CCNA 200-301 Portable Command Guide, 5th Edition

Chapter 1. IPv4 Addressing—How It Works

This chapter provides information concerning the following topics:

• What are IPv4 addresses used for?

• What does an IPv4 address look like?

• Network and subnetwork masks

• Ways to write a network or subnet mask

• Network, node, and broadcast addresses

• Classes of IPv4 addresses

  • IPv4 address classes

  • Network vs. node (host) bits

  • RFC 1918 (private) addresses

  • Local vs. remote addresses

• Classless addresses

• Lessons Learned

Before we can start to subnet IPv4 address spaces, we need to look at what an IPv4 address is used for, how it looks, how to write one down correctly through the use of network masks, and what role address classes formerly served.

What Are IPv4 Addresses Used For?

IPv4 addressing was created ...