Computer networks allow interconnected devices to communicate. They have advantages like resource sharing and cost savings but also disadvantages such as reduced productivity if poorly managed or servers fail. Early networks included ARPANET in 1969 and NSFNET in the 1980s, leading to the modern Internet. Networks transmit data via circuits, packets, or messages using techniques like circuit switching, packet switching, and message switching. Components include nodes, servers, clients, hardware, software and communication channels. Networks can be LANs, MANs, WANs or PANs depending on their area of coverage. Wired networks use media like twisted pair, coaxial or fiber optic cables while wireless uses radio waves.

1. COMPUTER NETWORKS

2. COMPUTER NETWORKS
• A computer network is a collection of interconnected computers
and other devices which are able to communicate with each
other. Also defined as - collection of hardware components and
computers interconnected by communication channels that
allow sharing of resources and information. Where at least one
process in one device is able to send/receive data to/from at least
one process residing in a remote device, then the two devices are
said to be in a network

3. ADVANTAGES OF NETWORKS
1.Resource Sharing
2.Cost Saving
3.Collaborative user interaction
4.Time savings
5.Increased storage

4. DISADVANTAGES OF NETWORKS
•If network are badly managed, services can
become unusable and productivity fails
•If software and files held centrally, it may be
impossible to carry out any work if the central server
fails.
•File security is more important especially if
connected to WAN e.g. protection from viruses
•To handle network of organization you may need
specialist staff to run the network

5. EVOLUTION OF NETWORKS
 1969 - First network came into existence
 ARPANET – Advanced Research Project Agency Network
 MID 80’S - NSFNET (National Science Foundation
Network)

6. INTERNET IS THE NETWORK OF NETWORKS.
1969
ARPANET
1980
NSFnet
1990
INTERNET
to connect computers
at u.s. defense and
different universities.
a high capacity
network
strictly
and
to be used
for academic
engineering
research.
the internetworking of
ARPANET, NSFnet and
other private networks
for more updates visit: www.python4csip.com

7. INTERNET
• A global computer network providing a variety of Information and
communication facilities, consisting of interconnected networks
using standardized communication protocols
 Network of Networks
 Popularly known as “NET”

8. INTRANET
• Intranet is a local or restricted communications network, especially a
private network created using World Wide Web softwares.
 It is managed by any person/ organization
 Intranet user can avail services of Internet whereas Internet
user cannot access intranet directly.

9. INTERSPACE
•Interspace is a client/server software program that
allows multiple users to communicate online
with real time audio, video and text chat in
dynamic 3D environment.
•Online video conferencing is an example of
Interspace.

10. COMPONENTS OF COMPUTER NETWORK
• NODES/HOSTS
• SERVER
• CLIENT
• NETWORK HARDWARE-NIC,SWITCH,ROUTER ETC.
• COMMUNICATION CHANNEL
• SOFTWARE

11. COMPONENTS OF COMPUTER NETWORKS

12. HOST
•A network host is a computer or other device
connected to a computer network. A host may work
as a server offering information resources, services,
and applications to users or other hosts on
the network. Hosts are assigned at least
one network address.
•Also called as workstation or node.

13. Servers
• Servers are computers that hold shared programs, files, and the
network operating system. Servers allow access to network
resources to all the users of the network.
• Servers are computers that runs operating system and hold data that can
be shared over a computer network.
• Types of Server
• Dedicated
• Non-Dedicated

14. Client
•A client is a computer that is connected to other
computers in the network and can receive data sent by
other computers.
•Clients are computer devices which access and uses the
network as well as shares network resources.They are
also users of the network, as they can send and receive
requests from the server.

15. NETWORK HARDWARE
• Networking hardware, also known as network equipment or computer
networking devices, are electronic devices which are required for
communication and interaction between devices on a computer network.
Specifically, they mediate data transmission in a computer network.[1] Units
which are the last receiver or generate data are called hosts, end
systems or data terminal equipment.

16. COMMUNICATION MEDIA
• Network media refers to the communication channels used to interconnect
nodes on a computer network.Typical examples of network media include
copper coaxial cable, copper twisted pair cables and optical fiber cables
used in wired networks, and radio waves used in wireless data
communications networks.

18. Network software
• Network software encompasses a broad range of software used for design,
implementation, and operation and monitoring of computer networks.
Traditional networks were hardware based with software embedded.
• It includes various protocols.
• Protocols are the set of rules governing the traffic over network
• Networking operating systems

19. NETWORK SERVICES
• DNS
• VoIP & Unified Communications
• File sharing
• Routing & Switching
• Security Appliances & Firewalls

20. TYPES OF AREA NETWORKS-BASED ON
WORKING OF NODES

21. TYPES OF AREA NETWORKS- AREA
COVERAGE
• The Network allows computers to connect and communicate
with different computers via any medium. LAN, MAN ,WAN and PAN are
the four major types of the network designed to operate over the area they
cover.

22. PERSONAL AREA NETWORK
 Network of communicating devices(computer, phone,
MP3 etc.)
 Cover area of few meters radius
 When we transfer songs from one cell phone to another
we setup a PAN of two phones
 Can be setup using guided or unguided media

23. √ Network of computing/ communication devices in a room,
building or campus
√ Cover area of few kilometer radius(approx. 1 – 10 KM)
√ Can be setup using wired or wireless media
√ Managed by single person or organization
√ Ethernet cable or Wi-Fi is used to establish LAN
LOCAL AREA NETWORK

24. METROPOLITIAN AREA NETWORK
 Network of computing/communicating devices within a city.
 Cover an area of few kilometers to few hundred kilometers
radius
 Network of schools, banks, government offices within a city are
example of MAN.
 It is typically formed by interconnected number of LANs
 Owned by organization or government.

25. WIDE AREA NETWORK
 Network of computing/communication devices
crossing the limits of city, country, or continent.
 Cover area of over hundreds of kilometer radius
 Network of ATMs, BANKs, National or International organization
offices spread over a country, continent are example of WAN
 It is usually formed by interconnecting LANs, MANs or may be other
WANs.
 Best example of WAN is internet

26. SWITCHINGTECHNIQUES
• In large networks, there may be more than one paths for transmitting data
from sender to receiver. Selecting a path that data must take out of the
available options is called switching.
SWITCHINGTECHNIQUES
CONNECTIONLESS CONNECTION-ORIENTED

27. Three types of Switching techniques
1.Circuit Switching
2.Packet Switching
3.Message Switching

28. CIRCUIT SWITCHING
• Circuit switching is a switching technique that establishes a dedicated path between sender
and receiver.
• ConnectionOriented
• In the Circuit SwitchingTechnique, once the connection is established then the dedicated path
will remain to exist until the connection is terminated.
• Circuit switching in a network operates in a similar way as the telephone works.
• A complete end-to-end path must exist before the communication takes place.
• In case of circuit switching technique, when any user wants to send the data, voice, video, a
request signal is sent to the receiver then the receiver sends back the acknowledgment to
ensure the availability of the dedicated path.After receiving the acknowledgment, dedicated
path transfers the data.
• Circuit switching is used in public telephone network. It is used for voice transmission.
• Fixed data can be transferred at a time in circuit switching technology.

29. Communication through circuit switching has 3 phases:
• Circuit establishment
• Data transfer
• Circuit Disconnect

30. Advantages Of Circuit Switching:
• In the case of Circuit Switching technique, the communication channel is dedicated.
• It has fixed bandwidth.
Disadvantages Of Circuit Switching:
• Once the dedicated path is established, the only delay occurs in the speed of data
transmission.
• It takes a long time to establish a connection approx 10 seconds during which no data can
be transmitted.
• It is more expensive than other switching techniques as a dedicated path is required for
each connection.
• It is inefficient to use because once the path is established and no data is transferred, then
the capacity of the path is wasted.
• In this case, the connection is dedicated therefore no other data can be transferred even if
the channel is free.

31. MESSAGE SWITCHING
• Message Switching is a switching technique in which a message is transferred as a
complete unit and routed through intermediate nodes at which it is stored and
forwarded.
• In Message Switching technique, there is no establishment of a dedicated path
between the sender and receiver.
• The destination address is appended to the message. Message Switching
provides a dynamic routing as the message is routed through the intermediate
nodes based on the information available in the message.
• Message switches are programmed in such a way so that they can provide the
most efficient routes.
• Each and every node stores the entire message and then forward it to the next
node.This type of network is known as store and forward network.
• Message switching treats each message as an independent entity.

32. MESSAGE SWITCHING

33. Advantages Of Message Switching
• Data channels are shared among the communicating devices that improve the
efficiency of using available bandwidth.
• Traffic congestion can be reduced because the message is temporarily stored in
the nodes.
• Message priority can be used to manage the network.
• The size of the message which is sent over the network can be varied.Therefore,
it supports the data of unlimited size.
Disadvantages Of Message Switching
• The message switches must be equipped with sufficient storage to enable them
to store the messages until the message is forwarded.
• The Long delay can occur due to the storing and forwarding facility provided by
the message switching technique.

34. PACKET SWITCHING
• The packet switching is a switching technique in which the message is sent in one
go, but it is divided into smaller pieces, and they are sent individually.
• The message splits into smaller pieces known as packets and packets are given a
unique number to identify their order at the receiving end.
• Every packet contains some information in its headers such as source address,
destination address and sequence number.
• Packets will travel across the network, taking the shortest path as possible.
• All the packets are reassembled at the receiving end in correct order.
• If any packet is missing or corrupted, then the message will be sent to resend the
message.
• If the correct order of the packets is reached, then the acknowledgment message
will be sent.

35. PACKET SWITCHING

36. Advantages Of Packet Switching:
• Cost-effective: In packet switching technique, switching devices do not require massive
secondary storage to store the packets, so cost is minimized to some extent.Therefore,
we can say that the packet switching technique is a cost-effective technique.
• Reliable: If any node is busy, then the packets can be rerouted.This ensures that the
Packet Switching technique provides reliable communication.
• Efficient: Packet Switching is an efficient technique. It does not require any established
path prior to the transmission, and many users can use the same communication channel
simultaneously, hence makes use of available bandwidth very efficiently.
Disadvantages Of Packet Switching:
• Packet Switching technique cannot be implemented in those applications that require low
delay and high-quality services.
• The protocols used in a packet switching technique are very complex and requires high
implementation cost.
• If the network is overloaded or corrupted, then it requires retransmission of lost packets. It
can also lead to the loss of critical information if errors are nor recovered.

37. DATA COMMUNICATION TERMINOLOGIES
Data means information in digital format and communication means to
exchange information between two or many users in anyways like speaking,
texting, or any other modes of the medium. So, data communication is simply
the exchange of data between two or many users through the transmission
media like twisted pair cable, coaxial cable, optical fibers, radio wave, satellite
microwave, etc.The user or device that sends the data is the source and the
user that receives the data is a receiver.
Here are some data communication terminologies that follows-

38. DATA CHANNEL
Channel simply means a path to carry or flow. Data channel means the flow of
data or to carry the data from one device to another. In other words, we can say
the data channel is a computer path or medium used to transfer the data from
sender to receiver. Transmission channel may be analog or digital. Data
channel may be a tangible medium like copper wire cables or broadcast

39. BITS PER SECOND (BPS) :
Its symbol is “bit/s”. It can be present in two forms i.e. bps (bits per second)
and Bps (Bytes per second). It’s also a measurement unit of speed at which the
data is transferred. Some other forms are also present as shown in the table
below:
S.No Rate Denoted By Full Form
1 Rate of thousand bits per second kbps Kilobits per second
2 Rate of thousand bytes per second Kbps Kilobytes per second
3 Rate of million bits per second mbps Megabits per second
4 Rate of Million bytes per second Mbps Megabytes per second

40. Bandwidth :
It’s the range of frequencies over which a communication system works. It generally measures
the amount of data that can be transferred in a given amount of time over a data channel. It’s
the difference between the highest and the lowest frequencies of a data channel.The
measurement unit of frequency is cycles per second i.e. hertz.
S.NO
TYPE OFTHE
SIGNAL
RANGE OF FREQUENCY IN
HERTZ
BANDWIDTH IN
HERTZ
1 Voice signal 300-3400 3, 100
2 TV signal 0-5 MHz 5 MHz
3 Digital Data 300-3400 3, 100
4 Music Signal 20-15000 14, 980
Some of the factors affecting a network’s bandwidth
include −
•Network devices used
•Protocols used
•Number of users connected
•Network overheads like collision, errors, etc.

41. DTR (DATATRANSFER RATES)
It determines the rate of speed at which the data is transferred from one point
to another. Its measurement unit is bits per second (bps), Bytes per second
(Bps), or baud. In computer, data transfer is mainly measured in Bytes per
second.
BAUD :
It’s actually a common measurement unit of data transfer. Baud rate measures
the rate at which the data is transferred from the sender to the receiver in the
data channel. It can be expressed in terms of bps (bits per second). It simply
determines the speed of data transfer.
•1 Bps = 1 Byte per second = 8 bits per second
•1 kbps = 1 kilobit per second = 1024 bits per second
•1 Mbps = 1 Megabit per second = 1024 Kbps
•1 Gbps = 1 Gigabit per second = 1024 Mbps

42. TRANSMISSION MEDIA

43. 1. Guided Media:
It is also referred to asWired or Bounded transmission media. Signals being
transmitted are directed and confined in a narrow pathway by using physical links.
Features:
• High Speed
• Secure
• Used for comparatively shorter distances
There are 3 major types of Guided Media:

44. Twisted Pair Cable
• Twisted Pair Cables are also known as
Ethernet cables.
• It is used for creating small computer
network. It contains four twisted pair
covered in an outer shield. These pair are
color coded. An RJ-45 is used to connect
this cable to a computer. It is available
in various forms such as CAT1, CAT2,
CAT3, CAT4, CAT5, CAT6.
 It is of 2 types:
• UTP (Unshielded Twisted Pair)
• STP(Shielded Twisted Pair)

45. COAXIAL CABLE
• Coaxial cable is a type of copper cable specially built with a metal
shield and other components engineered to block signal
interference. It is primarily used by cable TV companies to
connect their satellite antenna facilities to customer homes and
businesses.

46. FIBER OPTICAL CABLE
Although twisted-pair is the most
common type of guided media,
fiber-optic cable also is becoming
widely used. Instead of carrying
telecommunication signals in the
traditional electrical form, this
technology uses high-speed
streams of light pulses from lasers
or LEDs (light-emitting diodes)
that carry information inside hair-
thin strands of glass called optical
fibers.

47. COMPARISION-WIRED MEDIA
Twisted Pair
Cable
Coaxial Cable Optical fiber
cable
Data Transfer
Rate
10Mbps-
10Gbps
100Mbps >100Gbps
Data Transfer
Range
100 m 185-500m -
Interference
susceptibility
More Less than
Ethernet
cable
NIL
Cost Least cost More than
Ethernet
Very
Expensive

49. 2. Unguided Media:
It is also referred to asWireless or Unbounded transmission media. No physical medium is
required for the transmission of electromagnetic signals.
Features:
• Signal is broadcasted through air
• Less Secure
• Used for larger distances
Electromagnetic waves are used for wireless communication over computer
network. Based on their frequencies, electromagnetic waves are categorized into various
categories.
Radio Waves < Microwaves < Infra radiation < visible light < ultraviolet
radiation < x-rays < gamma rays
Out of these only radio waves, microwaves and infrared rays are used for wireless
communication

50. RADIOWAVES
• These are easy to generate and can
penetrate through buildings. The sending
and receiving antennas need not be
aligned. Frequency Range:3KHz –
1GHz. AM and FM radios and cordless
phones use Radiowaves for
transmission. It is Omni-directional.
• Wi-Fi / Bluetooth has become a
common word today also used radio
wave to transmit data among
connected device.
• Further Categorized as (i) Terrestrial and
(ii) Satellite.

51. MICROWAVES
 It is a line of sight transmission i.e. the sending and receiving antennas
need to be properly aligned with each other. The distance covered by the
signal is directly proportional to the height of the antenna. Frequency
Range:1GHz – 300GHz. These are majorly used for mobile phone
communication and television distribution.
 Travels in straight lines and cannot penetrate any solid object,
therefore for long distance microwave communication high
towers are built and microwave antennas are put on their top.
 It consists of transmitter, receiver and atmosphere

52. INFRARED
• Infrared waves are used for very short distance communication.They cannot
penetrate through obstacles.This prevents interference between systems. It
means that infrared system in one room of building will not interfere with a
similar system in adjacent room.
• Frequency Range:300GHz – 400THz
 Used for short range communication approx.5-10m
 Used in cordless mouse, keyboard, printer, remote controlled devices
 It is a line of sight transmission, so information passed to one device is not
leaked to another device.

53. Satellite(Microwave Communication)
 Used for very long distance wireless
communication.
 Transmission from earth to a
satellite is uplink (frequency
range 1.6GHz to 30.0 GHz) and
transmission from satellite to earth is
known as downlink(frequency range
1.5GHz to 20.0GHz)
 It covers large area of earth
 Expensive
 Require legal permissions.

54. NETWORKING DEVICES
Network devices are components used to
connect computers or other electronic devices
together so that they can share files or
resources like printers or fax machines.

55. NETWORKING DEVICES
 Modem
 RJ-45 connector
 Ethernet Card (NIC)
 Router
 Hub
 Switch
 Gateway
 Wi-Fi Card

56. MODEM
• Modem is a device that enables a computer to send or receive data over
telephone or cable lines. The data stored on the computer is digital whereas
a telephone line or cable wire can transmit only analog data.
• The main function of the modem is to convert digital signal into analog
and vice versa. Modem is a combination of two devices
− modulator and demodulator. The modulator converts digital data into
analog data when the data is being sent by the computer.
The demodulator converts analog data signals into digital data when it is
being received by the computer.

57. TYPES OF MODEM
Modem can be categorized in several ways like direction in which it can
transmit data, type of connection to the transmission line, transmission mode,
etc.
Depending on direction of data transmission, modem can be of these types −
• Simplex − A simplex modem can transfer data in only one direction, from
digital device to network (modulator) or network to digital device
(demodulator).
• Half duplex − A half-duplex modem has the capacity to transfer data in both
the directions but only one at a time.
• Full duplex − A full duplex modem can transmit data in both the directions
simultaneously.

58. RJ45 CONNECTOR
• RJ45 is the acronym for Registered Jack 45. RJ45 connector is an 8-pin jack
used by devices to physically connect to Ethernet based local area
networks (LANs). Ethernet is a technology that defines protocols for
establishing a LAN. The cable used for Ethernet LANs are twisted pair ones
and have RJ45 connector pins at both ends. These pins go into the
corresponding socket on devices and connect the device to the network.

59. ETHERNET CARD
• Ethernet card, also known as network interface card (NIC), is a
hardware component used by computers to connect to Ethernet LAN
and communicate with other devices on the LAN. The earliest
Ethernet cards were external to the system and needed to be
installed manually. In modern computer systems, it is an internal
hardware component. The NIC has RJ45 socket where network cable
is physically plugged in.
 Each NIC attached to workstation has a unique number identifying
it, known as MAC Address.
 Also known as Network Interface Unit.

60. LANs do not normally operate in isolation but
they are connected to one another or to the
Internet.
To connect LANs, connecting devices are needed
and various connecting devices are such as bridge,
switch, router, hub, repeater.

61. Connecting devices into five different categories
based on the layer in which they operate in a
network

62. HUB
• A hub is a common connection point for devices in a network. Hubs are
commonly used to connect segments of a LAN. A hub contains multiple
ports.When a packet arrives at one port, it is copied to the other ports
so that all segments of the LAN can see all packets.
Hubs can be either Passive or Active
• Active Hub : they amplify the signals as it moves from one
connected device to another like Repeaters.
• Passive Hub: allows signals to pass from one device to another without any
change.

64. SWITCH
Switch (also called switching hub, bridging hub, officially MAC
bridge) is a network device that connects other devices
to Ethernet networks through twisted pair cables. It uses packet
switching technique to receive, store and forward data
packets on the network.The switch maintains a list of network
addresses of all the devices connected to it.
On receiving a packet, it checks the destination address and
transmits the packet to the correct port. Before forwarding, the
packets are checked for collision and other network errors.The
data is transmitted in full duplex mode

66. Gateway
• Gateway is a network device used to connect two or more dissimilar
networks. In networking parlance, networks that use different protocols
are dissimilar networks.
• A network gateway can be implemented completely in software,
completely in hardware, or as a combination of both. Depending on the
types of protocols they support, network gateways can operate at any
level of the OSI model.
• As networks connect to a different network through gateways, these
gateways are usually hosts or end points of the network.
• Gateway uses packet switching technique to transmit data from one
network to another. In this way it is similar to a router, the only difference
being router can transmit data only over networks that use same protocols.

68. BRIDGE
• network bridge is a computer networking device that creates a single
aggregate network from multiple communication networks or network
segments. This function is called network bridging.

70. ROUTER
• A router is a networking device that forwards data packets between
computer networks.
• Routers perform the traffic directing functions on the Internet. A data
packet is typically forwarded from one router to another router through
the networks that constitute the internetwork until it reaches its
destination node.
• It work like a bridge, but can handle different protocol.Router uses
Logical Address whereas Bridge uses Physical Address

72. REPEATER
In a network signal travels a long distance in transmission media. Due to
resistance of media signal becomes weak. Repeater is a networking device
which regenerates the signal and forwards these signal with more power.

73. Hub Vs. Switch
A hub works on the physical layer (Layer 1) of OSI model while Switch works on
the data link layer (Layer 2). Switch is more efficient than the hub. A
switch can join multiple computers within one LAN, and a hub just connects
multiple Ethernet devices together as a single segment. Switch is smarter
than hub to determine the target of the forwarding data. Since switch has a
higher performance, its cost will also become more expensive.
Switch Vs. Router
In the OSI model, router is working on a higher level of network layer (Layer
3) than switch. Router is very different from the switch because it is for
routing packet to other networks. It is also more intelligent and sophisticated to
serve as an intermediate destination to connect multiple area networks together.
A switch is only used for wired network, yet a router can also link with the
wireless network. With much more functions, a router definitely costs higher
than a switch.

74. •Router vs Gateway
Gateway regulates traffic between two dissimilar networks, while router
regulator traffic between similar networks. A router is a hardware device that
forwards data packets between computer networks. Routers perform the
traffic directing functions on the Internet.
Connection In One Network With Router - For example, there are
30 computers connected inside Network A. All these
computers communicate with each other. In this situation, no gateway is
needed. Because a router with a routing table that defines the hops within
those 30 computers is enough.
Connection Between Different Networks With Gateway - In another
hand, we suppose that there are two networks, that are Network A and
Network B. Computer X from Network A wants to send data to
Computer Y from Network B, then there need to have both a Gateway A
and a Gateway B so that the two networks will be able to communicate.

75. Wi-Fi CARD
• Wi-Fi is the acronym for wireless fidelity.
• Similar to Ethernet card, but it allows our computer to connect with other
device without wire i.e. for wireless connectivity.
• Wi-Fi technology is used to achieve wireless connection to any network. Wi-Fi card
is a card used to connect any device to the local network wirelessly.The physical
area of the network which provides internet access through Wi-Fi is called Wi-Fi
hotspot. Hotspots can be set up at home, office or any public space. Hotspots
themselves are connected to the network through wires.
• It may be internal or external with built-in wireless radio and antenna.

76. NETWORKTOPOLOGY
Physical
Describes the geometric arrangement of
components that make up the LAN
Logical
Describes the possible connections
between pairs of networked end-points that
can communicate

78. There are a number of reasons:
•Impacts performance.
•A factor in determining the media type used to
cable the network.
•Impacts the cost of cabling the network.
•Some access methods can work only with specific
topologies.

79. Network topologies are categorized into the
following basic types:
• Bus
• Ring
• Star
• Tree
• Mesh .

80. Bus topology
• All networked nodes are interconnected, peer to peer, using a single, open-
ended cable
• Both ends of the bus must be terminated with a terminating resistor to
prevent signal bounce
80

81. Bus topology
81

82. Advantages of Bus topology
1) Easy to implement and extend
2) Well suited for temporary networks that must be set up in a hurry
3) Typically the least cheapest topology to implement
4) Failure of one station does not affect others
82

83. Disadvantages of Bus topology
1) Difficult to administer/troubleshoot
2) Limited cable length and number of stations
3) A cable break can disable the entire network; no redundancy
4) Maintenance costs may be higher in the long run
5) Performance degrades as additional computers are added
83

84. Ring topology
• started out as a simple peer-to-peer LAN topology
• Each networked workstation had two connections: one to each of its
nearest neighbors
• Data was transmitted unidirectionally around the ring
• Sending and receiving of data takes place by the help ofTOKEN
84

85. Token Passing
• Token contains a piece of information which along with data is sent by the
source computer
• This token then passes to next node, which checks if the signal is intended
to it
If yes, it receives it and passes the empty to into the network
otherwise passes token along with the data to next node
85

86. Ring topology
86

87. Advantages of Ring topology
1) This type of network topology is very organized
2) Performance is better than that of Bus topology
3) No need for network server to control the connectivity
between workstations
4) Additional components do not affect the performance of
network
5) Each computer has equal access to resources
87

88. Disadvantages of Ring topology
1) Each packet of data must pass through all the computers between source
and destination, slower than star topology
2) If one workstation or port goes down, the entire network gets affected
3) Network is highly dependent on the wire which connects different
components
88

89. Star topology
• Have connections to networked devices that “radiate” out form a common
point
• Each networked device in star topology can access the media independently
• Have become the dominant topology type in contemporary LANs
• Stars have made buses and rings obsolete in LAN topologies
89

90. Star topology
90

91. Advantages of star topology
1) Compared to Bus topology it gives far much better performance
2) Easy to connect new nodes or devices
3) Centralized management. It helps in monitoring the network
4) Failure of one node or link doesn’t affect the rest of network
91

92. Disadvantages of star topology
1) If central device fails whole network goes down
2) The use of hub, a router or a switch as central device increases the overall
cost of the network
3) Performance and as well number of nodes which can be added in such
topology is depended on capacity of central device
92

93. Advantages/Disadvantages of star topology
• Advantages:
More scalable than a peer-to-peer or ring network
Improved network performance. Hop count of three
• Disadvantages:
It creates a single point of failure
There is no route redundancy
93

94. Treetopology is a combination of bus and
startopologies.
 It is used to combine multiple star topology networks.
 All the stars are connected together like a bus.

95.  It offers easy way of network expansion
 Even if one network (star) fails, the other networks
remain connected and working.

96. PROTOCOL
 Refers to SET OF RULES
• In Network there are variety of computer connected to each other
and data in many ways.
 For interaction among these, some rules are applied like how
and when a device can send and receive data, how to send the
data packet and how to receive etc.

97.  Stands for Transmission Control Protocol and Internet
Protocol
 TCP is connection oriented protocol i.e. first the
connection between sender and receiver is established
through process called handshake
TCP divides the large packets to transmit into smaller
smaller data packets called datagrams.
At the receiving end it also reassemble the packet for
form original message.
IP (INTERNET PROTOCOL) : responsible for
providing address of each computer and performing
routing. Each packet is assigned with destination IP
address.
TCP/IP

98. FILE TRANSFER
PROTOCOL
• Stands for File Transfer Protocol
It allows transferring of files from one system to another
like uploading of file from local machine to web server using
FTP Client like FileZilla etc.
 FTP offers these advantages:
• Useful to transfer files from one network to another
• It is an effective way to get geographically dispersed group to co-
operate on a project.
• It is popular way to update web sites.

99. POINT-TO-POINT PROTOCOL
 Stands for Point-to-Point Protocol
 Point - to - Point Protocol (PPP) is a communication
protocol of the data link layer that is used to
transmit multiprotocol data between two directly
connected (point-to-point) computers.
 It is a byte - oriented protocol that is widely used in
broadband communications having heavy loads and
high speeds.

100. HTTP
• Stands for Hypertext Transfer Protocol
Used to transfer all files and other data(resources) from one computer to
another on the world wide web.
 Client(Browser) send request to Web Server using HTTP
protocol and Server respond back to Client using HTTP i.e. Client
and server over web communicate using HTTP protocol.
 See the format of URL:
• http://www.google.com

101. SMTP
•Stands for Simple Mail Transfer Protocol
SMTP is a set of communication guidelines that
allow software to transmit an electronic mail over
the internet is called Simple Mail Transfer
Protocol.
 It is a program used for sending
messages to other computer users based on e-
mail addresses
 Port 25 (non-encrypted, unsecure)
 Port 465 (encrypted, secure)

102. POP3
• Stands for Post Office Protocol (Version-3.0)
 POP3 is a client/server protocol in which e-mail is
• received and held for you by your Internet server.
 Periodically, you (or your client e-mail receiver) check your mail-box on
the server and download any mail, probably using POP3.
 It also allows to download the received messages on local machine
using tool like Outlook so that user can read them even when they are
not connected to the Internet.

103. VoIP
 Voice over Internet Protocol
 It is a protocol that enables voice communication over the Internet
through the compression of voice into data packets that can be
efficiently transmitted over data network and then convert back
into voice at receiving end.
 It uses packet switching (store and forward)
 It is an alternate to traditional telephone network.

104. REMOTE LOGIN
• Remote login is a network application that permits a
user sitting at a different location to work on a specific program on
another program.
 The user need ID of that computergenerated by remote
login application.
 It is done only when both PC are connected to Internet.
 Mainly used by customer support system to do some
installation, setting on client computer.
 The main programs are:
• Telnet
• AnyDesk
• Team Viewer

105. TELNET
 Telnet is one of the earliest remote login protocols on
• the Internet.
• Telnet is a network protocol used to virtually access a computer and to provide a
two-way, collaborative and text-based communication channel between two
machines.
• It follows a user commandTransmission Control Protocol/Internet Protocol
(TCP/IP) networking protocol for creating remote sessions.
 Through Telnet, an administrator or another user can access
someone else's computer remotely. On the Web, HTTP and FTP
protocols allow you to request specific files from remote computers, but
not to actually be logged on as a user of that computer.
 With Telnet, you log on as a regular user with whatever privileges you
may have been granted to the specific application and data on
that computer.
• a

106. THANK YOU
Presented by:
KIRTI GUPTA
PGT(CS)
KV NTPC DADRI