Computer Network (3150710) 240673107004

SAL Institute of Technology & Engineering

Research

CE/CSE Department

Computer Networks (3150710)

Laboratory Manual

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Practical: 1
Aim: - Introduction to Data Transmission in Network.
Data transmission is the process of sending and receiving data between two or
more devices through a communication medium, such as cables (wired) or radio
waves (wireless). It plays a key role in computer networks, telecommunications,
and digital communication systems.

❖ Introduction Of Computer Network:

Interconnection of two or more computing devices (like mobile, tablet, computer, laptop etc.) Such
that they can communicate with each other and allow sharing of resources and information e.g.
computer network, mobile network, internet etc.
Need of Networks:

The following are the potential needs for computer networks.

• File sharing: Networking of computers helps the network users to share data files.

• Information exchange: To exchange data and information between different individual users,
it is necessary to interconnect the individual users’ computers.

• Hardware sharing: Users can share devices such as printers, scanners, CD-ROM drives, hard
drives etc. Without computer networks, device sharing is not possible.

• Application sharing: Applications can be shared over the network, and this allows to implement
client/server applications.

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• User communication: Networks allow users to communicate using e-mail, newsgroups, and
videoconferencing etc.

❖ Types Of Network:

1. LAN (Local Area Network):

• A local area network (LAN) is a system in which computers and other devices connect to
each other in one location. While PANs connect devices around an individual, the scope
of a LAN can range from a few meters in a home to hundreds of meters in a large office.
The network topology determines how devices in LANs interconnect, such as a ring or
mesh topology.
• LANs use both wired and wireless connectivity options. Wireless LAN (WLAN) has
surpassed traditional wired LAN in popularity, but wired LAN remains the more secure
and reliable option. Wired LANs use physical cables, such as Ethernet, and switches.
WLANs use devices such as wireless routers and access points to interconnect network
devices through radio frequency waves.

• Wired LANs are usually more secure than WLANs because they require a physical cable
to form a connection and are less susceptible to compromise. However, network
administrators can implement security protocols and encryption standards to secure
wireless networks.

• Advantages:
1. Provides fast data transfer rates and high-speed communication.
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2. Easy to set up and manage.

3. Can be used to share peripheral devices such as printers and scanners.
4. Provides increased security and fault tolerance compared to WANs.

• Disadvantages:
1. Limited geographical coverage.

2. Limited scalability and may require significant infrastructure upgrades to accommodate

growth.

3. May experience congestion and network performance issues with increased usage.

• Applications:
1. LAN is used for school environment, offices, hospitals etc as it allows sharing of
resources like sharing data, scanners, printing and internet.

2. LAN serves users at home to access internet.

3. LAN’s are widely used in manufacturing industries where a central server coordinates
the activities of other machines.
4. High speed LANs are typically used to connect many slower networks together.

2. MAN (Metropolitan Area Network):

• MAN or Metropolitan area Network covers a larger area than that covered by a LAN and
a smaller area as compared to WAN.
• MAN has a range of 5-50km.

• It connects two or more computers that are apart but reside in the same or different cities.

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• It covers a large geographical area and may serve as an ISP (Internet Service Provider).

• MAN is designed for customers who need high-speed connectivity.

• Speeds of MAN range in terms of Mbps.

• It’s hard to design and maintain a Metropolitan Area Network

• Advantages:

1. Provides high-speed connectivity over a larger geographical area than LAN.

2. Can be used as an ISP for multiple customers.

3. Offers higher data transfer rates than WAN in some cases.

• Disadvantages:

1. Can be expensive to set up and maintain.

2. May experience congestion and network performance issues with increased usage. May
have limited fault tolerance and security compared to LANs

• Applications:

• Following are some of the uses of Metropolitan Area Network

1. University Campus

2. Airports

3. Public libraries

4. Hospitals

5. Different branches of schools and colleges

6. Cable Television

3. WAN (Wide Area Network):

• WAN or Wide Area Network is a computer network that extends over a large geographical
area, although it might be confined within the bounds of a state or country.

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• WAN has a range of above 50 km.

• A WAN could be a connection of LAN connecting to other LANs via telephone lines and
radio waves and may be limited to an enterprise (a corporation or an organization) or
accessible to the public.

• The technology is high-speed and relatively expensive

• There are two types of WAN: Switched WAN and Point-to-Point WAN.

• WAN is difficult to design and maintain.

• A Communication medium used for WAN is PSTN or Satellite Link. Due to long-distance
transmission, the noise and error tend to be more in WAN.

• The speed of WAN ranges from a few kilobits per second (Kbps) to megabits per second
(Mbps).

• Devices used for the transmission of data through WAN are Optic wires, Microwaves,
and Satellites.

• An example of a Switched WAN is the asynchronous transfer mode (ATM) network and
Point-to-Point WAN is a dial-up line that connects a home computer to the Internet.

• Advantages:

1. Covers large geographical areas and can connect remote locations.

2. Provides connectivity to the internet.

3. Offers remote access to resources and applications.

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4. Can be used to support multiple users and applications simultaneously.

• Disadvantages:

1. Can be expensive to set up and maintain.

2. Offers slower data transfer rates than LAN or MAN.

3. May experience higher latency and longer propagation delays due to longer distances
and multiple network hops.

4. May have lower fault tolerance and security compared to LANs.

• Applications:

1. Satellite systems
2. Network providers

3. Companies and offices

4. 4G mobile broadband systems

5. Internet

6. Telecommunication companies
7. A Network of bank cash dispensers

❖ Transmission Media :
A transmission media is a physical path between the transmitter and the receiver i.e. it is the
path along which data is sent from one device to another. Transmission Media is broadly
classified into the following types:

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Guided Media :

Guided media in computer networks also known as wired transmission media, uses physical
cables to transmit signals.

Guided media, which are those that provide a conduit from one device to another, include
Twisted-Pair Cable, Coaxial Cable, and Fiber-Optic Cable.

• Coaxial Cable

• Twisted pair cable

• Fiber optic cable

Coaxial Cable:

• Coaxial is called by this name because it contains two conductors that are parallel to each
other. Copper is used in this as Centre conductor which can be a solid wire or a standard one.
It is surrounded by PVC installation, a sheath which is encased in an outer conductor of metal
foil, barid or both.
• Coaxial cables are another type of guided media used primarily in television networks and
broadband internet connections.
• The structure of coaxial cables includes a central conductor, an insulating layer, a metallic
shield, and an outer plastic covering.

• Outer metallic wrapping is used as a shield against noise and as the second conductor which
completes the circuit. The outer conductor is also encased in an insulating sheath. The
outermost part is the plastic cover which protects the whole cable.
• This layered design provides excellent protection against external noise and interference,
making coaxial cables suitable for high-frequency applications.

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Advantages of Coaxial Cable :

• Bandwidth is high

• Used in long distance telephone lines.

• Transmits digital signals at a very high rate of 10Mbps.

• Much higher noise immunity

• Data transmission without distortion.

• The can span to longer distance at higher speeds as they have better shielding when
compared to twisted pair cable

Disadvantages of Coaxial Cable :

• Single cable failure can fail the entire network.

• Difficult to install and expensive when compared with twisted pair.

• If the shield is imperfect, it can lead to grounded loop.

Applications of Coaxial Cable :

• Coaxial cable was widely used in analog telephone networks, where a single coaxial network
could carry 10,000 voice signals.

• Cable TV networks also use coaxial cables. In the traditional cable TV network, the entire
network used coaxial cable. Cable TV uses RG-59 coaxial cable.

• In traditional Ethernet LANs. Because of it high bandwidth, and consequence high data rate,
coaxial cable was chosen for digital transmission in early Ethernet LANs. The 10Base-2, or
Thin Ethernet, uses RG-58 coaxial cable with BNC connectors to transmit data at 10Mbps with
a range of 185 m.

Twisted Pair Cable :

• A twisted pair consists of two conductors (normally copper), each with its own plastic
insulation, twisted together. One of these wires is used to carry signals to the receiver, and the
other is used only as ground reference.
Twisted Pair is of two types:

• Unshielded Twisted Pair (UTP)

• Shielded Twisted Pair (STP)

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Unshielded Twisted Pair Cable :

• It is the most common type of telecommunication when compared with Shielded Twisted
Pair Cable which consists of two conductors usually copper, each with its own colour plastic
insulator. Identification is the reason behind colored plastic insulation.
• UTP cables consist of 2 or 4 pairs of twisted cable. Cable with 2 pair use RJ-11 connector
and 4 pair cable use RJ-45 connector.
• These are a pair of two insulated copper wires twisted together without any other sulation.

• They reduce the external interference due to the presence of insulation.

• They are arranged in pairs so that we can add a new connection whenever required. The
DSL or telephone lines in our houses have one extra pair in them.
• When UTP are arranged in pairs, each pair is coded with a different color as defined by
the 25-pair color code.
• The Electronic Industries Association divides UTP into 7 categories based on some
standards. Categories are based upon cable quality where 1 is the highest quality and 7 is
the lowest quality. Each cable in a category is put to a different use as needed.

Advantages of UTP:

• Low cost and widely available.

• Simple and quick to install.
• Suitable for short-distance communication.
• These cables are cost-effective and easy to install owing to their compact size.
• They are generally used for short-distance transmission of both voice and data.
• It is less costly as compared to other types of cables.

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Disadvantages of UTP:

• Susceptible to external interference, especially in noisy environments.

• Limited to shorter distances compared to other types of cables.
• The connection established using UTP is not secure.
• They are efficient only for a distance up to 100 meters and have to be installed in pieces of
up to 100 meters.
• These cables have limited bandwidth.

Shielded Twisted Pair Cable

• These types of cables have extra insulation or protective covering over the conductors in
the form of a copper braid covering.

• This covering provides strength to the overall structure of the cable. It also reduces noise
and signal interference in the cable.

• The shielding ensures that the induced signal can be returned to the source via ground and
only circulate around the shield without affecting the main propagating signal. The STP
cables are also color-coded like the UTP cables as different color pairs are required for
analog and digital transmission.

Advantages of STP:

• They are generally used for long-distance communication and transmission and are
installed underground.

• The protective shield prevents external electromagnetic noise penetration into the cable.
• They have a higher bandwidth as compared to UTP.

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Disadvantages of STP:

• These cables are very expensive.

• They require a lot of maintenance which increases the cost more.

• These can be installed underground only.

• The length of the segment is similar to UTP for these cables.

Applications of Shielded Twisted Pair Cable:

• In telephone lines to provide voice and data channels. The DSL lines that are used by the
telephone companies to provide high-data-rate connections also use the high-bandwidth
capability of unshielded twisted-pair cables.

Fiber Optic Cable:

• A fiber-optic cable is made of glass or plastic and transmits signals in the form of light.
• Optical fibers use reflection to guide light through a channel.
• A glass or plastic core is surrounded by a cladding of less dense glass or plastic. The
difference in density of the two materials must be such that a beam of light moving through
the core is reflected off the cladding instead of being refracted into it.

Advantages of Optical Fiber Cables:

● Extremely high bandwidth, capable of transmitting massive amounts of data.
● Immune to electromagnetic interference, making them suitable for environments with
high levels of electrical noise.
● Lightweight and capable of long-distance communication without significant signal
loss.

Disadvantages of Optical Fiber Cables:

● Expensive to install and maintain.

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● Fragile and prone to damage if not handled carefully.

● Difficult to splice and repair if damaged

Unguided Media
• Unguided media, also known as wireless or unbounded media, refers to transmission
paths where electromagnetic signals are transmitted through the air without the need for
physical cables.
• This type of media is used for wireless communication over long distances and in areas
where installing cables is impractical or impossible.
• There are three types of Unguided Transmission Media:

Radio Waves
• Electromagnetic waves ranging in frequencies between 3 KHz and 1 GHz are normally
called radio waves.
• Radio waves are omnidirectional. When an antenna transmits radio waves, they are
propagated in all directions. This means that the sending and receiving antennas do not
have to be aligned.
• A sending antenna send waves that can be received by any receiving antenna. The
omnidirectional property has disadvantage, too. The radio waves transmitted by one
antenna are susceptible to interference by another antenna that may send signal suing the
same frequency or band.
• Radio waves, particularly with those of low and medium frequencies, can penetrate
walls. This characteristic can be both an advantage and a disadvantage. It is an advantage
because, an AM radio can receive signals inside a building. It is a disadvantage because
we cannot isolate a communication to just inside or outside a building.

Advantages of Radio Waves

• It is used in WAN (Wide Area Network).

• Used in mobile Cellular phones.
• Radio wave spread in large area so they can penetrate the wall.
• It's provide a higher transmission rate.

Applications of Radio Waves

• The omnidirectional characteristics of radio waves make them useful for multicasting in
which there is one sender but many receivers.

• AM and FM radio, television, maritime radio, cordless phones, and paging are examples
of multicasting.

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Micro Waves
• Electromagnetic waves having frequencies between 1 to 300 GHz are called micro
waves. Micro waves are unidirectional.
• When an antenna transmits microwaves, they can be narrowly focused. This means that
the sending and receiving antennas need to be aligned.
• The unidirectional property has an obvious advantage. A pair of antennas can be aligned
without interfering with another pair of aligned antennas.

Types of Microwaves

There are two types of microwaves:

1. Terrestrial Microwave :
Terrestrial Microwave are microwaves that transmits the beam of a radio signal from one
ground based antenna to another ground based antenna.

2. Satellite Microwave Communication :

A satellite is a object that revolve around the earth. A satellite microwave is a type of
communication technology that uses microwave radio waves to transmit data between a
ground-based station and an orbiting satellite.
Applications of Micro Waves

• Microwaves, due to their unidirectional properties, are very useful when

unicast(one-to-one) communication is needed between the sender and the receiver.

• They are used in cellular phones, satellite networks and wireless LANs.

Advantages of Microwave Transmission

• Used for long distance telephone communication

• Carries 1000's of voice channels at the same time

Disadvantages of Microwave Transmission

• It is very costly

Infrared Waves
• Infrared waves, with frequencies from 300 GHz to 400 THz, can be used for
short-range communication. Infrared waves, having high frequencies, cannot
penetrate walls.

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• This advantageous characteristic prevents interference between one system and

another, a short-range communication system in on room cannot be affected by
another system in the next room.

• we cannot use infrared waves outside a building because the sun's rays contain
infrared waves that can interfere with the communication.

• It's used for short-range communication like data transmission between two cell
phones, TV remote control operation, and data transfer between a computer and
a mobile phone in the same confined area.

• Infrared waves are regarded as a far safer form of unguided transmission medium.

Applications of Infrared Waves

• The infrared band, almost 400 THz, has an excellent potential for data
transmission. Such a wide bandwidth can be used to transmit digital data with a
very high data rate.
• The Infrared Data Association (IrDA), an association for sponsoring the use of
infrared waves, has established standards for using these signals for
communication between devices such as keyboards, mouse, PCs and printers.
• Infrared signals can be used for short-range communication in a closed area using
line-of-sight propagation.
Advantages
The advantages of infrared transmissions are as follows –
• It is a very high speed transmission.
• It has a large bandwidth.
• It is very cheap.
• It can be simple to create.
• It provides a wireless connection between two systems.
• There is no license needed to facilitate it.

Disadvantages
The disadvantages of infrared transmissions are as follows –
• It cannot permeate the barrier.
• It cannot use it for long-range communication.

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EXERCISE:

1) Write a program to convert character into binary and binary digits into character.

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Output:

QUIZ:
Answer the Followings:
1) Write ASCII range for A-Z, a-z, 0-9.
2) In the second program why does the “for loop” appear in reverse order?
3) Give the difference between ISO and OSI.
4) What is Protocol?
5) Differentiate “Node to Node Communication” and “End
to End Communication”

EVALUATION:

Problem Analysis Understanding Timely Mock Total

& Solution Level Completion
(3) (3) (2) (2) (10)

Signature with date: ___________________

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