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EngineeringNotes
Back to Network Layer
Module 04 • Part 02

IPv4 - Internet Protocol

The foundation of modern networking. Learn how IPv4 identifies and routes data across the global internet.

01

What is IP?

The Internet Protocol (IP) is a set of rules that governs how data packets are sent and received over the internet.

It works like a digital postal system. Every device (computer, smartphone, server) on a network is assigned a unique numerical label—the IP Address—which allows it to be identified and contacted by other devices.

Digital ID

An IP address is the unique identity of your device in the networking world.

02

Types of IP Addresses

Public vs Private

  • Public IP:Visible to the whole internet. Used for external communication.
  • Private IP:Used within local networks (LAN). Hidden from the outside world.

Static vs Dynamic

  • Static IP:Permanent address. Useful for servers and hosting.
  • Dynamic IP:Temporary address assigned by DHCP. Changes over time.
03

IPv4 Overview

"IPv4 is an unreliable connectionless datagram protocol—a best-effort delivery service."

Best-Effort Delivery

IPv4 packets can be corrupted, be lost, arrive out of order, or be delayed, and may create congestion for the network.

Datagram Approach

Each datagram is handled independently, and each datagram can follow a different route to the destination.

Reliability Pairing

If reliability is important, IPv4 must be paired with a reliable protocol such as TCP. This combination forms the standard TCP/IP protocols.

04

Technical Specifications

32

32-Bit Address Size

IPv4 addresses are 32 bits long, divided into four 8-bit octets.

4B

~4.3 Billion Addresses

The total address space is 2³² addresses, which is approximately 4,294,967,296.

Address Notation

192.168.1.1

"Dotted-Decimal Notation"

11000000
10101000
00000001
00000001
05

The IPv4 Ecosystem

"How IPv4 interacts with surrounding technologies to manage modern networks."

IPv4
NAT
Address Translation
DHCP
Automatic Configuration
CIDR
Efficient Routing
NAT

Network Address Translation: Mapping private IPs to a single public IP, conserving address space.

DHCP

Dynamic Host Configuration Protocol: Automatically assigning IP addresses to devices as they join the network.

CIDR

Classless Inter-Domain Routing: A method for allocating IP addresses and routing packets more efficiently.