Networking Essentials

Introduction - 2
Index
• Basic components of Computer Network
• Features of computer network
• Essential hardware components
• Data & Signals
• Network types
• Network architecture
• Network topology
Basic components of computer network

• Message: It is the data or information which needs to be transferred from one device to another device over a computer
network.
• Sender: Sender is the device that has the data and needs to send the data to other device connected to the network.
• Receiver: A receiver is the device which is expecting the data from other device on the network.
• Transmission media: In order to transfer data from one device to another device we need a transmission media such as
wires, cables, radio waves etc.
• Protocol: A protocol is a set of rules that are agreed by both sender and receiver, without a protocol two devices cannot
communicate.
• In order to establish a reliable communication or data sharing between two different devices we need set of rules that are called
protocol.
• For example, http and https are the two protocols used by web browsers to get and post the data to internet, similarly
smtp protocol is used by email services connected to the internet.
Features of computer network
• Performance
• The performance of a computer network is measured by how quickly it
responds. The time it takes to send and receive data between computers (or
nodes) in the network should be as short as possible.
• Data sharing
• Share data between different systems that are connected through a
transmission medium.
• Backup
• A computer network should have a central server that backs up all the data
shared over the network. This way, if there is a failure, the data can be quickly
recovered.
• Hardware & Software compatibility
• should support compatibility between different software and hardware
configurations.
Features of computer network
• Reliability
• There should be no failures in the network, but if one occurs, the recovery
should be quick.
• Security
• A computer network should be secure to protect data from unauthorized
access. Additionally, the data sent should be received exactly as it was
transmitted, with no loss during transmission.
• Scalability
• A computer network should allow the addition of new computers (or nodes)
to the existing network.
• For example, if a company has 100 computers for 100 employees and then
hires another 100 employees, the local area network (LAN) should be able to
accommodate the additional 100 computers.
Essential hardware components
• Server
• Centralized system which can take care of various factors like security, installations,
monitoring, data backup, facilitation of various software.
• Client
• Part of the network which connects various such systems to each other and gives
access to the end user for various activities.
• Transmission media
• All computers in a network are connected using transmission media like wires,
optical fibre cables, coaxial cables etc.
• Network Interface card
• Important role of NICs is to send & receive the data, format the data at receiver’s
end.
• Wired NIC
• The Wired NIC is present inside the motherboard. Cables and connectors are used with wired NIC
to transfer data.
• Wireless NIC
• The wireless NIC contains the antenna to obtain the connection over the wireless network. For
example, laptop computer contains the wireless NIC.
Essential hardware components
• Hub
• A hub is a device that connects all the computers in a network. When a client
computer sends a request, it first goes to the hub, which then transmits the request
over the network to the correct server. The server then responds to the request.
• Switch
• A switch is similar to a hub, but instead of broadcasting an incoming data request to
all devices, it uses the physical device address in the request to send it directly to the
correct server.
• Router
• A router connects multiple computer networks to each other. For example, if one
company has 100 computers on a local area network (LAN) and another company
has 150 computers on a different LAN, these two LANs can be connected through an
internet connection provided by the router.
• LAN cable
• A wire that is used to connect more than one computers or other devices such as
printers and scanner to each other.
Data & Signals
• Data
• Actual information being sent between devices or systems. It can be in any form like
text, files, audio, video or digital content that needs to be communicated.
• Signal
• Signals are the physical representations of data. They can be electrical or
electromagnetic impulses that carry the encoded information across cables, fiber
optics, or wireless channels.
• Key differences
• Nature
• Data is the content or information itself, while a signal is the physical form in which this
information is transmitted.
• Transmission
• Data is what we want to communicate, while signals are the means through which we
send this data across networks.
• Processing
• Computers handle data in its digital form, converting it into signals (analog or digital) for
transmission through physical mediums.
Data & Signals
•Types of Data & Signals
• Analog & Digital Data
• Analog data is continuous data that keeps changing over time
e.g. analog watch, speedometer in vehicles.

• Digital data represents information discretely at specific points

in time, such as the exact time displayed on a digital watch in
hours, minutes, and seconds.
Data & Signals
•Types of Data & Signals
• Analog Signals:
• Analog signals are continuous
waveforms that vary smoothly over
time. They can take on any value within
a range and are typically represented as
voltage or current levels.
• They are susceptible to noise and
degradation over long distances,
requiring amplification and filtering for
reliable transmission.
• E.g. Analog signals include audio signals
from microphones, video signals from
older televisions, and data transmitted
over analog telephone lines.
Data & Signals
• Types of Data & Signals
• Digital Signals:
• Digital signals are discrete and represent
information using binary digits (bits), which
can only have two states: 0 or 1.
• These signals are encoded using precise
voltage levels or frequencies.
• Digital signals are less susceptible to noise
and distortion compared to analog signals.
They can be regenerated and transmitted
over long distances without significant
degradation.
• E.g. Digital signals are used in modern
telecommunications, computers, and digital
devices such as smartphones. They are
essential for transmitting data reliably and
efficiently.
Data & Signals difference
Parameter Analog Signal Digital Signal
Analog signals convey information Digital signals transmit data in
Nature continuously over time. discrete time intervals.
Represents data using a continuous Represents data using discrete
Representation range of values. binary values (0 and 1).
Typically requires lower bandwidth Requires higher bandwidth due to
Bandwidth for transmission. discrete signal pulses.
Suitable for audio, video, and natural Used extensively in digital
Applications phenomena monitoring. electronics and data processing.
Prone to interference, affecting Resistant to noise, ensuring high
Noise Impact signal accuracy. data transmission accuracy.
Susceptible to inaccuracies due to Offers high accuracy and reliability in
Accuracy noise and interference. data representation.
Consumes more power due to Requires less power due to
Power Consumption continuous signal transmission. intermittent signal transmission.
Uses analog components like Relies on digital components such as
Components resistors and capacitors. transistors and logic gates.
Examples include temperature Examples include computers, digital
Examples sensors, analog cameras. cameras, and smartphones.
Network types
• LAN(Local Area Network)
• is a system that links computers and devices within a confined geographical
space, such as a home, school, office building, or a cluster of nearby buildings.
• The main goal of a LAN is to facilitate resource sharing and communication
among the connected devices.
• Advantages
• Resource sharing
• Communication
• Centralized data-management
• Cost efficiency
Network types
• MAN(Metropolitan Area Network)
• connects computers and devices throughout a city or metropolitan region,
usually covering several kilometers.
• It is larger than a Local Area Network (LAN) but smaller than a Wide Area
Network (WAN).
• MANs are designed to deliver high-speed connectivity and efficient data
transfer across a broader geographic area compared to LANs.
• Advantages
• High-speed connectivity
• Cost efficiency
• Scalability
Network types
• WAN(Wide Area Network)
• Connects computers and devices over a broad geographical area, often
spanning cities, countries, or continents.
• It is larger than both Local Area Networks (LANs) and Metropolitan Area
Networks (MANs).
• WANs are designed to facilitate communication and data transfer over long
distances, providing connectivity for remote offices, branches, and global
operations.
• Advantages
• Global connectivity
• Data backup & recovery
• Cost savings
Network types
• WLAN (Wireless Local Area Network)
• Connects devices within a limited area wirelessly, typically using Wi-Fi.

• Access Points (APs)

• WLANs typically use access points, which are devices that transmit and receive wireless signals. Access
points are connected to a wired network and serve as hubs for wireless clients to connect to the
network.
• Standards
• WLANs operate based on standards such as Wi-Fi (IEEE 802.11). Different standards (e.g.,
802.11a/b/g/n/ac/ax) provide varying speeds, frequencies, and range capabilities.
• Security
• WLANs implement security measures such as encryption (e.g., WPA2, WPA3) and authentication
protocols to protect data transmitted over the wireless network from unauthorized access and
interception.
• Range and Coverage
• The range of a WLAN can vary depending on factors like the type of equipment used, interference from
other devices, and physical obstacles. Access points can be strategically placed to extend coverage
throughout an area.

• Challenges
• WLANs may face challenges such as interference from other wireless devices, security vulnerabilities if
not properly configured, and potential performance issues in densely populated areas with many
simultaneous users.
Network architecture
• P2P architecture(Peer to Peer)
• All the computers from the network are connected to each other.
• Each node uses the same resources as others.
• No central “server” computer in other words all the nodes are also act as “server” to
store the data.
• File sharing networks, Blockchain & cryptocurrencies.

Advantages Disadvantages

Cost effective Security concerns

Scalability Management complexity
Resource sharing Performance issues
Redundancy Data consistency
Flexibility Limited control
Network architecture
• Client-server architecture
• Central server acts as a hub, handling requests from client computers.
• The server stores shared data, which it distributes to clients upon request.
• All communication, including data sharing between clients, must pass through the
server, ensuring centralized control and management of resources.
Advantages Disadvantages
Centralized control Single point of failure

Scalability Cost

Resource sharing Network dependency

Improved security Complexity

Reliability Latency
Network topology
• Network topology refers to the layout or arrangement of devices and
links in a computer network.
• These topologies vary in complexity, reliability, scalability, and cost,
influencing their suitability for different network environments and
applications.
Network topology
• Bus Topology
• Involves a single central cable (the bus) to which all devices connect.
• Devices communicate directly through the bus.
• Simple to set up and cost-effective for small networks, but can become slow
and unreliable as the network expands.
• Early network designs used bus topology.
• Star Topology
• Each device connects directly to a central hub or switch.
• Hub or switch manages data flow, enhancing reliability and simplifying
troubleshooting.
• Widely used in Ethernet LANs due to scalability and ease of management.
• E.g. Home, Office, Labs setups.
Network topology
• Ring Topology
• Devices form a closed loop or ring where each device connects to two others,
creating a pathway for data.
• Data travels in one direction around the ring.
• Less common today due to susceptibility to network disruptions from single link
failures.
• Token ring networks, SONET/SDH (Synchronous Optical Networking/Synchronous
Digital Hierarchy)

• Mesh Topology
• Every device connects to every other device, forming a fully interconnected mesh.
• Offers redundant paths and high fault tolerance.
• Complex to implement and manage, suitable for critical applications needing
reliability.
• E.g. Military and Emergency Services, IoT devices, Data centres.
Network topology
• Tree Topology
• Hierarchical structure with groups of star networks connected to a linear bus
backbone.
• Scalable and supports network expansion.
• Often used in WANs or large organizational networks.
• E.g. Hierarchical Network Design, organisational networks, campus networks.

• Hybrid Topology
• Combination of two or more different topologies (e.g., star-ring, star-bus).
• Provides flexibility and scalability, tailored to specific network needs.
• Requires careful planning and management to ensure compatibility and
performance.
• E.g. Campus, corporate offices.