
+=
ondRTTtotal sec002.0=∴
The transmission time is given as
BandwidthEthernet
SizeMessage
Ttx =
= 6
6
1010
1085
×
××

35
ondTtx sec0.4=∴
0.4002.0 +=
Throughput =
delayTimeTotal
sizeMessage
=
6
6
10995.9
002.4
1085
×=
××
In the second case,
BandwidthEthernet
SizeMessage
Ttx =
= 6
6
10100
1085
×
××
ondTtx sec4.0=∴
4.0002.0 +=
Throughput =
delayTimeTotal
sizeMessage
=
6
6
105.99
402.0
1085
×=
××

36
In the third case,
BandwidthEthernet
SizeMessage
Ttx =
= 6
6
101000
1085
×
××
ondTtx sec04.0=∴
04.0002.0 +=
Throughput =
delayTimeTotal
sizeMessage
=
6
6
1038.952
042.0
1085
×=
××
In the fourth case,
BandwidthEthernet
SizeMessage
Ttx =
= 6
6
10000,10
1085
×
××
ondTtx sec004.0=∴

37
004.0002.0 +=
Throughput =
delayTimeTotal
sizeMessage
=
6
6
1067.666,6
006.0
1085
×=
××
III. Considering a message size of 10MB to be transmitted having a one-way delay
round trip time of 1ms in order to receive an acknowledgment in 1ms. For this scenario,
determine the throughput of the Ethernet data transmission.
ii. If the link has a capacity of 100Mbps
In the first case,
acktotal TRTTRTT +=
= 1ms + 1ms = 2ms
:. RTT total = 0.002 second
Ttx =
andwidthEthernet
SizeMessage
B
= 10 x 8 x 106
10 x 106

38
:. Ttx = 8.0 second
= 0.002 + 8.0
:. Ttotal = 8.002 seconds
Throughput =
delayTimeTotal
sizeMessage
= 6
6
1099.9
002.8
10810
×=
××
In the second case,
BandwidthEthernet
SizeMessage
Ttx =
= 6
6
10100
10801
×
××
∴ ondTtx sec8.0=
= 0.002 + 0.8
Throughput =
delayTimeTotal
sizeMessage

39
=
6
6
1075.99
802.0
10801
×=
××
In the third case,
The Transmission time is given as
BandwidthEthernet
SizeMessage
Ttx =
= 6
6
10000,1
10801
×
××
ondTtx sec08.0=∴
ondT
TRTTT
total
txtotaltotal
sec082.0
08.0002.0
=∴
+=
+=
Throughput =
DelayTimeTotal
SizeMessage
=
082.0
10801 6
××
= 6
106.975 ×
MbpsThroughput 6.975=∴
In the fourth case,
BandwidthEthernet
SizeMessage
Ttx =
= 6
6
10000,10
10810
×
××
ondTtx sec008.0=∴

40
008.0002.0 +=
Throughput =
delayTimeTotal
sizeMessage
=
6
6
10000,8
01.0
10801
×=
××
:. Throughput = 000,8 Mbps
IV. Considering a message size of 15MB to be transmitted having a one-way delay
In the first case,
RTT total = RTT + Tack
= 1ms + 1ms = 2ms
Ttx = Message size
Ethernet Bandwidth

41
= 15 x 8 x 106
10 x 106
:. Ttx = 12.0 seconds
= 0.002 + 12.0
:. Ttotal = 12.002seconds
Throughput =
delayTimeTotal
sizeMessage
=
002.12
10815 6
×× 6
1099.9 ×=
In the second case,
BandwidthEthernet
SizeMessage
Ttx =
= 6
6
10100
10851
×
××
∴ ondTtx sec12=
= 0.002 + 1.2
Throughput =
delayTimeTotal
sizeMessage

42
=
6
6
1080.99
202.1
10851
×=
××
In the third case,
BandwidthEthernet
SizeMessage
Ttx =
= 6
6
10000,1
10851
×
××
ondTtx sec12.0=∴
ondT
TRTTT
total
txtotaltotal
sec122.0
12.0002.0
=∴
+=
+=
Throughput =
DelayTimeTotal
SizeMessage
=
122.0
10851 6
××
= 6
106.983 ×
In the fourth case,
BandwidthEthernet
SizeMessage
Ttx =
= 6
6
10000,10
10815
×
××
ondTtx sec012.0=∴

43
012.0002.0 +=
Throughput =
delayTimeTotal
sizeMessage
=
6
6
1042.571,8
014.0
10851
×=
××
V. Considering a message size of 20MB to be transmitted having a one-way delay
In the first case,
RTT total = RTT + Tack
= 1ms + 1ms = 2ms
Ttx = Message size
Ethernet Bandwidth

44
= 20 x 8 x 106
10 x 106
:. Ttx = 16 seconds
= 0.002 + 16.0
:. Ttotal = 16.002seconds
Throughput =
delayTimeTotal
sizeMessage
=
002.16
10820 6
×× 6
1099.9 ×=
In the second case,
BandwidthEthernet
SizeMessage
Ttx =
= 6
6
10100
10820
×
××
∴ ondTtx sec6.1=
= 0.002 + 1.6
Throughput =
delayTimeTotal
sizeMessage

45
=
6
6
1087.99
602.1
10820
×=
××
In the third case,
BandwidthEthernet
SizeMessage
Ttx =
= 6
6
10000,1
10820
×
××
ondTtx sec16.0=∴
ondT
TRTTT
total
txtotaltotal
sec162.0
16.0002.0
=∴
+=
+=
Throughput =
DelayTimeTotal
SizeMessage
=
162.0
10820 6
××
= 6
1065.987 ×
In the fourth case,
BandwidthEthernet
SizeMessage
Ttx =
= 6
6
10000,10
10820
×
××
ondTtx sec016.0=∴

46
016.0002.0 +=
Throughput =
delayTimeTotal
sizeMessage
=
6
6
1089.888,8
018.0
10820
×=
××
3.1.4 INTERNET BANDWIDTH CALCULATIONS
The University of Lagos, Yaba, Lagos as a case study of this thesis has the following
data as at 15th
September, 2011 shown in table 3.2 below. This is the most recent
numerical data of the total number of Internet Users of the campuses.
Table 3.2: Total Number of Internet Users
LOCATION TYPE OF
INTERNET USER
NUMBER OF
INTERNET USERS
Unilag MBA
Executive Complex,
Yaba.
Academic Staff
Non-Academic Staff
Student
40
30
930
LUTH, Unilag ,Idi-
Araba, Surulere.
Academic Staff
Non -Academic Staff
1,400
3,600
Unilag campus, Akoka,
Yaba.
Academic Staff
Non -Academic Staff
Student
2,450
4,950
7,600
Total Number of Internet Users 21,000

47
The Data table below was obtained from the Network Administrator’s Users Record at
which the ISP Actual Internet Bandwidth is 80Mbps. Measurement at peak periods (i.e.
1:00pm to 2:00pm) from the SNMP and Solaris Bandwidth Manager Program installed
on the Internet Servers showed that the campus has the following measured data analysis
in the table below.
Table 3.3: Actual Bandwidth versus Acceptable Number of Internet Users
Year Acceptable number of
internet users
Actual Internet
Bandwidth
2009 9,000 60Mbps
2010 14,000 70Mbps
2011 19,000 80Mbps
In the last three years, we have three measured data points which can be interpolated so
as to predict the effective actual Bandwidth and the acceptable number of internet users
for the Internet access in the entire campus community. For better analysis: Let
xi Represents the Acceptable number of Internet users (’000)
F(xi) Represents the Actual Bandwidth (Mbps).
The measured data points are tabulated in table 3.4 below:
Table 3.4: Actual Bandwidth with Acceptable Number of Internet Users
Xi(‘000) F(xi) (Mbps)
9.00 60
14.00 70
19.00 80

48
Using Lagrange’s interpolation Polynomial in [4] and [12] on the three data points
measured, we have )()()()()()()( 2221110 xfxLxfxLxfxLxP oon ++=
Where,
)()(
)()(
)(
2
2
xxxx
xxxx
xL
OiO
i
oo
−−
−−
= ,
)()(
)()(
)(
211
2
11
xxxx
xxxx
xL
O
i
−−
−−
= , and
From the available data points,
)199()149(
)19()14(
)( 00
−−
−−
=
xx
xL ,
)1914()914(
)19()9(
)( 11
−−
−−
=
xx
xL and
)1419()919(
)14()14(
)( 22
−−
−−
=
xx
xL
At this junction, we can now obtain values for the expected number of internet users and
the corresponding effective actual Bandwidth. For 20,000 internet users, the
corresponding effective actual Bandwidth will be calculated as follows:
)()()()()()()20( 222111 xfxLxfxLxfxLP ooon ++=
=
)1914()914(
)70()1920()920(
)199()149(
)60()1920()1420(
−−
−−
+
−−
−−
+
)1419()919(
)80()1420()920(
−−
−−
=
)10()5(
)60()1()6(
−−
+
)5()5(
)70()1()11(
−
+
)5()10(
)80()6()11(
= 7.2 - 30.8 + 105.6
:.P(20) = 82 Mbps
For 25,000 Internet users, the corresponding effective actual bandwidth will be
evaluated as follows:
P(25) =
)1914()914(
)70()1925()925(
)199()149(
)60()1925()1425(
−−
−−
+
−−
−−
+
)1419()919(
)80()1425()925(
−−
−−
)()(
)()(
)(
122
1
22
xxxx
xxxx
xL
O
i
−−
−−
=

49
=
50
)60()6()11(
-
25
)70()6()16(
+
50
)80()11()16(
= 1.32(60) - 3.84(70) + 3.52(80)
= 79.2- 268.8 + 281.6
:.P(25) = 92Mbps
For 30,000 internet users the required effective actual Bandwidth will be calculated as
follows.
P(30) =
)1914()914(
)70()1930()930(
)199()149(
)60()1930()1430(
−−
−−
+
−−
−−
+
)1419()919(
)80()1430()930(
−−
−−
=
50
)60()11()16(
-
25
)70()11()21(
+
50
)80()16()21(
= 211.2 - 646.8 + 537.6
= 79.2 - 268.8 + 281.6
:.P(30) = 102Mbps
For 35,000 internet users, the required effective actual Bandwidth will be evaluated as
follows.
P(35) =
)1914()914(
)70()1935()935(
)199()149(
)60()1935()1435(
−−
−−
+
−−
−−
+
)1419()919(
)80()1435()935(
−−
−−
=
50
)60()16()21(
-
25
)70()16()26(
+
50
)80()21()26(
= 403.2 - 1,164.8 + 873.6
:.P(35) = 112Mbps
For 45,000 internet users, the required effective actual bandwidth will be evaluated as
follows:
( ) ( ) ( )
( ) ( )
( ) ( ) ( )
( ) ( )
( ) ( ) ( )
( ) ( )1419919
801445945
1914914
701945945
199149
6019451445
)45(
−−
−−
+
−−
−−
+
−−
−−
=nP
=
( )( ) ( ) ( ) ( ) ( ) ( ) ( ) ( )
50
803136
25
702636
50
602631
+−
= 967.2 – 2,620.8 + 1,785.6

50
:.P(45) = 132Mbps
For 50,000 internet users, the required actual bandwidth will be calculated as follows:
( ) ( ) ( )
( ) ( )
( ) ( ) ( )
( ) ( )
( ) ( ) ( )
( ) ( )1419919
801450950
1914914
701950950
199149
6019501450
)50(
−−
−−
+
−−
−−
+
−−
−−
=nP
=
( )( ) ( ) ( ) ( ) ( ) ( ) ( ) ( )
50
803641
25
703141
50
603136
+−
= 1,339.2 – 3,558.8 + 2,361.6
:.P(50) = 142Mbps
For 55,000 internet users, the required actual bandwidth will be evaluated as follows:
( ) ( ) ( )
( ) ( )
( ) ( ) ( )
( ) ( )
( ) ( ) ( )
( ) ( )1419919
801455955
1914914
701955955
199149
6019551455
)55(
−−
−−
+
−−
−−
+
−−
−−
=nP
=
( )( ) ( ) ( ) ( ) ( ) ( ) ( ) ( )
50
804146
25
703646
50
603641
+−
= 1,771.2 – 4,636 +3,017.6
:.P(55) = 152Mbps
For 60,000 internet users, the required effective actual bandwidth will be calculated as
follows:
( ) ( ) ( )
( ) ( )
( ) ( ) ( )
( ) ( )
( ) ( ) ( )
( ) ( )1419919
801460960
1914914
701960960
199149
6019601460
)60(
−−
−−
+
−−
−−
+
−−
−−
=nP
=
( )( ) ( ) ( ) ( ) ( ) ( ) ( ) ( )
50
804151
25
704151
50
604146
+−
= 2,263.2 – 5,854.8 + 3,753.6
:.P(60) = 162Mbps
3.1.5 NETWORK SWITCH HARDWARE TYPES
It is not much of a stretch to argue that switches are network administrator’s dream
come true at least most of the time. When we decide is something else to consider. As an

51
answer to this, the type of switches used with most LANs of Unilag network were
thoroughly studied in the course of this research work. Actually, not all switches use the
same technology. The importance of this distinction depends on which of these
functions of a switch is the most important to us:
i. Increasing the bandwidth for computers attached to a switch.
ii. Decreasing the possibility that frame errors will be propagated end-to-end in a
network link.
Much architecture is used for switching, and because of that many approaches have been
and are being tried. Some involve software that makes decision much like router
software that makes decision much like a router and sends frames on their way. Others
are hardware-based and can perform much better because no single components such as
a CPU can be bogged down when too much traffic passes through the switch. Two basic
modes of operation can be used by a switch when it forwards a packet out of a selected
port: cut-through and store-and-forward mode [8].
3.1.5.1 CUT-THROUGH SWITCHES
A cut-through switch begins transmitting the incoming frame on the outgoing frame on
the outgoing port after it receives the header information, or about 20 or 30bytes. The
entire switch needs to determine on which port to output the frame is the designation
address (Hardware Address), which is determined by the MAC address found in the
frame header. The switch continues to receive information and transmit it until the frame
has been “switched” frame one port to another. The advantage to this mode of operation
is speed. As long as nothing else goes wrong, the packet continues onto its destination at
a fast pace with little time involved in the switch. The switch is said to be switching at
wire speed. That is, the delay introduced by the switching function is so insignificant to
the end workstations since the full bandwidth is available for use.

52
This method has several disadvantages. However, the switch begins to send the packet
out before it knows whether the frame is damaged in any way. If the frame has been
corrupted data, the switch won’t be able to detect it unless it first receives the entire
frame and then compute the CRC (Cyclic Redundancy Check) value stored in the frame
check sequence filed. If a frame is badly malformed, as when an NIC sends out a frame
that is too long, a cut-through switch might think it is a broadcast packet and send it out
of all ports, causing unnecessary traffic congestion [8].
3.1.5.2 STORE-AND-FORWARD SWITCHES
In the store-and-forward switch, the switch buffers the frame in its own memory before
beginning to send it out to the appropriate port. This technique has two main advantages:
(i) The switch can connect two different topologies, such as 10Mbps and
100Mbps network, without having to worry about the different speeds.
(ii) The switch can operate like a bridge and check the integrity of the frame,
allowing it to discard damaged frame and not propagate them onto other
network segments.
This means that a malformed frame received from a local port can be discarded
immediately, instead of being sent through the entire switched network until the end-
node discovers that an error has occurred. A good example of this type of switch is the
ATM switch. It is possible to determine the store-and-forward delay at a single ATM
switch for a link rate, R of 155Mbps (A popular link speed for ATM) for packet length,
L of 1500bytes and Ethernet packet length, L of 48 bytes.
In this scenario,
The store-and-forward delay is given as:
R
L
SpeedLinkedRateLink
LengthPacketSizeMessageLinked
SF ==
)(
)(
For the maximum link message size, L = 1500bytes

53
sSF
R
L
SF
μ4.77
104.77
10155
81500
min
6
6
max
max
=∴
×=
×
×
==
−
For the minimum link message size, L = 48bytes
sSF
R
L
SF
μ5.2
105.2
10155
848
min
6
6
min
min
=
×=
×
×
==
−
The average store-and-forward delay is given as
sSF
s
ss
SFSF
SF
ave
ave
μ
μ
μμ
40
95.39
2
5.24.77
2
minmax
=
=
+
=
+
=
This shows that the average store-and-forward delay in an ATM switch is sμ40 .
Although the store-and-forward technology increases the latency factor, this delay
usually is not a big concern when you consider the increased throughput we can achieve
with a LAN switch in [11].
3.1.5.3 LAYER 3 SWITCHES
As switches are on an evolutionary upgrade path from hubs and bridges, an enhanced
breed of networking device is becoming increasingly popular in large networks like the
one of University of Lagos, Yaba. Layer 3 of the OSI model is the network. Generally,
switches are deployed in LAN, whereas routers, which use layer 3 addresses (such as an
IP address) are used to connect LANs that are separated by some distance, such as in a
campus LAN or to connect WANs. The main difference here is that the switch must
examine only a small amount of the frame header to determine the hardware address of a
frame and then send the frame out to the correct port.

54
However, routers need to dig further into the packet to find the higher-level protocol
address, such as an IP address. Routers also must modify the frame header, substituting
the routers MAC address as the source address of the frame, examining and modifying
the TTL field in the packet and performing checksum calculations to ensure the integrity
of the packet. Because of the extra processing involved, routers generally operate at a
lower speed than switches. Standard routers operating at slower speeds than switches
tend to become great bottlenecks in a network. To solve this problem, layer 3 switching
device usually take a different approach to the functions a router performs. Routers are
like computers (indeed, sometimes a computer with multiple NICs is used for routing in
a small network), and a processor must examine each packet and perform all the
functions just mentioned. Layer 3 switches usually implement these functions in
application-specific-integrated circuits (ASICs). By implementing these functions in
hardware, some layer 3 switches can operate at just about the wire speed, which
ordinary routers cannot do. Some layer 3 switches use proprietary technologies, because
standards are not complete for this type of device at this time.
Whatever method they use, the idea is to identify streams of traffic that are all traveling
to the same destination, and output them on the appropriate port as fast as possible. A
true layer 3 switch should support most of the following features which includes:
i. Support for TCP/IP as well as other protocol such as SNA, XNS, AppleTalk
and IPX
ii. Multicast control for broadcasting streaming video and audio
iii. SNMP support for network and switch management
iv. IEEE 802.1D spamming tree protocol support
v. IEEE 802.1Q VLAN support
vi. Port trunking to provide automatic switchover to parallel backbone
connections
vii. IEEE 802.3X full-duplex flow control support

55
viii. Fault tolerance features such as hot-swapping multiple fans and power supplies
and multiple CPUs.
3.1.6 WIRELESS NETWORK
Wireless data transmissions do not require the physical cabling or physical connectors
that wire connections do. Instead, a wireless medium can send and receive data
transmissions without using an electrical or optical conductor. With wireless
networking, we can obtain access to our WAN and send information without being
physically attached. Presently, this mode of having access to internet services is not
prominent in the operation of Unilag campus network. We can choose technology
solutions based on radio frequency (RF) technology, infrared and microwave. From a
business perspective, each of these modes of wireless communication has some
advantages. This allows us to work from just about anywhere [4]. The technologies are:
I. RADIO FREQUENCY
Radio frequency or radio wave technology has become very prevalent in wireless local
area network implementations. The technology allows communication among wireless
devices in our LANs by incorporating into each wireless device a tiny transceiver
(transmitter plus receiver) and antenna. Wireless devices transmit and receive data
using radio frequency that don’t interfere with other radio frequency users such as radio
stations. Radio frequencies are allocated by the Federal communications Commission
(FCC), and these allocations are specific to each of the different types of radio frequency
wireless transmission technologies.
That is, different wireless technologies utilize different radio frequencies as allocated by
the FCC. For wireless LAN devices to communicate with other wireless devices on our
LAN, we’ll implement radio frequency access points such as wireless hubs, switches, or
routers. Access points utilize tiny antennas and transceivers to receive and transmit data
with the wireless devices. In addition, the access points acts as a translation junction
between the wireless devices and the “wired” devices on our LAN. This is achieved by

56
connecting each of our access points with UTP or fiber- optic cabling to our “wired”
LAN devices [9].
II INFRARED
Infrared data transmission technology uses light frequencies that are invisible to the
human eye and operate below the red band of the visible spectrum. Although, the
incorporation of this some laptops in the 1990’s showed that the technology was limited
to short distances and susceptible to many types of interference such as rain and for a
obstruction standing between two computers that were trying to communicate. Infrared
is still available, and we can configure it for point-to-point transmission or broadcast
transmission. With point-to-point optical devices are incorporated to focus the light
beam between devices. Practical implementations of this technology include wireless
mice, keyboards and some printers. For broadcast transmission, the infrared signal is
spread as it is generated; making the signal less susceptible to direct interference but the
signal is generally distance limited to a single room [9].
III MICROWAVE
Microwave data communication technology uses very high frequency radio waves to
transmit, and receive information between separate buildings or even distant geographic
regions. The technology can be used in local area networks, generally between
buildings but it is more practicable in Campus or Wide Area Networking scenarios in
which other connectivity solutions are either cost prohibitive or impracticable.
One microwave technology, terrestrial microwave utilizes the horn antenna with
parabolic dish to generate and receive the microwave transmissions. Terrestrial
microwave, as the name implies, is earth-based’ and requires a line-of-sight path
between antennas to ensure data transmission. In most cases, when building towers are
involved, the microwave antenna are attached or installed on the tops of tall buildings
[9].

57
3.2 DATA GATHERING ANALYSIS
The data gathering table of selected institutions of higher learning in Nigeria is shown
below:
Table 3.5: Data Gathering Analysis
University
of Ibadan
Obafemi
Awolowo
University
University
of Lagos
Lagos State
Polytechnic
Yaba
College of
Technology
IP
standard
IPV4 IPV4 IPV4 IPV4 IPV4
Network
cable
UTP UTP UTP UTP UTP
ISP
Bandwidth
100Mbps 100Mbps 80Mbps 20Mbps 20Mbps
NIC type 10/100Mbps 10/100Mbps 10/100Mbps 10/100Mbps 10/100Mbps
No of ISP
Link
2 2 3 3 1
No of
Internet
Users
11,500 9,000 21,000 5,000 6,000
Network
Switch
Store and
Forward
Store and
Forward
Store and
Forward
Store and
Forward
Store and
Forward
From table 3.5 above, the following explicitly described the level of Internet Services
performance of the institutions:

58
3.2.1 The institutions in the above table are currently installed with same IPV4 standard
and this appears to be a general feature which will definitely affect the Internet Services
performance in the future.
3.2.2 The selected institutions have same cabling standard. This is a uniform cabling
system but it is a general shortcoming.
3.2.3 The Universities were able to subscribe for higher Internet Bandwidth compared to
the Polytechnics in these findings. The population of the Internet users in the university
campuses must have been the cause of this wide gap in bandwidth subscription.
3.2.4 The selected institutions have same NIC type installed on their Servers and
Workstations. This is a major drawback as well.
3.2.5 The Universities could afford the subscription for more than one ISP links while
the Polytechnics could not. The Polytechnic that currently has more than one link has
three campus locations.
3.2.6 The Universities has a larger number of internet users compared to the
Polytechnics. This is as a result of the high population of staff and student in the various
universities in Nigeria.
3.2.7 The selected institutions were installed with same type of Network Switch. This
type is of lower performance compared to the Layer 3 Ethernet Network switches.

59
CHAPTER FOUR
4.0 RESULTS AND DISCUSSION
4.1 NETWORK INTERFACE CARD
Examining the Ethernet data transmission analysis, the results showed that 10Gigabit
Ethernet is the best. The detailed results are in the tables and graphs below. The source
code of the Matlab program is shown in Appendix A. However, the detail operation of
the Ethernet card is explicitly shown in Appendix B.
Table 4.1: The performance of 10Mbps Ethernet Card
MESSAGE SIZE (MB) DATA TRANSMISSION
TIME (S)
THROUGHPUT
(Mbps)
1.0 0.8000 9.97
5.0 4.0000 9.99
10.0 8.0000 9.99
15.0 12.0000 9.99
20.0 16.0000 9.99
Table 4.2: The performance of 100Mbps Ethernet Card
TIME (S)
THROUGHPUT
(Mbps)
1.0 0.0800 97.56
5.0 0.4000 99.50
10.0 0.8000 99.75
15.0 1.2000 99.80
20.0 1.6000 99.87

60
TIME (S)
THROUGHPUT
(Mbps)
1.0 0.0080 800.00
5.0 0.0400 952.38
10.0 0.0800 975.60
15.0 0.1200 983.60
20.0 0.1600 987.65
TIME (S)
THROUGHPUT
(Mbps)
1.0 0.0008 2,857.14
5.0 0.0040 6,666.67
10.0 0.0080 8,000.00
15.0 0.0120 8,571.42
20.0 0.0160 8,888.89

61
0 5 10 15 20 25
0
2
4
6
8
10
12
14
16
18
20
Massage size(MB)
DataTransmissiontime(s)
A/ There is a linear relationship between the data transmission time and the message
size. Therefore, a 10Mbps Ethernet can transfer a message size of 20MB in 16seconds
over the network.
0 5 10 15 20 25
9.97
9.975
9.98
9.985
9.99
9.995
10
Massage size(MB)
Throughput(Mbps)
B/ This is an asymptotic plot of the throughput versus the message size. Therefore, a
10Mbps Ethernet card could have a channel capacity of 9.99Mbps while transmitting a
message size of 20MB on the network.
Fig. 4.1: The Performance of 10Mbps Ethernet card.

62
0 5 10 15 20 25
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
Massage size(MB)
A/ There is linear relationship between the data transmission time and the message size.
Therefore, a 100Mbps Ethernet card can transmit a nessage size of 20MB in 1.6 seconds
on the network.
0 5 10 15 20 25
97
97.5
98
98.5
99
99.5
100
Massage size(MB)
Throughput(Mbps)
100Mbps Ethernet card could have a channel capacity of 99.87Mbps while transmitting
a message size of 20MB on the network.
Fig. 4.2: The performance of 100Mbps Ethernet card

63
0 5 10 15 20 25
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
0.18
0.2
Massage size(MB)
size. Therefore, a 1,000Mbps Ethernet card could transmit a message size of 20MB on
the network in 0.16 second.
0 5 10 15 20 25
800
820
840
860
880
900
920
940
960
980
1000
Massage size(MB)
Throughput(Mbps)
1,000Mbps Ethernet card could have a channel capacity of 987.65Mbps while
transmitting a message size of 20MB on the network.
Fig 4.3: The Performance of 1,000Mbps Ethernet Card

64
0 5 10 15 20 25
0
0.002
0.004
0.006
0.008
0.01
0.012
0.014
0.016
0.018
0.02
Massage size(MB)
size. Therefore, a 10,000Mbps Ethernet card can transmit a message size of 20MB in
0.016 second on the network.
0 5 10 15 20 25
3000
4000
5000
6000
7000
8000
9000
10000
Massage size(MB)
Throughput(Mbps)
B/ This is an asymptotic plot of the throughput versus message size. Therefore, a
10,000Mbps Ethernet card could have a channel capacity of 8,888.89Mbps while
transmitting a message size of 20MB on the network.

65
4.2 INTERNET BANDWIDTH
The result of the interpolated actual bandwidth and the acceptable number of internet
users is shown below. The source code of the Matlab program is in Appendix C. Also,
the detail of Internet Bandwidth optimization is clearly shown in Appendix D. The
results of the Lagrange Interpolation are shown in the table and graph below.
Table 4.4: Interpolated Actual Bandwidth with Acceptable Number of Internet Users
Xi (‘000) F (xi) (Mbps)
9.00 60
14.00 70
19.00 80
20.00 82
25.00 92
30.00 102
35.00 112
40.00 122
45.00 132
50.00 142
55.00 152
60.00 162
65.00 172

66
Fig 4.5: Graph of Effective Actual Bandwidth versus Acceptable Number of
Internet Users
In this graphical representation above:
We represent Effective Internet Bandwidth (Mbps) as B and the Number of Acceptable
Internet Users (‘000) as U. Mathematically; we have the relation governing the two
parameters as shown below:
B = mU + C0 ,
Where, m = The gradient of the straight line and
C0= The Starting Internet Bandwidth.
Also, m = B/ U = (122 – 82)/(40 – 20) = 40/20 =2. Therefore,
B = 2U + C0
From the graph, C0 = 42 Mbps.
The final relation could be written as
B = 2U + 42 ………………. (1)
The equation (1) above governs the relationship between the Effective Internet
Bandwidth (B) and Number of Acceptable Internet Users (U) in the University of Lagos
as the case study of this thesis.
0 10 20 30 40 50 60 70 80 90 100
0
50
100
150
200
250
Number of internet users("000)
EffectiveactualBandwidth(Mbps)

67
4.3 NETWORK CABLING SYSTEM
The excellent performance of the fiber-optic cabling is preferable to that of UTP
Category 5 and the detailed analysis is in Appendix E.
4.4 IP ADDRESS STANDARD
The performance of IPV6 is much better than that of IPV4. The detailed operation and
performance of IPV6 is in Appendix F.
4.5 WIRELESS NETWORK SYSTEM
The dual-band wireless technology is the best wireless operation that could be
implemented in all institution. Detail about the dual-band wireless operation is in
Appendix G.
4.6 NEWORK SWITCH STANDARD
The Layer 3 Stackable and Chassis switches will produce the best data transfer speed.
This Network Switch has better performance when compared with the store-and-forward
type used in the institution of higher learning. Detail about its mode of operation is in
Appendix H.

68
CHAPTER FIVE
5.0 CONCLUDING REMARKS
In this research work, the performance of IP Address version 4.0 and IP Address version
6.0 is studied. The performance of the Network cabling system including UTP, STP and
fiber optic with respect to their file transfer speed and reliability is examined.
The method of Internet Bandwidth Optimization using the Link-Load Balancer which
had resulted to zero down-time in the availability of internet access was analyzed.
The performance of the Actual Internet bandwidth on the entire WAN with respect to
the acceptable number of internet users is studied.
The performance analysis of different Network interface Cards (NIC) with respect to
their data transmission time and throughput is examined.
The performance of Layer 3 Network switch with respect to its advantages over the
store-and-forward type is also studied.
In addition, the performance of wireless network operation is effectively examined as
well.

69
CHAPTER SIX
6.0 RECOMMENDATIONS
6.1 IP ADDRESS STANDARD.
The IP version 6.0 is highly recommended to be implemented in Wide Area Networks of
the higher institutions. IPV6 has a lot of advantages over IPV4 which include data flow
and address space. Since IPV6’s flow header and traffic class header will be more
efficient than the type of service field found in IPV4, IPV6 will definitely provide high
quality of service.
6.2. CABLING SYSTEM
In most institutions, the UTP category 5e or 6e is the prevalent cabling system. The
better features of the optic- fiber give it a full recommendation for the campus network.
In term of high throughput, flexibility, reliability and efficiency, the optic- fiber is the
choice for this and next generation.
6.3 INTERNET BANDWIDTH
The installation of ISP link-load balancer is highly recommended for all institution of
higher learning operating the multi-homing internet service. This will enhance zero
downtime in the overall Internet access of the entire campus community. The University
of Lagos as a case study is not left out in this portion of recommendation. It is also
recommended that each campus network be provided with the relationship between the
effective actual bandwidth and equivalent acceptable number of internet users to ensure
reliable future projections.

70
6.4 NETWORK INTERFACE CARD
Having compared the performances of different network interface cards, it is mandatory
that each campus network be installed with 10Gigabit Ethernet Card from the servers to
all workstation.
6.5 NETWORK SWITCH
The network switch happened to be the heart of every local area network (LAN). Since
the institutions has larger networks, it is highly recommended that Layer 3 stackable and
chassis switches be installed because they provide better management capabilities,
support for the simple Network Management Protocol (SNMP) and Remote Monitoring
(RMON) and the capability to create Virtual LANs (VLANs). One of the best
manufacturers of these switches happened to be CISCO. Therefore, the institution must
ensure correct brand of this product during the process of procurement.
6.6 WIRELESS NETWORK OPERATION
As a means of achieving standard Internet Service operation in the higher institutions, a
dual-band wireless network is highly recommended. Actually, a dual-band wireless
client (PC) is essentially a universal client for standard wireless networks which benefit
from greater speed when connected to a dual-band wireless network that separate high-
bandwidth traffic from low-bandwidth traffic.
6.7 EXTENSION OF RESEARCH WORK
It is highly recommended that this thesis is extended to other areas not covered within
the period of the research work.
Therefore,
- Further research should include more detailed investigation on the performance of
the Network Routers used to interconnect the different local area networks
(LANs) to form the WAN of the institution.

71
- Further work should also include comprehensive study on the Internet Service
Provider (ISP) link standard in order to ensure reliable services and quality of
service.
- More detail work is expected on the rate of population growth and demographic
data tables in the higher institutions, since the campuses precisely the universities
has similar Wide Area Network (WAN) connectivity in Nigeria. This will
enhance sound numerical data analysis with respect to effective actual bandwidth
and the corresponding acceptable number of internet users.
- Extensive research should include more detailed study of Bluetooth Wireless
technology which can further improve the internet service performance of the
higher institutions.
Finally, an advance work on this thesis will involve the Virtual Machine Matrix
(VMM) or V-matrix which provides backward compatible solutions for
improving the interactivity, scalability and reliability of internet applications.
This could be best examined as dissertation for Doctor of Philosophy (PhD)
degree in the nearest future.

72
REFERENCES
[1] Miller, Mark A. (1998), Implementing IPV6, 1st
Edition, M&T Books, New York.
USA.
[2] Wu-Chaug Feng, Dilip D. Kandlur, Debanjan Sha and Kang G. Shin,
Understanding and improving TCP performance Over Networks with minimum
Rate Guarantees, IEEE/ACM Transactions on Networking, Vol. 7, April, 1999.
[3] Carlos Oliveira, Jaime Bae Kim and Tatsuya Suda, An Adaptive Bandwidth
Reservation Scheme for High-Speed Multimedia Wireless Networks, IEEE
Journal on Selected Areas in Communications, Vol. 16, August, 1999.
[4] Youghwan Kim and San-qi Li, Performance Analysis of Data Packet Discarding
in ATM Networks, IEEE/ACM Transactions on Networking, Vol. 7, April, 1999.
[5] Vern Paxson, End-to-End Internet Packet Dynamics, IEEE/ACM Transactions on
Network, Vol. 7, June 1999.
[6] Sudhin Ramakrishna and Jackrishna and Jack M. Holtzman, a scheme for
Throughput Maximization in a Dual-class CDMA System, IEEE Journals on
Selected Areas in Communications, Vol. 16, August. 1999.
[7] Comer, Douglas (1997), Computer Networks and Internets, 2nd
Edition, Prentice
Hall, New Jersey, USA.
[8] Terry W. Ogletree and Mark E. Soper (2006), Upgrading and Repairing
Networks, 5th
Edition, Que Publishing. USA.
[9] Dave, Miller (2006), Data Communications and Networks, 1st
Edition, McGraw-
Hill. New York. USA.
[10] Buttler Lampson, Venkatachary Srinivasan and George Varghese, IP Lookups
Using Multi-way and Multicolumn Search IEEE/ACM Transactions on Networks,
Vol. 7. June 1999.

73
[11] James F. Kurose and Keith W. Ross (2000), Computer Networking: A Top-
Down Approach Featuring the Internet, 1st
Edition, Addison – Wesley Publishing,
USA.
[12] Stroud K .A. and Booth D.J, (2003), Advanced Engineering Mathematics, 4th
Edition, Palgrave Macmillian Limited. USA.

74
APENDDIX A
clc
clear
N=[1,5,10,15,20];
T1 =[0.8,4.0,8.0,12.0,16.0];
T2 =[9.97,9.99,9.99,9.99,9.99];
T3 =[0.08,0.4,0.8,1.20,1.60];
T4 =[97.56,99.60,99.75,99.80,99.87];
T5 =[0.008,0.04,0.08,0.12,0.16];
T6 =[800,952.38,975.60,983.60,980.65];
T7 =[0.0008,0.004,0.008,0.012,0.016];
T8 =[2857.14,6666.667,8000,8571,8888.8890];
figure(1), plot(N,T1, '*-'),axis([0,25,0,20])
xlabel('Message size(MB)')
ylabel('Data Transmission time (s)')
grid on
figure(2), plot(N,T2, '*-'),axis([0,25,9.97,10])
ylabel('Throughput(Mbps)')
grid on
grid on

75
grid on
figure(5), plot(N,T5, '*-'),axis([0,25,0,0.2])
grid on
grid on
figure(7), plot(N,T7, '*-'),axis([0,25,0,0.02])
grid on
grid on

76
APPENDIX B
NETWORK INTERFACE CARD
A network interface card sometimes called a network adapter or network card or simply
NIC, is the physical interface between a computer, or other device and a local area
network, practically, a network interface card connects your computer to the LAN
cabling. NICs come in various forms: some are built in to the computer’s motherboard:
others are in the form of an expansion card that “plays into” your computer’s
motherboard: some are PC cards; and still others can attach to the computer’s USB port.
Additional hardware specifications define whether a NIC will be used with co-axial
cable twisted pair, fiber optic or even wireless. Also, these cards are available at a
designated data transmission rate such as 10Mbps, 16Mbps, 100Mbps, and 1Gbps and
so on.
The network interface card is a physical connectivity that assembles data into an
acceptable format for transmission across a network medium. Likewise, the NIC accepts
information from the network medium and “translates” that information into a format
the computer can understand. When sending data such as file from a computer to
another computer through a LAN, it is fairly simple process. If you are using e-mail, you
click on send. If you are accessing a file transfer protocol (FTP) or hypertext transfer
protocol (HTTP) server, you click upload. If you simply want to save a file to another
computer such as a server on the LAN, you click File save, and then specify a filename
and location on the other system.
However, there is a lot technology going on within the computer to help you convert
your file medium into bits stream data. The data must exit the computer through the
network interface card, but before it can do so, the NIC segments your data transmission
into chunks called FRAMES, that the physical network can manage. In other words, an
entire file would be broken into hundreds or thousands of smaller pieces and transmitted

77
as frames as the file is being sent from your computer to another location across the
LAN.
Each frame includes not only a portion of the data being sent, but also the address
information of both the sending and the receiving network cards. Each frame needs to
have this source and destination address information so that the data can find its
intended destination as well as known were it originated. This address information is
sometimes called the physical address of the network interface card, or simply the
hardware address, because it is encrypted into a chip on the NIC. But this address is
associated with the data link layer of the OSI model discussed in chapter two, so we call
the address of each network interface card a data link layer address.
Every NIC has a unique, 48-bit address known as a media access control, (MAC)
address. The MAC-address is comprised of a 24-bit Organizationally Unique Identifier
(OUI) that is always assigned by the IEEC for a fee to the manufacturer, plus a
manufacturer generated 24-bit code that is concatenated or appended to the OUI. The
address is represented as a series of six, eight-bit fields such as AF: 00: CE: 3A: 8B: 0C.
MAC addresses are encoded, into one of the integrated circuits on each NIC so that
every computing device on a LAN can be uniquely identified. When devices generated
requests or send information the LAN, the MAC address of both the sending and
destination computers is added to each packet of information that is placed on the
network media. Computing devices on the LAN read the destination MAC address on
the DATA PACKETS and determine whether to receive or ignore these packets. For
example, if you are using a computer installed with Windows 2000 or Windows XP
Professional, you can open a command prompt and enter the command
“IPCONFIG/ALL”. This command will display a MAC address in the format: 00-03-47-
8F-FF-8E along with other pieces of information and information about various LAN
services that support configuration such as Domain Name Services (DNS) and Dynamic
Host Configuration Protocol (DHCP).

78
ETHERNET NIC
Ethernet was originally developed at Xerox Palo Alto research center laboratories in the
1970s. Robert Metcalfe was charged with the responsibility of networking a group of
computers that could all use a new Laser Printer that Xerox had developed. Xerox also
had just developed what was probably the first personal workstation, and had a need to
network more than the usual two or three computers that you would find in a single
building during that time.
The original Ethernet standard was developed over the next few years, and this resulted
in a paper titled “Ethernet: Distributed Packet-Switching for Local Computer
Networks”, written by R. Metcalfe and D. Boggs (communications of the ACM,
Volume 19, Number 5, July, 1976, pp 395 – 404). In this first Ethernet experimental
network described in the paper, the network covered a distance of 1 kilometer, ran a
3Mbps bandwidth and had 256 stations connected to it.
Later, a consortium of three companies – Digital Equipment Corporation, Intel and
Xerox further developed the Ethernet II standard, sometimes referred to in older
literature as the DIX standard, based on the first initials of the participating corporations.
These companies used the technology to add networking capabilities to their digital
equipment corporation had the largest commercial network in the world, using DEC net
protocols connecting Ethernet LANs. Today, the dominant protocol used with Ethernet
is TCP/IP. We can now run an Ethernet network on wired media such as co-axial cable,
twisted-pair wiring (shielded and unshielded) and fiber-optic cabling. Now, Ethernet
obviously functions with wireless technologies for internet access.
In 1985, the IEEE standard 802.3 “Carrier Sense Multiple Access with Collision
Detection (CSMA/CD) Access Method and Physical Layer Specifications” was
published. These specifications made it easy for vendors to create hardware, from
cabling to LAN cards, which could interoperate. The many different Ethernet standards
available are all identified by a name that includes “IEEE 802” followed by a number

79
and possibly a letter or two. “The IEEE LAN/MAN committee networking standards”,
contains short descriptions of some of the more relevant standards that were defined for
LAN/MAN networks. The committee is made up of various working group and
technical advisory groups. For example, IEEE 802.3 is the working group for standard
Ethernet CSMA/CD technology, whereas IEEE 802.3z is the standard for Gigabit
Ethernet, which is an updated faster version of the original 802.3. Different forms of
Ethernet are also referred to using a naming scheme that links the network speed, the
word “BASE” (for baseband signaling), and an alpha or numeric suffix that specifies the
network media used. An example of this is 10BASE – T, which broken down like this
10 = Ethernet, running at a speed (bandwidth) of 10Mbps
BASE = Baseband and signaling
T = Over twisted – pair (T) wiring.
COMMON STANDARDS-BASED ETHERNET NIC
The original Ethernet II network operated at a blazingly fast speed of 10Mbps. The most
recent standard that is integrated into Laptop system is 10Gigabit Ethernet, now that it
has been standardized. These are the most common standards-based Ethernet solutions
from the past to the present.
I/10BASE – 5: this is often referred to as “Thickwire” or “thicknet”, and this standard
uses thick co-axial cable. The 10 in this name indicates the speed of the network, which
is 10megabits/second (Mbps). As said earlier, the term “base” reference the technology
used, which is baseband. The number 5 in the name indicates that the maximum length
allowed for any segment using this topology us 500 meters.
II/10BASE – 2: this is popularly referred to as “Thinwire” or “Thinnet” and this
Ethernet standard runs at the same speed as a 10base – 5 networks (10Mbps) but uses a
smaller, more flexible cable. The number 2 in the name indicates a maximum segment
length of 200meters. This is a bit misleading, because it is actually rounded up from the
true maximum segment length of 185meters. It is common to see older networks

80
composed of multiport repeaters, with each port using thinnet cable to connect one or
multiple computers. Using a BNC T-connector, it is possible to create a simple daisy-
chain bus using 10BASE - 2
III/10BASE – 36: This is rarely used Ethernet specification. It uses broadband instead
of baseband signaling despite the fact that the name implied the use of baseband. The
co-axial cable for this technology uses a co-axial cable that has three sets of wires, each
for a separate channel, and each channel operates at 10Mbps and can extend over a
distance of about 3,600 meters.
IV/10BASE– T: The network connection is made from workstations to a central switch
(also known as a concentrator), using a physical star topology. The use of twisted-pair
wiring (hence the “T” in the name), which is cheaper and much more flexible than
earlier co-axial cables, makes routing cables through ceilings and walls a much simpler
task. Centralized wiring also makes it easier to test for faults and isolate bad ports or
move users from one area to another. It is expected that any LAN using this should be
upgraded to at least 100BASE-T.
V/10BASE-FL: This version of Ethernet also operates at 10Mbps, but instead of using
copper wires, fiber-optic cables (FL) are used – specifically multimode fiber cable
(MMF), with a 62.5μ m fiber-optic core and 125μ m outer cladding. Separate strands of
fiber are used for transmit and receive functions, allowing full-duplex to operate easily
across this kind of link. It is very common to find this technology on most legacy
network today.
VI 100BASE-TX: it uses category 5 UTP or STP cabling system. The wiring is to allow
a distance of up to 100meters between the workstation and the switch. Four wires (two
pairs) in the cable are used for communications. This technology is till for a while until
applications mandate the necessity of upgrading your network to use 10Gigabit Ethernet
to the desktop.

81
VII 100BASE-T4: It uses category 3 or category 5 UTP wiring to allow for a distance
of up to 100meters between the workstation and the switch. Four wires (two pairs) in the
cable are used for data communications. This is another 100Mbps technology that was
used to provide an upgrade path for installations that had not yet upgraded to category 5
cabling (or better). If it was discovered that there is network congestion and excessive
errors are occurring, it is better to consider an upgrade.
VIII 100BASE-FX: It uses multimode fiber-optic cable to allow for a distance of up to
412 meters between the workstation and the switch. One strand of the cable is used for
transmitting data while the other is used for receiving data.
IX 1000 BASE-SX: The IEEE 802.3z standards document, approved in 1998, defined
several Gigabit Ethernet networking technologies. The 1000BASE-SX is intended to
operate over fiber links using multimode fiber, operating with lasers that produce light at
approximately 1850nanometers (nm). The “S” in the name implies a short wavelength of
light. The maximum length for a segment of 1000BASE-SX is 550 meters.
X 1000BASE-LX: This fiber-based standard defines Ethernet when used with single-
mode or multimode fiber. The “L” in the name implies a longer wavelength of light,
from 1,270 to 1,355 nanometers. The maximum length for a single segment of
1000BASE-LX is 550 meters using multimode fiber, and up to 5,000 meters using
single-mode fiber.
XI 1000BASE-CX: The IEEE 802.3ab standard allows for Gigabit Ethernet across
shielded Copper wires. It is designed primarily for connecting devices that are only a
short distance away – (i.e. 25 meters or less)
XII 1000BASE-T: The IEEE 802.3ab standard added to the physical layer of Gigabit
Ethernet category 5 UTP wire cables. The maximum distance for any segment using
1000BASE-T is 100 meters.

82
THE CARRIER SENSE MULTIPLE ACCESS WITH COLLISION DETECTION
(CSMA/CD)
A collision occurs when two workstations on the network both sense that the network is
idle and both start to send data at approximately the same time, resulting in a garbles
transmission. The term collision itself seems to imply that something is gone wrong. In
technical literature, this kind of event is called Stochastic Arbitration Event (SAE),
which sounds much less like an error than that of collision. However, collisions are
expected in older Ethernet networks. Only when they become excessive is it time to
search for the source of the collisions and rearrange some workstations or network
devices as appropriate.
A 10Mbps Ethernet network signals at a speed of 10 million bits per second. The
standard says that the round-trip time (RTT) can be no more than 51.2 milliseconds –
(this is the amount of time it takes to transmit about 64bytes of data at 10Mbps). Thus,
the rules state that a device must continue to transmit for the amount of time it would
take for its signal to travel to the most distant point in the network and back - the round-
trip time.
If the device does not continue transmitting for the duration of the round-trip time, it is
not capable of detecting that a collision occurred with that frame before it began to
transmit another frame.
If a frame that needs to be transmitted is less than 64 bytes in length, the sending node
will pad it with zeros to bring it up to this minimum length.
A maximum size of the frame was also added by the Ethernet I specification, resulting
in a frame size with a minimum of 64 bytes and a maximum size of 1,500 bytes.
The method that a device uses to communicate on the network is described in the
following steps:
I - Listen to the network to determine whether any other device is
currently transmitting (carrier sense – CS).

83
II - If no other transmission is detected (i.e. the line is free), start transmitting.
III - If more than one device sense that no transmission is occurring, both
can start transmitting at the same time. The network physical connection is a
shared (medium multiple Access – MAC).
IV - When two devices start transmitting at the same time the signal
becomes garbled and the devices detect this condition (collision Detection – CD).
V - After transmitting data onto the network, the device again listens to the
network to determine whether the transmission was successful or whether a
collision has occurred. The first device that detects the collision sends out a
jamming signal for a few bytes of arbitrary data to inform other devices on
the network.
VI - Each device that was involved in the collision then pauses for a short time
(a few milliseconds), listens to the network to see whether it is in use, and then
tries the transmission again. Each device that caused the collision uses a random
back off timer, reducing the chances of a subsequent collision. This assumes, of
course, that the network segment is not highly populated, in which cause
excessive collisions can be a problem that needs troubleshooting and correction.
THE BACK-OFF ALGORITHM
Without a back-off algorithm, the device that detects a collision will stop and then try
once again to transmit its data onto the network. If a collision occurs because two
stations are trying to transmit at about the same time, they might continue to cause
collision because both will pause and then start transmitting at the same time again. This
will occur unless a back-off algorithm is used.
The back-off algorithm is an essential component of CSMA/CD. Instead of waiting for a
set amount of time when a device backs off and stops transmitting, a random value is
calculated and us used to set the amount of time for which the device delay
transmission.

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