Data Communication and Computer Networks.pptx

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DATA COMMUNICATION
AND
NETWORKS
Prepared by : Sunya Osama Baig

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CONTENTS
1. Human Communication
2. Data Communication
3. Components Of Data Communication
4. Transmission Modes In Computer Networks
5. Computer Network
6. Use Of Computer Network
7. Types Of Computer Network
8. Network Topologies
9. Network Architecture
10. Network Devices
11. Common Terminologies

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• A transmitter: mouth
• A receiver: ear
• The media: air
Question: Can you talk at outer space?
• The protocol: a common human language
Question: why do we learn English and Urdu?
HUMAN COMMUNICATIONS

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WHAT IS DATA COMMUNICATION?
 The process in which two or more computers or devices transfer data is
known as
data communications.
 Today, even the smallest computers and devices can communicate directly with
one another, with hundreds of computers on a corporate network, or with
millions of other computers around the globe — often via the Internet.
 Some communications involve wires; others are sent wirelessly through the air.

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There are three components of data communication
 A sending device that initiates an instruction to transmit data, instructions, or
information. A communications device that connects the sending device to
transmission media.
 The transmission media, or a communications channel, on which the data,
instructions, or information travel. A communications device that connects the
transmission media to a receiving device
 A receiving device that accepts the transmission of data, instructions, or
information
 The network protocols are a set of rules governing exchange of information in an easy,
reliableand secure way.
COMPONENTS OF DATA COMMUNICATION

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(contd.)

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TRANSMISSION MODES IN COMPUTER
NETWORKS
Transmission mode refers to the mechanism of transferring of data between two devices
connected over a network. It is also called Communication mode. These modes direct
the direction of flow of information.
There are three types of transmission modes.
1. Simplex Mode
2. Half duplex Mode
3. Full duplex Mode

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WHAT IS COMPUTER NETWORK?
A network is a collection of computers and devices connected together via
communications
devices and transmission media.
Types of Networks:
1. Personal Area Network (PAN)
2. Local Area Network (LAN)
3. Wireless Local Area Network (WLAN)
4. Campus Area Network(CAN)
5. Metropolitan Area Network (MAN)
6. Wide Area Network (WAN)
7. Body Area Network (BAN)

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 Personal communication
 Email & Messaging
Instantaneous communication
 Conferencing
Tele conferencing
Videoconferencing
Audio-conferencing
 Voice over IP
Traditional Phone / mobile communication over internet
USE OF COMPUTER NETWORKS

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1. Personal Area Network (PAN)
 Very small-scale network
 Range is less than 2 meters
 Cell phones, PDAs, MP3 players
 Wearable devices such as
Smartwatch
Goggles
Wearable Healthcare Gadgets

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2. Local Area Network (LAN)
 Contains printers, servers and computers
 Systems are close to each other
 Contained in one office or building
 Organizations often have several LANS

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3. Wireless Local Area Network (WLAN)
 Functioning like a LAN,
 WLANs make use of wireless network technology, such as WiFi.
 Typically seen in the same types of applications as LANs, these types of networks don’t
require that devices rely on physical cables to connect to the network.

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4. Campus Area Network (CAN)
 A campus area network (CAN) is a network of
multiple interconnected local area networks (LAN)
in a limited geographical area.
 A CAN is also known as A corporate area network
(CAN).
 Example university campus, military bases, or
organizational campuses etc.

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5. Metropolitan Area Network (MAN)
 Large network that connects
different organizations
 Shares regional resources
 A network provider sells time
 Ownership and maintenance is
handled by either a single
person or company (a local
council, a large company, etc.).

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6. Wide Area Network (WAN)
 Two or more LANs connected
 Over a large geographic area
 Typically use public or leased lines
 Phone lines
 Satellite
 The Internet is a WAN

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7. Body Area Network
 A body area network (BAN), sometimes
called a body Sensor network (BSN), is a
type of PAN that wirelessly connects
sensors worn by, carried by, implanted in,
or attached to a human body.
 It is a short-range
wireless network comprised
of devices positioned in,
on, and around the body.
 It provides data communication over
short distances, limited to ranges of just
a few meters.

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NETWORK TOPOLOGIES
Physical layout or the way in which network connection are made is
called
network topologies.
By Wired Topology
1. Bus topology
2. Star topology
3. Ring topology
4. Mesh topology
By Wireless Topology
5. Infrastructure topology
6. Ad Hoc topology

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Bus Topology
 Also called linear bus
 One wire connects all nodes
 Terminator ends the wires
 Advantages
 Easy to setup
 Small amount of wire
 Disadvantages
 Easy to crash
 Slow

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Star Topology
 Star topology uses a central hub.
 Hub can be a switch, router, or hub device.
 Devices connect via UTP (RJ45) cables.
 One cable fails → only one device affected.
 Hub fails → entire network down.

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Ring Topology
 Devices connect in a closed loop.
 Each device acts as a repeater, boosting the signal.
 Uses a “token” to transmit data (Token Ring network).
 If one device fails, the entire network fails.
Out of these three network topologies, the Star
topology is the best network type and is
based on the Ethernet standard.

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Mesh Topology
 Mesh topology connects every
device to every other device.
 Offers multiple data paths for
communication.
 Provides high reliability and fault
tolerance.
 One device failure doesn’t affect the
network.
 Expensive and complex to set up.

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 Links that connect nodes
 Choice impacts
 Speed
 Security
 Size
NETWORK MEDIA

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Wired Media
Feature Coaxial Cable Twisted Pair Cable Fibre Optic Cable
Core Material Single copper core Two twisted copper wires Glass or plastic fibers
Speed Moderate
High (especially Cat5e,
Cat6)
Extremely high
Interference Good resistance
Prone (less in shielded
types)
Immune
Cost Moderate to high Low Very high
Flexibility Less flexible Highly flexible Rigid and fragile
Installation Harder Easy Difficult and complex
Typical Use TV, old LANs Ethernet (LAN)
Long-distance, high-speed
communication
Bandwidth Limited Moderate to high Very high
Distance Support Moderate Short to moderate Long distances

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,
NETWORK ARCHITECTURES
The configuration of computers, devices, and media on a network is
sometimes called the
network architecture.
1 Client / Server
 Divides roles into clients and servers
 Server provides resources/services (e.g., files, printers, databases)
 Clients request and use services from the server
 Centralized control and management
 Scalable and supports many users
 Easier to manage security and backups
 If server fails, clients lose access to services
 Used in business, web, and database applications

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Network Architectures (contd.
2. Peer-to-Peer
 No central server; all devices are equal
peers
 Each device can act as both client and
server
 Resources and files are shared directly
between devices
 Simple and inexpensive to set up
 Best for small networks
 Less centralized control and security
 If one device fails, only its resources are
affected
 Common in file sharing and home networks

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Network Devices
What are 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.
Devices used to setup a Local Area Network (LAN) are the most common type of
network devices used by the public. A LAN requires a hub, switch, router.
 Networking Devices are also called Communicating Devices.
List of common network devices:
 Hub
 Switch
 Router
 Bridge
 Gateway
 Modem
 Repeater
 Access Point

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Hub
 Central connection point in a network
 Operates at physical layer (Layer 1)
 Broadcasts data to all connected devices
 No filtering or intelligence (does not direct traffic)
 Simple and inexpensive device
 Can cause network collisions and congestion
 Mostly replaced by switches in modern networks

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Switches
 Central device connecting network devices
 Operates at data link layer (Layer 2)
 Forwards data only to the intended device using MAC addresses
 Reduces network collisions and improves performance
 Supports full-duplex communication
 Can manage VLANs for network segmentation
 More intelligent and efficient than hubs
 Commonly used in modern Ethernet networks

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Router
 Connects multiple networks together
 Operates at the network layer (Layer 3)
 Routes data packets based on IP
addresses
 Directs traffic between different networks
(e.g., LAN to Internet)
 Can provide firewall and security functions
 Supports network address translation (NAT)
 Enables wireless connectivity when
combined with access points
 Essential for Internet access and complex
network setups

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Bridges
 Connect two or more network
segments
 Operate at data link layer
(Layer 2)
 Filter and forward traffic based
on MAC addresses
 Reduce network collisions by
dividing traffic
 Less common now, often
replaced by switches

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Gateway
 Connects different networks using
different protocols
 Translates data between incompatible
systems
 Works across multiple layers of the
network
 Real-life example: Home router acting
as a gateway between your local Wi-Fi
network and the Internet
 Enables devices on your LAN to
access external networks seamlessly

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 IP Address: Unique identifier for a device on a network.
 MAC Address: Hardware address assigned to a network interface card.
 Subnet: A smaller network segment within a larger network.
 Protocol: Rules governing data communication between devices.
 Bandwidth: Maximum data transfer rate of a network or connection.
 Latency: Delay before data transfer begins following an instruction.
 Firewall: Security device or software that controls incoming and outgoing
network traffic.
COMMON TERMINOLOGIES

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 DNS (Domain Name System): Translates domain names into IP
addresses.
 DHCP (Dynamic Host Configuration Protocol): Automatically
assigns IP addresses to devices.
 Packet: Unit of data transmitted over a network.
 Packet Header: Part of a packet containing control information
like source/destination addresses.
 Payload: The actual data carried inside a packet.
 Subnet Mask: Defines network and host portions of an IP
address.
COMMON TERMINOLOGIES (contd.)

Data Communication and Computer Networks.pptx

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