Ip Addressing Configuration; Ip Addressing Overview; Ip Address Classes - HP A5120 EI Series Configuration Manual

IP addressing configuration

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.
Host ID: Identifies a host on a network.

IP addresses are divided into five classes, as shown in
class. The first three classes are widely used.
Figure 10 IP address classes
0
Class A 0 Net ID
Class B 1 0
Class C 1 1 0
Class D 1 1 1 0
Class E 1 1 1 1
Table 1 IP address classes and ranges
Class
A
B
C
D
7 15
Host ID
Net ID Host ID
Net ID
Multicast address
0 Reserved
Address range
0.0.0.0 to
127.255.255.255
128.0.0.0 to
191.255.255.255
192.0.0.0 to
223.255.255.255
224.0.0.0 to
239.255.255.255
Figure 10. The shaded areas represent the address
23 31
Host ID
Remarks
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.
––
––
Multicast addresses.
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