3. OSI Model, TCP/IP Model, TCP vs UDP and the 3-Way Handshake
Chala mitrano, aaj aapan networking cha "map" shikuya – OSI aani TCP/IP models. Production madhe kahi bighadla ki changla engineer ghabrat nahi, to layer-by-layer check karto. Security madhe pan tasech – firewall kontya layer var kaam karto, WAF kontya layer var, Wireshark madhe kontya layer cha header disto – he sagla ya chapter nantar ekdum clear hoil. Ghabru naka, majhya sobat raha.
What you will learn in this chapter
- The seven OSI layers, their PDUs, protocols and devices
- Encapsulation (आवरण घालणे) and decapsulation
- The four-layer TCP/IP model and how it maps to OSI
- TCP vs UDP, and when each is used
- The TCP 3-way handshake, TCP flags and connection close
- What happens when you open a website – the favourite interview question
Concepts in this chapter
- 3.1The Seven OSI Layers
- 3.2Encapsulation and Decapsulation
- 3.3The TCP/IP Model and OSI Comparison
- 3.4TCP vs UDP
- 3.5The TCP 3-Way Handshake, TCP Flags and Connection Close
- 3.6What Happens When You Open a Website?
The chapter recap is at the end of the last concept page.