Web Arichitecture - Electives 2

Web Architecture

Refers to the design and structure of the World Wide Web, encompassing the technologies, protocols, and systems that enable the web to function.

Key Components of Web Architecture:

Clients

Devices or software (e.g., web browsers, mobile apps) that request and display content from servers. Examples: Chrome, Firefox, Safari, or mobile apps.

Key Components of Web Architecture:

Server

Computers or systems that store, process, and deliver resources (e.g., web pages, data) to clients. Examples: Web servers (Apache, Nginx), application servers, and database servers.

Key Components of Web Architecture:

Network

The infrastructure (e.g., internet, routers, DNS) that facilitates communication between clients and servers.

Key Components of Web Architecture:

Protocol

Rules and standards for communication between clients and servers. Examples: HTTP/HTTPS (for web requests), TCP/IP (for data transmission), and Websocket (for real time communication)

Key Components of Web Architecture:

Databases

Systems that store and manage data for web applications. Examples: MySQL, MongoDB, PostgreSQL.

Key Components of Web Architecture:

Middleware

Software that connects different components of a web application, such as APls, authentication systems, and load balancers.

Client Server Model

The client-server model is a distributed application structure that divides tasks between service providers (servers) and service requesters (clients).

How Client Server Works:

Client Request

A client sends a request to a server for a specific resource (e.g., a web page, image, or data). Example: Typing a URL in a browser sends an HTTP request to a web server.

How Client Server Works:

Server Processing

The server receives the request, processes it, and retrieves or generates the requested resource. Example: A web server fetches an HTML file or queries a database.

How Client Server Works:

Server Response

The server sends the requested resource back to the client.

Example: The server returns an HTML page, which the browser renders.

Disadvantage of Client-Server Architecture:

Single Point of Failure

If the server fails, all clients lose access.

Disadvantage of Client-Server Architecture:

Network Dependency

Requires a stable network; poor connectivity disrupts service.

Disadvantage of Client-Server Architecture:

Scalability Challenges

Handling more clients can overwhelm the server, making scaling costly and complex.

Disadvantage of Client-Server Architecture:

Security Risks

Servers are prime targets for attacks (e.g., DDoS, data breaches).

Common Web Architecture:

Monolithic Architecture

A single, unified application where all components (Ul, logic, database) are tightly coupled.

Example: Traditional web applications built as a single codebase.

Common Web Architecture:

Micro services Architecture

Breaks the application into small, independent services that communicate over APls.

Example: Modern cloud-based applications like Netflix or Amazon.

Common Web Architecture:

Serverless Architecture

Uses cloud services to run code without managing servers. Example: AWS Lambda or Google Cloud Functions.

Key Protocols in Web Architecture:

HTTP/HTTPS

Hypertext Transfer Protocol (Secure) for transferring web pages and data.

Key Protocols in Web Architecture:

TCP/IP

Protocol suite for data transmission across networks. (Note: the source PDF mistakenly repeats the HTTP/HTTPS wording here.)

Key Protocols in Web Architecture:

Websocket

Enables real-time, bidirectional communication between clients and servers.

Key Protocols in Web Architecture:

DNS

Domain Name System for translating domain names into IP addresses.

HTML

standard markup language for creating Web pages

Types of Client-Server Architecture:

Two -Tier Architecture

Involves a client and a server directly communicating. Example: A web browser (client) interacting with a web server.

Examples of Client-Server Architecture:

File Sharing

Accessing files on a network server, where your computer is the client and the file server is the server.

Scalability

Servers can handle multiple clients simultaneously.

Centralized Management

Data and resources are managed centrally on servers.

Efficiency

Clients offload processing tasks to servers, reducing their workload.

Security

Servers can enforce security policies and protect sensitive data.

Client Rendering

The client receives the response and displays or processes the data. Example: The browser renders the HTML page and displays it to the user.

Types of Client-Server Architecture:

Three-Tier Architecture

Divides the application into multiple layers (e.g., presentation, business logic, data storage). Example: Modern web applications with separate layers for UI, APIs, and databases.

Types of Client-Server Architecture:

N-Tier Architecture

Adds a middle tier (e.g., application server) between the client and server. Example: Browser $\rightarrow$ Application Server $\rightarrow$ Database Server.

Examples of Client-Server Architecture:

Web Browsing

Browsing the internet, where your browser is the client and the web server is the server.

Examples of Client-Server Architecture:

Email

Sending and receiving emails, where your email client is the client and the email server is the server.