Ip addressing configuration, Ip addressing overview, Ip address classes – H3C Technologies H3C SecBlade NetStream Cards User Manual
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IP addressing configuration
This chapter includes these sections:
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•
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Displaying and maintaining IP addressing
IP addressing overview
IP address classes
IP addressing uses a 32-bit address to identify each host on a network. To make addresses easier to read,
they are written in dotted decimal notation, each address being four octets in length. For example,
address 00001000000000010000000100000001 in binary is written as 10.1.1.1.
Each IP address breaks down into two parts:
•
Net ID: Identifies a network. The first several bits of a net ID, known as the class field or class bits,,
identify the class of the IP address.
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Host ID: Identifies a host on a network.
IP addresses are divided into five classes, shown in
. The shaded areas represent the address
class. The first three classes are widely used.
Figure 22 IP address classes
describes the address ranges of these five classes.
Table 8 IP address classes and ranges
Class Address
range Remarks
A
0.0.0.0 to
127.255.255.255
The IP address 0.0.0.0 is used by a host at startup for temporary
communication. This address is never a valid destination address.
Addresses starting with 127 are reserved for loopback test.
Packets destined to these addresses are processed locally as input
packets rather than sent to the link.
B
128.0.0.0 to
191.255.255.255
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