Network Layer - Toshiba E-STUDIO190F Service Manual

9.3.

Network Layer

9.3.1. IP Address
An IP address is a set of four numbers, or octets, that can range in value between 0 and 255. Each octet is
separated by a period (i.e. 192.168.31.1). All devices on a network that runs the TCP/IP protocol suite need
a unique IP address. Most machines use a Domain Name, which are easier for people to remember.
The IP addresses are actually broken down into three distinct classes, knows as class A, class B and class
C addresses.
Class A IP addresses contain a number between 1 and 127 before the first dot. In class A address, this first
octet represents the network address, and the last three octets represent the node or host number.
Class B IP addresses can range in value from 128 to 191 for the first octet, but it is the first two octets that
make up the network address, and the last two octets that make up the host ID.
Class C IP addresses can range in value from 192 to 223 for the first octet, and the first three octets make
up the host ID.
There are class D and E addresses as well. For these addresses, the first octet is a number greater than
223. These addresses are not currently available to be used and are reserved for other purposes.
Class A : First octet reserved for the network address
Class B : First two octets reserved for the network address
Class C : First three octets reserved for the network address
0
Class A
Class B 1
Class C 1
Network address represented as
Private networks that do not connect to the Internet (operate internally) allow additional flexibility with IP
addresses. Three classifications are available as shown below:
Class A : 10.0.0.0 - 10.255.255.255
Class B : 172.16.0.0 - 172.31.255.255
Class C : 192.168.0.0 - 192.168.255.255
0
1 0
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