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Chapter 3
Internet Protocols
fewer bits for hosts, so the more subnets, the fewer bits available for defin-
ing hosts.
In this section you will learn how to create subnets, starting with Class C
addresses. But before you actually implement subnetting, you need to deter-
mine your current requirements as well as plan for future conditions. Follow
these steps:
1.
Determine the number of required network IDs:
One for each subnet
One for each wide area network connection
2.
Determine the number of required host IDs per subnet:
One for each TCP/IP host
One for each router interface
3.
Based on the above requirement, create the following:
One subnet mask for your entire network
A unique subnet ID for each physical segment
A range of host IDs for each subnet
Understanding the Powers of 2
Powers of 2 are important to understand and memorize for use with IP sub-
netting. To review powers of 2, remember that when you see a number with
another number to its upper right (called an exponent), this means you
should multiply the number by itself as many times as the upper number
specifies. For example, 2
3
is 2
Ч 2 Ч 2, which equals 8. Here's the list of pow-
ers of 2 you should commit to memory:
2
1
= 2
2
2
= 4
2
3
= 8
2
4
= 16
2
5
= 32
2
6
= 64
2
7
= 128
2
8
= 256
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