thesis datacom final
TRANSCRIPT
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ACKNOWLEDGEMENT
I would like to acknowledgement with the sincere and warmest
gratitude to all the person who had extended their full support and
assistance to make this research possible.
To my family for the continues financial and moral support and
the love they have shown all trough out my life.
To my professor, ENGR. EPIFANIO TORRES for all the advice,
guidance and patience in teaching us.
To all the staff of EDP New Exec Bldg. Mandaluyong City Hall
Engineering Department for allowing me to propose a LAN design to
their office.
Above all to all mighty GOD whos been with me every single
moment of my life. For giving me a healthy body and healthy mind and
a healthy spirit that help me finished the research.
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CHAPTER Iy Introductiony Background of the Study
y Objectives
y Significance of the Study
y State of the Problem
y Scope and the Delimitation of the Study
y Conceptual and Framework
y Definition of Terms
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The advent of personal computers changed the type of information sent
over office computer networks. Terminals were no longer "dumb," but
contained the power to perform their own instructions and maintain their
own memories. This took considerable pressure off mainframe devices,
whose energies could now be devoted to more complex tasks.
LANs allowed for the transmission of data between workers. In turn,
they enabled this shared data to be directed to a common printer,
serving a larger group of users. This eliminated the need for each
worker to have a printer and ensured that the one printer provided was
not underutilized. In addition, LANs allowed data to be called up directly
on other workers' computers, providing immediate communication and
eliminating the need for paper. The most common application was in
interoffice communications, or electronic mail (e-mail). Messages could
be directed to one or several people and copied to several more over
the LAN. As a result, an e-mail system became something of an official
record of communications between workers. Addressees became
obligated to respond to e-mail messages in a timely manner because
their failure to answer could be easily documented for supervisors.
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BACKGROUND OF THE STUDY
A Local Area Network (LAN) is a group of computers and
associated devices that share a common communications line or
wireless link. Typically, connected devices share the resources
of a single processor or server within a small geographic area (for
example, within an office building). A local area network may serve as
few as two or three users (for example, in a home network) or as many
as thousands of users (for example, in an FDDI network).
As larger universities and research labs obtained more
computers during the late 1960s, there was an increasing pressure to
provide high-speed interconnections. A report in 1970 from the
Lawrence Radiation Laboratory detailing the growth of their "Octopus"
network gives a good indication of the situation. Cambridge Ring was
developed at Cambridge University in 1974 but was never developed
into a successful commercial product. Ethernet was developed at Xerox
PARC in 19731975, and filed as U.S. Patent 4,063,220. In 1976, after
the system was deployed at PARC, Metcalfe and Boggs published their
seminal paper, "Ethernet: Distributed Packet-Switching for Local
Computer Networks
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Standards evolution
The development and proliferation of CP/M-based personal
computers from the late 1970s and then DOS-based personal
computers from 1981 meant that a single site began to have dozens or
even hundreds of computers. The initial attraction of networking these
was generally to share disk space and laser printers, which were both
very expensive at the time. There was much enthusiasm for the
concept and for several years, from about 1983 onward, computer
industry pundits would regularly declare the coming year to be the year
of the LAN. In practice, the concept was marred by proliferation of
incompatible physical Layer and network protocol implementations, and
a plethora of methods of sharing resources. Typically, each vendor
would have its own type of network card, cabling, protocol, and network
operating system. A solution appeared with the advent of Novell
NetWare which provided even-handed support for dozens of competing
card/cable types, and a much more sophisticated operating system
than most of its competitors. Netware dominated the personal computer
LAN business from early after its introduction in 1983 until the mid
1990s when Microsoft introduced Windows NT Advanced Server and
Windows for Workgroups. Of the competitors to NetWare, only Banyan
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Vines had comparable technical strengths, but Banyan never gained a
secure base. Microsoft and 3Com worked together to create a simple
network operating system which formed the base of 3Com's 3+Share,
Microsoft's LAN Manager and IBM's LAN Server - but none of these
were particularly successful. During the same period, Unix computer
workstations from vendors such as Sun Microsystems, Hewlett-
Packard, Silicon Graphics, Intergraph, NeXT and Apollo were using
TCP/IP based networking. Although this market segment is now much
reduced, the technologies developed in this area continue to be
influential on the Internet and in both Linux and Apple Mac OS X
networkingand the TCP/IP protocol has now almost completely
replaced IPX, AppleTalk, NBF, and other protocols used by the early
PC LANs.
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Cabling
Early LAN cabling had always been based on various grades of
coaxial cable, IBM's Token Ring used shielded twisted pair cabling of
their own design, and in 1984 Star LAN showed the potential of simple
Cat3 unshielded twisted pairthe same simple cable used for
telephone systems. This led to the development of 10Base-T (and its
successors) and structured cabling which is still the basis of most
commercial LANs today. In addition, fiber-optic cabling is increasingly
used in commercial applications. As cabling is not always possible
wireless is the most common technology in residential premises as the
cabling required is minimal.
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OBJECTIVES
y To be familiar with Local Area Network(LAN) as the company
must be provide
y To be share and connect workstations, personal computers,
printers, servers, and other devices
y To be able to maintain the confidentiality of data as it is stored,
processed or transmitted on a LAN
y To determine how my proposed LAN design will help the
company
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CONCEPTUAL FRAMEWORK
Finding for a potential company that is appropriate to the study.
Make a permit or permission letter to the potential company for their approval.
Went to the company and see the actual floor plan of the facility.
Analyzed and identify the existing problems of their LAN installation.
Formulate goals and objectives to be achieved.
Formulate and create a design that is cheaper and much better than their current LAN
connection.
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STATEMENT OF THE PROBLEM
LANs are susceptible to many kinds of transmission errors.
Electromagnetic interference from motors, power lines, and sources of
static, as well as shorts from corrosion, can corrupt data. Software bugs
and hardware failures can also introduce errors, as can irregularities in
wiring and connections. LANs generally compensate for these errors by
working off an uninterruptable power source, such as batteries, and
using backup software to recall most recent activity and hold unsaved
material. Some systems may be designed for redundancy, such as
keeping two file servers and alternate wiring to route around failures.
Security problems can be an issue with LANs. They can be
difficult to manage and access because the data they use is often
distributed between many different networked sources. In addition,
many times this data is stored on several different workstations and
servers. Most companies have specific LAN administrators who deal
with these issues and are responsible for the use of LAN software.
They also work to backup files and recover lost files.
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SIGNIFICANCE OF THE STUDY
One of the great attributes of a LAN is that it may be installed
simply, upgraded or expanded with little difficulty, and moved or
rearranged without disruption. LANs are also useful because they can
transmit data quickly. Perhaps most importantly, anyone familiar with
the use of a personal computer can be trained to communicate or
perform work over a LAN. But despite their great potential and
capabilities, LANs have yet to demonstrate an increase in office
productivity. They have certainly eliminated paper and speeded the flow
of information, but in many cases they have also created additional
work in terms of organization, maintenance, and trouble-shooting. It will
help the researcher to pass the subject as well as to gain information
and more knowledge about networking.
For the EDP New Exec Bldg. Mandaluyong City Hall Engineering
Department this study will improve their productivity and efficiency in
providing services to those concerned individuals. This study will make
easier to their work, especially in sharing documents.
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SCOPE AND DELIMITATION OF THE STUDY
This research consists mainly of information, documents and
architecture regarding Local Area Network design for EDP New Exec
Bldg. Mandaluyong City Hall Engineering Department, in which the
design made, is intended to. This research discusses the different
factors that influence the Local Area Network design. The researcher
concentrates in making the design for the local area network of EDP
New Exec Bldg. Mandaluyong City Hall. The design is made exclusively
for the Mandaluyong City Hall Engineering Department, application of
such design to other establishment may not compliment well with their
existing material.
The researcher is limited to making the Local Area Network Design,
other issues that may be brought up other than the design domain is
not the researchers concern. Problems that may arise from the
execution of the design, like viruses, defective computer units,
inefficient installers, and other troubles that originates from something
other than the design itself is outside the scope of the study.
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DEFINITION OF TERMS
LOCALAREA NETWORK TOPOLOGIES
Bus Network Topology
networks employing a bus topology use a common physical
connection for communication. That means the physical media is
shared between stations. When one station transmits on the bus, all
devices hear the transmission. If more than one device transmits at the
same
Ring Network Topology - is a network topology in which each node
connects to exactly two other nodes, forming a single continuous
pathway for signals through each node- a ring. Data travels from node
to node, with each node along the way handling every packet.
Because a ring topology provides only one pathway between any two
nodes, ring networks may be disrupted by the failure of a single link ]. A
node failure or cable break might isolate every node attached to the
ring.
Star Network Topology - are one of the most common computer
network topologies. In its simplest form, a star network consists of one
central switch, hub or computer, which acts as a conduit to transmit
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messages. Thus the hub and leaf nodes, and the transmission lines
between them, form a graph with the topology of a star. If the central
node is passive, the originating node must be able to tolerate the
reception of an echo of its own transmission, delayed by the two-way
transmission time plus any delay generated in the central node. An
active star network has an active central node that usually has the
means to prevent echo-related problems.
The star topology reduces the chance of network failure by connecting
all of the systems to a central node. When applied to a bus-based
network, this central hub rebroadcasts all transmissions received from
any peripheral node to all peripheral nodes on the network, sometimes
including the originating node. All peripheral nodes may thus
communicate with all others by transmitting to, and receiving from, the
central node only. The failure of a transmission line linking any
peripheral node to the central node will result in the isolation of that
peripheral node from all others, but the rest of the systems will be
unaffected.
Mesh networking is a type of networking wherein each node in the
network may act as an independent router, regardless of whether it is
connected to another network or not. It allows for continuous
connections and reconfiguration around broken or blocked paths by
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hopping from node to node until the destination is reached. A mesh
network whose nodes are all connected to each other is a fully
connected network. Mesh networks differ from other networks in that
the component parts can all connect to each other via multiple hops,
and they generally are not mobile. Mesh networks can be seen as one
type of ad hoc network. Mobile ad hoc networks (MANET) and mesh
networks are therefore closely related, but MANET also have to deal
with the problems introduced by the mobility of the nodes. Mesh
networks are self-healing: the network can still operate when one node
breaks down or a connection goes bad. As a result, the network may
typically be very reliable, as there is often more than one path between
a source and a destination in the network. Although mostly used in
wireless scenarios, this concept is also applicable to wired networks
and software interaction. The animation at the right illustrates how
wireless mesh networks can self form and self heal.
Tree topology - is a combination of the bus and the Star Topology. The
tree like structure allows you to have many servers on the network and
you can branch out the network in many ways. This is particularly
helpful for colleges, universities and schools so that each of the
branches can identify the relevant systems in their own network and yet
connect to the big network in some way.
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A Tree Structure suits best when the network is widely spread and
vastly divided into many branches. Like any other topologies, the Tree
Topology has its advantages and disadvantages. A Tree Network may
not suit small networks and it may be a waste of cable to use it for small
networks. Tree Topology has some limitations and the configuration
should suit those limitations.
LAN DEVICES
Repeater - is a physical layer device used to interconnect the media
segments of an extended network. A repeater essentially enables a
series of cable segments to be treated as a single cable. Repeaters
receive signals from one network segment and amplify, retime, and
retransmit those signals to another network segment. These actions
prevent signal deterioration caused by long cable lengths and large
numbers of connected devices. Repeaters are incapable of performing
complex filtering and other traffic processing. In addition, all electrical
signals, including electrical disturbances and other errors, are repeated
and amplified. The total number of repeaters and network segments
that can be connected is limited due to timing and other issues.
Network Hub - is a fairly unsophisticated broadcast device. Hubs do
not manage any of the traffic that comes through them, and any packet
entering any port is regenerated and broadcast out on all other ports.
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Since every packet is being sent out through all other ports, packet
collisions result which greatly impedes the smooth flow of traffic.
Hub - is a networking device, which is used to connect the two
segments of a wired network. In star topology, every computer is
directly connected with the hub. In case of any fault in the hub, the data
communication in the network computers stops. In an Ethernet-based
network a hub is a central device that is used to connect all the
computers with each other. A hub has multiple ports such as 6, 8, 16
and 24 etc. When data packets are reached at hub, they are
broadcasted to all the computers unlike a switch and only the destined
computer receives the data. When you want to connect more than
computers with each other a hub or switch is required in a local area
network. There are two types of a hub passive hub and active hub.
LAN card - network interface card or NIC is used to join the computers
in a network. A NIC card is installed in any available PCI port inside the
computer. A unique MAC (Media Control Access) address is assigned
to LAN card. A MAC address is consists of two portions manufactures
id and the card id (PROM on the network interface card holds the
addresses). LAN card operates on the physical and data link layer of
the OSI model. A LAN card usually has twisted pair, BNC and AUI
sockets where the Ethernet cables are connected.
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LAN Extender - forwards traffic between LANs transparent to higher
network-layer protocols over distances that far exceed the limitations of
standard Ethernet. A LAN, or Local Area Network, is a high-speed data
network (usually employing Ethernet technology) to connect computer
workstations, printers, servers, and other devices. The Ethernet LAN
typically serves computer users within a single organization to provide
mutual access and file sharing for all the networked computing devices.
In addition to the devices the LAN connects, additional devices are
commonly employed to increase the overall efficiency, reach and range
of the Ethernet network. Such devices include LAN extenders,
repeaters, hubs, bridges, switches, and routers. While such devices all
provide similar services, each provides a selected feature set to
address a specific issue or problem facing network administrators.
LAN Switching is a form of packet switching used in local area
networks. Switching technologies are crucial to network design, as they
allow traffic to be sent only where it is needed in most cases, using fast
and hardware-based methods.
Router - is an electronic device that interconnects two or more
computer networks, and selectively interchanges packets of data
between them. Each data packet contains address information that a
router can use to determine if the source and destination are on the
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same network, or if the data packet must be transferred from one
network to another. When multiple routers are used in a large collection
of interconnected networks, the routers exchange information about
target system addresses, so that each router can build up a table
showing the preferred paths between any two systems on the
interconnected networks. A router is a networking device whose
software and hardware are customized to the tasks of routing and
forwarding information. A router has two or more network interfaces,
which may be to different physical types of network (such as copper
cables, fiber, or wireless) or different network standards. Each network
interface is a specialized device that converts electric signals from one
form to another.
Switch - a network switch performs the same functionality in a network
as a hub except a different that switch does not broadcast the data
packets to all the computers in a network like a hub. A network switch
has multiple ports like 4, 8, 16 and 24 etc. All the computers in a wired
network are directly connected with the switch through Ethernet cable.
Switches limit the traffic to and from each port and all the devices
connected to the switch has maximum available bandwidth. Switch
doesnt provide the built-in firewall capabilities like the routers. In the
telecommunication and packet switched infrastructure switches play an
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important role. They transmit the data towards its destination based on
the IP address.
Gateway - a gateway can be hardware or software and it acts as a
bridge between two networks. A gateway is an entrance point of a
network. A gateway connects a LAN with internet. A router acts as a
gateway device in a network. In big networks, a computer server which
acts as a gateway also acts as a proxy server and a firewall server. A
gateway computer is usually attached with the router and switch.
Bridges - a bridge is a network communication device that is used to
connect two segments of a LAN that uses the same protocol. Bridge is
like a router but it doesnt analyze the data before sending. A bridge
operates at the data link layer of the OSI model and it can be used to
connect the physically different networks and the networks that use the
different protocols such as Ethernet and Token Ring.
Modems - a modem is communication device that performs two
different functions such as modulation and demodulation i.e. it converts
the digital data into analog and analog into digital. The faster types of
the modems are used by the internet such as DSL modem, cable
modem and optical modems. The features like BPS, auto answer, data
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compression, voice/data, fax capability and flash memory distinguish
one modem from the other.
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NETWORKS
a network is a series of points or nodes interconnected by
communication paths. Networks can interconnect with other networks
and contain subnetworks.
The most common topology or general configurations of networks
include the bus, star, Token Ring, and mesh topologies. Networks can
also be characterized in terms of spatial distance as local area
networks (LANs), metropolitan area networks (MANs), and wide area
networks (WANs).
Network Components:
You will all have come across the term 'Computer Networks' many
times. The chances are you know all about LANs and WANs, network
topologies, Intranets and Internet.
In order for a computer to operate on a network, there are a range of
different components that are required. As part of the OCR syllabus, you
need to be able to describe various devices and explain their role within a
network.
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Network software - Networks consist of hardware, such as servers,
Ethernet cables and wireless routers, and networking software.
Networking software differs from software applications in that the
software does not perform tasks that end-users can see in the way
word processors and spreadsheets do. Instead, networking software
operates invisibly in the background, allowing the user to access
network resources without the user even knowing the software is
operating.
Cables - is the medium through which information usually moves from
one network device to another. There are several types of cable which
are commonly used with LANs. In some cases, a network will utilize
only one type of cable, other networks will use a variety of cable types.
The type of cable chosen for a network is related to the network's
topology, protocol, and size. Understanding the characteristics of
different types of cable and how they relate to other aspects of a
network is necessary for the development of a successful network.
Connectors - on the cable are the weakest points in any network. To
help avoid problems with your network, always use the BNC connectors
that crimp.
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Typical hardware devices that may form part of a network are:
y Personal computers used as terminals
y One or more central processing units acting as dedicated files servers
or print servers
y Disk drives
y Scanners
y Printers
By scale
Computer networks may be classified according to the scale: Personal
area network (PAN), Local Area Network (LAN), Campus Area Network
(CAN), Metropolitan area network (MAN), or Wide area network (WAN).
As Ethernet
increasingly is the standard interface for networks, these distinctions
are more important to the network administrator than the user. Network
administrators may have to tune the network, to correct delay issues
and achieve the desired performance level.
By connection method
Computer networks can also be classified according to the hardware
technology that is used to connect the individual devices in the network
such as Optical fibre, Ethernet, Wireless LAN, HomePNA, or Power line
communication.
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Ethernets use physical wiring to connect devices. Often they employ
hubs, switches, bridges, and/or routers.
Wireless LAN technology is built to connect devices without wiring.
These devices use a radio frequency to connect.
By functional relationship (Network Architectures)
Computer networks may be classified according to the functional
relationships which exist between the elements of the network, e.g.,
Active Networking, Client-server and Peer-to-peer (workgroup)
architecture.
By network topology
Computer networks may be classified according to the network
topology upon which the network is based, such as Bus network, Star
network, Ring network, Mesh network, Star-bus network, Tree or
Hierarchical topology network, etc.
Network Topology signifies the way in which intelligent devices in the
network see their logical relations to one another. The use of the term
"logical" here is significant. That is, network topology is independent of
the "physical" layout of the network. Even if networked computers are
physically placed in a linear arrangement, if they are connected via a
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hub, the network has a Star topology, rather than a Bus Topology. In
this regard the visual and operational characteristics of a network are
distinct; the logical network topology is not necessarily the same as the
physical layout.
Types of networks:
Below is a list of the most common types of computer networks in order
of scale.
Personal Area Network (PAN)
A personal area network (PAN) is a computer network used for
communication among computer devices close to one person. Some
examples of devices that may be used in a PAN are printers, fax
machines, telephones, PDAs or scanners. The reach of a PAN is
typically within about 20-30 feet (approximately 6-9 metres).
Personal area networks may be wired with computer buses such as
USB[3] and FireWire. A wireless personal area network (WPAN) can
also be made possible with network technologies such as IrDA and
Bluetooth.
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Local Area Network (LAN)
A network covering a small geographic area, like a home, office, or
building. Current LANs are most likely to be based on Ethernet
technology. For example, a library will have a wired or wireless LAN for
users to interconnect local devices and to connect to the internet. All of
the PCs in the library are connected by category 5 (Cat5) cable, running
the IEEE 802.3 protocol through a system of interconnection devices
and eventually connect to the internet. The cables to the servers are on
Cat 5e enhanced cable, which will support IEEE 802.3 at 1 Gbit/s.
Typical library network, in a branching tree topology and controlled
access to resources
All interconnected devices must understand the network layer (layer 3),
because they are handling multiple subnets (the different colors). Those
inside the library, which have only 10/100 Mbit/s Ethernet connections
to the user device and a Gigabit Ethernet connection to the central
router, could be called "layer 3 switches" because they only have
Ethernet interfaces and must understand IP. It would be more correct to
call them access routers, where the router at the top is a distribution
router that connects to the Internet and academic networks' customer
access routers.
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The defining characteristics of LANs, in contrast to WANs (wide area
networks), include their higher data transfer rates, smaller geographic
range, and lack of a need for leased telecommunication lines. Current
Ethernet or other IEEE 802.3 LAN technologies operate at speeds up to
10 Gbit/s. This is the data transfer rate. IEEE has projects investigating
the standardization of 100 Gbit/s, and possibly 40 Gbit/s.
Campus Area Network (CAN)
A network that connects two or more LANs but that is limited to a
specific and contiguous geographical area such as a college campus,
industrial complex, or a military base. A CAN may be considered a type
of MAN (metropolitan area network), but is generally limited to an area
that is smaller than a typical MAN. This term is most often used to
discuss the implementation of networks for a contiguous area. This
should not be confused with a Controller Area Network
Metropolitan Area Network (MAN)
A Metropolitan Area Network is a network that connects two or more
Local Area Networks or Campus Area Networks together but does not
extend beyond the boundaries of the immediate town, city, or
metropolitan area. Multiple routers, switches & hubs are connected to
create a MAN.
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Wide Area Network (WAN)
A WAN is a data communications network that covers a relatively broad
geographic area and that often uses transmission facilities provided by
common carriers, such as telephone companies. WAN technologies
generally function at the lower three layers of the OSI reference model:
the physical layer, the data link layer, and the network layer.
Global Area Network (GAN)
Global area networks (GAN) specifications are in development by
several groups, and there is no common definition. In general, however,
a GAN is a model for supporting mobile communications across an
arbitrary number of wireless LANs, satellite coverage areas, etc. The
key challenge in mobile communications is "handing off" the user
communications from one local coverage area to the next. In IEEE
Project 802, this involves a succession of terrestrial Wireless local area
networks (WLAN).[4]
Internet work
Two or more networks or network segments connected using devices
that operate at layer 3 (the 'network' layer) of the OSI Basic Reference
Model, such as a router. Any interconnection among or between public,
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private, commercial, industrial, or governmental networks may also be
defined as an internet work.
In modern practice, the interconnected networks use the Internet
Protocol. There are at least three variants of internet work, depending
on who administers and who participates in them:
y Intranet
y Extranet
y Internet
Intranets and extranets may or may not have connections to the
Internet. If connected to the Internet, the intranet or extranet is normally
protected from being accessed from the Internet without proper
authorization. The Internet is not considered to be a part of the intranet
or extranet, although it may serve as a portal for access to portions of
an extranet.
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Intranet
An intranet is a set of interconnected networks, using the Internet
Protocol and uses IP-based tools such as web browsers and ftp tools,
that is under the control of a single administrative entity. That
administrative entity closes the intranet to the rest of the world, and
allows only specific users. Most commonly, an intranet is the internal
network of a company or other enterprise. A large intranet will typically
have its own web server to provide users with browseable information.
Extranet
An extranet is a network or internet work that is limited in scope to a
single organization or entity but which also has limited connections to
the networks of one or more other usually, but not necessarily, trusted
organizations or entities (e.g. a company's customers may be given
access to some part of its intranet creating in this way an extranet,
while at the same time the customers may not be considered 'trusted'
from a security standpoint). Technically, an extranet may also be
categorized as a CAN, MAN, WAN, or other type of network, although,
by definition, an extranet cannot consist of a single LAN; it must have at
least one connection with an external network.
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Internet
A specific internet work, consisting of a worldwide interconnection of
governmental, academic, public, and private networks based upon the
Advanced Research Projects Agency Network (ARPANET) developed
by ARPA of the U.S. Department of Defense also home to the World
Wide Web (WWW) and referred to as the 'Internet' with a capital 'I' to
distinguish it from other generic internet works.
Participants in the Internet, or their service providers, use IP Addresses
obtained from address registries that control assignments. Service
providers and large enterprises also exchange information on the
reachability of their address ranges through the Border Gateway
Protocol (BGP).
Basic Hardware Components
All networks are made up of basic hardware building blocks to
interconnect network nodes, such as Network Interface Cards (NICs),
Bridges, Hubs, Switches, and Routers. In addition, some method of
connecting these building blocks is required, usually in the form of
galvanic cable (most commonly Category 5 cable). Less common are
microwave links (as in IEEE 802.11) or optical cable ("optical fiber").
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Network Interface Cards
A network card, network adapterorNIC (network interface card) is a
piece of computer hardware designed to allow computers to
communicate over a computer network. It provides physical access to
a networking medium and often provides a low-level addressing system
through the use of MAC addresses. It allows users to connect to each
other either by using cables or wirelessly.
Repeaters
A repeater is an electronic device that receives a signal and
retransmits it at a higher level or higher power, or onto the other side of
an obstruction, so that the signal can cover longer distances without
degradation. In most twisted pair ethernet configurations, repeaters are
required for cable runs longer than 100 meters.
Hubs
A hub contains multiple ports. When a packet arrives at one port, it is
copied to all the ports of the hub. When the packets are copied, the
destination address in the frame does not change to a broadcast
address. It does this in a rudimentary way, it simply copies the data to
all of the Nodes connected to the hub.[5]
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Bridges
A network bridge connects multiple network segments at the data link
layer (layer 2) of the OSI model. Bridges do not promiscuously copy
traffic to all ports, as hubs do, but learns which MAC addresses are
reachable through specific ports. Once the bridge associates a port and
an address, it will send traffic for that address only to that port. Bridges
do send broadcasts to all ports except the one on which the broadcast
was received.
Bridges learn the association of ports and addresses by examining the
source address of frames that it sees on various ports. Once a frame
arrives through a port, its source address is stored and the bridge
assumes that MAC address is associated with that port. The first time
that a previously unknown destination address is seen, the bridge will
forward the frame to all ports other than the one on which the frame
arrived.
Bridges come in three basic types:
1. Local bridges: Directly connect local area networks (LANs)
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2. Remote bridges: Can be used to create a wide area network
(WAN) link between LANs. Remote bridges, where the
connecting link is slower than the end networks, largely have
been replaced by routers.
3. Wireless bridges: Can be used to join LANs or connect remote
stations to LANs.
Switches
A switch is a device that performs switching. Specifically, it forwards
and filters OSI layer 2 datagrams (chunk of data communication)
between ports (connected cables) based on the Mac-Addresses in the
packets.[6] This is distinct from a hub in that it only forwards the
datagrams to the ports involved in the communications rather than all
ports connected. Strictly speaking, a switch is not capable of routing
traffic based on IP address (layer 3) which is necessary for
communicating between network segments or within a large or complex
LAN. Some switches are capable of routing based on IP addresses but
are still called switches as a marketing term. A switch normally has
numerous ports with the intention that most or all of the network be
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connected directly to a switch, or another switch that is in turn
connected to a switch.[7]
Switches is a marketing term that encompasses routers and bridges, as
well as devices that may distribute traffic on load or by application
content (e.g., a Web URL identifier). Switches may operate at one or
more OSI layers, including physical, data link, network, or transport
(i.e., end-to-end). A device that operates simultaneously at more than
one of these layers is called a multilayer switch.
Overemphasizing the ill-defined term "switch" often leads to confusion
when first trying to understand networking. Many experienced network
designers and operators recommend starting with the logic of devices
dealing with only one protocol level, not all of which are covered by
OSI. Multilayer device selection is an advanced topic that may lead to
selecting particular implementations, but multilayer switching is simply
not a real-world design concept.
Routers
Routers are networking devices that forward data packets between
networks using headers and forwarding tables to determine the best
path to forward the packets. Routers work at the network layer of the
TCP/IP model or layer 3 of the OSI model. Routers also provide
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interconnectivity between like and unlike media (RFC 1812). This is
accomplished by examining the Header of a data packet, and making a
decision on the next hop to which it should be sent (RFC 1812) They
use preconfigured static routes, status of their hardware interfaces, and
routing protocols to select the best route between any two subnets. A
router is connected to at least two networks, commonly two LANs or
WANs or a LAN and its ISP's network. Some DSL and cable modems,
for home (and even office) use, have been integrated with routers to
allow multiple home/office computers to access the Internet through the
same connection. Many of these new devices also consist of wireless
access points (waps) or wireless routers to allow for IEEE 802b/g
wireless enabled devices to connect to the network without the need for
a cabled connection.
PHYSICAL COMPONENTS OF LANS
The physical properties of a LAN include network access units (or
interfaces) that connect the personal computer to the network. These
units are actually interface cards installed on computer motherboards.
Their job is to provide a connection, monitor availability of access to the
LAN, set or buffer the data transmission speed, ensure against
transmission errors and collisions, and assemble data from the LAN
into usable form for the computer.
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The next part of a LAN is the wiring, which provides the physical
connection from one computer to another, and to printers and file
servers. The properties of the wiring determine transmission speeds.
The first LANs were connected with coaxial cable, the same type used
to deliver cable television. These facilities are relatively inexpensive and
simple to attach. More importantly, they provided great bandwidth (the
system's rate of data transfer), enabling transmission speeds initially up
to 20 megabits per second.
Another type of wiring, developed in the 1980s, used ordinary twisted
wire pair (commonly used for telephones). The primary advantages of
twisted wire pair are that it is very cheap, simpler to splice than coaxial,
and is already installed in many buildings. The downside of this
simplicity is that its bandwidth is more limited.
A more recent development in LAN wiring is optical fiber cable. This
type of wiring uses thin strands of glass to transmit pulses of light
between terminals. It provides tremendous bandwidth, allowing very
high transmission speeds and because it is optical rather than
electronic, it is impervious to electromagnetic interference. Still, splicing
it can be difficult and requires a high degree of skill. The primary
application of fiber is not between terminals, but between LAN buses
(terminals) located on different floors. As a result, fiber distributed data
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interface is used mainly in building risers. Within individual floors, LAN
facilities remain coaxial or twisted wire pair.
When a physical connection cannot be made between two LANs, such
as across a street or between buildings, microwave radio may be used.
However, it is often difficult to secure frequencies for this medium.
Another alternative in this application is light transceivers, which project
a beam of light similar to fiber optic cable, but through the air rather
than over cable. These systems do not have the frequency allocation or
radiation problems associated with microwave, but they are susceptible
to interference from fog and other natural obstructions.
TRANSMISSION METHODS USED BY LANS
LANs function because their transmission capacity is greater than any
single terminal on the system. As a result, each station terminal can be
offered a certain amount of time on the LAN, like a timesharing
arrangement. To economize on this small window of opportunity,
stations organize their messages into compact packets that can be
quickly distributed. When two messages are sent simultaneously, they
could collide on the LAN causing the system to be temporarily
disrupted. Busier LANs usually utilize special software that virtually
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eliminates the problem of collisions by providing orderly, non-contention
access.
The transmission methods used on LANs are either baseband or
broadband. The baseband medium uses a high-speed digital signal
consisting of square wave DC voltage. While it is fast, it can
accommodate only one message at a time. As a result, it is suitable for
smaller networks where contention is low. It also is very simple to use,
requiring no tuning or frequency discretion circuits. This transmission
medium may be connected directly to the network access unit and is
suitable for use over twisted wire pair facilities.
By contrast, the broadband medium tunes signals to special
frequencies, much like cable television. Stations are instructed by
signaling information to tune to a specific channel to receive
information. The information within each channel on a broadband
medium may also be digital, but they are separated from other
messages by frequency. As a result, the medium generally requires
higher capacity facilities, such as coaxial cable. Suited for busier LANs,
broadband systems require the use of tuning devices in the network
access unit that can filter out all but the single channel it needs.
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THE FILE SERVER
The administrative software of the LAN resides either in a dedicated file
server; in a smaller, less busy LAN; or in a personal computer that acts
as a file server. In addition to performing as a kind of traffic controller,
the file server holds files for shared use in its hard drives, administers
applications such as the operating system, and allocates functions.
When a single computer is used as both a workstation and a file server,
response times may lag because its processors are forced to perform
several duties at once. This system will store certain files on different
computers on the LAN. As a result, if one machine is down, the entire
system may be crippled. If the system were to crash due to under
capacity, some data may be lost or corrupted.
The addition of a dedicated file server may be costly, but it provides
several advantages over a distributed system. In addition to ensuring
access even when some machines are down, its only duties are to hold
files and provide access.
OTHER LAN EQUIPMENT
LANs are generally limited in size because of the physical properties of
the network including distance, impedance, and load. Some equipment,
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such as repeaters, can extend the range of a LAN. Repeaters have no
processing ability, but simply regenerate signals that are weakened by
impedance. Other types of LAN equipment with processing ability
include gateways, which enable LANs operating dissimilar protocols to
pass information by translating it into a simpler code, such as ASCII. A
bridge works like a gateway, but instead of using an intermediate code,
it translates one protocol directly into another. A router performs
essentially the same function as a bridge, except that it administers
communications over alternate paths. Gateways, bridges, and routers
can act as repeaters, boosting signals over greater distances. They
also enable separate LANs located in different buildings to
communicate with each other.
The connection of two or more LANs over any distance is referred to as
a wide area network (WAN). WANs require the use of special software
programs in the operating system to enable dial-up connections that
may be performed by a telephone lines or radio waves. In some cases,
separate LANs located in different citiesand even separate
countriesmay be linked over the public network.
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CHAPTERIII
y Instrumentation
y Validation process
y Treatment of data
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SOURCES OF DATA
INTERNET
BOOKS
INSTRUMENTS AND TOOLS USED
INTERVIEW - The researcher conducted a personal interview with the
employees of Engineering department and I.T department of Mandaluyong
City Hall to gather information about the LAN design of their office and what
changes do they to do to their department.
OBSERVATION - The researcher conducted observation about their office
facilities and area. Also, the activities of the employees in engineering office
are observed in order to know how the LAN will be designed.
INTERNET RESEACH - The researcher used the internet to gathered more
information about constructing local area network and n order to have general
and specific concepts about the construction of the LAN design, it is necessary
to use the internet because of its comprehensive and broad contents that are
maybe useful for the researcher to based the design.
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DATAGATHERING PROCEDURE
The researcher initially used the world-wide-web by analyzing and evaluating
the data and articles published on-line by the Google and Wikipedia (on-line
encyclopedia) and other possible resources. After data gathering and
analyzing the information, the researcher sent a request letter to the Office of
the Mandaluyong city hall, then in the EDP I.T. division office tagged it as
received and they scheduled the researcher to go back the next day for the
personal interview with the employee of the Mandaluyong city hall engineering
office. They also allowed the researcher to conduct observation to their
facilities. After the interviews and observations, the researcher requested the
floor plan of EDP engineering office . The employee from EDP engineering
office produced a photo copy of the floor plan. The researcher analyzes
studied the floor plan and started designing the possible LAN design using
MicrosoftVisio.
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CHAPTERV
y Summary
y Conclusion
y Recommendation
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SUMMARY
Communication channels and hardware may have different lay-outs or
networks, ranging size from large to small: Wide area networks, metropolitan
area network, and local area network. A network or communication network is
a system of interconnected computers, telephones, and other communications
devices that can communicate with another and share applications and data.
Actually, there are some types of networks but this study focused only in LAN.
LAN may be client-server or peer-to-peer network and include components
such as cabling, networks interface cards, network operating system, other
shared devices and bridges and gateways. The topology, or shape, of a LAN
may be: star, ring, bus, mesh and tree. In the LAN design of EDP engineering
office, all basic concepts about LAN were studied and analyzed first
particularly the specifications of components to be used and applied in LAN.
After studying the EDP engineering office area and facilities, all facts
were arranged logically before formulating the solutions. It may be recalled
that there were problems raised at the introductory part.
Consequently, the researcher laid-out the design based upon the floor
plan of EDP engineering office. After lay-outing and designing was
established, the hardware and software to be purchased are canvassed and
quoted in by three suppliers so that the researcher can chose among of them
is affordable and advisable to deal with. After presenting the design, all
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findings were discussed and explained before to and recommend to interested
sectors.
CONCLUSION
By this time in the midst of the recent improvement of technology, it is
the best way to have the advantage of network. With a network, a user must
explicitly log onto move files around and generally handle all the network
management personally. With a distributed system nothing has to be done
explicitly, it is all automatically done by the system without the users
knowledge. From the research study conducted, I conclude that an efficient
and flexible Local Area Network (LAN) would be a save to resources for it will
minimize expenses, workstations well be connected, users will be working
efficiently and the work output is great.
RECOMMENDATION
Every layer or workstations have a mechanism for connection
established. Since a network normally has many computers, some which
have multiple process one peripheral to specify with whom it wants to
established a connection. As consequences having a multiple destinations,
some form of addressing is needed to order of specific a destination. Closely
related the peripherals for establishing connections, across the network are
peripherals for terminating them once they are no longer needed. Not all
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communication channels preserve the order of message sent on them. To
deal of the possible loss of sequencing, the protocol must have explicit
provision for the receiver to allow the pieces to back together properly. An
obvious solution is to number pieces, but his solution still leave open the
question of what be done with pieces that arrive out of order.
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CHAPTERIV
y DIMENSIONING
y COMPANY DESIGN (FLOOR PLAN)
y NETWORKING DESIGN
y PROPOSED DESIGN
y DISCUSSION OF PROPOSED DESIGN
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LOCALAREA NETWORK (LAN)
A Reseach Paper Presented to
ENGINEER EPIFANIO TORRES
Coe Department Head
Eulogio Amang Rodriguez
Institute of Science and Technology
In Partial Fulfillment of the
Requirements forApplied Research
Poliquit, Jinnon G.
1
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TABLE OF CONTENTS
Title page i
Preface ii
Acknowledgment
Table of contents iv
CHAPTER I
THE PROBLEM AND ITS BACKGROUND
INTRODUCTION 1
BACKGROUND OF THE STUDY 4
OBJECTIVES . 7
CONCEPTUAL FRAMEWORK .. 8
STATEMENT OF THE PROBLEM 9
SIGNIFICANCE OF THE STUDY 10
SCOPE AND DELIMITATION OF THE STUDY.. 11
DEFINITION OF TERMS. 12
CHAPTER II
REVIES OF RELATED LITERATURE 21
CHAPTER III
SOURCES OF DATA .40
INSTRUMENTS AND TOOLS USED 40
DATA GATHERING PROCEDURE. 41
CHAPTER IV
DIMENSIONING i
COMPANY DESIGN (FLOOR PLAN).. ii
NETWORKING DESIGN iii
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PROPOSED DESIGN iv
DISCUSSION OF PROPOSED DESIGN 42
COMPANY PROFILE 43
CHAPTER V
SUMMARY 44
CONCLUSION 45
RECOMMENDATION... 46
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PREFACE
Local Area Network is now taking over a big part on different
companies. As a big solution to what previously tons of paperwork,
calls, records and files, and some other related office works is now
easily manageable and flexible.
From the traditional approach of manual encoding by computer
assistance, the designer proposed a Local Area Network especially
created and designed for the needs and requirements of Division Office
of Quezon City, for the company acquiring a reliable technology in
demand for the company as of now.