Reference Manual for the 54 Mbps Wireless Router with Phone Adapter WGR826V
Network, Routing, and Firewall Basics B-3
202-10051-01, March 2005
There are five standard classes of IP addresses. These address classes have different ways of
determining the network and host sections of the address, allowing for different numbers of hosts
on a network. Each address type begins with a unique bit pattern, which is used by the TCP/IP
software to identify the address class. After the address class has been determined, the software
can correctly identify the host section of the address. The follow figure shows the three main
address classes, including network and host sections of the address for each address type.
Figure B-1: Three Main Address Classes
The five address classes are:
• Class A
Class A addresses can have up to 16,777,214 hosts on a single network. They use an eight-bit
network number and a 24-bit node number. Class A addresses are in this range:
1.x.x.x to 126.x.x.x.
• Class B
Class B addresses can have up to 65,354 hosts on a network. A Class B address uses a 16-bit
network number and a 16-bit node number. Class B addresses are in this range:
128.1.x.x to 191.254.x.x.
• Class C
Class C addresses can have 254 hosts on a network. Class C addresses use 24 bits for the
network address and eight bits for the node. They are in this range:
192.0.1.x to 223.255.254.x.
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lass A
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etwork Node
C
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lass C
Network Node
Network Node