Networking Concepts Quiz

Introduction to Web

• This lecture covers basic web concepts.
• The presenter is Dr. Heba Mamdouh from Minia University.

Internet

• The Internet is a worldwide system of interconnected computer networks.
• Networks use protocols (like TCP/IP) to exchange data.
• Each computer on the Internet has a unique IP address.
• The Internet is accessible globally.

Advantages and Disadvantages

• Advantages: Social networking, education, entertainment, internet services.
• Disadvantages: Threats to personal information, spamming, cybercrime, virus attacks.

Intranet

• A private network within organizations.
• Used to share resources and information among coworkers.
• Access is limited to authorized personnel within the organization

Internet vs. Intranet

• Internet: Worldwide network, accessible to everyone, less secure, less reliable, less expensive
• Intranet: Localized network, restricted access, more secure, more reliable, more expensive

Extranet

• A private network that securely shares information or operations with external partners.
• Extends an organization's intranet.
• Uses the Internet to connect with authorized outsiders in a controlled manner.
• Enables collaboration with customers and suppliers.

Extranet vs. Intranet

• Extranet: Internal network accessible externally, extension of the intranet
• Intranet: Internal network NOT accessible externally, limited to internal users

Network Overview

• A network is two or more computers connected for communication and resource sharing (e.g., printer, internet access).
• Components include workstations, servers, switches, routers, and printers.

Networks (LAN and WAN)

• LAN (Local Area Network): Usually confined to a single building or group of buildings. Connects computers in limited areas (schools, labs, homes, offices).
• WAN (Wide Area Network): Spans larger geographical areas, often uses public or commercial communication systems (e.g., the internet).

The Client/Server Model

• A relationship between two computer programs (client and server).
• Client: Requests service (like filing or database).
• Server: Fulfills the request and sends results.

The Internet Client/Server Model

• Client: Web browser
• Server: Web server
• Client sends request, server responds

World Wide Web (WWW)

• A vast collection of files and documents stored on computers (servers).
• Written in HTML (Hypertext Markup Language), which instructs browsers on how to display information.
• A technical definition of the WWW is all resources and users on the internet using the Hypertext Transfer Protocol (HTTP).
• The internet is not the same as the web. The web uses the internet to pass information.

WWW Operation

• Steps:
  • User enters a URL (like www.yahoo.com).
  • Browser requests the domain name server for the corresponding IP address.
  • After receiving the IP address, the browser sends the HTTP request.
  • The server finds the requested web page and sends it back with an HTTP response.
  • The browser interprets the page and displays it.

Web Page

• A document on the WWW, stored on a web server, and viewed using a web browser.
• Can contain text, graphics, audio, video, and hyperlinks (links to other pages)
• A collection of linked web pages on a server is called a website.
• Each web page has a unique Uniform Resource Locator (URL).

Web Browser

• Application software that allows users to view and explore information on the web.
• Users request web pages by entering URLs in the address bar.

Most Common Web Browsers

• Internet Explorer (Microsoft)
• Google Chrome (Google)
• Mozilla Firefox (Mozilla)
• Opera (Opera Software)
• Safari (Apple)

How Browsers Display Web Pages

• Browsers read and interpret HTML files.
• Format the page for display.
• Download external files (like images) from the server and display them.
• HTML files are text files containing references to external files, not embedded files..

Web Server

• A specific computer that stores the content of websites (web pages).
• Software component that responds to requests for web resources.

How Web Servers Work

• If a client requests a web page, the server searches for the page.
• If found, the server sends the page to the client with an HTTP response.
• If not found, the server sends an HTTP response error (404).
• If the client requests other resources, the server may contact an application server for the appropriate response.

IP Addresses

• A unique logical address assigned to a device on the network.
• Identifies a computer's location.
• Is a unique set of numbers (e.g., 137.170.4.124).
• 32 bits (4 bytes) long.
• Composed of network and host components.

Domain Name

• Names an organization or entity on the Internet.
• Easy-to-remember alternative to IP addresses.
• Translated to IP addresses by DNS (Domain Name Servers).

Domain Extension Types

• .com: Company/commercial
• .net: Networks
• .org: Organizations
• Country-specific extensions (e.g., .us, .uk)
• Others (e.g., .biz, .info, .tv)

The Domain Name System (DNS)

• Associates domain names with IP addresses.
• Automatically translates domain names to IP addresses.

Uniform Resource Locator (URL)

• Identifies the location of a document on a website.
• Comprised of protocol, subdomain/server, domain name, folder name, and file name (e.g., http://www.example.com/folder/page.html).
• The protocol part (e.g., HTTP) tells the browser how to handle the file.

Internet Protocols

• Rules governing client-server communication on the internet.
• Multiple protocols are needed for different internet functions. (e.g., HTTP, FTP, SMTP, POP, IMAP)

FTP: File Transfer Protocol

• Used for exchanging files between computers.
• Commonly used by web developers to transfer webpage files.
• Also used to download software and files from other servers onto an individual computer.

E-mail Protocols

• Sending: SMTP (Simple Mail Transfer Protocol)
• Receiving: POP (Post Office Protocol) or IMAP (Internet Mail Access Protocol)

HTTP: Hypertext Transfer Protocol

• Set of rules for exchanging files (e.g., text, images, videos).
• Used for communication between clients (web browsers) and web servers.

Basic Web Programming

• HTML: Defines the content of webpages.
• CSS: Specifies the layout of webpages (style and formatting).
• JavaScript: Programs the behavior of webpages.
• Other dynamic programming technologies (e.g., ASP.NET, SQL, AJAX, PHP).

The Web Programming Triangle

• A visual representation of the relationships between HTML, CSS, and JavaScript.
• HTML structures the content, CSS styles the presentation, and JavaScript behaves webpages.

References

• References to web tutorials for HTML, CSS, and JavaScript. (links provided).