Definitions

Question 1

Network

Answer 1

= collection of hardware components and computers interconnected by
communication channels that allow sharing of information and resources.

Question 2

why is Networking Needed?

Answer 2

needed to facilitate communication and the transfer of information between different destinations + it enables speedy data transfer and has made the world a smaller place.

Question 3

Topology

Answer 3

• refers to the virtual shape or structure of a network.
• it is a schematic description of how the network is arranged, including its nodes (devices) and connecting lines.
• In other words, topology defines how devices are connected and how data is transmitted within a network.

it can be either physical or logical

Question 4

What are the physical topology ?

Answer 4

a. Bus topology
b. Ring topology
c. Star topology
d. Tree topology
e. Mesh topology.

Question 5

Bus topology

Answer 5

type of network topology where all the nodes (systems) are connected to a common main cable called a bus.

Advantages = easy to install and use + the failure of any device connected to the network does not affect the functioning of other devices.

Disadvantage = when the number of nodes connected to the bus increases, the performance may decrease.
+ if the bus fails, the entire network will be down.

Question 6

Ring Topology

Answer 6

= a type of network topology where every device is connected to two neighboring devices, forming a closed loop.
* Messages can only travel in one direction
* If the loop gets cut, the entire network will be affected.

Question 7

Star Topology

Answer 7

• = a simple network topology where all the devices are directly connected to a central server, computer, or hub.
• Each node = connected to the central server, allowing for easy communication between devices.
  Advantage = the failure of one cable or device will not affect the functioning of other nodes in the network.
  Disadvantage = this topology requires more cables, which can increase the cost factor.

Question 8

Tree topology

Answer 8

• = a combination of two or three star networks connected to a main bus.
• In this topology, central hubs or servers of the star networks are connected to a main bus.
• Advantage = expansion is relatively easier as multiple networks can be included.
• Disadvantage = installation process = complex.

Question 9

Mesh Topology

Answer 9

• = a type of network topology where each node is directly connected to every other node in the network.
  Two schemes used for mesh topology: full mesh and partial mesh.
• In a full mesh, every node is connected to every other node
• In a partial mesh, only a few nodes are connected to all the nodes and the rest are connected only to specific nodes they want to communicate with.
  Advantage = if a link fails, it will only affect that specific connection and not the entire network.
  Disadvantage = setting up a full mesh can be complex.

Question 10

Logical topology

Answer 10

= paths through which signals flow from one node to another.

Question 11

Components of a typical network ?

Answer 11

• network adapters
• repeaters
• bridges
• hub
• switch
• routers
• gateways

Question 12

network adapters

Answer 12

• Role = act as interfaces between computers or devices and a network.
• = necessary for connecting machines to a network.
• Various types of network adapters available => Ethernet or Wi-Fi adapters.

Question 13

repeaters

Answer 13

• = a device used in networking to strengthen and transmit signals over longer distances without distortion or loss.
  Role = acts as an amplifier :
• => it receives a signal from a transmitter
• => amplify it
• => re-transmit it with better strength.

Question 14

bridges

Answer 14

• = a vital component in networking
  Role = used to connect two different networks or split a network into separate segments.

Question 15

hub

Answer 15

• = a device used to facilitate data sharing between computers within a network.
• used in star topology networks.
  => When a computer sends information, it transmits the signal to the hub, which then retransmits the signal to the destination computer.
  Hubs can be either active or passive.
• Passive hubs simply relay the signal
• Active hubs act as repeaters and can regenerate the signal.

Question 16

switch

Answer 16

• = an intelligent device that is used in computer networking.
• Role = acts as a central point of a network and is an improved version of a hub.

it examines the destination address (MAC address) from the packet header and redirects the packet to the destination alone.
=> This is possible because the switch maintains a table with details of all ports and corresponding device’s MAC addresses.
* By using a switch, the bandwidth utilization becomes more effective and is managed more efficiently.

Question 17

routers

Answer 17

• = devices used to communicate between networks in an efficient and intelligent way.
• They transfer packets from the source to the destination using the best and shortest route.

When a data packet is received, the router reads the destination address, looks at the path to reach the destination, and sends the packet through the shortest path (= chemin).
* Routers play a crucial role in ensuring effective and reliable communication between networks

Question 18

gateways

Answer 18

• = device used to connect two different networks.
  Role = acts as a converter
  => it allows communication between networks that use different protocols or technologies.
  For example => it can connect a VoIP network to a PSTN network (= 2 networks that use different protocols or technologies)

Question 19

1. Local Area Network (LAN)

Answer 19

= a type of computer network that connects devices within a shorter proximity, such as a building, school, college, internet cafes, or a home.
It can be maintained and controlled by a single person due to its small operational area.

LANs can also have groups of LANs within them, where each room in a home, for example, can be considered a LAN.

Question 20

Wide Area Network (WAN)

Answer 20

= a network that covers a larger area, such as connecting branches of an organization across different geographical regions.
* WANs are formed by joining multiple Local Area Networks (LANs) together.
* Technologies like optical fibers, ATM, and Frame relays are commonly used for establishing long-distance connectivity in WANs.
* The internet = a WAN => because it covers the entire globe.

Question 21

Metropolitan Area Network (MAN)

Answer 21

• = a network that covers a larger physical area than a Local Area Network (LAN) but is smaller than a Wide Area Network (WAN).
• It typically covers a city or a metropolitan area.
• MANs are used by government bodies and organizations on a larger scale.
• The diagram in Figure 1.17 shows three different buildings in New York City connected by a MAN.

Question 22

Personal Area Network (PAN)

Answer 22

= a short-range network that uses Bluetooth technology to connect devices such as computers, printers, and mobile phones without the need for cables.
=> typically covers only a few meters and is commonly used for transferring songs or data between mobile phones.
=> it requires pairing (= couplage) = establish communication between two devices in a PAN

Question 23

Intranet

Answer 23

• = a personalized version of the internet that is only accessible within an organization. It is not available to the outside world.
• If an intranet is connected to the internet, it is protected by a firewall.
• The firewall controls access between the intranet and the internet, allowing access to the intranet only for authorized individuals within the organization.

Question 24

Extranet

Answer 24

• = a partially accessible intranet that allows authorized outsiders to access certain parts of the intranet.
• The actual server that serves up the web pages of the intranet is also protected by a firewall, which controls access to the intranet based on access permissions set for individuals or groups of outside users.
• Access to the intranet can be based on a username and password or an IP address.

Question 25

The Internet Protocol (IP)

Answer 25

= a set of rules that governs the format of data packets and the addressing scheme used to identify devices on a computer network.

It is responsible for routing data packets from the source device to the destination device over the network.

Question 26

Physical Layer:

Answer 26

This layer is responsible for the physical transmission of data over the network, including the electrical, mechanical, and functional specifications of the hardware.

Question 27

Data Link Layer:

Answer 27

The data link layer is responsible for node-to-node validity and integrity of transmission. It divides the raw bit stream into frames and handles physical addressing, flow control, error notification, and topology.

Question 28

Network Layer:

Answer 28

The network layer is responsible for routing data to different LANs and WANs based on network addresses. It determines the best path for data transmission and manages network problems such as congestion and packet switching

Question 29

Transport Layer:

Answer 29

The transport layer ensures the reliable and transparent transfer of data between source and destination. It provides end-to-end data transfer and handles any packet loss or errors that may occur in the lower layers.

Question 30

Session Layer:

Answer 30

The session layer establishes, manages, and terminates communication sessions between applications. It provides services such as session establishment, data synchronization, and session recovery.

Question 31

Presentation Layer:

Answer 31

The presentation layer is responsible for data representation and encryption. It ensures that data is properly formatted and encrypted for secure transmission.

Question 32

Application Layer:

Answer 32

The application layer is the topmost layer and is responsible for providing network services to user applications. It interacts directly with the user and hides the complexities of the lower layers.

Question 33

IMPs

Answer 33

= computers that connected host computers to the ARPANET and handled the transmission of data packets.

they acted as intermediaries between the host computers and the network, ensuring that data was transmitted correctly and efficiently.

Question 34

Packed switching

Answer 34

allow connections all over the world/travel over large distance on better routes (= scalability/efficiency/reliability/flexibility/faster

Question 35

The TCP/IP model

Answer 35

= a set of protocols that govern communication between devices on the Internet.

played a crucial role in developing the Internet by providing a simple but powerful and flexible protocol for communication. It provided a set of protocols that allowed different networks to communicate with each other seamlessly.

prioritized robustness and flexibility => enabling the Internet to scale and adapt to different technologies and network sizes (= scalability/flexibility

Question 36

TCP (Transmission Control Protocol)

Answer 36

handled communication between computers

Question 37

IP (Internet Protocol)

Answer 37

handled internetwork connections between networks.

Question 38

ARPANET

Answer 38

= a network developed by ARPA (Advanced Research Projects Agency) in the late 1960s.

= one of the first operational packet-switching networks and served as the foundation for the development of the Internet.

The ARPANET connected computers at various research institutions and allowed them to communicate and share resources.

Question 39

3 basic building blocks of the Internet

Answer 39

Protocols = TCP/IP

Client server = time-sharing (def in lecture 2)

Infrastructure = packed switching/ IMPs

Question 40

Gateway machines

Answer 40

= devices that bridge various networks together, allowing them to communicate as if they were on the same network.

They maintain routing tables with the addresses of computers on their own local networks.

enable communication between different networks by streamlining the functions of the gateway computers.

Question 41

Open standards network

Answer 41

= a network that allows for the use of equipment and technologies from multiple suppliers while still maintaining strict central control.

In the context of the telecommunications industry, the creation of an open standards network = a solution to the concern of becoming dependent on equipment manufacturers.

By adopting open standards, the telecommunications giants could ensure that equipment could be produced by a variety of suppliers, while still retaining control over the network.

This approach aimed to avoid monopolies in networking equipment and promote competition among suppliers.

Question 42

Limitations of Web 2.0

Answer 42

ethical issues : privacy/security of users rights (risks of leaks personal data)

limited interconnectivity and knowledge sharing between platforms across community boundaries.

Question 43

Semantic web

Answer 43

= a collaborative movement led by the WWW Consortium (W3C) that aims to provide a common framework for sharing and reusing data across different applications, enterprises, and communities.

It enables machines to understand and respond to complex human requests based on the meaning of the data.

Question 44

Differences between Web 2.0//Semantic Web

Answer 44

Web 2.0 focuses on user-generated content and collaboration, where users can create and share content on the web.

=> It targets the creativity of both users and producers.

Semantic Web focuses on linked data sets and aims to make the meaning of data explicit and structured.

=> It aims to create a web of interconnected data where machines can understand and process the information.

Web 2.0 is more about user interaction and social networking, while the Semantic Web is about making connections between related data and enabling machines to understand and process that data.

Question 45

Web browser

Answer 45

= a software application that allows users to access and view web pages on the World Wide Web.

It acts as an interface between the user and the World Wide Web, enabling the user to navigate through web pages, interact with web content, and perform various tasks such as searching, downloading files, and streaming media.

Ex : Mosaic/Google Chrome/Safari/

Question 46

HTML

Answer 46

stands for Hypertext Markup Language :

= standard markup language used for creating web pages and applications.

It uses tags to structure the content and define the layout of a web page.

These tags are enclosed in angle brackets (<>) and are used to define elements such as headings, paragraphs, links, images, and more.

HTML allows web developers to create structured documents that can be interpreted by web browsers to display the content in a visually appealing and interactive manner.

Question 47

HTTP

Answer 47

stands for Hypertext Transfer Protocol :
= a protocol that allows for the retrieval and transfer of information on the World Wide Web.
= the foundation of data communication for the web, enabling the exchange of hypertext, which includes text, images, videos, and other multimedia content.
= a client-server protocol, where the client (such as a web browser) sends a request to the server, and the server responds with the requested information.
HTTP uses a set of rules and conventions to ensure the proper formatting and transmission of data between the client and server.

Question 48

URI

Answer 48

stands for Uniform Resource Identifier :

= a string of characters that identifies a resource on the internet.

URIs are used to locate and access resources such as web pages, images, videos, and documents.

—> They can be in the form of a web address (URL) or a unique identifier (URN).

Question 49

Static web

Answer 49

refers to the early version of the web, known as Web 1.0.

=> In this version, web pages were read-only and did not allow for user interaction or content contribution.

The web was primarily used to search for information and read it, with very little in the way of user engagement.

The content of static web pages was created and managed solely by webmasters, and updates to the content were the responsibility of the webmaster.

The web pages were primarily composed of static HTML documents and lacked dynamic representation or web consoles for performing dynamic events.

Question 50

The Semantic Web follows the Linked Data 4 principles, which involve :

Answer 50

using URIs as names for things

using HTTP URIs to look up those names

providing useful information through RDF standards

including links to other URIs to discover more things.

Question 51

Web 4.0

Answer 51

= also known as the Ultra-Intelligent Electronic Agent, is the next generation of the World Wide Web.

It is characterized by the concept of an intelligent agent that can read and understand the contents of the web, making decisions on what to execute first in order to load websites quickly and efficiently.

Aims to provide superior quality and performance, with machines acting as powerful as the human brain.

It also emphasizes global transparency, governance, distribution, participation, and collaboration in various communities.

Web 4.0 is envisioned to function like an operating system, parallel to the human brain => enabled highly intelligent interactions (like interacting with an AI).

Question 52

folksonomy

Answer 52

= a user-generated system of classifying and organizing online content into different categories by the use of metadata such as electronic tags.

Question 53

Web 1.0:

Answer 53

= first implementation of the web, lasting from 1989 to 2005.
It was a read-only web, where users could search for information and read it, but there was limited interaction with websites.
—> primarily focused on delivering static content and did not allow for user-generated content or interaction with websites.

Question 54

Web 3.0:

Answer 54

Web 3.0 (or the semantic web) = the next phase of the web’s evolution.
It aims to make the web more intelligent and intuitive by using artificial intelligence and machine learning techniques.
Web 3.0 focuses on linked data sets and aims to provide more personalized and context-aware experiences for users.

Question 55

Main Characteristics of Social Networking

Answer 55

Internet-based

User-generated content.

Formation and maintenance of relationships.

User-generated content and interactions.

Question 56

Différences traditional//social media

Answer 56

social media is interactive and allows for two-way communication, whereas traditional media is typically one-way communication.

Users of social media platforms can engage with content, share their own thoughts and opinions, and interact with others.

Traditional media = controlled by a few entities and does not provide the same level of interaction.

Social media is more accessible and has a wider reach compared to traditional media.
Social media platforms can be accessed anytime and anywhere.

—> allows for real-time updates and instant sharing of information.

Traditional media = limited by physical distribution and broadcasting schedules.
Social media allows for user-generated content, where individuals can create and share their own content.

—> gives users a sense of ownership and empowerment, as they can contribute to the conversation and shape the narrative.

Traditional media = typically produced by professionals and controlled by media organizations.
Social media has the potential for viral spread and amplification of content.

—> Through sharing and engagement, content on social media can quickly reach a large audience and gain traction.

Traditional media relies on editorial decisions and limited space or airtime for content dissemination.

Question 57

Packets

Answer 57

= small units of data that are sent over a network.
When a large file or message is sent over the network, it is broken down into smaller packets, which are then transmitted individually and reassembled at the receiving end.
Each packet contains a portion of the data being sent, along with information about its destination and other metadata.
The metadata is stored in the packet header, which includes information such as the source and destination IP addresses, the protocol being used, and the packet’s sequence number.

Question 58

Blockchain

Answer 58

est une technologie décentralisée qui permet de stocker et de partager des informations de manière sécurisée. Elle fonctionne en enregistrant les transactions dans des blocs, qui sont ensuite liés les uns aux autres de manière chronologique, formant ainsi une chaîne de blocs. La blockchain est connue pour sa transparence, son immuabilité et son potentiel de créer des applications décentralisées dans divers domaines tels que les paiements, les contrats intelligents et la gestion de l’identité.

Question 59

Routers

Answer 59

= networking devices that connect different networks together and forward packets between them.

Question 60

Hosts

Answer 60

= devices that are connected to a network and generate or consume data.

Question 61

Internet services:

Answer 61

Email – the primary communication mechanism used in business, government and research.

The world-wide-web (WWW) – most widely used Internet service, hypermedia system that allows users to follow links from one web page to another.

Internet of things (IoT) – sensors and actuators that can be accessed and controlled over the Internet.

Internet search – widely popular service provided by search engines indexing webpages keywords and other characteristics.

Voice over Internet protocol (VoIP) - a technology that allows voice communication sessions to be delivered over Internet

Protocol (IP) networks, such as the Internet, rather than traditional telephone lines or mobile phone connections.

File transfer protocol (FTP) – allow users to down/upload files and list the contents of folders on a remote computer, without owning or operating a server.

Question 62

Unstructured web page search

Answer 62

refers to the process of finding relevant information within a web page that does not follow a strict structure or format, such as a blog post or news article.

—> This is typically done using search engines, which use a combination of text analysis and ranking algorithms to identify and present relevant results to the user.