| Restaurant Component | Network Architecture Component | Technical Role in Web Communication |
|---|---|---|
| Hungry Customer | Client (Web Browser) | Initiates request for resources (e.g. clicks link, types URL). Does not prepare food. |
| Menu Card | API Endpoints / URLs | Lists available resources and operations that the client is permitted to request. |
| Waiter | Network Protocol (HTTP/TCP) | Carries structured request message to kitchen and brings cooked response back to customer. |
| Kitchen Chef | Web / Application Server | Processes the order, executes business logic, and coordinates with store room. |
| Store Room / Fridge | Database (MySQL/PostgreSQL) | Stores raw persistent ingredients (user records, product catalogues, images). |
| Code Range | Category | Meaning | Top Exam Examples |
|---|---|---|---|
| 1xx | Informational | Request received, continuing process | 100 Continue, 101 Switching Protocols |
| 2xx | Success | Action successfully received and accepted | 200 OK (Standard success), 201 Created |
| 3xx | Redirection | Further action needed to complete request | 301 Moved Permanently, 302 Found (Temporary) |
| 4xx | Client Error | Request contains syntax error or resource missing | 400 Bad Request, 401 Unauthorized, 403 Forbidden, 404 Not Found |
| 5xx | Server Error | Server failed to fulfill an apparently valid request | 500 Internal Server Error, 502 Bad Gateway, 503 Service Unavailable |
• Client-Server: Centralized authority, asymmetric roles, single point of failure (server down = all clients down), easy to secure.
• Peer-to-Peer (P2P): Decentralized, symmetric roles (every node is both client AND server / servent), highly fault tolerant (BitTorrent, Blockchain).