Basics of Computer Networks Fundamentals

Introduction to Computer
Networks

Outline
 Why Computer Networks?
 Computer network basics
 Applications of Computer Networks
 Transmission media

Course Structure
Module 1 (9 hours)
• Why Computer Networks: Applications of Networks, Transmission Media, Connecting Devices, Local Area
Networks: LAN topologies: Bus topology, Ring topology, Star topologies, Mesh topology, Hybrid topology, OSI
reference model, TCP/IP Protocol suite, Physical Layer: Services, Line coding scheme, Modulation, Multiplexing,
Switching methods, Ethernet, Bluetooth, Wi-Fi, Wi-Fi Direct, WPA/WPA2/WPA3, Data Link layer: Services,
Framing, Switches.
Module 2 (8 hours)
• Reliable Data Delivery: Error detection, Error Correction, Flow control: Stop and wait, Go Back-N, Flow control:
S-R Protocol, Error control (Retransmission techniques, timers), Medium Access sub layer - Channel Allocations,
LAN protocols
• /ALOHA protocols, CSMA, CSMA/CD, Network Layer Protocols: Services (IP, ICMP), IP addressing, sub
netting, Super netting (CIDR), IPV4, IPV6.
Module 3 (9 hours)
• Routing and Forwarding, Static and dynamic routing, Unicast and Multicast Routing, Distance-Vector Routing,
Link-State Routing, Shortest path computation-Dijkstra's algorithm, Address mapping-ARP, RARP, BOOTP,
DHCP, Transport Layer: Services, UDP and TCP segment formats, connection establishment and termination,
Expert Lecture from Industry, Congestion control, Congestion control: Open Loop and closed loop, Quality of
service, Flow characteristics, Techniques to improve QoS.

Course Structure
Module 4 (7 hours)
• Session Layer: Services, Protocols, Presentation layer: Services, Protocols, Application
layer: Services, DNS, SIP, RTP, Telnet/SSH, HTTP, HTTPS, Remote login, Electronic mail,
SMTP, FTP Commands and Replies, WWW, SNMP, Addressing Schemes, Uniform
Resource Identifiers.
Module 5 (9 hours)
• Principles of Cryptography, Symmetric key, Public key, Authentication protocols, Digital
signatures, Firewalls, Security in different layers: Secure E-mail SSL, IP security, Advanced
Topics in CN: Dark Net, CASS: Content-Aware Search System, Service-centric networking,
Software-defined networking, Cloud Systems: Services, Data center, 4G and 5G Networks,
Body area sensor Networks, Satellite networks, SWARM networks.

Why Computer Networks?
• File/Application sharing- users can transfer data files
through a network
• Hardware sharing- enables users in a network to share
hardware devices, such as printers and hard drives;
• Client-server model- allows data to be stored on servers
where end-user devices (or clients) can access that data;
• Voice over IP (VoIP) - enables users to send voice data
through internet protocols
• Storage- enables users to access data that's stored
remotely or on other network devices.

Computer
network basics
 Network: A set of devices (or nodes)
connected by media link is called a
Network.
 A node can be a device which can send or
receiving data generated by other nodes
on the network like a computer, printer
etc.
 The links connecting the devices are
called Communication channels.
 Computer network is a
telecommunication channel used to share
data connected to the same network.
 The best example of computer network is
Internet.

Computer network
application
 Marketing and sales: –Marketing professionals collect, exchange,
and analyzes data relating to customer requirements and product
development cycles.
 Manufacturing: – computer-assisted manufacturing (CAM) and
computer –assisted designing (CAD) both of which permit multiple
users to work on a project simultaneously.
 Financial Services: It includes credit history searches, foreign
exchange and investment services, and Electronic Funds Transfer
(EFT).
 Teleconferencing:- Conferences are possible to occur without the
participants being in the same place. It includes simple text
conferencing, voice conferencing, and video conferencing.
 Cable Television:- It can include video on request.

Computer network
application
 Electronic Messaging:– Electronic mail (e-mail)
 Electronic Data Interchange (EDI):– EDI permits
business information to be transferred without using paper.
 Directory services: –It is possible to store the last of files
in a central location to speed worldwide search operations.
 Cellular Telephone: –cellular network make it possible to
maintain wireless phone connections even while travelling
over large distances.

Data Communication
The exchange of data between two devices through a
transmission medium is called Data Communication.
Communication Types:
Local communication: The communicating devices are in
the same geographical area, same building, or face-to-face
etc.
Remote communication: The devices are communicating
over a distance
The effectiveness of a data communication can be
measured through the following features :
 Delivery: Delivery should be done to the correct
destination.
 Timeliness: Delivery should be on time.
 Accuracy: Data delivered should be accurate.

Data
communication:
Components
1. Message: It is the information to be delivered.
2. Sender: Sender is the person who is sending the message.
3. Receiver: Receiver is the person to whom the message is
being sent to.
4. Medium: It is the medium through which the message is
sent.
5. Protocol: These are some set of rules which govern data
communication.

Connection types: Point to point
Communication link between
two devices and it is simple to
establish.
 For example, computer
connected by telephone line,
connection between remote
control and Television.

Connection types:
Multipoint
The link is shared in
space shared, or time
shared between
many devices

Connection types
A Network is nothing, but a connection made
through connection links between two or more
devices.
There are two ways to connect the devices :
Point-to-Point connection or dedicated
connection
Multipoint connection or shared
connection

A _______ is the physical path over
which a message travels.
A. Path
B. Medium
C. Protocol
D. Route

Transmission
Modes
It refers to the mechanism of transferring of data between
two devices connected over a network.
These modes direct the direction of flow of information.

Transmission
Modes
 Simplex mode
 Half Duplex mode
 Full Duplex mode

Transmission
Media
 The function of the
media is to carry
information through a
LAN.

Three or more devices share a link in
________ connection.
A. Unipoint
B. Multipoint
C. Point to point
D. Simplex

Transmission Media :
Guided
A signal travelling along guided media is directed and
contained by the physical limits of the medium.
Twisted-pair and coaxial cable use metallic (copper)
conductors that accept and transport signals in the
form of electric current.
Optical fiber is a cable that accepts and transports
signals in the form of light.

Guided : Twisted
pair cable
 A physical media made up of a pair of cables
twisted with each other.
 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.
 A pair of wire is twisted over a double helix.

Guided : Unshielded twisted pair
(UTP) Vs Shielded twisted pair (STP)
• This type of cable can block interference and does
not depend on a physical shield for this purpose.
• In computer network, Cat-5, Cat-5e, and Cat-6
cables are mostly used.
• UTP cables are connected by RJ45 connectors.
• STP cable includes a particular jacket for blocking
outside interference.
• It is used in rapid data rate Ethernet, in voice &
data channels of telephone lines.
• Eliminates crosstalk and comparatively faster

Guided : Coaxial
 Coaxial - It contains two conductors
parallel to each other.
 The middle core is made up of non-
conductive cover that separates the inner
conductor from the outer one and is
responsible for the data transferring
whereas the copper mesh prevents from
Electromagnetic interference.
 Categories of coax
RG-59 (Cable TV),
RG-58 (Thin Ethernet), and RG-11 (Thick
Ethernet).
Advantage
• high speed data transmission.
• Better shielding as compared to
twisted pair cable.
• It provides higher bandwidth.
Disadvantage
 More expensive as compared to twisted pair
cable.
 If any fault occurs in the cable causes the failure
in the entire network

Guided : Fiber Optic
 It works on the properties of light and provides
highest speed.
 The plastic coating protects the optical fibers from
heat, cold, electromagnetic interference from
other types of wiring.
 Data transfer modes:
 Single mode fiber: Carry a single ray of
light
 Multimode fiber: Carry multiple beams of
light.
To connect and access fiber optic special type of
connectors are used (e.g. Subscriber Channel (SC),
Straight Tip (ST), or MT-RJ.
Advantage
Greater Bandwidth and Faster speed
Longer distances
Disadvantage
It is more expensive as compared copper cable
Installation & maintenance is difficult

Question
• Which of the following is not a
guided media?
a) Fiber optical cable
b) Coaxial cable
c) Wireless LAN
d) Copper wire

Basics of Computer Networks Fundamentals

More Related Content

Similar to Basics of Computer Networks Fundamentals

Recently uploaded

Basics of Computer Networks Fundamentals