CCENT/CCNA ICND1 640-822 Official Cert Guide

Chapter 15. Analyzing Existing Subnet Masks

This chapter covers the following subjects:

Defining the Format of IPv4 Addresses: This section explains how subnet masks and address class separate IP addresses into parts called network, subnet, and host.

Practice Analyzing Subnet Masks: This section supplies suggestions for how to practice the math related to this chapter.

When you examine an existing subnet design, you can learn a lot about the subnetting design by analyzing the subnet mask. First, the mask divides addresses into two parts: prefix and host. Then, the network class further subdivides the addresses, breaking the prefix part into the network and subnet parts.

Once you know the size of the three parts of an IP address, you can make ...