The Application Layer in Web Communication.pptx
- 1. T H E A P P L I C AT I O N L AY E R I N W E B C O M M U N I C AT I O N User-server state: cookies, cookies example, web caches(proxy server), its example, HTTPS: introduction and working HTTP Vs HTTPS
- 2. I N T R O D U C T I O N T O T H E A P P L I C AT I O N L A Y E R • Top layer of the OSI model: Manages communication between applications. • Enables end-user services: Web browsing, email, file transfer, etc. • Key protocols: HTTP, HTTPS, FTP, DNS, SMTP.
- 3. U S E R - S E R V E R S TAT E : C O O K I E S • What are Cookies? • Small text files stored on a user's device by a website. • Used to remember information about the user (login status, preferences, etc.). • How Cookies Work? • When a user visits a website, the server sends a cookie to the user's browser, which stores it. • On subsequent visits, the browser returns the cookie to the server to identify the user. • Cookies Example: • When you log into an e-commerce site, the server stores your login status in a cookie so that you don’t have to log in every time.
- 4. T Y P E S O F C O O K I E S : • Session Cookies: • Description: Temporary cookies stored only for a browsing session. • Purpose: Used to remember temporary information, like form inputs or shopping cart contents. • Lifecycle: Deleted when the browser is closed. • Example: When you add items to a shopping cart on an e-commerce site, session cookies store the data until checkout. • Persistent Cookies: • Description: Cookies that remain on the user's device even after the browser is closed. • Purpose: Used to remember login details, language preferences, or personalized settings across multiple sessions. • Lifecycle: Have an expiration date set by the server, lasting from days to years. • Example: A website remembering your username, so you don’t have to log in every time you visit.
- 5. • First-Party Cookies • Description: Cookies set by the website the user visits (directly from the domain). • Purpose: Mainly used to remember user settings and preferences for a specific website. • Lifecycle: Can be either session or persistent. • Example: A news website remembering your preferred language setting. • Third-Party Cookies • Description: Cookies set by a domain other than the website the user is visiting. • Purpose: Primarily used for tracking user activity across multiple sites, often for targeted advertising. • Lifecycle: Typically persistent, enabling advertisers to track users over time. • Example: Ads that follow you around the web after visiting an online shopping site.
- 6. W E B C A C H E S ( P R O X Y S E R V E R ) •Definition: Temporary storage of web content to reduce server load and improve load times. •How Proxy Servers Work: •Acts as an intermediary between the browser and the web server. •Checks if requested content is available in the cache before fetching from the server. •Benefits: •Faster access to frequently visited pages. •Reduces bandwidth usage. •Lowers the load on web servers. •Example: •Content Delivery Networks (CDNs): Global networks of servers caching website content closer to users for faster access.
- 7. H T T P ( H Y P E R T E X T T R A N S F E R P R O T O C O L ) • It was initiated by Tim Berners- Lee at CERN in 1989 • It is protocol for transmitting hypermedia documents, such as HTML. • HTTP is the foundation of data communication for the World Wide Web. • It was designed for communication between web browsers and web servers • HTTP is a stateless protocol.
- 8. H T T P S ( H Y P E R T E X T T R A N S F E R P R O T O C O L S S E C U R E ) is an extension of the Hypertext Transfer Protocol (HTTP) It uses encryption for secure communication over a computer network Two types of encryptions Secure socket layer (SSL) Transport Layer Security
- 9. W O R K I N G O F H T T P S
- 10. H T T P S A N D H T T P Feature HTTP HTTPS Security No encryption; data is sent in plain text. Encrypted using SSL/TLS for secure communication. Port Default port is 80. Default port is 443. SSL/TLS Does not use SSL/TLS. Uses SSL/TLS for encryption. SEO Benefit No ranking benefit. Websites with HTTPS get an SEO boost. Use Case Suitable for non-sensitive data transmission. Essential for sensitive information (payments, logins).
- 11. C O N C L U S I O N • The application layer facilitates key services for users, making the web experience seamless and secure. • Technologies like cookies, web caching, and HTTPS enhance the efficiency and safety of user-server interactions. • HTTPS ensures secure communication in a world increasingly concerned with privacy and data protection, making it a cornerstone of modern web interactions.
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