Author: Chirag

UDP is the opposite of TCP. No handshake, no acknowledgments, no retransmissions. Just send and hope. Why DNS, video calls, and games rely on it.

TCP is what makes HTTP, SSH, and email work. Streams, ordering, retransmission, congestion control — all hidden behind a simple read/write API.

How one public IP serves a whole house, office, or country. Source NAT, destination NAT, port translation, and why CGNAT exists.

Why your laptop has a 192.168.x.x address but websites don’t. How private IP ranges work and when to use which.

Why we needed IPv6, how 128-bit addresses work, dual-stack, and how to read those long colons.

How /24 means 255.255.255.0, how to plan IP ranges for a network, and how to do subnet math without a calculator.

Dotted decimal, octets, classes, and CIDR — what an IP address actually is and how the internet uses it to route packets.

Three things people use interchangeably and shouldn’t. Bandwidth is capacity, latency is delay, throughput is what you actually get.

The OSI model is academic; the TCP/IP stack is what actually runs the internet. Four layers instead of seven, mapped to real protocols.

Physical, Data Link, Network, Transport, Session, Presentation, Application — what each layer does and why this mental model is the foundation of all networking.