3Com 4210 PWR, Configuration Manual

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7
IP A
DDRESSING
C
ONFIGURATION
IP Addressing
Overview
IP Address Classes IP addressing uses a 32-bit address to identify each host on a network. An
example is 01010000100000001000000010000000 in binary. To make IP
addresses in 32-bit form easier to read, they are written in dotted decimal
notation, each being four octets in length, for example, 10.1.1.1 for the address
just mentioned.
Each IP address breaks down into two parts:
■
Net ID: The first several bits of the IP address defining a network, also known as
class bits.
■
Host ID: Identifies a host on a network.
For administration sake, IP addresses are divided into five classes, as shown in the
following figure (in which the blue parts represent the address class).
Figure 34 IP address classes
Table 48 describes the address ranges of these five classes. Currently, the first
three classes of IP addresses are used in quantity.
0 Net-id Host-id
1 Net-id Host-id 0
1
Net-id Host-id
0 1
1 Multicast address 0 1 1
1 Reserved 1 1 1
Class A
0 7 15 23 31
Class B
Class C
Class D
Class E