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Numbers as Bits

Lesson 1 of 46 in Coddy's IP Addressing and Subnetting course.

Every IP address is, underneath, just numbers stored as bits: switches that are either 0 or 1. Eight bits together make a byte, and a byte can hold any number from 0 to 255.

Each position in a byte has a value: 128 64 32 16 8 4 2 1, from left to right. A number is written by switching on the positions that add up to it. For example, 172 is 10101100 because 128 + 32 + 8 + 4 = 172.

Subnetting is binary arithmetic in disguise. Get comfortable turning a decimal number into its bits and the whole topic becomes simple bookkeeping.

Challenge

Beginner

Convert the number 172 to 8-bit binary by hand: start at 128 and work down, switching on each position that fits. Then print your answer with echo.

Expected output:

10101100

Try it yourself

Terminal

All lessons in IP Addressing and Subnetting

1Bits and Binary

Numbers as BitsBinary to Decimal Powers of Two Recap - Binary Warm-up

4CIDR Notation

Goodbye Classes Reading CIDR Block Sizes Recap - CIDR Reading

7Special Addresses

Private Ranges Loopback Link-Local Zero and Broadcast

10Capstone - The Office

The Floor Plan Sizing Each Team Carving the Block The Router's View Recap - Ship the Plan

2IPv4 Anatomy

Four Octets The 32-Bit View Network and Host Valid or Not Recap - Read an Address

5Inside a Subnet

Network Address Broadcast Address Usable Hosts First and Last Host Recap - Subnet Facts

8Planning Networks

Right-Sizing VLSM Step by Step Allocation Order Checking for Overlap Recap - Plan a Network

3The Subnet Mask

What a Mask Does Mask to Prefix Prefix to Mask ANDing It Out Recap - Mask Basics

6Subnetting Drills

The Block Size Trick Which Subnet Am I In Splitting a /24 Splitting Again Recap - Subnetting Drills

9IPv6 First Steps

Why IPv6 Reading IPv6 Prefixes in IPv6 Recap - IPv6 Basics

Practice on your own: Terminal playground