Module 1 CN -new.pptx

COMPUTER NETWORKS
MODULE I
Dr.Preethi
Assistant Professor
School of CS and IT

COURSE DISCUSSION
1. Course Content
2. Learning Objectives
3. Course Outcomes
4. Prescribed & Reference text book
3

COURSE
DIVISIO
N
4
UNITS CHAPTER
Unit 1
----------------
• Introduction to Computer Network
---------------------------------------
Unit 2
----------------
• Physical Layer
• Data Link Layer
---------------------------------------
Unit 3
------------------
• The Network Layer
• Routing algorithms
----------------------------------------
Unit 4
-------------------
Unit 5
• Transport Layer
• Internet Transport Protocols
-----------------------------------------
• Application Layer and its services
• Applications layer paradigms

CHAPTER -1 INTRODUCTION TO
CN
Introduction to Networks:
Network and uses of Networks, Types and topologies of
Networks, TCP/IP Model, The OSI vs TCP/IP reference
model, Architecture of Internet, Guided and wireless
transmission media, Switching.
5

PRESCRIBED & REFERENCE TEXT
BOOKS
6
Text Books:
1. Computer Networks by Andre S. Tanenbaum published by Pearson Education, 4th Edition, 2018.
2. Packet Tracer Network Simulator by Jesin A published by Packt Publishing, 1st Edition, 2014.
Reference books:
1. Data Communications and Networking (SIE) by Behrouz A. Forouzan published by McGraw Hill Education, 4th Edition, 2017
2. Computer Networking: A Top-Down Approach Featuring the Internet by James F. Kurose, K. W. Ross published by
Pearson Education, 3rd Edition,2017
3. Understanding communications and Networks by W. A. Shay published by Cengage Learning, 3rd Edition, 1998.

BASIC OF
COMPUTER
NETWORKS & ITS
USES
1. Introduction
7

1. Computer
2. Computer system
3. Network
4. Computer Network
• Basic of computer network & Its uses
8

Q.1 What is computer ?
Q.2 What is computer system?
Q. 3 How the communication is carried out within computer system?
Q.4 What is network?
Q. 5 What is computer network?
• Lecture-1 : Basic Of Computer Network & Its uses
9

COMPUTER
IPO - Principle
• A computer is an electronic device that manipulates information, or data. It has the ability
to store, retrieve, and process data.
10

COMPUTER SYSTEM
1. It is a collection of entities(hardware, software and human ware) that are designed
to receive, process, manage and present information in a meaningful format.
11

COMMUNICATION WITHIN
COMPUTER SYSTEM
1. Software or Hardware alone will not serve purpose, need to channelize
communication between them
12
Hardware
devices
Operating system
API
Programs
End users

NETWORK
1. An arrangement of intersecting horizontal and vertical lines.
2. Ex: A group or system of interconnected people or things;
3. A complex system of roads, railroads, or other transportation routes.
13

COMPUTER NETWORK
1. A computer network is a set of computers that are connected together so that they
can share information or to establish communication.
14

COMPONENTS OF COMPUTER
NETWORK
1. Computer networks share common devices, functions, and features including servers, clients,
transmission media, shared data, shared printers and other hardware and software resources,
network interface card(NIC), local operating system(LOS), and the network operating system
(NOS).
15

WHY COMPUTER NETWORKS?
1. -Purposes
16
Sharing files
Sharing devices: such as printers, scanners and photocopiers
Communicating : using email, video, instant messaging and other methods
Sharing software : and operating programs on remote system
Allowing network users to easily access and maintain information

WHAT ARE THE USES OF
COMPUTER NETWORKS?
1) Business Applications
a) Resource Sharing
b) Server-Client model
c) Communication Medium
d) E-Commerce
2) Home Applications
a) Access to remote information
b) Person-to-person communication
c) Interactive Entertainment
• -Applications
17

TYPES OF NETWORK DEVICES
1. Connecting Devices
18
Communicating Devices
Networking Devices Internetworking Devices
1. Hub - Physical layer device
2. Repeaters – Physical layer
3. Bridges – Data layer devices
4. Switches - 2nd and 3rd layer
device
1. Routers - Network layer / 4th layer
device
2. Gateway – 5th layer device

CONNECTING DEVICES - DEFINITION
HUB
1. a device for connecting multipleEthernet devices together and making
them act as a single network segment
2. Hubs neither provide security, or identification of connected devices
3. HUB works at physical layer.

• Repeaters are used only between two identical
networks to create a single physical and logical network.
Networking With
REPEATERS
8/2/2023 20

• A bridge is an internetworking device that provides a communication
pathway between two or more network segments
• The bridge provides a way for devices on one network to send
messages to a device on another network
BRIDGES
8/2/2023 DEPARTMENT OF MECHANICAL ENGINEERING 21

• Routers are small physical devices that join
multiple networks together.
• TYPES
Networking With A Router
Router
802.11b 802.11g
8/2/2023 23

• Modern routers are used primarily in new network
installations where the functionality of both a bridge and a
router is required.
• Bridging performance is usually at full bridging speeds while
routing speeds tend to be slower.
8/2/2023 25
routers

• Gateway is a router or a proxy server that routes
between networks
• gateway is to overcome problems associated with
protocol incompatibility
GATEWAYS
8/2/2023 26

• A device used on a computer network to physically
connect devices together.
• Switches manage the flow of data across a network by
only transmitting a received message to the device for
which the message was intended
SWITCHES

TYPES OF NETWORK DEVICES
1. Connecting Devices
29

LINKS
30
1. A Medium serves as the means of communication .
2. A Link is a communication pathway that transfer data from one device to
another.
3. A Channel refers to the means of transmission of a message between the
sender and the receiver.
1. A medium, which is an abstraction, can be oral , written or non verbal.
2. Channel, on the other hand could be a letter, a report, a book, a
memorandum, a fax, an email, the television, the telephone, etc.

TRANSMISSION TECHNOLOGY
1. Point-to-Point Network & Broadcast Network
32
Sl. No Point-to-point Link Broadcast Link
1. It connects individual pairs of
machines.
The communication channel is
shared by all the machines on the
network.
2. Dedicated Channel Shared Channel
3. Packets sent reaches to intended
machine only
Packets sent by any machine are
received by all the others.
(An address field within each packet
specifies the intended recipient.)
4. Ex: Telephone, Leased line. Ex: Radio, Television

BROADCAST NETWORK
1. Casting – the way to stream data from source point to nor of destination point.
33

TRANSMISSION MODES
• Communication mode.
• Transferring of data between two devices.
• Direction of flow of information.
35
• Unidirectional
• used by simplex system.
• Ex: loud speaker, TV, Radio, monitor etc
etc
Simplex Mode
• Transfer both direction but only one at
time.
• Ex: Walkie-Talkie
Half –Duplex Mode
• Bi-directional : at a time send and
receive data.
• Ex: Telephone Network
Full-Duplex Mode

LAYER 1- NETWORK DEVICE
1. Hub & Repeater
36
Passive Hub
Device
Active Hub
Device
Repeater

LAYER 2- NETWORK DEVICE
1. Bridge & Switch
37
Bridge
S
Switch

LAYER 3 – NETWORK DEVICE
1. Router
39
Router

GATEWAY
1. Software layer- Network device
40
Gateway

NetworkTypes orCLASSIFICATIONOF
AREABY THEIRGEOGRAPHY

LOCALAREANETWORK(LAN)
 LAN isa network which isdesigned to operate
over a small physical area suchas an office,
factory or a group of buildings.
 LAN’s are easy to design and troubleshoot
 Exchange of information and sharing of resources
becomes easy because of LAN.
 In LAN all machinesare connected to a single
cable.
 Different types of topologies such as star, tree,
bus, ring, etc Can be used
 It isusually a privately owned network.

WIDE AREANETWORK(WAN)
 When network spans over a large distance or
when the computers to be connected to each other
are at widely separated locations a local area
network cannot be used. A wide area
network(WAN) isinstalled.
 The communication between different users of
WAN isestablished using leased telephone lines,
satellite links and similar channels.
 It ischeaper and more efficient to use the phone
network for the link.
 Most WAN networks are used to transfer large
blocks of data between its users.

PERSONALAREANETWORK(PAN)
 A personal area network isa computer network
organized around an individual person.
 It generally consistsof a mobile computer, a cell
phone or personal digital assistant. PAN enables
the communication among thesedevices.
 It can also be used for communication among
personal devicesthemselves for connecting to a
digital level network and internet.
 The PANs can be constructed using wireless or
cables.

CAMPUSAREANETWORK(CAN)
 The campus area network ismade up of an
interconnection of LAN with limited
geographical area.
 Network equipments suchasswitches,routers
and the transmission media i.e. optical fibre
etc are almost entirely owned by the campus
owner.

METROPOLITANAREANETWORK(MAN)
 It isin between LAN & WAN technology that
coversthe entire city.
 It usessimilar technology as LAN.
 It can be a single network suchas cable TV
network, or a measure of connecting a
number of LAN’s o a large network so that
resourcescan be shared LAN to LAN aswell as
device to device.

PARAMETERS LAN WAN MAN
Ownership of
network
Private Private or public Private or public
Geographic
al area
covered
Small Very large Moderate
Design and
maintenanc
e
Easy Not easy Not easy
Communicatio
n medium
Coaxial cable
PSTN or
satellite
links
Coaxial
cables,
PSTN, optical
fibre, cables,
wireless
Bandwidth Low High moderate
Data
rates(spee
d)
High Low moderate
DISTINGUISHBETWEENLAN,WAN,MAN

NETWORK TOPOLOGY
49
Network topology is
the arrangement of
the elements
(links, nodes, etc.) of
a communication
network.
Physical topology is
the placement of the
various components
of a network (e.g.,
device location and
cable installation)
Logical
topology illustrates
how data flows
within a network.

Network Topology
• Computer network topology is the way various components of a
network (like nodes, links, peripherals, etc) are arranged. Network
topologies define the layout, virtual shape or structure of network,
not only physically but also logically. The way in which different
systems and nodes are connected and communicate with each other
is determined by topology of the network.

Topology can be physical or logical
• Physical Topology is the physical layout of
nodes, workstations and cables in the
network.
• Logical topology is the way information flows
between different components.

Types of Physical Network Topologies
• Bus Topology
• Star Topology
• Ring Topology
• Mesh Topology
• Tree Topology
• Hybrid Topology

Bus Topology
• In the bus topology, the computers are
connected through a common communication
media. A special type of central wire is used as
communication media. This central wire is
called Bus. The computer are attached
through the bus the ends of the bus are closed
with the terminator .The terminators are used
to absorb signals.

BUS TOPOLOGY
1. Type- 1
56
Advantages Disadvantages
1. Installation: Easy
2. Cost: Cheap
3. Connection: Every computer is connected to
single cable through drop lines.
4. Transmit: Signals/ data stream travels from
one end to another end of cable in one
direction no bi-directional.
5. Sharing: cable sharing is carried out.
1. Maintenance : High cost
2. Robust: No
3. Performance: Slow
4. Troubleshoot: Difficult
5. Security: Less secure
6. Termination : proper loop termination required.

Ring Topology
• Every computer is connected to the next computer in the
ring and each transmits what it receives from the previous
computer. The messages flow around the ring in one
direction.
Some ring network do ring token passing. A short message
called token (memory area)is passed around a ring until a
computer wishes to send information to other computers.
That computer modifies token, adds an electronic address
and data and send it around the ring. Each computer in
sequence receives the token and next computer until either
the electronic address matches the address of a computer
Or the token return to its origin .The receiving computer
returns a message to the sender indicating that message
has been received.

RING TOPOLOGY
1. Type- 2
59
1. Installation: Easy
2. Cost: cheap
3. Connection: Every computer is connected to
single cable through drop lines with closed
loop.
4. Transmit: Unidirectional
5. Data Transmission: Transmit the data, only
when station hold the token
6. Sharing: cable sharing .
7. Performance: quite good than bus topology
8. Termination : performed by monitor station
9. Data transfer: High
10. Collision : minimum collision.
1. Performance: lesser than star topology
2. Robust: Less
3. Troubleshoot: Difficult
4. Impact : get disturbed on addition or removal
5. Security: Less

Star Topology
• The star topology uses a separate cable for
each work station as shown in fig.The cable
connects the work station to a central device
typically a HUB. The configuration provides a
more reliable network that is easily expended.
With star there is no central point of failure in
the cable .if there is a problem with the cable
only the station connected to that cable is a
effected .to add more work stations simply
connect another HUB

STAR TOPOLOGY
1. Type- 3
62
1. Installation : Easy
2. Cost: less expensive as each device
require only one I/O port & needs
to be connected with hub with
one link.
3. Impact : If one link fails other links
works fine.
4. Fault detection: easy as link
identification is easily.
1. Central management : if hub goes
down network goes down.
2. More cables required.

Mesh Topology
• A mesh network or mesh topology uses
separate cable to connect each device to
every other device on the network, providing
a straight communication path. For sending
messages, check the cable connected into two
devices. A message is send directly from
sender to receiver because each one has
individual and separate connection.

Hybrid Topology
• Hybrid networks use a combination of any two or
more topologies in such a way that the resulting
network does not exhibit one of the standard
topologies (e.g., bus, star, ring, etc.). For example,
a tree network connected to a tree network is still
a tree network topology. A hybrid topology is
always produced when two different basic
network topologies are connected. Two common
examples for Hybrid network are: star ring
network and star bus network.

TCP/IP Model, The OSI vs TCP/IP reference model
68
Note that the OSI
model itself is not a
network architecture
because it does not
specify the exact
services and
protocols to be used
in each layer. It just
tells what each layer
should do.

The OSI Reference Model
• The OSI Reference Model is composed of seven layers, each
specifying particular network functions.
• Each layer provides a service to the layer above it in the
protocol specification.
• Each layer communicates with the same layer’s software or
hardware on other computers.
• The lower 4 layers (transport, network, data link and
physical —Layers 4, 3, 2, and 1) are concerned with the flow
of data from end to end through the network.
• The upper four layers of the OSI model (application,
presentation and session—Layers 7, 6 and 5) are orientated
more toward services to the applications.
• Data is Encapsulated with the necessary protocol
information as it moves down the layers before network
transit. 69

OSI Group
70
The OSI model
consists of seven
layer is further
grouped according to
their function into
three groups;
• Network Group
• Transport Group
• Application
Group

The Physical Layer
• This is lowermost layer of the OSI model. It
provides the electrical and mechanical interface
to the network medium (cable).
• This layer consists of simply the wire or media
by which the network signals are conducted.
Physical layer includes hardware (wire, plugs
and sockets etc.).
• In other words, this layer represent the physical
aspects of the network such as cable and
connectors.
• The basic functions of this layer are handles
voltages, electrical pulses, connectors and
switches so that data can be transmitted from
one network device to another. 71

The Data Link Layer
• The data link layer provides access to the
networking media and physical transmission
across the media and this enables the data to
locate its intended destination on a network.
• The data link layer provides reliable transit of
data across a physical link by using the Media
Access Control (MAC) addresses.
• The data link layer uses the MAC address to
define a hardware or data link address in order
for multiple stations to share the same medium
and still uniquely identify each other.
• Concerned with network topology, network
access, error notification, ordered delivery of
frames, and flow control. 72

The Network Layer
• This layer establishes the route between the
sending and receiving stations.
• It handles the routing of data (sending in the
right direction to the right destination on
outgoing transmissions and receiving
incoming transmission at the packet). The
layer does routing & forwarding of data.
• The network layer also defines how to
fragment a packet into smaller packets to
accommodate different media.
• This layer uses the Internet protocol (IP).
73

The Transport Layer
• The transport layer is responsible for constructing
stream of data packets, sending and checking for
correct delivery.
• This layer manages the end to end control (for example
determining whether all packets have arrived) and
error checking.
• The transport layer ensures data is successfully sent
and received between two nodes.
• If data is sent incorrectly, this layer has the
responsibility to ask for retransmission of the data.
• Specially it provides a reliable network independent
message interchange service to the application group.
• This layer acts as an interface between the bottom and
top three layers.
• This layer uses of TCP (Transmission Control Protocol) &
UDP (User Datagram Protocol).
74

The Session Layer
• The session layer defines how to start,
control and end conversations (called
sessions) between applications.
• This includes the control and management of
multiple bi-directional messages using
dialogue control.
• It also synchronizes dialogue between two
hosts' presentation layers and manages their
data exchange.
• The session layer offers provisions for
efficient data transfer.
• This layer uses POP, TCP/IP protocols.
75

The Presentation Layer
• The presentation layer ensures that the
information that the application layer of one
system sends out is readable by the
application layer of another system.
• If necessary, the presentation layer translates
between multiple data formats by using a
common format.
• Provides encryption and compression of
data.
• In this layer POP, SMTP, FTP protocol are
used.
76

The Application Layer
• The application layer is the OSI layer that is closest
to the user.
• It provides network services to the user’s
applications.
• It differs from the other layers in that it does not
provide services to any other OSI layer, but rather,
only to applications outside the OSI model.
• Examples of such applications are spreadsheet
programs, word processing programs, and bank
terminal programs.
• The application layer establishes the availability of
intended communication partners, synchronizes
and establishes agreement on procedures for error
recovery and control of data integrity.
77

The TCP/IP Reference Model
• A set of protocols allowing communication
across diverse networks
• It is named from two of the most important
protocols in it:
• the Transmission Control Protocol (TCP) and
• the Internet Protocol (IP).
• The TCP/IP protocol suite is the engine for the
Internet and networks worldwide.
• The main design goal of TCP/IP was to build an
interconnection of networks, referred to as an
internetwork, or internet, that provided
universal communication services over
heterogeneous physical networks.
78

The TCP/IP Reference Model (2)
The TCP/IP reference model with some protocols we
will study
Computer Networks, Fifth Edition by Andrew Tanenbaum and David Wetherall, © Pearson Education-Prentice Hall, 2011

Network Interface Layer (Link)
• Responsible for sending and receiving TCP/IP packets on the
network medium (physical/Data Link)
• Applicable LAN technologies
• Ethernet, Token Ring, FDDI (Fiber Distributed Data
Interface) etc.
• Applicable WAN technologies
• X.25 (old), Frame Relay, ATM etc.
• Note that some technologies such as ATM and FDDI may be
used at both the WAN and the LAN levels
82

Internet Layer
• Packaging
• Addressing
• Routing
• IP
• A connectionless unreliable protocol that is part of the
TCP/IP protocol suite
• ARP (Address Resolution Protocol)
• Resolves IP addresses to MAC addresses
• ICMP (Internet Control Message Protocol)
• Diagnostics and error reporting
• IGMP (Internet Group Management Protocol)
• Management of group multicast
83

Internet Layer
• The internetwork layer, also called the
internet layer or the network layer, provides
the “virtual network” image of an internet
(this layer shields the higher levels from the
physical network architecture below it).
• Internet Protocol (IP) is the most important
protocol in this layer. It is a connectionless
protocol that does not assume reliability
from lower layers.
• IP does not provide reliability, flow control,
or error recovery. These functions must be
provided at a higher level.
84

Transport Layer
• Sequencing and transmission of packets
• Acknowledgment of receipts
• Recovery of packets
• Flow control
• In essence, it engages in host-to-host transportation of
data packets and the delivery of them to the
application layer.
• TCP (Transmission Control Protocol): provides
connection-oriented reliable data delivery, duplicate
data suppression, congestion control, and flow control.
• UDP (User Datagram Protocol): provides
connectionless, unreliable, best-effort service. UDP is
used by applications that need a fast transport
mechanism and can tolerate the loss of some data.
85

Application Layer
• The application layer is provided by the program
that uses TCP/IP for communication.
• The interface between the application and
transport layers is defined by port numbers and
sockets.
• This layer contains all the high level protocols:
virtual terminal (TELNET), file transfer (FTP) and
electronic mail (SMTP).
• The virtual terminal protocol allows a user on
one machine to log into a distant machine and
work there.
• The file transfer protocol provides a way to
more data efficiency from one machine to
other.
86

Comparison of OSI & TCP/IP Models
• The OSI & TCP/IP models are more or less
similar. The layer functionality is similar.
• The two models can be distinguished based on
concepts:
• Service; Interfaces; Protocols
• OSI: Each layer in OSI performs some service for
the layer above it. A layer’s interface tells the
processes above it how to access it. The peer
protocol used in the layer are the layer’s own
business. It can use ant protocol it want to.
• TCP/IP: The TCP/IP model did not clearly
distinguish between service, interface and
protocol.
87

Comparison of OSI & TCP/IP
Models
• The OSI model was devised before the invention of
protocols, hence they are not biased towards one particular
set of it.
• The OSI model have 7 layers while TCP/IP have only 4 layers.
• The OSI model supports both connectionless and
connection-oriented communication in the network layer,
but only connection-oriented communication in the
transport layer.
• The TCP/IP model has only one connectionless mode in the
network layer but supports both modes in the transport
layer.
88

TRANSMISSI
ON MEDIA
1. Guided and unguided
89

LECTURE - 13
Recap
1. Electromagnetic waves
2. Bandwidth
3. Broadband & Baseband
4. Modulation
Objectives
• Transmission media or Guided media
• Non-Transmission media or Unguided
media
90
Transmission Media

TRANSMISSION MEDIA
1. - Guided media
91

COTIND…..
1. It is defined as the physical medium through which the signals are
transmitted.
2. It is also known as Bounded media.
3. Types Of Guided media: Shielded Twisted Pair & Unshielded Twisted
Pair
4. Twisted pair is a physical media made up of a pair of cables twisted with
each other.
5. A twisted pair cable is cheap as compared to other transmission media.
Installation of the twisted pair cable is easy, and it is a lightweight cable.
6. The frequency range for twisted pair cable is from 0 to 3.5KHz.
92

COAXIAL CABLE IS OF TWO
TYPES:
1. Baseband transmission: It is defined as the process of transmitting a single signal
at high speed.
2. Broadband transmission: It is defined as the process of transmitting multiple signals
simultaneously.
Advantages :
• The data can be transmitted at high speed.
• It has better shielding as compared to twisted pair cable.
• It provides higher bandwidth.
Disadvantages :
• It is more expensive as compared to twisted pair cable.
• If any fault occurs in the cable causes the failure in the entire network.
93

UNGUIDED TRANSMISSION
• An unguided transmission transmits the electromagnetic waves without
using any physical medium. Therefore it is also known as wireless
transmission.
• In unguided media, air is the media through which the electromagnetic
energy can flow easily.
Radio waves
• Radio waves are the electromagnetic waves that are transmitted in all the
directions of free space.
• Radio waves are omnidirectional, the signals are propagated in all the
directions.
• The range in frequencies of radio waves is from 3Khz to 1 khz. 94

TRANSMISSION MEDIA
1. - Unguided media
97

UNGUIDED OR WIRELESS MEDIA
98
Infrared
Waves
• Light waves, Electromagnetic waves,
• Radiation waves, Average frequency carrier wave
Micro
waves
• Low frequency carrier wave
Satellite
& Radio
waves
• Very frequency carrier wave

SWITCHING
1. Technique to reduce # of devices and links in network
99
• Message switching
• Circuit switching
Traditional
Switching
• Circuit packet switching
• Datagram packet switching
Packet Switching
• Cellular switching
Mobile Switching

1. Switching is the most valuable asset of computer networking. Every time in computer network you
access the internet or another computer network outside your immediate location, or your messages
are sent through a maze of transmission media and connection devices. The mechanism for
exchange of information between different computer networks and network segments is called
switching in Networking. On the other words we can say that any type signal or data element
directing or Switching toward a particular hardware address or hardware pieces.
2. Hardware devices that can be used for switching or transfering data from one location to another
that can use multiple layers of the Open Systems Interconnection (OSI) model. Hardware devices
that can used for switching data in single location like collage lab is Hardware switch or hub but if
you want to transfer data between to
3. different location or remote location then we can use router or gatways.

For example: whenever a telephone call is placed, there are numerous
junctions in the communication path that perform this movement of data from
one network onto another network. One of another example is gatway,that
can be used by Internet Service Providers (ISP) to deliver a signal to another
Internet Service Providers (ISP). For exchange of information between
different locations various types of Switching Techniques are used in
Networking.

SWITCHING TECHNIQUE
CLASSIFICATION
102

Message switching does not set up a dedicated channel (or circuit) between the sender and recipient
during the communication session. In Message Switching each message is treated as an independent
blocks.
In this type of networking, each message is then transmitted from first network device to second network
device through the internetwork i.e. message is transmitted from the sender to intermediator device.
The intermediate device stores the message for a time being, after inspects it for errors, intermediate
device transmiting the message to the next node with its routing information. Because of this reason
reason message switching networks are called store and forward networks in networking.

1. Circuit Switching
Circuit-switching is the real-time connection-oriented system. In
Circuit Switching a dedicated channel (or circuit) is set up for a
single connection between the sender and recipient during the
communication session. In telephone communication system, the
normal voice call is the example of Circuit Switching. The
telephone service provider maintain a unbroken link for each
telephone call.Circuit switching is pass through three phases, that
are circuit establishment, data transfer and circuit disconnec

PACKET SWITCHING
The basic example of Packet Switching is the Internet.In Packet Switching,
data can be fragmented into suitably-sized pieces in variable length or blocks
that are called packets that can be routed independently by network devices
based on the destination address contained certain “formatted” header within
each packet. The packet switched networks allow sender and recipient
without reserving the circuit. Multiple paths are exist between sender and
recipient in a packet switching network.They does not require a call setup to
transfer packets between sender and recipient.

Advantage Packet Switching
The main advantage of packet switching network is the efficiency.The other advantage is that, it is faults
tolerant. In packet switching,the quality of data transmission is kept high (error free).
There are two type of Packet Switching connectionless or Connection-Oriented.
Connectionless Packet Switching
It is also known as datagram switching. In this type of network each packet routed individually by
network devices based on the destination address contained within each packet. Due to each packet is
routed individually, the result is that each packet is delivered out-of-order with different paths of
transmission, it depend on the networking devices like (switches and routers) at any given time. After
reaching recipient location, the packets are reassemble to the original form.
Connection-Oriented Packet Switching
It is also known as virtual circuit switching.in this type of Networking packets are send in sequential order
over a defined route.

LAYERS, PROTOCOL, INTERFACES
114
Protocol: is an
agreement between
the communicating
parties on how
communication is to
proceed.
Interface: Between
each pair of
adjacent layers.
Services: A service is
formally specified
by a set of
primitives .

LAYERS, PROTOCOL, INTERFACES
115

NETWORK PROTOCOL STACK
1. Protocol Stack: A list of protocols used by a certain system, one protocol per layer
116
TCP/IP Model OSI Ref Model Protocols
Application Layer
Application Layer FTP, HTTP, Telnet
Presentation layer JPEG,MPEG
Session Layer NFS,SQL,PAP
Transport Layer Transport Layer TCP,UDP
Internet Layer Network Layer IPV4,IPV6
Network Access Layer
Data Link Layer ARP,CDP,STP
Physical Layer Ethernet, Wi-fi

CONNECTION-ORIENTED VS
CONNECTIONLESS SERVICE
1. Also Known as Reliable and Unreliable Connection
117

118
Connection-oriented communication :
It is a network communication mode in telecommunications and computer networking, where
a communication session or a semi-permanent connection is established before any useful
data can be transferred, and where a stream of data is delivered in the same order as it was
sent.
Connectionless communication:
It is a data transmission method used in packet switching networks in which each data unit is
individually addressed and routed based on information carried in each unit, rather than in the
setup information of a prearranged, fixed data channel as in connection-oriented
communication.

119

CONNECTION-ORIENTED SERVICES
1. Service primitives: Communication between adjacent protocol layers (i.e. within the same
communications node) are managed by calling functions, called primitives, between the layers.
There are various types of actions that may be performed by primitives
120
Sl.No Primitives Meaning
1. LISTEN Block waiting for an incoming connection
2. CONNECT Establish a connection with a waiting peer
3. ACCEPT Accept an incoming connection from a
peer
4. RECEIVE Block waiting for an incoming message
5. SEND Send a message to the peer
6. DISCONNECT Terminate a connection.

CONNECTION-ORIENTED &
CONNECTIONLESS-ORIENTED
COMPARISON
121
Criteria Connection-Oriented Connection-Less
Connection Prior connection need to be established No prior connection need to be
established
Resource Allocation Resources need to be allocated No prior allocation of resources is
required
Reliability It ensures reliable transfer of data Reliability is not guaranteed as it is best
effort service.
Congestion Congestion is not at all possible Congestion can occur likely
Transfer Mode It can be implemented either using
circuit switching or virtual circuits.
It is implemented using packet switching
(Datagram).
Retransmission It is possible to retransmit the possible
lost data bits.
It is not possible
Suitability It is suitable for long and steady
communication
It is suitable for bursty transmission
Signalling Connection is established through
process of signalling
There is no concept of signalling
Packet travel Packet travel from source to destination
in sequential manner.
Packets move in random fashion.
Delay There is more delay in transfer but once
connection established fast delivery
No delay as connection is not required.

SUMMARY
Q. 1 What is protocol, interface, services?
Q. 2 What is connection services and connectionless services?
Q. 3 What are the differences between connection services and connectionless
services?
Q. 4 What is protocol stack?
Q. 5 Discuss the relationship between layers, interface, protocol and services.
• Lecture 8 : Network Software
122

ACTIVITY - 7
1. https://www.youtube.com/watch?v=ojT2Iza0I00
• Lecture 8: Network Software
123

REFERENCE
MODEL
1. OSI & TCP Model
124

LECTURE –9
Recap
1. Types of Software-
• Application software
• Network Protocol
• Drivers of the NIC
2. Network Protocol
3. CO Services Vs CL Service.
Objectives
• OSI Reference model
• TCP/IP Reference model
• Direct vs Indirect communication
• Physical/vertical vs Logical/horizontal
communication
• Data Encapsulation & Stripping
• Data Units, Message delivery types, Address
types
125
Reference Model

NETWORK ARCHITECTURE
1. NA: Set of Layers + Set of Protocols + (style in which request and service
established)
126

COMMUNICATION BETWEEN
SENDER AND RECEIVER
128

COMMUNICATION BETWEEN
SENDER AND RECEIVER –
1. Direct and Horizontal communication
129

NON- HORIZONTAL
COMMUNICATION
130

ACTUAL VS LOGICAL/VIRTUAL
COMMUNICATION
132

DIRECT VS INDIRECT
COMMUNICATION
133

TYPES OF DATA UNITS
1) Upper layer-> Data or message.
2) Transport layer-> Segments
3) Network Layer-> Packets
4) Data-link Layer-> Frames
5) Physical Layer-> Bits/signals
• Data Units:
134

DATA ENCAPSULATION &
STRIPPING -1
137

DATA ENCAPSULATION &
STRIPPING -2 ( SIZE)
138

TYPES OF MESSAGE DELIVERY IN
NA
1. Message delivery at peer-to-peer level
140
Sl.No NA Layers Message Delivery
1. Data Link Layer Node-to-Node Message
delivery
2. Internet/ Network layer End-to-End Message Delivery
3. Transport Layer Process-to-process Message
Delivery.

TYPES OF ADDRESSES IN NA
1. Addressing carried out in each layer
141
1. Upper layer Domain Address
2. Transport layer- Port Address (Socket address=
port address + IP address
3. Network Layer IP address
4. Data link layer- MAC address.

SIZE OF ADDRESSING SCHEME IN
NA
1. Bits level Address size
142
1. Domain address- part of URL
2. Port address- 16 bits
3. IP address- IPV4- 32 bits(4*8) , IPV6- 128 bits
4. MAC address- hardware address-> 48 bits.

TCP/IP LAYER
1. 5 layered Network reference model
143

COMPARISON BETWEEN TCP/IP &
OSI
144

SUMMARY
Q. 1 What is ISO OSI / 7 layered architecture?
Q. 2 What is TCP/IP or 5 layered architecture?
Q. 3 What are the differences between OSI and TCP/IP reference model?
• Lecture 8 : Network Reference Model
145

ACTIVITY - 8
Website:
https://www.studytonight.com/computer-networks/uses-of-computer-
networks
Quiz:
http://highered.mheducation.com/sites/0072967722/student_view0/chapter_1
_quiz.html
• Lecture 8 : Network Reference Model
146

STANDARDS &
ORGANIZATIO
N
1. Apex Bodies
147

LECTURE –10
Recap
1. OSI Reference model
2. TCP/IP Reference model
3. Direct vs Indirect communication
4. Physical/vertical vs Logical/horizontal communication
5. Data Encapsulation & Stripping
6. Data Units, Message delivery types, Address types
Objectives
• Network Standards
• Network Organizations
148
Network Standards & Organization

NETWORK STANDARDS
149
Standards :
Define what is needed for interoperability: No more , No Less
Protocol Standards :
Defines the protocol over the wire but not the service interface
inside the box
. (However, the real service interface are often proprietary).

NETWORK STANDARDS
150
Sl.No Standards Meaning
1. De-Facto ( Latin: “by fact” or “by
convention”)
•Standards that have not been approved by an
organized body but have been adopted as
standards through widespread use .
• De facto standards are often established
originally by manufacturers who seek to define
the functionality of a new product or technology.
•These are also known as Market Standards.
2. De-jure (Latin: “by Law” or “by organization”) Those standards that have been legislated by an
officially recognized body .

STANDARD ORGANIZATION
1. Standards developed through the cooperation of standards creation committees, forums, and
government regulatory agencies.
151
Sl.N
o
Standards Expansion Area
1. ISO International Organisation for
Standardisation
• Scientific , Technological, Economic
actively.
2. ITU-T International Telecommunication Union-
Telecommunication Standards
Telecommunication
Ex: G.992,ADSL,H.264,MPEG4
3. IETF Internet Engineering Task Force Internet
Ex: 802.3,Ethernet,802.11,Wi-fi
4. IEEE Institute of Electrical & Electronics
Engineers
Communication standards

STANDARD ORGANIZATION
152
Sl.No Standards Expansion Area
5. W3C World Wide Web Consortium
(Inventor: Tim Berners-Lee)
Web Standards
Ex: HTML,CSS
6. EIA •Electronic Industries Association
7. ANSI • American National Standards Institute Development of voluntary consensus
standards for products, services, processes,
processes, systems, and personnel in the
United States.

SUMMARY
Q. 1 What is De-facto?
Q. 2 What is De-jeure?
Q. 3 How to convert de-facto to de-jure?
Q. 4 Name some of the international organisation in the world of
communication and internet?
• Network Standard organization
153

DATA &
SIGNALS
1. Base for communication
154

LECTURE - 11
Recap
1. Network Standardisation
2. Standard Organisation
Objectives
• Data & Signals
• Characteristics of Signal
• Analogue & Digital Devices
• Analogue-Digital Conversion
• Digital-Analogue Conversion
155
Data & Signals

DATA & SIGNALS
156
Data : These are characteristics collected through observation .
Data is a set of values of qualitative or quantitative variables about one or
more persons or objects, while a datum (singular of data) is a single value
of a single variable.
Signal: A signal is an electrical or electromagnetic current that is used for
carrying data from one device or network to another.

CHARACTERISTICS OF SIGNAL
157
Analogue Signal
• Frequency
• Wavelength
• Amplitude
• Phase
Digital Signal
• Bit Rate
• Bit interval
• Bit length

ANALOGUE & DIGITAL DEVICES
158

ANALOGUE-DIGITAL CONVERSION
1. Devices used to covert analogue signal to digital signal .
159

DIGITAL- ANALOGUE CONVERSION
1. Devices used to convert digital signal to analogue signal.
160

SUMMARY
Q.1 What is data?
Q.2 What is signal?
Q.3 What are the types of data & signal?
Q.4 How signals are represented?
Q.5 How data/signal conversion carried out?
• Data & Signals
161

ACTIVITY- 9
Reading:
Transmission impairment – attenuation, distortion, noise
Data Rate limits – bandwidth, signal level, quality of the channel
Performance – bandwidth, throughput, latency, bandwidth-delay product.
Waves:
1. https://www.youtube.com/watch?v=R8kCskG7hKI ( Characteristics of waves).
2. https://www.youtube.com/watch?v=UMC1EI-2sLo (Characteristics of waves).
3. https://www.youtube.com/watch?v=P798-zzEwT4 (Physics demonstration).
• Lecture 10 : Data , Signal & Basic of Waves
162

ELECTROMAGN
ETIC WAVE
MODULATION
163

LECTURE - 12
Recap
1. Data & Signals
2. Characteristics of Signal
3. Analogue & Digital Devices
4. Analogue-Digital Conversion
5. Digital-Analogue Conversion
Objectives
• Electromagnetic waves
• Bandwidth
• Broadband & Baseband
• Modulation
164
Electromagnetic waves ,Bandwidth & Modulation

ELECTROMAGNETIC WAVES
1. - Longitudinal waves, compression rarefaction waves, vacuum waves
165

BANDWIDTH
1. Network bandwidth is the capacity of a wired or wireless network communications link to transmit the maximum
amount of data from one point to another over a computer network or internet connection in a given amount of time.
166
Baseband
• Baseband technology transmits a single data signal,
stream, channel at a time
• General Ex: Railway track; Technical ex: Ethernet (
TDM)
Broadband
• Broadband technology transmits multiple data
signals/streams/channels simultaneously at the same
time.
• General Ex: Road ; Technical Ex: DSL, Cellular, Cable
modern, Satellite ( FDM, WDM)

MODULATION
1. It is the process of mixing data signal to the carrier signal to form new signal. Mixing of
low frequency signal with high frequency carrier signal is called Modulation.
2. Modulation types :
1. Analog modulation
2. Digital modulation
Message Signal + Carrier Signal = Modulation
167

ANALOGUE MODULATION
1. Amplitude modulation where the amplitude of the carrier signal is modulated or altered .
168

ANALOG MODULATION
1. Frequency modulation where the frequency of the carrier signal is modulated or altered .
169

DIGITAL MODULATION
1. Types of Digital Modulation
170

SUMMARY
Q.1 What is Electromagnetic waves?
Q.2 What is Bandwidth?
Q.3 What is Baseband & Broadband?
Q.4 What is Modulation?
• EMW, BW, Baseband & Broadband, Modulation
171

ACTIVITY -10
Electromagnetic Spectrum
https://science.nasa.gov/ems/01_intro
https://www.youtube.com/watch?v=Elv3WpL32UE
Bandwidth:
https://www.youtube.com/watch?v=IS8pRayVlYc
Speed vs Bandwidth
https://www.youtube.com/watch?v=A_-L-kn9biw
Bandwidth: Baseband vs Broadband
https://www.youtube.com/watch?v=bNUIliQocTc
Modulation:
https://www.youtube.com/watch?v=dvGcCk1vbjk
• Lecture 11: EMW, BW, Baseband & Broadband, Modulation
172

TRANSMISSI
ON MEDIA
173

LECTURE - 13
Recap
1. Electromagnetic waves
2. Bandwidth
3. Broadband & Baseband
4. Modulation
Objectives
• Transmission media or Guided media
• Non-Transmission media or Unguided
media
174
Transmission Media

TRANSMISSION MEDIA
1. - Guided media
175

COTIND…..
1. It is defined as the physical medium through which the signals are
transmitted.
2. It is also known as Bounded media.
3. Types Of Guided media: Shielded Twisted Pair & Unshielded Twisted
Pair
4. Twisted pair is a physical media made up of a pair of cables twisted with
each other.
5. A twisted pair cable is cheap as compared to other transmission media.
Installation of the twisted pair cable is easy, and it is a lightweight cable.
6. The frequency range for twisted pair cable is from 0 to 3.5KHz.
176

COAXIAL CABLE IS OF TWO
TYPES:
1. Baseband transmission: It is defined as the process of transmitting a single signal
at high speed.
2. Broadband transmission: It is defined as the process of transmitting multiple signals
simultaneously.
Advantages :
• The data can be transmitted at high speed.
• It has better shielding as compared to twisted pair cable.
• It provides higher bandwidth.
Disadvantages :
• It is more expensive as compared to twisted pair cable.
• If any fault occurs in the cable causes the failure in the entire network.
177

UNGUIDED TRANSMISSION
• An unguided transmission transmits the electromagnetic waves without
using any physical medium. Therefore it is also known as wireless
transmission.
• In unguided media, air is the media through which the electromagnetic
energy can flow easily.
Radio waves
• Radio waves are the electromagnetic waves that are transmitted in all the
directions of free space.
• Radio waves are omnidirectional, the signals are propagated in all the
directions.
• The range in frequencies of radio waves is from 3Khz to 1 khz. 178

GUIDED OR WIRED MEDIUM
181
Twisted
pair
cable
• Less data, Inference
Coaxial -
Cable
• Relatively more data, Inference
Fibre-
optics
• More data, Inference

TRANSMISSION MEDIA
1. - Unguided media
182

UNGUIDED OR WIRELESS MEDIA
183
Infrared
Waves
• Light waves, Electromagnetic waves,
• Radiation waves, Average frequency carrier wave
Micro
waves
• Low frequency carrier wave
Satellite
& Radio
waves
• Very frequency carrier wave

SUMMARY
Q.1 What is guided media?
Q.2 What is unguided media?
Q.3 list the examples for wired medium and wireless medium.
Q. 4 What are the advantages of optical fibre over coaxial-cable?
Q.5 Explain the importance Radio and satellite waves.
• Lecture 12 : Transmission media
184

ACTIVITY - 11
Video & Reading : Optical Fibre
1. https://www.britannica.com/science/fiber-optics
2. https://www.youtube.com/watch?v=02wPSDOXMhc
• Lecture 12 : Guided and Un-guided media
185

MULTIPLEXI
NG
1. Bandwidth utilization technique
186

LECTURE - 14
Recap
1. Transmission media or Guided media
2. Non-Transmission media or Unguided media
Objectives
• Multiplexing
• Analogue Vs Digital multiplexing
• Frequency division multiplexing
• Wavelength division multiplexing
• Time division multiplexing
187
Multiplexing

MULTIPLEXING
1. Bandwidth utilization technique for Efficiency
188
Analog Signal
• Frequency division
multiplexing (FDM)
• Wavelength division
multiplexing (WDM)
Digital Signal
• Synchronous Time division
multiplexing
• Statistical Time division
multiplexing

FDM : FREQUENCY DIVISION
MULTIPLEXING
1. Analogue Multiplexing
189

WDM : WAVELENGTH DIVISION
MULTIPLEXING
1. Working Principle
190

WDM : WAVELENGTH DIVISION
MULTIPLEXING
1. Mechanism
191

TDM : TIME DIVISION
MULTIPLEXING
1. Working Principle
192

SUMMARY
Q.1 What is multiplexing and why?
Q.2 How channels in link are created?
Q.3 How multiplexing is carried down?
Q. 4 Explain the types of multiplexing, its features and limitation?
Q.5 What are the differences between FDM & TDM?
• Multiplexing
195

ACTIVITY - 12
Reading : WDM
1. http://www.fiber-optic-transceiver-module.com/wavelength-division-
multiplexing-wdm-technology.html
• Lecture 13 : Multiplexing
196

LECTURE - 15
Recap
1. Multiplexing
2. Analogue Vs Digital multiplexing
3. Frequency division multiplexing
4. Wavelength division multiplexing
5. Time division multiplexing
Objectives
• Switching
• Virtual circuit packet switching
198
Switching

SWITCHING
1. Technique to reduce # of devices and links in network
199
Traditional
Switching
• Circuit packet switching
Packet Switching
• Cellular switching
Mobile Switching

SWITCHING TECHNIQUE
CLASSIFICATION
200

SUMMARY
Q. 1 What is switching and why?
Q. 2 What device used for switching?
Q. 3 What are the types of switching?
Q. 4 What are the differences between MS,CS, PS?
Q.5 What are the differences between VCPS and DPS?
• Switching
206

REFER THE BELOW LINK
1. All about MAC
207

Module 1 CN -new.pptx

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