Networking Fundamentals

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OSI Model

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TCP/IP

TCP (Transmission Control Protocol)

TCP Three-Way Handshake

TCP Connection Termination

TCP vs UDP

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HTTP/1.1 vs HTTP/2 vs HTTP/3

HTTP/2 Multiplexing

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TLS/SSL

TLS Handshake

TLS 1.3 (Faster)

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DNS (Domain Name System)

DNS Resolution Process

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Load Balancing

Load Balancing Algorithms

Layer 4 vs Layer 7 Load Balancing

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WebSockets

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Server-Sent Events (SSE)

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CDN (Content Delivery Network)

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Connection Pooling

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Common Interview Questions

1. TCP vs UDP?
2. TCP: Reliable, ordered, connection-based

3. UDP: Fast, no guarantee, connectionless

4. What happens when you type URL in browser?

5. DNS resolution → TCP handshake → TLS handshake

6. HTTP request → Server processing → Response rendering

7. HTTP/2 vs HTTP/1.1?

8. HTTP/2: Binary, multiplexing, header compression

9. Single connection for multiple requests

10. How does HTTPS work?

11. TLS handshake establishes encrypted channel
12. Certificate verification, key exchange

13. Symmetric encryption for data

14. Layer 4 vs Layer 7 load balancing?

15. L4: TCP/IP level, faster, no content awareness
16. L7: HTTP level, content-based routing, SSL termination

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