Visual Guide to TCP at the Transport Layer

karan — Thu, 21 May 2026 07:35:08 +0000

I built a detailed visual diagrams for the Transmission Control Protocol (TCP) — one of the core protocols powering the internet, that operates at the Transport Layer (Layer 4) of the OSI model.

I broke down:
🔹 TCP Segment Structure: -
Source & destination ports
Sequence number
Acknowledgment number
Flags (SYN, ACK, FIN, RST, PSH, URG)
Window size
Checksum
Options & payload
Here the full animated diagram svg link of TCP structure: - https://github.com/knkrn5/Programming-Concepts/blob/main/computer-networking/protocols/transmission-control-protocol/TCP-segment/tcps.svg

🔹 TCP 3-Way Handshake: -
SYN
SYN-ACK
ACK
Sequence & acknowledgment numbers
Window size negotiation
MSS negotiation
How a connection becomes ESTABLISHED
Here the full animated diagram svg link of TCP handshake: - https://github.com/knkrn5/Programming-Concepts/blob/main/computer-networking/protocols/transmission-control-protocol/tcp-handshake/tcph.svg

While studying networking, I realized many resources explain TCP theoretically but not visually.
So I created these diagrams to make the packet flow and header fields easier to understand step-by-step.

One thing I found especially interesting:
TCP reliability is achieved through sequence numbers, acknowledgments, retransmissions, and flow control — all working together behind the scenes every time we browse a website or send data online.

Understanding protocols at this level really changes how you see networking and distributed systems.

A Visual Guide to the OSI Model

karan — Wed, 20 May 2026 03:04:22 +0000

I have been building a visual breakdown of the OSI Model and what actually happens when data travels from your browser to a server. 🌐

Most explanations stop at “7 layers,” but I wanted to understand the real flow behind the scenes:
• How HTTP requests move through the stack
• Where ARP, MAC addresses, switches, and routers come into play
• How Ethernet frames are created and stripped
• How bits become electrical signals, radio waves, or light pulses
• What happens at every hop between client and server

While studying networking, I realized the OSI model becomes much easier once you connect theory with real packet flow.
This diagram helped me visualize:
→ Encapsulation & decapsulation
→ Application → Physical layer journey
→ Local subnet vs gateway communication
→ Ethernet, Wi-Fi, fiber optics, and routing concepts
If you're interested in exploring the full high-quality SVG version (the uploaded image might gets blurry when zoomed), here’s the complete diagram link: https://github.com/knkrn5/Programming-Concepts/blob/main/computer-networking/network-models/open-systems-interconnection/osi.svg

In upcoming posts, I’ll also break down each OSI layer in detail — what it does, how protocols work internally, and how data actually moves across networks. 🚀

Forem: karan

Visual Guide to TCP at the Transport Layer

A Visual Guide to the OSI Model