---
title: "Web architecture and web-tier components"
subject: "Web Technology"
chapter: 2
key: "semester_7/web_technology:web-architecture-tiers"
source: https://www.bctengineer.com/q/semester_7/web_technology/web-architecture-tiers
site: BCT Engineering
---

# Web architecture and web-tier components

Web Technology · Chapter 2: Web basics

- Asked in: 2074 Asoj, 2+2+4 marks
- Video: [Web Application Architecture: Full Request-Response Lifecycle](https://www.youtube.com/watch?v=xv0Be4QfkH0) — ByteMonk
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_7/web_technology/web-architecture-tiers
- Whole chapter: https://www.bctengineer.com/md/semester_7/web_technology/chapter-2

## Question

Define web architecture with its importance. Explain the components of web-tier architecture.

## Short answer

Web architecture is the structure and communication of components such as browsers, servers, and databases over HTTP. Multi-tier architecture includes client, web, application, and data tiers, giving scalability, maintainability, security, and reliability.

## Answer

#### Web architecture
**Web architecture** is the overall structure of a web system: its components (browsers, web servers, application servers, databases), how they are arranged, and how they communicate using protocols such as HTTP. It describes how requests flow and how the work is divided.

#### Importance
- **Scalability:** Components can be added or replicated independently as users grow.
- **Maintainability:** Separation of concerns makes code easier to change and test.
- **Performance:** Caching, load balancing and distribution of work reduce delay.
- **Security:** Sensitive data stays on inner tiers behind firewalls.
- **Reusability and interoperability:** Standard protocols allow different systems to work together.
- **Reliability:** Failure of one component can be isolated or handled by redundancy.

#### Components of web-tier (multi-tier) architecture
```text
+----------------+   +-------------+   +--------------+
| Client tier    |-->| Web tier    |-->| Application  |
| Browser (HTML, |   | Web server  |   | / business   |
| CSS, JS)       |   | (Apache)    |   | tier (PHP,   |
+----------------+   +-------------+   | Java, .NET)  |
                                       +------+-------+
                                              |
                                       +------v-------+
                                       | Data tier    |
                                       | Database     |
                                       +--------------+
```
1. **Client (presentation) tier:** The browser displays pages and runs client-side scripts. It sends requests and shows results.
2. **Web tier:** The web server (Apache, Nginx, IIS) accepts HTTP requests, serves static files, handles sessions, SSL and forwards dynamic requests to the application tier.
3. **Application (business logic) tier:** Executes server-side code (PHP, Servlets/JSP, ASP.NET, Node.js) that applies business rules, authentication and processing, and builds dynamic pages.
4. **Data tier:** Database servers (MySQL, PostgreSQL, Oracle) store and retrieve persistent data.

Supporting parts: proxy servers, load balancers, firewalls and caches placed between the tiers.

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. What does web architecture describe?
   A. Only the page colours
   B. Only the database schema
   C. Only the ISP
   D. Components, their arrangement, and how they communicate
   Answer: D. It describes how requests flow and work is divided. (Key point: Web architecture)

2. What does the web tier do?
   A. Accepts HTTP requests, serves static files, forwards dynamic requests to the application tier
   B. Stores persistent data
   C. Displays the UI in the browser
   D. Applies business rules in PHP
   Answer: A. The web server (Apache, Nginx, IIS) handles HTTP and forwards dynamic requests. (Key point: Web tier)

3. Which tier runs business logic such as PHP, Servlets or ASP.NET?
   A. Client tier
   B. Application tier
   C. Data tier
   D. Web tier
   Answer: B. The application tier executes server-side code and builds dynamic pages. (Key point: Application tier)

4. Why does multi-tier help security?
   A. All data is in the browser
   B. The database is exposed to clients
   C. Sensitive data stays on inner tiers behind firewalls
   D. There are no firewalls
   Answer: C. Inner tiers are protected from direct access. (Key point: Security benefit)

## Related in Web Technology

- [Server side languages and multi-tier architecture](https://www.bctengineer.com/question.md?key=semester_7%2Fweb_technology%3Aserver-side-languages-multitier) — Web Technology, chapter 3
- [Web services architecture; SOAP and WSDL roles](https://www.bctengineer.com/question.md?key=semester_7%2Fweb_technology%3Aweb-services-soap-wsdl) — Web Technology, chapter 8
- [Components that make up the Web](https://www.bctengineer.com/question.md?key=semester_7%2Fweb_technology%3Acomponents-of-web) — Web Technology, chapter 2
- [CMS and MVC architecture](https://www.bctengineer.com/question.md?key=semester_7%2Fweb_technology%3Acms-and-mvc) — Web Technology, chapter 5

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- [Conditional GET; 3-tier architecture components](https://www.bctengineer.com/question.md?key=semester_8%2Finternet_and_intranet%3Aconditional-get-3tier) — Internet and Intranet, chapter 4
- [Web log mining and WWW mining architecture](https://www.bctengineer.com/question.md?key=semester_7%2Fdata_mining%3Aweb-log-mining-architecture) — Data Mining, chapter 7
- [Components of CORBA architecture](https://www.bctengineer.com/question.md?key=semester_7%2Fdistributed_system%3Acorba-components) — Distributed System, chapter 4, asked 2×
- [Data warehouse architecture and components](https://www.bctengineer.com/question.md?key=semester_7%2Fdata_mining%3Adw-architecture-components) — Data Mining, chapter 1