Introduction to

Computer Network
Presented by : Oussama BOUSSAHLA
Prepared by: Collaboration with Montassir Benaida
 Networks Affect our Lives
1- Networks Connect Us
• Communication is essential for human existence, nearly as vital as basic
needs like air, water, food, and shelter.

• Modern networks enable instant global connectivity, facilitating

collaboration, sharing of news and discoveries, and social interactions across
vast distances.
 Networks Affect our Lives
2- No bounderies
- Networking advancements are reducing barriers like borders and distances,
making location and time less relevant.
- The internet fosters global communities, enabling instant communication and
collaboration across various spheres.
- Online communities enhance productivity through idea and information
exchange.
- Cloud technology enables convenient access to data and applications from
anywhere, on any device.
What is a network?
A network refers to a system of interconnected nodes or entities that
communicate and share resources with each other.

In a normal context, the term “network” can refer to a group or system of

interconnected people, organizations or things that work together or share
information.
E.g. Social network, Traffic and road network, computer network…
What is computer
network?
A computer network consists of two or more computers
that are linked in order to share resources (such as
printers and CDs), exchange files, or allow electronic
communications.

The computers on a network may be linked through

cables, telephone lines, radio waves, satellites, or
infrared light beams.
Computer
networking field
The computer networking field encompasses a wide
range of technologies, practices, and applications related
to the design, implementation and maintenance of
computer networks.
Network
components
 Client/server
1. Hosts and Clients: Hosts are devices directly connected to a network, often referred to as end devices.
Clients are a type of host that request and display information obtained from servers.
2. Internet Protocol (IP) Address: Each host on a network is assigned an IP address, which identifies the
host and its network.

3. Servers: Servers are computers with software that provide services like email or web pages to other
devices on the network. Different services require separate server software.
4. Client Software: Clients have software for requesting and displaying information obtained from servers.
Examples include web browsers like Chrome or Firefox, which can run simultaneously with other client
software.
5. Simultaneous Services: A server can provide services to many clients simultaneously. Similarly, a single
computer can run multiple types of client software simultaneously.
Client/server
 Peer to peer
1. Client-Server Relationship: Client and server software typically run on separate computers, but one
computer can serve both roles simultaneously.
2. Peer-to-Peer Networks: In small businesses and homes, many computers serve as both servers and
clients on the network, forming a peer-to-peer network.
3. Network Connections: Computers in a network are connected via network interface cards (NICs) to
facilitate communication. Other peripherals, like printers, may also be connected to the network.
4. Print Sharing Example: In the provided scenario, the print sharing PC connects to a printer via USB
and to the file sharing PC via a network connection, allowing for print sharing functionality.
Peer to peer
Peer to peer
 End devices
End Devices: End devices are the most familiar network devices to people. Each end device has
an address, which is used to distinguish it from others on the network.
Addressing: When an end device initiates communication, it uses the address of the destination
end device to specify where to deliver the message.
Source and Destination: An end device is either the source (initiating) or destination (receiving)
of a message transmitted over the network.
End devices
 Intermediary Devices
Intermediary Devices: Intermediary devices connect individual end devices to the network and
enable the flow of data.
Internetwork Connectivity: Intermediary devices can connect multiple individual networks to
create an internetwork, ensuring seamless communication.
Path Determination: Intermediary devices use destination end device addresses and network
interconnection information to determine the path for message transmission through the network.
 Intermediary Devices
Intermediary Devices: Intermediary devices connect individual end devices to the network and
enable the flow of data.
Internetwork Connectivity: Intermediary devices can connect multiple individual networks to
create an internetwork, ensuring seamless communication.
Path Determination: Intermediary devices use destination end device addresses and network
interconnection information to determine the path for message transmission through the network.
Intermediary Devices
Intermediary Devices
Intermediary Devices

Lets change the view

Intermediary Devices
Network Media
Network Media
Network
Representations and
Topologies
 Network representations
Network architects and administrators must be able to show what their networks
will look like. They need to be able to easily see which components connect to
other components, where they will be located, and how they will be connected
so they use topology diagrams.

Diagrams of networks often use symbols, like those shown in the figure, to
represent the different devices and connections that make up a network.
Network representations
Network representations
Network representations
physical topology diagram
Network representations
Logical topology diagram
Common Types of
Networks
 Networks of many sizes
- Networks vary in size, ranging from simple setups connecting two computers to vast
networks linking millions of devices.
- Simple home networks enable resource sharing among local end devices, such as printers,
documents, and media.
- Small office and home office (SOHO) networks support remote work, self-employment
tasks like advertising, selling products, and communication with customers.
- Businesses and large organizations utilize networks for data consolidation, storage, and
access via network servers, facilitating internal communication and customer service.
- The internet, the largest network, is a "network of networks," comprising interconnected
private and public networks.
LANs and WANs
 LANs and WANs
Summary:
- LANs (Local Area Networks) are network infrastructures that cover a small
geographical area, like homes, schools, offices, or campuses.
- LANs interconnect end devices within this limited area and are usually
administered by a single organization or individual, enforcing security and access
control policies.
- LANs provide high-speed bandwidth to internal end devices and intermediary
devices, such as switches.
 LANs and WANs
- WANs (Wide Area Networks) interconnect LANs over wider geographical areas,
like between cities, states, or countries.
- WANs are typically managed by service providers (SPs) or Internet Service
Providers (ISPs) and offer slower speed links between LANs due to the larger
geographical distances covered.
LANs and WANs
 Internet
Some of the LAN examples are connected to each other through a WAN connection.
WANs are then connected to each other. The red WAN connection lines represent all
the varieties of ways we connect networks. WANs can connect through copper wires,
fiber-optic cables, and wireless transmissions (not shown).

The internet is not owned by any individual or group. Ensuring effective

communication across this diverse infrastructure requires the application of consistent
and commonly recognized technologies and standards as well as the cooperation of
many network administration agencies. There are organizations that were developed
to help maintain the structure and standardization of internet protocols and
processes. These organizations include the Internet Engineering Task Force (IETF),
Internet Corporation for Assigned Names and Numbers (ICANN), and the Internet
Architecture Board (IAB), plus many others.
Internet
Intranets and Extranets
OSI Model
OSI Model
OSI Model
OSI Model
 Resources
1. Networking fundamental: Data Com
https://link.springer.com/chapter/10.1007/978-981-19-3029-4_1

2. ‫ الوصف الوظيفي‬- ‫ مهندس شبكات‬Network Engineer

https://www.for9a.com/careers/%D9%85%D9%87%D9%86%D8%AF%D8
%B3-%D8%B4%D8%A8%D9%83%D8%A7%D8%AA-Network-Engineer
 Quiz
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 Contact me:
Fb: Oussama Boussahla
Linkedin: Oussama BOUSSAHLA
Instagram: b.oussama8
E-mail: oussamaboussahl2017@gmail.com
Telegram: @boussahlaoussama
Thank you!!