This is useful for School Students.

1. Networking
Technology
Submitted By: Sabin Dhakal
Class: 10 “Topaz”
Submitted To : Roshan Maharjan

2. 02
02
01
❖ Data Communication
❖ Telecommunication
❖ Transmission Modes
❖ Direction of Data
Transmission
❖ Communication Media
03
❖ Networking
Terminology
❖ Computer Network
Components
❖ Hardware Components
❖ Network Software
❖ Computer Network
Models
04
❖ Computer Network
Categories
❖ Physical Topologies For
LAN
❖ Network Connectivity
Devices
Slides
And
Topics
❖ Computer Network
❖ Importance And
Disadvantages
❖ Computer Network
Services

3. Communication And Basic Elements Of a Communication System
Communication is the process of transferring messages from one point to
another. It’s basic elements of any communication system are:
➢ A sender, which creates the messages to be transmitted.
➢ A medium, which carries the message.
➢ A receiver, which receives the message.
Sender
Medium
Receiver

4. Data Communication
Data communications refers to the
transmission of this digital data between two
or more computers and a computer network
or data network is a telecommunications
network that allows computers to exchange
data. A data communication system has the
following components:
❖ Message: It is the information or data to
be communicated. It can consist of text,
numbers, pictures, sound or video.
❖ Sender: It is the device that generates and
sends that message.
❖ Receiver: It is the device that receives the
message.
❖Medium: The path that is used to send or
receive the messages from the sender to the
receiver.
❖ Protocol: It is a set of rules that govern the
communication between the devices.

5. Telecommunication
Telecommunication is the transmission of data and information between computers using a
communication link such as a standard telephone line.
Transmission Modes
Data Transmission mode defines the direction of the flow of information between
two communication devices. It is also called Data Communication or Directional Mode. It
specifies the direction of the flow of information from one place to another in a computer network.
Its transmission is characterized by:
1. The direction of the exchanges
2. The transmission mode
3. Synchronization between the transmitter and receiver
Direction of Data Transmission
There are three different transmission modes characterized according to the direction of the
exchanges:

6. Types of Data Transmission
❖Simplex Mode Communication:
Simplex is the data transmission mode in which the data can flow only in one direction, i.e.,
the communication is unidirectional. In this mode, a sender can only send data but can not
receive it. Similarly, a receiver can only receive data but can not send it.
For Example, Radio and TV transmission, keyboard, mouse, etc. operate in simplex mode.
❖ Half Duplex Mode Communication: Half-Duplex is the data transmission mode in which the
data can flow in both directions but in one direction at a time. It is also referred to as Semi-
Duplex. In other words, each station can both transmit and receive the data but not at the
same time. When one device is sending the other can only receive and vice-versa.
Transmitter Receiver

7. Full Duplex Mode Transmission
❖Full-Duplex is the data transmission mode in which the data can flow in both directions at
the same time. It is bi-directional in nature. It is two-way communication in which both the
stations can transmit and receive the data simultaneously. For Example, a Telephone
Network, in which both the persons can talk and listen to each other simultaneously.

8. Communication Media
❖ Communication media refers to the mode of physical connection needed for data transmission. There are two types of
communication media: bounded and unbounded media.
❖ Bounded Media: A transmission media where data signals are transmitted along a specific path through cable is known
as Guided Transmission Media. It transfer data from one place to another with the help of wire. There are three types of
cables used for wired network. They are:
1. Twisted Pair cable:
The twisted pair cable consists of a pair of insulated copper wire twisted around each other. The number of twisted
pair may 1, 2, 4 or more. The twisted pair cable is mostly used for connecting computers on the network.
The twisted pair cable comes into two categories:
a. Unshielded Twisted Pair (UTP):A UTP cable is one of the most popular LAN cables. This cable consists of 4 twisted
pairs of metal wires (means there are 8 wires). Adding RJ-45 connector at both ends of the cable, it becomes a
LAN cable that we generally use.
b.Shielded twisted Pair (STP):A shielded twisted pair cable (also known as IBM Type I) is similar to UTP but it has
metallic covering placed just underneath the plastic casing. It is more expensive than UTP cables. STP cable offer
the best protection from interference. It can support data transfer rate from 16 to 500 Mb/s (millions of bit per
second).

9. ❖ Coaxial Cable
Coaxial cable(coax) is an electrical cable with an inner conductor surrounded by a flexible, tubular,
insulating layer, surrounded by a tubular conducting shield. Coaxial cable have wide bandwidth and noise
immunity. These are widely used in long distance telephone lines. It's transmission speed is much higher
than twisted pair cables. It is used as a transmission line for radio frequency signals, internet connections
and distributing cable television signals.
❖Fiber Optic:
Fiber optic cables are made up of plastic or glass fibers and gives high quality transmission of signal at a
very high speed. Fiber optic cable transmission are not affected by electromagnetic interference. These can
be used to communicate either analog or digital signals. These are most commonly used for point to point
one way communication.

10. Unbounded Media
❖It is the transmission medium in which data/signal is sent through the air instead of cables. It includes wireless
transmission methods such as radio networking, infrared transmission and microwave transmission to
interconnect the other components of a network.
➢ Radio networking:
Radio networking is a form of wireless transmission in which signals are sent via radio
frequency(RF) waves in the 10KHz and 1GHz.There are two major types of radios used in networking:
baseband and broadband. Baseband technology transmits a single data signal/stream/channel at a time
while broadband technology transmits multiple data signals/streams/channels simultaneously at the same time.
➢ Infrared Transmission:
Infrared transmission is a form of wireless transmission in which signals
are sent via pulses of infrared light. It is used for networking computers together and connecting devices.
➢ Microwave Transmission:
Microwave Transmission is a form of wireless transmission that involves the sending and
receiving of microwave signals over a microwave link. This microwave link is made up of a string of microwave
radio antennas located at the top of towers at various microwave sites. It is commonly used by communication
systems on the surface of the earth, in satellite communications, and in deep space radio communications.

11. • Satellite Communication is a form of wireless transmission that use artificial satellites to
provide communication links between various points on the Earth. Satellite communication
has two main components: the ground segment, which consists of fixed or mobile
transmission, reception, and ancillary equipment, and the space segment, which primarily is
the satellite itself.
• Bluetooth technology is an open wireless technology standard for exchanging data over
short distances from fixed and mobile devices, creating personal area networks with high
levels of security. It was created by telecoms vendor Ericsson in 1994.
• Wi-Fi technology is a technology that uses radio waves to provide network connectivity. A
wi-fi connection is established using a wireless adapter to create hotspots. Wi-Fi provides
wireless connectivity to your devices by emitting frequencies between 2.4GHz-5GHz, based
on the amount of data on the network.
• WiMAX technology is a wireless technology standard for long-range wireless networking, for
both mobile and fixed connections. WiMAX operates at higher speeds over greater distances
and for a greater number of users. WiMAX was formed in April 2001.

12. Computer Network
The group of interconnected computers through transmission media in-order to communicate and
share resources like hardware, data and software is known as communication media. It is a system for
communication between networks. The computers in the network may be connected through cables,
telephone-lines, beams etc.
❖Advantage of Computer Network
i. The computers on the network can share hardware devices like printer, scanner etc.
ii. Data and software can be shared within the computer on the network.
iii. Files can be transferred from one computer to another computer.
iv. Computers in the network can communicate with each other.
v. Saving of money
vi. Back-Up and Support
❖Disadvantages of Computer Network
i. Data and information maybe stolen by computer hackers.
ii. If any computer in the network get affected by the virus, there is high chance of spreading
computer virus.
iii. Computers on the network have to depend on the server.
iv. Proper maintenance of a network computer requires considerable time and expertise.

13. Computer Network Services
• The Basic services of a computer network are:
a) File Services: It include file transfer and storage, data migration, file update
synchronization, etc.
b) Print Services: It accept print job requests, interpret print job formats and printer
configurations, manage print queues, and interact with network printers and fax
equipment for network clients.
c) Message services: It allow the users to pass on the messages from one computer to
other computer in the network which deals with the communication interactions
between computer users, user applications and network applications, or documents.
d) Application services: These are the services that run software for network clients and
allow computers to share processing power.
e) Database Services: It provide centralized data storage and retrieval to network clients.

14. Networking Terminology
a. Node: A node is any network device that can connect to the network and can generate,
process or transfer network data. It could be a computer, printer, or data storage device.
b. Client: A client is a network computer that utilizes the resources of other network computers,
including other clients.
c. Peer: A peer is a self-sufficient computer that acts both as a server and a client to other similar
computers on the network.
d. Server: A server is a network computer that shares resources with and responds to requests
from other network computers, including other servers.
e. Host computer: A host is any hardware device that has the capability of permitting access to
a network via a user interface, specialized software, network address, protocol stack, or any
other means.
f. Terminal: A terminal is a specialized network device on a host-based network that transmits
the data entered by the user to the host for processing and display the results.

15. Computer Network Components
• The main components of networking components are:
Hardware components and Networking software
The Hardware Components in a network are:
❖Computer systems(Servers or clients) −Servers are high-configuration computers that
manage the resources of the network. The network operating system is typically installed in
the server and so they give user accesses to the network resources. Servers can be of
various kinds: file servers, database servers, print servers etc.
Clients − Clients are computers that request and receive service from the servers to access and
use the network resources.
❖Network Connectors: A connector is a device that terminates a segment of cabling or provides
a point of entry for networking devices such as computers, hubs, and routers.
❖Networking cables: Networking cables are networking hardware used to connect one network
device to other network devices or to connect two or more computers to
share printers, scanners etc.
❖Network Interface Card: Network Interface Card(NIC) is a computer circuit board that is
installed in a computer so that it can be connected to a network. It is a hardware device which
contains electronic circuitry needed to ensure reliable communication between workstation and
server.

16. Networking Software
• Network operating System(NOS): It is an operating system that manages network
services: essentially, an operating system that includes special functions for connecting
computers and devices into a local area network (LAN).Examples: UNIX, Netware, etc.
• Network Protocol :A network protocol is an established set of rules that determine how data is
transmitted between different devices in the same network. Its functions are:
1. Identifying the different devices in the communication path
2. Establishing the speed and method to be used for the transmission of data
3. Determining how errors are to be detected and corrected
4. Altering the receiving device to incoming data and defining the way receipt to be acknowledged
by the receiving device.
Some of the popular protocols are:
a) TCP/IP
b) HTTP
c) SMTP
d) POP3

17. • Transmission Control Protocol: It is a communications protocol developed under contract from
U.S Department of Defense. TCP is the component that collects and reassembles the packets
of data, while IP is responsible for making sure that the packets are sent at the right
destination.
• AppleTalk: It is a proprietary suite of protocols developed by Apple. Inc. for computer
networking.
• HTTP(Hyper text transfer Protocol): HTTP is a protocol which allows the fetching of resources,
such as HTML documents. It is the foundation of any data exchange on the Web and it is a
client-server protocol, which means requests are initiated by the recipient, usually the Web
browser.
• Simple Mail Transfer Protocol: SMTP or Simple Mail Transfer Protocol is an application that is
used to send, receive, and relay outgoing emails between senders and receivers.
• Post Office Protocol: Post Office Protocol (POP) is a type of computer networking and Internet
standard protocol that extracts and retrieves email from a remote mail server for access by the
host machine. POP is an application layer protocol in the OSI model that provides end users
the ability to fetch and receive email.
• NetBEUI: NetBEUI stands for NetBIOS Extended User Interface, is a
networking protocol developed by IBM and Microsoft in 1985 that is used for workgroup-size
local area networks (LANs) with up to 200 stations.

18. Computer Network Models
• Three Primary Network Models are:
1. Centralized computing Network
2. Client/server Network
3. Peer-to-Peer Network
❖ Centralized Computing Network: It is a network model in which a host computer connected to
other computers or terminals provide data or computing services via a network. Centralized
computing is computing done at a central location, using terminals that are attached to a
central computer. ... Alternatively, if the terminals have the capability, they may be able to
connect to the central computer over the network. The terminals may be text terminals or
thin clients, for example.

19. Computer Network Models
• Client Server Network: In it, computers are connected to a central device (server) and
communication is done through it. The server is the main computer which provides services to
the workstation. The server computer provides resources to the workstations when the request is
made. An unauthorized person cannot access the resources of the server. There are different
types of server like print server, file server and network server, etc.
• Peer- to- peer Network: It is sometimes called workgroups. In this network, all the computers
have equal responsibilities. Each computer has access to at least some of the resources on all the
computer. Each computer in this network has equal right. It is suitable for the only small
geographical area such as small rooms, building, school, etc.

20. Computer Network Categories
• Computer network is classified into three category. They are: Local Area Network , Metropolitan
Area Network and Wide Area Network.
• Local Area Network (LAN):
A local area network (LAN) is a small network of computer. It is a network of
computers within a small area like room, building, or colleges. Nowadays instead of cables, wireless
media are used as a data transmission channel. LAN, where wireless media are used, is known as
Wireless Local Area Network.
Characteristics Of LAN:
1. Data transfer are high, usually 1Mbps-100Mbps.
2. Owned by a single organization.
3. Diameter of not more than 3 kilometers.
4. The transmission media is shared by all the connected devices in the network.

21. ❖Metropolitan Area Network (MAN)
It is larger network than LAN. Metropolitan Area Network (MAN) is a network of computers within a
city or between neighboring cities. Big companies like banks, offices etc. use MAN. In MAN, cables
and unbounded communication media are used as the transmission channels. Its characteristics
are:
• Network size generally ranges from 5 to 50 km. It may be as small as a group of buildings in a
campus to as large as covering the whole city.
• Data rates are moderate to high.
• In general, a MAN is either owned by a user group or by a network provider who sells service to
users, rather than a single organization as in LAN.
• It facilitates sharing of regional resources.
• They provide uplinks for connecting LANs to WANs and Internet.

22. • Wide Area Network (WAN)
A wide area network (WAN) is a very large network of computers. WAN is a network of computers in
a wide geographical area such as country, neighboring countries, continent etc. A WAN can be
formed by joining many LANs and WANs. The Internet and Intranet are the WANs. Its characteristics
are:
1. Multiple computers are connected together.
2. It connects devices that are separated by a broader geographical area.
3. A WAN usually interconnects multiple WANs.
❖ Physical Bus Topology: Bus topology uses a single cable which connects all
the included nodes. The main cable acts as a spine for the entire network. One of the computers
in the network acts as the computer server. When it has two endpoints, it is known as a linear bus
topology.
Advantages:
• Cost of the cable is very less as compared to other topology, so it is widely used to build small
networks.
• Famous for LAN network because they are inexpensive and easy to install.
• It is widely used when a network installation is small, simple, or temporary.
• It is one of the passive topologies. So computers on the bus only listen for data being sent, that
are not responsible for moving the data from one computer to others.

23. Disadvantages
• In case if the common cable fails, then the entire system will crash down.
• When network traffic is heavy, it develops collisions in the network.
• Whenever network traffic is heavy, or nodes are too many, the performance time of the
network significantly decreases.
• Cables are always of a limited length.
Ring Topology
In this topology, all the computers or devices are connected to each other in a closed loop by single
communication cable. Data transfer takes place in one direction from one node to another around
the ring. It is also called loop network.
• Advantages:
1.Each computer does not have to depend on the central device as each computer controls
transmission to and from itself.
2.It has short cable connection which increases network reliability.
3.It supports very high data transmission rate.
• Disadvantages:
1.It is difficult to change network structure.
2.If a single computer fails, at least a portion of the network won't work.

24. • Star Topology:
In the star topology, all the computers connect with the help of a hub. This cable is called
a central node, and all other nodes are connected using this central node. It is most
popular on LAN networks as they are inexpensive and easy to install.
❑Advantages:
• Here are pros/benefits of start topology:
• Easy to troubleshoot, set up, and modify.
• Only those nodes are affected, that has failed. Other nodes still work.
• Fast performance with few nodes and very low network traffic.
• In Star topology, addition, deletion, and moving of the devices are easy.
❑Disadvantages:
• Here are cons/drawbacks of using Star:
• If the hub or concentrator fails, attached nodes are disabled.
• Cost of installation of star topology is costly.
• Heavy network traffic can sometimes slow the bus considerably.
• Performance depends on the hub's capacity
• A damaged cable or lack of proper termination may bring the network down

25. Network Connectivity Devices
• Network Devices are components used to connect clients to the network and assist in moving a
data around in the most efficient manner. Some of the devices commonly used in network
connectivity are ethernet hub, network switch, repeaters, bridges, routers, gateway and MODEM.
➢Ethernet Hub: An Ethernet hub, active hub, network hub, repeater hub, multiport repeater, or
simply hub is a network hardware device for connecting multiple Ethernet devices together and
making them act as a single network segment. It is a simple, small, inexpensive device that joins
multiple computers together. Hubs are designed to work with Twisted pair cabling and normally
use RF45 jack to connect the devices. Network devices(Servers, workstations, printers, Scanners,
etc.) are attached to the hub by individual network cables.

26. Network Connectivity Devices
➢Network Switch: Network switch is a networking device that is used to segment networks into different
subnetworks called subnets or LAN segments. A network switch (also) called switching hub, bridging hub, and, by
the IEEE, MAC bridge) is networking hardware that connects devices on a computer network by using
packet switching to receive and forward data to the destination device. It allows to connect multiple devices and
port can be manage, Vlan can create security also can Apply.
➢Network Repeater: Network repeater is a network device that amplifies and restores signals for long-distance
transmission. Its job is to regenerate the signal over the same network before the signal becomes too weak or
corrupted so as to extend the length to which the signal can be transmitted over the same network.
➢Network Bridge: Network bridge is a network device that establishes an intelligent connection between two local
networks with the same standard but with the different types of cables. A bridge is a repeater, with add on the
functionality of filtering content by reading the MAC addresses of source and destination. It is also used for
interconnecting two LANs working on the same protocol. It has a single input and single output port, thus making
it a 2 port device.
➢Wireless Access Points: Wireless Access Point is a device that provides connection between wireless
devices and can connect to wired networks.

27. ➢ Router: Router is a networking device that can connects multiple networks that use the same protocol. It
sends data between networks by examining the network addresses contained in the packets they process.
Router divide broadcast domains of hosts connected through it.
➢Gateway: Gateway is a network device that can connects dissimilar
networks with different protocols. is a passage to connect two networks
together that may work upon different networking models. They basically
work as the messenger agents that take data from one system, interpret it
, and transfer it to another system. Gateways are also called protocol
converters and can operate at any network layer. Gateways are generally
more complex than switches or routers. Gateway is also called a protocol converter.
➢ MODEM: “MODEM” stands for Modulator-Demodulator. Modulation is the name of the process of converting
from digital to analog. Demodulation is the process of converting from analog to digital. It is a device attached
to the computer or other digital device to analog signals and convert them into digital signals for the
computer or any other digital device.