Seminar report-networking

A TECHNICAL SEMINAR REPORT
on
INTRODUCTION TO NETWORKING
Submitted in partial fulfillment of the requirement
For the award of the degree of Bachelor of Technology
in
Computer Science & Engineering
Submitted to: Submitted by:
Er. Rakesh Rana Jyoti Bhamar
Lecturer 3910000
(CSE Department) CSE(5th sem)
DEPARTMENT OF COMPUTER SCIENCE & ENGINEERING
MODERN INSTITUTE OF ENGINEERING & TECHNOLOGY
(Affiliated To Kurukshetra University, Kurukshetra, Haryana, India)

CONTENTS
1. Abstract
2. Introduction to computer networking
3. Need of computer network
4. Networking models
4.1. Centralized
4.2. Distributed
4.3. Collaborative
5. Type of computer networks
5.1. LAN
5.2. WAN
5.3. MAN
6. Components of network
6.1. Network services
6.1.1. File services
6.1.2. Print services
6.1.3. Message services
6.1.4. Application services
6.1.5. Database services
6.2. Transmission media
6.2.1. Guided Media
6.2.1.1. Twisted pair
6.2.1.1.1. Shielded twisted pair
6.2.1.1.2. Unshielded twisted pair
6.2.1.2. Coaxial
6.2.1.3. Fiber optic
6.2.1.3.1. Single mode
6.2.1.3.2. Multimode
6.2.2. Unguided Media
6.2.2.1. Radio wave
6.2.2.2. Microwave
6.2.2.3. Infrared
6.3. Protocols
7. Data Transmission modes
7.1. Simplex
7.2. Half duplex
7.3. Full duplex

8. Connectors
8.1. RJ11
8.2. RJ45
8.3. BNC
9. Cables
9.1. Straight cable
9.2. Crossover cable
9.3. Rolled over cable
10. Network devices
10.1. NIC
10.2. Hubs
10.3. Switches
10.4. Repeaters
10.5. Multiplexer
10.6. MODEM
10.7. Routers
10.8. Bridges
10.9. Brouters
10.10. Gateway

1. ABSTRACT
Computer networks have become increasingly ubiquitous. The rapid proliferation of
Computer networks has changed the landscape of 21th century. In the world of computers,
networking is the practice of linking two or more computing devices together for the purpose of
sharing data. Networks are built with a mix of computer hardware and computer software.
The applications like e-mail, web-browsing, digital library, audio-video conferencing,
video on demand, e-commerce, file transfer, Wi-Fi, remote desktop assistance, cloud computing,
digital signatures, social networking sites and many more has forced people to use networking.
Through networking people can take advantage of these applications. Therefore networking is
the concept of sharing resources and services.
As we can no longer imagine our life without computers. Today they are an integral part
of our homes and offices. The Internet, employing computer networking at its best, has brought
the world at our fingertips. There is better storage and collaboration of information and
communication is faster. Not only individuals, but entire economies have been empowered to
function efficiently, making our lives easier and more streamlined. Here, we welcome you to
explore and learn more about computer networking.

2. INTRODUCTION TO COMPUTERNETWORKING
Computer networking is the interconnection of two or more computers. We connect
several computers at different locations to exchange information or do other works in a shared or
mutually accessible data base i.e. Computer networking is the establishment or use of Computer
Network.
Computer network is a group of computer and other peripheral devices, connected by
communication lines (cables or other channels), which are capable of sharing files and other
resources between several users. The communication lines connecting the devices are often
called communication channels or transmission media. The performance of the network depends
on no. of users, type of transmission medium, hardware, and software.
Computer network

3. NEED OF COMPUTER NETWORK
Need of computer network arose due to these reasons:
Resource sharing: All computers in the network can share resources such as printers,
fax machines, modems, and scanners.
Cost Reduction: Cost can be reduced by sharing resources (devices) in the network.
Flexible Access: Networks allow their users to access files from computers
throughout the network. This means that a user can begin work on a project on one
computer and finish up on another. Multiple users can also collaborate on the same
project through the network.
File Sharing: Networks offer a quick and easy way to share files directly. Instead of
using a disk or USB key to carry files from one computer or office to another, you
can share files directly using a network.
Communication: Even outside of the internet, those on the network can
communicate with each other via electronic mail over the network system. When
connected to the internet, network users can communicate with people around the
world via the network.
Security: Specific directories can be password protected to limit access to authorized
users.
Error Reduction and Improve Consistency: One can reduce errors and improve
consistency by having all staff work from a single source of information, so that
standard versions of manuals and directories can be made available, and data can be
backed up from a single point on a scheduled basis, ensuring consistency.

4. NETWORKING MODELS
There are several different models of how computers work together in a network. Three
general models are:
4.1 Centralized: Centralized computing centers around large host computers. These
hosts are generally mainframe handles all the data storage and data processing. The dumb
terminals are connected to them normally acts as input/output devices, since they have little or no
processing power. They are expensive but they provide centralized administration. The dumb
terminal, the user could run programs, access resources, and copy files as all the processing took
place in one central location.
4.2 Distributed: The distributed models of computing involve a network of intelligent
computers, called client, which are able to share the processing load. Each client can process its
own task, some data is actually stored and processed at the client end and services are requested
and provided by the server. We can even categorize this model of networking as:
 Client/Server
 Peer to Peer
In Client/Server environment client depends upon server for sharing of resources,
services and security only. Else everything processed at a client end. Generally this type
of computing used in big to very big networks.
In a Peer-to-Peer environment all computers have a similar storage and processing
power. They are used in very small and friendly environment where security issue not
considered. All system acts as client all act as server.
4.3 Collaborative: collaborative computing is a combination of computers working
together processing the same task. A computer might run a part of program on another computer
in order to maximize processing power. It is extension of distributed computing model. Like
distributed computing, it involves clients with internal processing power that can share data and
services.

5. TYPES OF COMPUTER NETWORK
The types of network are categorized on the basis of the number of systems or devices
that are under the networked area. In order to be proficient in network security, you have to
understand the different types of networks since each network type poses different challenges,
issues and risks.
5.1 LAN: A Local Area Network (LAN) is a relatively small network that is confined to
a small geographic area, such as a single office or a building. Laptops, desktops, servers,
printers, and other networked devices that make up a LAN are located relatively close to each
other. From a security context, LANs are the point at which trusted users typically access your
network and server resources. The maximum speed of a LAN can be 1000 megabits per second.
LANs tend to have fewer problems associated with them, as there are a smaller amount of
systems to deal with.
5.2 WAN: A Wide Area Network (WAN) covers a significantly larger geographic area
than LANs or MANs. A WAN uses public networks, telephone lines, and leased lines to tie
together smaller networks such as LANs and MANs over a geographically dispersed area.
Connecting devices in different geographic areas together for information sharing, WANs are an
important piece of enterprise networks. The best example of a WAN could be the Internet that is
the largest network in the world. The maximum speed of a WAN can be 150 megabits per
second. A WAN is usually slower because it has lower bandwidth. WANs tend to be fewer faults
tolerant. As it consists of a large amount of systems there is a lower amount of fault tolerance.
5.3 MAN: The term Metropolitan Area Network (MAN) is typically used to describe a
network that spans a citywide area or a town. MANs are larger than traditional LANs and
predominantly use high-speed media, such as fiber optic cable, for their backbones. MANs are
common in organizations that need to connect several smaller facilities together for information
sharing. This is often the case for hospitals that need to connect treatment facilities, outpatient
facilities, doctor's offices, labs, and research offices for access to centralized patient and
treatment information. MANs share many of the same security threats as LANs, but on a larger
scale. The maximum speed of a MAN can be 80 megabits per second.

6. COMPONENTS OF NETWORK
Every network needs to have certain components in order to work properly. The required
components are:
6.1 Network services: such as printing, e-mail, file sharing exchanged between service
requesters, and service providers.
6.1.1 File services: File service enables networked computers to share files. Some
key file services include file transfer, file storage, data migration, file updating. All files are
stored on single server from where other host request files. It can be easily managed and the cost
is also distributed between many users.
6.1.2 Print services: Printing is the second incentive of installing a LAN. Many
users can share same printer. Printer can be located anywhere, not just next to user’s PC. Queue
based network printing is also supported that make service more efficient.
6.1.3 Message services: Message services include variety of communication
methods that go far beyond simple file services. With message services, data can take the form of
graphics, digitized video, and audio as well as text and binary data. The main types of message
services are e-mail, directory services.
6.1.4 Application services: Application services enables applications to leverage
the computing power and specialized capabilities of other computers on a network. For example
one application is installed with licensed key and other users in LAN can use it with no
additional cost.
6.1.5 Database services: Database services enable applications to be designed in
separate client and server components, such applications are frequently called client/server
databases.
6.2 Transmission media: They are the physical or wireless pathways that connect PCs or
other devices. Transmission media can be broadly classified into 2 broad categories:
6.2.1 Guided media: Guided media, which are those that provide a conduct
from one device to another, include twisted-pair, coaxial and fiber optic.
A signal traveling along any of these media is directed and is contained by
the physical limits of the medium.
6.2.1.1 Twisted pair: Twisted pair cable is the cheaper and oldest form of
transmission medium which is used today. In this type of line a
pair of insulated wires is twisted together. They are insulated from
each other. One is used for signal and other is used for ground
reference. It reduces crosstalk. They are suitable for bit rates of the
order of 1 Mbps over short distances. They are most commonly
used in connections of stars and hub networks.

6.2.1.1.1 Shielded Twisted Pair: Often abbreviated as STP, a
type of copper telephone wiring in which each of the
two copper wires that are twisted together are coated
with an insulating coating that functions as a ground for
the wires. The extra covering in shielded twisted pair
wiring protects the transmission line from
electromagnetic interference leaking into or out of the
cable. STP cabling often is used in Ethernet networks,
especially fast data rate Ethernets.
6.2.1.1.2 Unshielded Twisted Pair: Often abbreviated as UTP, a
popular type of cable that consists of two unshielded
wires twisted around each other. Due to its low cost,
UTP cabling is used extensively for local area network
(LANs) and telephone connections. UTP cabling does
not offer as high bandwidth or as good protection from
interference as coaxial or fiber optic cables, but it is less
expensive and easier to work with. UTP is the most
common form of twisted pair wiring, because it is less
expensive and easier to work with than STP.
6.2.1.2 Coaxial: Coaxial cable, or coax, is an electrical cable with an
inner conductor surrounded by a flexible, tubular insulating layer,
surrounded by a tubular conducting shield. Coaxial cable is one of
the most important kinds of transmission media used in LANs. The
major problems of higher attenuation and signal power lost at high
frequencies of twisted pair cables were minimized by using coaxial
cable. In this the signal and ground reference wires run
concentrically inside a solid outer circular conductor. The space
between two conductors is filled with dielectric insulating material
with a honey comb structure. The skin effect and power losses
were minimized by these cables.
6.2.1.3 Fiber optic: An optical fiber is a thin, flexible, transparent fiber
that acts as a waveguide, or "light pipe", to transmit light between
the two ends of the fiber. The field of applied science and
engineering concerned with the design and application of optical
fibers is known as fiber optics. Optical fibers are widely used in
fiber-optic communications, which permits transmission over
longer distances and at higher bandwidths (data rates) than other
forms of communication.
6.2.1.3.1 Single mode: Single mode fiber refers to the fact that
only a single wavelength (one color of light) is

transmitted over the physical medium. It is true doped
fiberglass fibers wrapped in a plastic cladding. Single
mode typically has much longer reach, but a larger bend
radius than multi-mode.
6.2.1.3.2 Multimode: Multimode fiber can carry multiple
wavelengths, is made of special clear plastic material
and has a much smaller bend radius that single mode
fiber. It does not have as long a reach as single mode
fiber.
6.2.2 Unguided Media: Unguided media transport electromagnetic waves
without using a physical conductor. This type of communication is often
referred to as wireless communication. Signals are normally broadcast
through the air and thus are available to any one who has the device
capable of receiving them.
6.2.2.1 Radio wave: Radio waves are Omni-directional. 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 sends waves that can be receiving by
any receiving antenna. Radio is most famously utilized to send
audio, images, and text in the form of signals. Radio waves are
used for multicast communications, such as radio and television,
and paging systems.
6.2.2.2 Microwave: Microwaves are unidirectional. When an antenna
transmits microwave waves, they can be narrowly focused. The
sending and receiving antennas need to be aligned. Microwave
system uses very high frequency radio signal to transmit data
through space. Microwaves are used for unicast communication
such as cellular phones, satellite networks, and wireless LANs.
6.2.2.3 Infrared: 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. This advantage
characteristic prevents interface between one system and another; a
short-range communication system in one room cannot be affected
by another system in the next room. Used for very short line sight
transmission, remote car locking systems, wireless security alarms,
TV remote.
6.3 Protocols: A protocol is a set of rules that governs the communications between
computers on a network. The key elements of a protocol are syntax, semantics, and
timing. Eg. FTP, SMTP, TCP/IP, ARP, UDP, HTTP, DHCP etc.

7. DATA TRANSMISSION MODES
A given transmission on a communication channel between two machines can occur in
several ways. The transmission is characterized by the direction of the exchanges, no. of bits sent
simultaneously, synchronization between sender and receiver.
7.1 Simplex: A simplex connection is a connection in which the data flows in only one
direction, from the transmitter to the receiver. This type of connection is useful if the
data do not need to flow in both directions. For example, from your computer to the
printer or from the mouse to your computer.
7.2 Half duplex: A half-duplex connection is a connection in which the data flows in
both directions, but not both at the same time. With this type of connection, each end
of the connection transmits in turn. For example, walkie-talkie.
7.3 Full duplex: A connection is a connection in which the data flow in both directions
simultaneously. Each end of the line can thus transmit and receive at the same time,
which means that the bandwidth is divided in two for each direction of data
transmission. For example, telephone, mobile.

8. CONNECTORS
A connector is best known for providing a physical link between two components.
8.1 RJ11: Registered jack (RJ) is a standardized physical network interface.RJ11 is
more commonly known as a phone connector, phone jack or phone line, the RJ-11 is short for
Registered Jack-11 and is a four or six wire connection primarily used for telephones and
computer modem connectors.
8.2 RJ45: Short for Registered Jack-45, a RJ-45 is a 8-pinconnection used for Ethernet
network adapters. This connector resembles to the RJ-11 or 6-pin connector used with
telephones, but they're completely different. On the connector are eight contacts corresponding to
the eight wires in the cable, and these match the eight contacts of the RJ-45 port on your
computer or network device. Local Area Networks (LAN) use Ethernet cables and RJ-45
connectors to connect two or more computers on the same network. Ethernet cables are plugged
into a hub, router or switch to make up the LAN.
8.3 BNC: Short for Bayonet Neill Concelman connector, a BNC connector is a type of
connector used with coaxial Ethernet cable. The connector is bayonet-style, meaning that it is put
in then turned and locked in position. This connector is commonly used on a Token Ring
network. BNC is also short for Bayonet Nut Connector or British Naval/Navy Connector
although more appropriately known as the Bayonet Neill Concelman.

9. CABLES
Cables are used to connect one network device to other network devices or to connect
two or more computers to share printer, scanner, router etc.
9.1 Straight cable: Straight cable is use to connect different type of devices. This type of
cable will be used most of the time and can be used to connect a computer to a switch/hub's
normal port, connect a computer to a cable/DSL modem's LAN port, connect a router's WAN
port to a cable/DSL modem's LAN port, and connect a router's LAN port to a switch/hub's uplink
port, connect 2 switches/hubs with one of the switch/hub using an uplink port and the other one
using normal port.
9.2 Crossover cable: Crossover cable usually used to connect same type of devices. A
crossover cable can be used to connect 2 computers directly, connect a router's LAN port to a
switch/hub's normal port, and connect 2 switches/hubs by using normal port in both
switches/hubs.
9.3 Rolled over cable: Rollover cable also known as Cisco console cable or a Yost cable
is a type of null-modem cable that is often used to connect a computer terminal to a
router's console port. This cable is typically flat (and has a light blue color) to help
distinguish it from other types of network cabling. It gets the name rollover because
the pin outs on one end are reversed from the other, as if the wire had been rolled
over and you were viewing it from the other side.

10 NETWORK DEVICES
10.1 NIC: A network interface card more commonly referred to as a NIC, is a
device that allows computers to be joined together in a LAN, or local area
network. Networked computers communicate with each other using a given
protocol or agreed-upon language for transmitting data packets between the
different machines, known as nodes. The network interface card acts as the
liaison for the machine to both send and receive data on the LAN.A network
interface card (NIC) is basically a computer circuit board or card that is installed
in a computer so that it can be connected to a network.
10.2 Hubs: Connects all computers in a network to each other and helps direct
messages to appropriate recipients; as more users join the network, more hubs
may be added. The hub is a central connection point for wiring the network. A
typical hub has multiple ports to which computers and peripheral devices such as
servers are attached. The hub receives, re-times and regenerates signals received
from any attached station. The hub also functions as a filter i.e. it discards
severely distorted frames.

10.3 Switches: A concentrator is a device that provides a central connection point for
cables from workstations, servers, and peripherals. It Provide packet filtering
between the LANs. Increase network performance by providing each port with
dedicated bandwidth without requiring users to change any existing equipment, such
as NICs, hubs, wiring, or any routers or bridges that are currently in place. Switches
can also support numerous transmissions simultaneously.
10.4 Repeaters: When a signal travels along a cable, it tends to lose strength. A
repeater is a device that boosts a network's signal as it passes through. The repeater
does this by electrically amplifying the signal it receives and re-broadcasting it.
Repeaters can be separate devices or they can be incorporated into a concentrator.
They are used when the total length of the network cable exceeds the standards set
for the type of cable being used.
10.5Multiplexer: A multiplexer (or MUX) is a device that selects one of several analog
or digital input signals and forwards the selected input into a single line and the
process is known as multiplexing.

10.6 MODEM: A modem (modulator-demodulator) is a device that modulates an
analog carrier signal to encode digital information, and also demodulates such a
carrier signal to decode the transmitted information. The goal is to produce a signal
that can be transmitted easily and decoded to reproduce the original digital data. The
most familiar example is a voice band modem that turns the digital data of a personal
computer into modulated electrical signals in the voice frequency range of a
telephone channel. These signals can be transmitted over telephone lines and
demodulated by another modem at the receiver side to recover the digital data.
10.7 Routers: The difference between a router and a bridge is that a router operates at
level 3 in the OSI seven layer model, whereas a bridge operates at level 2. This
means that a router can be used to connect different types of networks and, because it
has access to level 3 routing information, can dynamically make the best (cheapest,
fastest, etc) choice of route between the networks. Routers divide the network
logically instead of physically. A router will decide whether to forward a packet by
looking at the protocol level addresses (e.g. TCP/IP addresses) rather than MAC
address.
10.8 Bridges: A bridge will connect to distinct segments (usually referring to a physical
length of wire) and transmit traffic between them. A bridge therefore serves two
purposes. It connects two similar networks. For example, if two LANs are connected
with a bridge, the users of each LAN can access the other network’s file server
without making any physical changes to their data. A bridge allows segmentation of
large networks into two smaller, more efficient networks.
10.9 Brouters: A bridge router or brouter is a network device that works as a bridge
and as a router. The brouter routes packets for known protocols and simply forwards
all other packets as a bridge would. Brouters operate at both the network layer for
routable protocols and at the data link layer for non-routable protocols.
10.10 Gateways: A gateway is a network point that acts as an entrance to another
network. A gateway may contain devices such as protocol translators, impedance
matching devices, rate converters, fault isolators, or signal translators as necessary to
provide system interoperability. It also requires the establishment of mutually
acceptable administrative procedures between both networks.

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